Imagine a portable 3D printer you could hold in the palm of your hand. The tiny device could enable a user to rapidly create customized, low-cost objects on the go, like a fastener to repair a wobbly bicycle wheel or a component for a critical medical operation.

Researchers from MIT and the University of Texas at Austin took a major step toward making this idea a reality by demonstrating the first chip-based 3D printer. Their proof-of-concept device consists of a single, millimeter-scale photonic chip that emits reconfigurable beams of light into a well of resin that cures into a solid shape when light strikes it.

The prototype chip has no moving parts, instead relying on an array of tiny optical antennas to steer a beam of light. The beam projects up into a liquid resin that has been designed to rapidly cure when exposed to the beam’s wavelength of visible light.

By combining silicon photonics and photochemistry, the interdisciplinary research team was able to demonstrate a chip that can steer light beams to 3D print arbitrary two-dimensional patterns, including the letters M-I-T. Shapes can be fully formed in a matter of seconds.

In the long run, they envision a system where a photonic chip sits at the bottom of a well of resin and emits a 3D hologram of visible light, rapidly curing an entire object in a single step.

This type of portable 3D printer could have many applications, such as enabling clinicians to create tailor-made medical device components or allowing engineers to make rapid prototypes at a job site.

“This system is completely rethinking what a 3D printer is. It is no longer a big box sitting on a bench in a lab creating objects, but something that is handheld and portable. It is exciting to think about the new applications that could come out of this and how the field of 3D printing could change,” says senior author Jelena Notaros, the Robert J. Shillman Career Development Professor in Electrical Engineering and Computer Science (EECS), and a member of the Research Laboratory of Electronics.

Joining Notaros on the paper are Sabrina Corsetti, lead author and EECS graduate student; Milica Notaros PhD ’23; Tal Sneh, an EECS graduate student; Alex Safford, a recent graduate of the University of Texas at Austin; and Zak Page, an assistant professor in the Department of Chemical Engineering at UT Austin. The research appears today in Nature Light Science and Applications.

Printing with a chip

Experts in silicon photonics, the Notaros group previously developed integrated optical-phased-array systems that steer beams of light using a series of microscale antennas fabricated on a chip using semiconductor manufacturing processes. By speeding up or delaying the optical signal on either side of the antenna array, they can move the beam of emitted light in a certain direction.

Such systems are key for lidar sensors, which map their surroundings by emitting infrared light beams that bounce off nearby objects. Recently, the group has focused on systems that emit and steer visible light for augmented-reality applications.

They wondered if such a device could be used for a chip-based 3D printer.

At about the same time they started brainstorming, the Page Group at UT Austin demonstrated specialized resins that can be rapidly cured using wavelengths of visible light for the first time. This was the missing piece that pushed the chip-based 3D printer into reality.

“With photocurable resins, it is very hard to get them to cure all the way up at infrared wavelengths, which is where integrated optical-phased-array systems were operating in the past for lidar,” Corsetti says. “Here, we are meeting in the middle between standard photochemistry and silicon photonics by using visible-light-curable resins and visible-light-emitting chips to create this chip-based 3D printer. You have this merging of two technologies into a completely new idea.”

Their prototype consists of a single photonic chip containing an array of 160-nanometer-thick optical antennas. (A sheet of paper is about 100,000 nanometers thick.) The entire chip fits onto a U.S. quarter.

When powered by an off-chip laser, the antennas emit a steerable beam of visible light into the well of photocurable resin. The chip sits below a clear slide, like those used in microscopes, which contains a shallow indentation that holds the resin. The researchers use electrical signals to nonmechanically steer the light beam, causing the resin to solidify wherever the beam strikes it.

A collaborative approach

But effectively modulating visible-wavelength light, which involves modifying its amplitude and phase, is especially tricky. One common method requires heating the chip, but this is inefficient and takes a large amount of physical space.

Instead, the researchers used liquid crystal to fashion compact modulators they integrate onto the chip. The material’s unique optical properties enable the modulators to be extremely efficient and only about 20 microns in length.

A single waveguide on the chip holds the light from the off-chip laser. Running along the waveguide are tiny taps which tap off a little bit of light to each of the antennas.

The researchers actively tune the modulators using an electric field, which reorients the liquid crystal molecules in a certain direction. In this way, they can precisely control the amplitude and phase of light being routed to the antennas.

But forming and steering the beam is only half the battle. Interfacing with a novel photocurable resin was a completely different challenge.

The Page Group at UT Austin worked closely with the Notaros Group at MIT, carefully adjusting the chemical combinations and concentrations to zero-in on a formula that provided a long shelf-life and rapid curing.

In the end, the group used their prototype to 3D print arbitrary two-dimensional shapes within seconds.

Building off this prototype, they want to move toward developing a system like the one they originally conceptualized — a chip that emits a hologram of visible light in a resin well to enable volumetric 3D printing in only one step.

“To be able to do that, we need a completely new silicon-photonics chip design. We already laid out a lot of what that final system would look like in this paper. And, now, we are excited to continue working towards this ultimate demonstration,” Jelena Notaros says.

This work was funded, in part, by the U.S. National Science Foundation, the U.S. Defense Advanced Research Projects Agency, the Robert A. Welch Foundation, the MIT Rolf G. Locher Endowed Fellowship, and the MIT Frederick and Barbara Cronin Fellowship.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

I needed desk space badly as my desk of hobby/actual work was completely claimed by the A1 Mini and the AMS Lite doohicky sitting next to it. Together they were taking about three horizontal feet of desk space and I didn’t have six inches of desk I could see that wasn’t 3D printer related or not easily accessible.

I checked the options for compacting the printer and they were wall mount, which was rated “probably the best option” by several people I don’t know, and adding a riser to place the AMS directly over the A1 Mini.

As I don’t have a wall behind the unit (it’s a window) I decided to go ahead and try printing up this riser from here by Spar-Fuchs24.de.

Before I go too far into this story I’ll mention I’ve run two perfect prints and my table does not appear to be shaking around as much, but this may be hopeful thinking.

The print lasted somewhere in the neighborhood of 4 hours – I was out of the office, looked in on Bambu Studio, and there was a printed riser just hanging out living its best life. I got into work today and that was no longer the case – at some point after printing it decided it was going to detach from the plate and make a run for it.

No damage noted I set about removing the printed supports and installing it on the machine. It’s pretty evident what you need to do – remove a top of pole screw, when you remove said screw the top comes off, there’s a plate in there with 3 screws that can be removed with the tools that shipped with the printer, remove that and set the 3 screws aside, and get to screwing them in.

I unloaded all my spools from the AMS because I suspected it was going to be a pain to mount with the spools on, and proceeded to mount it with no real issues. The tubing looked like it was not going to work any more as it was now pretty darn high, but worked fine.

Loaded up, two perfect prints in and with about two feet of additional desk space I’m enjoying it.

I’ll update if I end up with any sub par prints in the next bit, but the added weight seems to have caused the unit to travel less.

Oh yeah, while I cannot find this at the time I’m writing this I ran across a video yesterday while looking for a solution that said that the main problem with this was not being able to access spools 3 & 4 easily. The unit with spools weighs something like 2 fat guinea pigs, just turn the unit if this is a concern.

Added a riser to my Bambu A1 Mini and… well, it’s tall now by Paul E King first appeared on Pocketables.

Today was an interesting day – as I may have mentioned I’m printing up fast removable suite number signs as a work project using a Bambu A1 Mini. Today’s task was to get our logo and a quick left/right directory for an elevator in which you’re given a quick orientation for which way to go when you exit the elevator.

The difficulty was our logo’s font does not exist, it was designed by an artist sometime in the 80s or 90s and we have a couple of high resolution files but no vector graphics. So my challenge was take a high resolution image and turn it into a sign with directional indicators to be placed in an elevator.

I decided I was going to use MakerWorld’s Make My Sign (free) for making this thing which did everything I needed it to do except provide arrows and turn a PDF the size of Rhode Island into an SVG.

For the arrows I just googled “left arrow emoji” and “right arrow emoji” and cut and paste them in a text box because that looked perfect. Placed white text on a dark background and I had everything I needed except our logo.

The task of turning a PDF image into an SVG involved me cutting the logo in Windows using windows-shift-s and pasting it into an MSPaint document, saving as a PNG, then going to PNGtoSVG.com (also free, no registration required, no emailing of link,) and playing with simplifying the logo from multicolor to 1 or 2.

Downloaded the SVG, imported into Make My Sign, resized, positioned, and printed.

Now it’d be really cool if I showed you what I made, but I’m not entirely enthused at the prospect of broadcasting where I work to the world (you can find it easy enough,) so I’ll just throw in the image of the Pocketables printable logo I made while attempting to figure out all the steps required to make my project work.

Fun times. As a note I have printed several suite numbers with the removable contraption but this one was fun and made me a wee bit giddy printing up my company’s logo. Yeah I’m boring.

Today I made my first 3D printed logo/sign by Paul E King first appeared on Pocketables.

I’ve got my A1 Mini at work because 1) I’ve got a large work project I am doing on it 2) I have no space at home, and 3) every time that printer is printing I am sneezing. So I use it when I can be in another location.

I started a print on Friday with some brand new PLA from Bambu labs. I had printed a few things earlier in the day and had no problem but then one of the projects I downloaded from Maker World printed so weirdly I aborted it (globs, not sticking to the surface.) I was in a rush and closing down the software and accidentally chose to update preferences and now I get spaghetti.

Womp womp. The above spaghetti is off of a spool which was not the new spool and had been nothing but working prints until I accidentally updated something.

I highly suspect I managed to break the settings on a project, but yeah now I’m trying to figure out how to fix this. Fun time since it’s not at my house and I can’t clear the plate to fix until tomorrow.

So I now know spaghetti detection is not implemented yet on the A1 mini…

Oddly not seeing a lot of help when I’m searching this up other than delete a profile, log back into the program, and do not sync cloud profiles.

Will reveal the amazing solution when I find it. At a little over a month this is the first challenge I’ve faced made more of a challenge by being 8 miles away from me at the moment.

Fix appears to have been close Bambu Studio, open it, log out, log back in, do not sync cloud values and settings. I’m at 3/4ths of an SS Benchy with the new filament and no evident issues.

That said, the spaghetti I was printing up there appears to have been fine through about a quarter of the print and then the base was flung off the textured plate. I now have questions about whether this may be an issue of the print piece not being centered more than a bad setting.

But all appears well with the world at the moment… which is nice because I actually lost sleep trying to retrace my steps

Other possibility is a Dreo fan I recently reviewed was running at an odd number, may have been blowing on the unit and cooling the front of the plate down which is where all my fails seem to have occurred. I suspect Google Assistant misheard something and set it to Tornado.

Had my first spaghetti print on the A1 Mini by Paul E King first appeared on Pocketables.

Last month I picked up a 3D printer, the Bambu A1 Mini. My plans for this are to design two items that simply do not exist, and a project for work. For the moment I’m learning quite a bit and printing up fidget toys and waiting on some black filament for the work project.

So far I’ve had no major disasters, a couple of minor printing errors that I believe were due to shaky table and badly positioned trash bucket, and have been impressed at the point I’ve stepped into the game it appears really user friendly. I guess going on for the past 40 something years have given it a pretty good head start for me.

I had a short vacation during this time, so there’s only a couple of weeks of me playing with the thing but man, the A1 mini has been a really good experience thus far.

A coworker is going to be bringing in another 3D printer that was abandoned by his kids because it was too hard to learn and we’re going to see if his kids just had a problem or if the thing really is that much harder. Supposedly was a good printer, but I’m new to the game so just taking that on what was told to me.

If you’ve ever been curious about it, Bambu’s entry price wasn’t bad, and I’ve so far printed up enough toys to probably have offset the price.

Now my task is to see whether I can actually create what I want to build and it be useful. One of my personal tasks unfortunately requires more print space than I can get with the A1 Mini, so I’ve got to figure out a way to print it in parts and while that doesn’t seem that difficult it’s something I had not factored into my near-impulse buy.

What I am have invented is going to make life slightly better for people in a couple of highly specific situations… if I can figure out how to print a medium sized build on a mini sized printer.

Or maybe it’s crap, but I can probably tell within the next week or two.

Man, I wonder what I would have done when I had more than 5 minutes between interruptions.

3D printing, about 4 weeks in by Paul E King first appeared on Pocketables.

3D printing ceramics is more accessible than ever, but it still has some quirks. Here's how to get started.

The post 3D Printing Ceramics: Going From the 3D Printer to the Kiln appeared first on Make: DIY Projects and Ideas for Makers.

Imagine a portable 3D printer you could hold in the palm of your hand. The tiny device could enable a user to rapidly create customized, low-cost objects on the go, like a fastener to repair a wobbly bicycle wheel or a component for a critical medical operation.

Researchers from MIT and the University of Texas at Austin took a major step toward making this idea a reality by demonstrating the first chip-based 3D printer. Their proof-of-concept device consists of a single, millimeter-scale photonic chip that emits reconfigurable beams of light into a well of resin that cures into a solid shape when light strikes it.

The prototype chip has no moving parts, instead relying on an array of tiny optical antennas to steer a beam of light. The beam projects up into a liquid resin that has been designed to rapidly cure when exposed to the beam’s wavelength of visible light.

By combining silicon photonics and photochemistry, the interdisciplinary research team was able to demonstrate a chip that can steer light beams to 3D print arbitrary two-dimensional patterns, including the letters M-I-T. Shapes can be fully formed in a matter of seconds.

In the long run, they envision a system where a photonic chip sits at the bottom of a well of resin and emits a 3D hologram of visible light, rapidly curing an entire object in a single step.

This type of portable 3D printer could have many applications, such as enabling clinicians to create tailor-made medical device components or allowing engineers to make rapid prototypes at a job site.

“This system is completely rethinking what a 3D printer is. It is no longer a big box sitting on a bench in a lab creating objects, but something that is handheld and portable. It is exciting to think about the new applications that could come out of this and how the field of 3D printing could change,” says senior author Jelena Notaros, the Robert J. Shillman Career Development Professor in Electrical Engineering and Computer Science (EECS), and a member of the Research Laboratory of Electronics.

Joining Notaros on the paper are Sabrina Corsetti, lead author and EECS graduate student; Milica Notaros PhD ’23; Tal Sneh, an EECS graduate student; Alex Safford, a recent graduate of the University of Texas at Austin; and Zak Page, an assistant professor in the Department of Chemical Engineering at UT Austin. The research appears today in Nature Light Science and Applications.

Printing with a chip

Experts in silicon photonics, the Notaros group previously developed integrated optical-phased-array systems that steer beams of light using a series of microscale antennas fabricated on a chip using semiconductor manufacturing processes. By speeding up or delaying the optical signal on either side of the antenna array, they can move the beam of emitted light in a certain direction.

Such systems are key for lidar sensors, which map their surroundings by emitting infrared light beams that bounce off nearby objects. Recently, the group has focused on systems that emit and steer visible light for augmented-reality applications.

They wondered if such a device could be used for a chip-based 3D printer.

At about the same time they started brainstorming, the Page Group at UT Austin demonstrated specialized resins that can be rapidly cured using wavelengths of visible light for the first time. This was the missing piece that pushed the chip-based 3D printer into reality.

“With photocurable resins, it is very hard to get them to cure all the way up at infrared wavelengths, which is where integrated optical-phased-array systems were operating in the past for lidar,” Corsetti says. “Here, we are meeting in the middle between standard photochemistry and silicon photonics by using visible-light-curable resins and visible-light-emitting chips to create this chip-based 3D printer. You have this merging of two technologies into a completely new idea.”

Their prototype consists of a single photonic chip containing an array of 160-nanometer-thick optical antennas. (A sheet of paper is about 100,000 nanometers thick.) The entire chip fits onto a U.S. quarter.

When powered by an off-chip laser, the antennas emit a steerable beam of visible light into the well of photocurable resin. The chip sits below a clear slide, like those used in microscopes, which contains a shallow indentation that holds the resin. The researchers use electrical signals to nonmechanically steer the light beam, causing the resin to solidify wherever the beam strikes it.

A collaborative approach

But effectively modulating visible-wavelength light, which involves modifying its amplitude and phase, is especially tricky. One common method requires heating the chip, but this is inefficient and takes a large amount of physical space.

Instead, the researchers used liquid crystal to fashion compact modulators they integrate onto the chip. The material’s unique optical properties enable the modulators to be extremely efficient and only about 20 microns in length.

A single waveguide on the chip holds the light from the off-chip laser. Running along the waveguide are tiny taps which tap off a little bit of light to each of the antennas.

The researchers actively tune the modulators using an electric field, which reorients the liquid crystal molecules in a certain direction. In this way, they can precisely control the amplitude and phase of light being routed to the antennas.

But forming and steering the beam is only half the battle. Interfacing with a novel photocurable resin was a completely different challenge.

The Page Group at UT Austin worked closely with the Notaros Group at MIT, carefully adjusting the chemical combinations and concentrations to zero-in on a formula that provided a long shelf-life and rapid curing.

In the end, the group used their prototype to 3D print arbitrary two-dimensional shapes within seconds.

Building off this prototype, they want to move toward developing a system like the one they originally conceptualized — a chip that emits a hologram of visible light in a resin well to enable volumetric 3D printing in only one step.

“To be able to do that, we need a completely new silicon-photonics chip design. We already laid out a lot of what that final system would look like in this paper. And, now, we are excited to continue working towards this ultimate demonstration,” Jelena Notaros says.

This work was funded, in part, by the U.S. National Science Foundation, the U.S. Defense Advanced Research Projects Agency, the Robert A. Welch Foundation, the MIT Rolf G. Locher Endowed Fellowship, and the MIT Frederick and Barbara Cronin Fellowship.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

Today was an interesting day – as I may have mentioned I’m printing up fast removable suite number signs as a work project using a Bambu A1 Mini. Today’s task was to get our logo and a quick left/right directory for an elevator in which you’re given a quick orientation for which way to go when you exit the elevator.

The difficulty was our logo’s font does not exist, it was designed by an artist sometime in the 80s or 90s and we have a couple of high resolution files but no vector graphics. So my challenge was take a high resolution image and turn it into a sign with directional indicators to be placed in an elevator.

I decided I was going to use MakerWorld’s Make My Sign (free) for making this thing which did everything I needed it to do except provide arrows and turn a PDF the size of Rhode Island into an SVG.

For the arrows I just googled “left arrow emoji” and “right arrow emoji” and cut and paste them in a text box because that looked perfect. Placed white text on a dark background and I had everything I needed except our logo.

The task of turning a PDF image into an SVG involved me cutting the logo in Windows using windows-shift-s and pasting it into an MSPaint document, saving as a PNG, then going to PNGtoSVG.com (also free, no registration required, no emailing of link,) and playing with simplifying the logo from multicolor to 1 or 2.

Downloaded the SVG, imported into Make My Sign, resized, positioned, and printed.

Now it’d be really cool if I showed you what I made, but I’m not entirely enthused at the prospect of broadcasting where I work to the world (you can find it easy enough,) so I’ll just throw in the image of the Pocketables printable logo I made while attempting to figure out all the steps required to make my project work.

Fun times. As a note I have printed several suite numbers with the removable contraption but this one was fun and made me a wee bit giddy printing up my company’s logo. Yeah I’m boring.

Today I made my first 3D printed logo/sign by Paul E King first appeared on Pocketables.

I’ve got my A1 Mini at work because 1) I’ve got a large work project I am doing on it 2) I have no space at home, and 3) every time that printer is printing I am sneezing. So I use it when I can be in another location.

I started a print on Friday with some brand new PLA from Bambu labs. I had printed a few things earlier in the day and had no problem but then one of the projects I downloaded from Maker World printed so weirdly I aborted it (globs, not sticking to the surface.) I was in a rush and closing down the software and accidentally chose to update preferences and now I get spaghetti.

Womp womp. The above spaghetti is off of a spool which was not the new spool and had been nothing but working prints until I accidentally updated something.

I highly suspect I managed to break the settings on a project, but yeah now I’m trying to figure out how to fix this. Fun time since it’s not at my house and I can’t clear the plate to fix until tomorrow.

So I now know spaghetti detection is not implemented yet on the A1 mini…

Oddly not seeing a lot of help when I’m searching this up other than delete a profile, log back into the program, and do not sync cloud profiles.

Will reveal the amazing solution when I find it. At a little over a month this is the first challenge I’ve faced made more of a challenge by being 8 miles away from me at the moment.

Fix appears to have been close Bambu Studio, open it, log out, log back in, do not sync cloud values and settings. I’m at 3/4ths of an SS Benchy with the new filament and no evident issues.

That said, the spaghetti I was printing up there appears to have been fine through about a quarter of the print and then the base was flung off the textured plate. I now have questions about whether this may be an issue of the print piece not being centered more than a bad setting.

But all appears well with the world at the moment… which is nice because I actually lost sleep trying to retrace my steps

Other possibility is a Dreo fan I recently reviewed was running at an odd number, may have been blowing on the unit and cooling the front of the plate down which is where all my fails seem to have occurred. I suspect Google Assistant misheard something and set it to Tornado.

Had my first spaghetti print on the A1 Mini by Paul E King first appeared on Pocketables.

Last month I picked up a 3D printer, the Bambu A1 Mini. My plans for this are to design two items that simply do not exist, and a project for work. For the moment I’m learning quite a bit and printing up fidget toys and waiting on some black filament for the work project.

So far I’ve had no major disasters, a couple of minor printing errors that I believe were due to shaky table and badly positioned trash bucket, and have been impressed at the point I’ve stepped into the game it appears really user friendly. I guess going on for the past 40 something years have given it a pretty good head start for me.

I had a short vacation during this time, so there’s only a couple of weeks of me playing with the thing but man, the A1 mini has been a really good experience thus far.

A coworker is going to be bringing in another 3D printer that was abandoned by his kids because it was too hard to learn and we’re going to see if his kids just had a problem or if the thing really is that much harder. Supposedly was a good printer, but I’m new to the game so just taking that on what was told to me.

If you’ve ever been curious about it, Bambu’s entry price wasn’t bad, and I’ve so far printed up enough toys to probably have offset the price.

Now my task is to see whether I can actually create what I want to build and it be useful. One of my personal tasks unfortunately requires more print space than I can get with the A1 Mini, so I’ve got to figure out a way to print it in parts and while that doesn’t seem that difficult it’s something I had not factored into my near-impulse buy.

What I am have invented is going to make life slightly better for people in a couple of highly specific situations… if I can figure out how to print a medium sized build on a mini sized printer.

Or maybe it’s crap, but I can probably tell within the next week or two.

Man, I wonder what I would have done when I had more than 5 minutes between interruptions.

3D printing, about 4 weeks in by Paul E King first appeared on Pocketables.

Hi, I’m Paul and I recently discovered I needed to make a few things that apparently don’t exist at the moment. Now, the journey to making those things isn’t this article, this is just about setting up the unit, my first tugboat, and my first print on the first 3D printer I’ve ever had access to.

TL;DR – total noob vs well planned out device

After discussing in the discord channel that I was looking for a 3D printer Bambu Labs was mentioned and I went on to watch a few videos discussing why the A1 Mini was not terrible. I was more interested in the “meh, get it” reviews than the vast majority of the reviews out there saying that it was great. Even people with the absurd systems tended to think at least it was a great starter printer and all around probably pretty decent.

I checked the rave reviews after this and decided that if I had checked them first I probably would have wandered off due to built in positive commercial blocking.

So I decided to order the Bambu Lab A1 Mini Combo and 3 spools of Filament due to there being an anniversary sale (still going on) and that I thought I was ordering 4 spools… eh, my bad.

I placed the order, and maybe two days later I had the spools and notification that the A1 Mini Combo had shipped.

What happened next, only UPS knows as they took possession of it and then it sat with the status “emergency situation or extreme weather” for several days. I wasn’t in a particular rush as I didn’t have the place set up for it and I had a vacation I had to attend to, but Bambu Lab had done their part and I contacted them the day UPS released it and gave a date for delivery.

I wanted to devote 3 hours to setting it up and a first print, so it sat for a few days until I could do this. Based on the pictures I have from unboxing to printing my first tugboat was an hour and 13 minutes. This included several minutes in which the printer went through an initial calibration and noise testing and otherwise did things it will probably not do on a routine basis.

I was a bit surprised at the packaging and setup process. The packaging seemed overkill and includes having to remove 4 screws and an arm that exists solely to prevent movement. This encased in foam, cardboard, etc. I’ve got a trash can full of half recyclable materials here. Maybe better safe than sorry.

Attempting to pair the printer to my Bambu Handy account had some bumps… seems like I had some minor issue creating the account where it would just sit and spin for a minute before giving me an error message and then disappearing. That either cleared up or I chose to log in using Google, I can’t remember which.

My first print started and after gazing at a print head printing stuff for suitably long enough I returned to another project. Things seemed to be going along well so I left it unattended until I heard a weird noise, turned around, and most of the printing part of the unit was off of a table and about to throw itself to the floor.

I didn’t know what to do at this point other than grab the not-hot and not moving parts of it and move it back to the table. As such I believe was the creation of the issues with the back of the boat and at least one line on the front. The unit was not in a stable enough position and was shaking itself silly.

I decided to do a second print and was informed there was an error and that I needed to do run a self test. Wish I’d taken screen shots, but I ended up having to Google it and whatever it did took less than a minute and as it finished I was informed there was a firmware update and chose to take it.

After the firmware update and issues I didn’t have enough time to do a second print that day – it was now saying it wanted me to oil the Y access and I saw no printed documentation for that. Figured I would do that in the morning and print up something one of my children wanted. I did not want to run another print unattended because 1) I had not oiled it yet and wanted to make sure I did everything properly, 2) I did not want to come back to a printer on the ground.

A quick and easy lube later I printed my first Axolotl (highest rated in the Bambu Handy app, I have no idea how to link it yet.) With the printer positioned in a much more stable location and using a different filament I had no visible printing issues like I had previously with the boat.

I fully realize at the end of day 2 I have only reached the point of printing other people’s stuff, but with the time I have been able to devote to it that’s where I expect to be.

My goal tomorrow is to take a logo for my work with a font that does not exist and print up a small door plate. This is going to be interesting because I see how to do it if you have the font, but many moons ago (sometime in the 90’s) work’s logo text was designed and drawn and as such I have PSDs, PDFs, but no fonts.

So far I feel like I’m on a guided adventure with the Bambu Lab A1 Mini Combo… there was the thrill of setting it up, the boat which was there waiting for me (assuming on the SD card,) my first error and having to figure out how to get the printer to do anything (if you say I need to run a self check give me a button to run a self check people,) a requirement for lubricating the Y access after the first print, and who knows what the rest is going to bring as I have grease as well, and a couple of tools that have not be used or referenced yet.

I’ll probably end up shortly making some drawer organizers and lock pick holders because I’m cool like that.

Anyhow, just a story of my first two days… I’m on print #3 now and may trust the unit now that it’s positioned better to print something when I am not in the building.

I picked up a Bambu Lab A1 Mini Combo knowing next to nothing about 3D printing by Paul E King first appeared on Pocketables.

3D printing ceramics is more accessible than ever, but it still has some quirks. Here's how to get started.

The post 3D Printing Ceramics: Going From the 3D Printer to the Kiln appeared first on Make: DIY Projects and Ideas for Makers.

Imagine a portable 3D printer you could hold in the palm of your hand. The tiny device could enable a user to rapidly create customized, low-cost objects on the go, like a fastener to repair a wobbly bicycle wheel or a component for a critical medical operation.

Researchers from MIT and the University of Texas at Austin took a major step toward making this idea a reality by demonstrating the first chip-based 3D printer. Their proof-of-concept device consists of a single, millimeter-scale photonic chip that emits reconfigurable beams of light into a well of resin that cures into a solid shape when light strikes it.

The prototype chip has no moving parts, instead relying on an array of tiny optical antennas to steer a beam of light. The beam projects up into a liquid resin that has been designed to rapidly cure when exposed to the beam’s wavelength of visible light.

By combining silicon photonics and photochemistry, the interdisciplinary research team was able to demonstrate a chip that can steer light beams to 3D print arbitrary two-dimensional patterns, including the letters M-I-T. Shapes can be fully formed in a matter of seconds.

In the long run, they envision a system where a photonic chip sits at the bottom of a well of resin and emits a 3D hologram of visible light, rapidly curing an entire object in a single step.

This type of portable 3D printer could have many applications, such as enabling clinicians to create tailor-made medical device components or allowing engineers to make rapid prototypes at a job site.

“This system is completely rethinking what a 3D printer is. It is no longer a big box sitting on a bench in a lab creating objects, but something that is handheld and portable. It is exciting to think about the new applications that could come out of this and how the field of 3D printing could change,” says senior author Jelena Notaros, the Robert J. Shillman Career Development Professor in Electrical Engineering and Computer Science (EECS), and a member of the Research Laboratory of Electronics.

Joining Notaros on the paper are Sabrina Corsetti, lead author and EECS graduate student; Milica Notaros PhD ’23; Tal Sneh, an EECS graduate student; Alex Safford, a recent graduate of the University of Texas at Austin; and Zak Page, an assistant professor in the Department of Chemical Engineering at UT Austin. The research appears today in Nature Light Science and Applications.

Printing with a chip

Experts in silicon photonics, the Notaros group previously developed integrated optical-phased-array systems that steer beams of light using a series of microscale antennas fabricated on a chip using semiconductor manufacturing processes. By speeding up or delaying the optical signal on either side of the antenna array, they can move the beam of emitted light in a certain direction.

Such systems are key for lidar sensors, which map their surroundings by emitting infrared light beams that bounce off nearby objects. Recently, the group has focused on systems that emit and steer visible light for augmented-reality applications.

They wondered if such a device could be used for a chip-based 3D printer.

At about the same time they started brainstorming, the Page Group at UT Austin demonstrated specialized resins that can be rapidly cured using wavelengths of visible light for the first time. This was the missing piece that pushed the chip-based 3D printer into reality.

“With photocurable resins, it is very hard to get them to cure all the way up at infrared wavelengths, which is where integrated optical-phased-array systems were operating in the past for lidar,” Corsetti says. “Here, we are meeting in the middle between standard photochemistry and silicon photonics by using visible-light-curable resins and visible-light-emitting chips to create this chip-based 3D printer. You have this merging of two technologies into a completely new idea.”

Their prototype consists of a single photonic chip containing an array of 160-nanometer-thick optical antennas. (A sheet of paper is about 100,000 nanometers thick.) The entire chip fits onto a U.S. quarter.

When powered by an off-chip laser, the antennas emit a steerable beam of visible light into the well of photocurable resin. The chip sits below a clear slide, like those used in microscopes, which contains a shallow indentation that holds the resin. The researchers use electrical signals to nonmechanically steer the light beam, causing the resin to solidify wherever the beam strikes it.

A collaborative approach

But effectively modulating visible-wavelength light, which involves modifying its amplitude and phase, is especially tricky. One common method requires heating the chip, but this is inefficient and takes a large amount of physical space.

Instead, the researchers used liquid crystal to fashion compact modulators they integrate onto the chip. The material’s unique optical properties enable the modulators to be extremely efficient and only about 20 microns in length.

A single waveguide on the chip holds the light from the off-chip laser. Running along the waveguide are tiny taps which tap off a little bit of light to each of the antennas.

The researchers actively tune the modulators using an electric field, which reorients the liquid crystal molecules in a certain direction. In this way, they can precisely control the amplitude and phase of light being routed to the antennas.

But forming and steering the beam is only half the battle. Interfacing with a novel photocurable resin was a completely different challenge.

The Page Group at UT Austin worked closely with the Notaros Group at MIT, carefully adjusting the chemical combinations and concentrations to zero-in on a formula that provided a long shelf-life and rapid curing.

In the end, the group used their prototype to 3D print arbitrary two-dimensional shapes within seconds.

Building off this prototype, they want to move toward developing a system like the one they originally conceptualized — a chip that emits a hologram of visible light in a resin well to enable volumetric 3D printing in only one step.

“To be able to do that, we need a completely new silicon-photonics chip design. We already laid out a lot of what that final system would look like in this paper. And, now, we are excited to continue working towards this ultimate demonstration,” Jelena Notaros says.

This work was funded, in part, by the U.S. National Science Foundation, the U.S. Defense Advanced Research Projects Agency, the Robert A. Welch Foundation, the MIT Rolf G. Locher Endowed Fellowship, and the MIT Frederick and Barbara Cronin Fellowship.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

Today was an interesting day – as I may have mentioned I’m printing up fast removable suite number signs as a work project using a Bambu A1 Mini. Today’s task was to get our logo and a quick left/right directory for an elevator in which you’re given a quick orientation for which way to go when you exit the elevator.

The difficulty was our logo’s font does not exist, it was designed by an artist sometime in the 80s or 90s and we have a couple of high resolution files but no vector graphics. So my challenge was take a high resolution image and turn it into a sign with directional indicators to be placed in an elevator.

I decided I was going to use MakerWorld’s Make My Sign (free) for making this thing which did everything I needed it to do except provide arrows and turn a PDF the size of Rhode Island into an SVG.

For the arrows I just googled “left arrow emoji” and “right arrow emoji” and cut and paste them in a text box because that looked perfect. Placed white text on a dark background and I had everything I needed except our logo.

The task of turning a PDF image into an SVG involved me cutting the logo in Windows using windows-shift-s and pasting it into an MSPaint document, saving as a PNG, then going to PNGtoSVG.com (also free, no registration required, no emailing of link,) and playing with simplifying the logo from multicolor to 1 or 2.

Downloaded the SVG, imported into Make My Sign, resized, positioned, and printed.

Now it’d be really cool if I showed you what I made, but I’m not entirely enthused at the prospect of broadcasting where I work to the world (you can find it easy enough,) so I’ll just throw in the image of the Pocketables printable logo I made while attempting to figure out all the steps required to make my project work.

Fun times. As a note I have printed several suite numbers with the removable contraption but this one was fun and made me a wee bit giddy printing up my company’s logo. Yeah I’m boring.

Today I made my first 3D printed logo/sign by Paul E King first appeared on Pocketables.

I’ve got my A1 Mini at work because 1) I’ve got a large work project I am doing on it 2) I have no space at home, and 3) every time that printer is printing I am sneezing. So I use it when I can be in another location.

I started a print on Friday with some brand new PLA from Bambu labs. I had printed a few things earlier in the day and had no problem but then one of the projects I downloaded from Maker World printed so weirdly I aborted it (globs, not sticking to the surface.) I was in a rush and closing down the software and accidentally chose to update preferences and now I get spaghetti.

Womp womp. The above spaghetti is off of a spool which was not the new spool and had been nothing but working prints until I accidentally updated something.

I highly suspect I managed to break the settings on a project, but yeah now I’m trying to figure out how to fix this. Fun time since it’s not at my house and I can’t clear the plate to fix until tomorrow.

So I now know spaghetti detection is not implemented yet on the A1 mini…

Oddly not seeing a lot of help when I’m searching this up other than delete a profile, log back into the program, and do not sync cloud profiles.

Will reveal the amazing solution when I find it. At a little over a month this is the first challenge I’ve faced made more of a challenge by being 8 miles away from me at the moment.

Fix appears to have been close Bambu Studio, open it, log out, log back in, do not sync cloud values and settings. I’m at 3/4ths of an SS Benchy with the new filament and no evident issues.

That said, the spaghetti I was printing up there appears to have been fine through about a quarter of the print and then the base was flung off the textured plate. I now have questions about whether this may be an issue of the print piece not being centered more than a bad setting.

But all appears well with the world at the moment… which is nice because I actually lost sleep trying to retrace my steps

Other possibility is a Dreo fan I recently reviewed was running at an odd number, may have been blowing on the unit and cooling the front of the plate down which is where all my fails seem to have occurred. I suspect Google Assistant misheard something and set it to Tornado.

Had my first spaghetti print on the A1 Mini by Paul E King first appeared on Pocketables.

Last month I picked up a 3D printer, the Bambu A1 Mini. My plans for this are to design two items that simply do not exist, and a project for work. For the moment I’m learning quite a bit and printing up fidget toys and waiting on some black filament for the work project.

So far I’ve had no major disasters, a couple of minor printing errors that I believe were due to shaky table and badly positioned trash bucket, and have been impressed at the point I’ve stepped into the game it appears really user friendly. I guess going on for the past 40 something years have given it a pretty good head start for me.

I had a short vacation during this time, so there’s only a couple of weeks of me playing with the thing but man, the A1 mini has been a really good experience thus far.

A coworker is going to be bringing in another 3D printer that was abandoned by his kids because it was too hard to learn and we’re going to see if his kids just had a problem or if the thing really is that much harder. Supposedly was a good printer, but I’m new to the game so just taking that on what was told to me.

If you’ve ever been curious about it, Bambu’s entry price wasn’t bad, and I’ve so far printed up enough toys to probably have offset the price.

Now my task is to see whether I can actually create what I want to build and it be useful. One of my personal tasks unfortunately requires more print space than I can get with the A1 Mini, so I’ve got to figure out a way to print it in parts and while that doesn’t seem that difficult it’s something I had not factored into my near-impulse buy.

What I am have invented is going to make life slightly better for people in a couple of highly specific situations… if I can figure out how to print a medium sized build on a mini sized printer.

Or maybe it’s crap, but I can probably tell within the next week or two.

Man, I wonder what I would have done when I had more than 5 minutes between interruptions.

3D printing, about 4 weeks in by Paul E King first appeared on Pocketables.

Hi, I’m Paul and I recently discovered I needed to make a few things that apparently don’t exist at the moment. Now, the journey to making those things isn’t this article, this is just about setting up the unit, my first tugboat, and my first print on the first 3D printer I’ve ever had access to.

TL;DR – total noob vs well planned out device

After discussing in the discord channel that I was looking for a 3D printer Bambu Labs was mentioned and I went on to watch a few videos discussing why the A1 Mini was not terrible. I was more interested in the “meh, get it” reviews than the vast majority of the reviews out there saying that it was great. Even people with the absurd systems tended to think at least it was a great starter printer and all around probably pretty decent.

I checked the rave reviews after this and decided that if I had checked them first I probably would have wandered off due to built in positive commercial blocking.

So I decided to order the Bambu Lab A1 Mini Combo and 3 spools of Filament due to there being an anniversary sale (still going on) and that I thought I was ordering 4 spools… eh, my bad.

I placed the order, and maybe two days later I had the spools and notification that the A1 Mini Combo had shipped.

What happened next, only UPS knows as they took possession of it and then it sat with the status “emergency situation or extreme weather” for several days. I wasn’t in a particular rush as I didn’t have the place set up for it and I had a vacation I had to attend to, but Bambu Lab had done their part and I contacted them the day UPS released it and gave a date for delivery.

I wanted to devote 3 hours to setting it up and a first print, so it sat for a few days until I could do this. Based on the pictures I have from unboxing to printing my first tugboat was an hour and 13 minutes. This included several minutes in which the printer went through an initial calibration and noise testing and otherwise did things it will probably not do on a routine basis.

I was a bit surprised at the packaging and setup process. The packaging seemed overkill and includes having to remove 4 screws and an arm that exists solely to prevent movement. This encased in foam, cardboard, etc. I’ve got a trash can full of half recyclable materials here. Maybe better safe than sorry.

Attempting to pair the printer to my Bambu Handy account had some bumps… seems like I had some minor issue creating the account where it would just sit and spin for a minute before giving me an error message and then disappearing. That either cleared up or I chose to log in using Google, I can’t remember which.

My first print started and after gazing at a print head printing stuff for suitably long enough I returned to another project. Things seemed to be going along well so I left it unattended until I heard a weird noise, turned around, and most of the printing part of the unit was off of a table and about to throw itself to the floor.

I didn’t know what to do at this point other than grab the not-hot and not moving parts of it and move it back to the table. As such I believe was the creation of the issues with the back of the boat and at least one line on the front. The unit was not in a stable enough position and was shaking itself silly.

I decided to do a second print and was informed there was an error and that I needed to do run a self test. Wish I’d taken screen shots, but I ended up having to Google it and whatever it did took less than a minute and as it finished I was informed there was a firmware update and chose to take it.

After the firmware update and issues I didn’t have enough time to do a second print that day – it was now saying it wanted me to oil the Y access and I saw no printed documentation for that. Figured I would do that in the morning and print up something one of my children wanted. I did not want to run another print unattended because 1) I had not oiled it yet and wanted to make sure I did everything properly, 2) I did not want to come back to a printer on the ground.

A quick and easy lube later I printed my first Axolotl (highest rated in the Bambu Handy app, I have no idea how to link it yet.) With the printer positioned in a much more stable location and using a different filament I had no visible printing issues like I had previously with the boat.

I fully realize at the end of day 2 I have only reached the point of printing other people’s stuff, but with the time I have been able to devote to it that’s where I expect to be.

My goal tomorrow is to take a logo for my work with a font that does not exist and print up a small door plate. This is going to be interesting because I see how to do it if you have the font, but many moons ago (sometime in the 90’s) work’s logo text was designed and drawn and as such I have PSDs, PDFs, but no fonts.

So far I feel like I’m on a guided adventure with the Bambu Lab A1 Mini Combo… there was the thrill of setting it up, the boat which was there waiting for me (assuming on the SD card,) my first error and having to figure out how to get the printer to do anything (if you say I need to run a self check give me a button to run a self check people,) a requirement for lubricating the Y access after the first print, and who knows what the rest is going to bring as I have grease as well, and a couple of tools that have not be used or referenced yet.

I’ll probably end up shortly making some drawer organizers and lock pick holders because I’m cool like that.

Anyhow, just a story of my first two days… I’m on print #3 now and may trust the unit now that it’s positioned better to print something when I am not in the building.

I picked up a Bambu Lab A1 Mini Combo knowing next to nothing about 3D printing by Paul E King first appeared on Pocketables.

Imagine a portable 3D printer you could hold in the palm of your hand. The tiny device could enable a user to rapidly create customized, low-cost objects on the go, like a fastener to repair a wobbly bicycle wheel or a component for a critical medical operation.

Researchers from MIT and the University of Texas at Austin took a major step toward making this idea a reality by demonstrating the first chip-based 3D printer. Their proof-of-concept device consists of a single, millimeter-scale photonic chip that emits reconfigurable beams of light into a well of resin that cures into a solid shape when light strikes it.

The prototype chip has no moving parts, instead relying on an array of tiny optical antennas to steer a beam of light. The beam projects up into a liquid resin that has been designed to rapidly cure when exposed to the beam’s wavelength of visible light.

By combining silicon photonics and photochemistry, the interdisciplinary research team was able to demonstrate a chip that can steer light beams to 3D print arbitrary two-dimensional patterns, including the letters M-I-T. Shapes can be fully formed in a matter of seconds.

In the long run, they envision a system where a photonic chip sits at the bottom of a well of resin and emits a 3D hologram of visible light, rapidly curing an entire object in a single step.

This type of portable 3D printer could have many applications, such as enabling clinicians to create tailor-made medical device components or allowing engineers to make rapid prototypes at a job site.

“This system is completely rethinking what a 3D printer is. It is no longer a big box sitting on a bench in a lab creating objects, but something that is handheld and portable. It is exciting to think about the new applications that could come out of this and how the field of 3D printing could change,” says senior author Jelena Notaros, the Robert J. Shillman Career Development Professor in Electrical Engineering and Computer Science (EECS), and a member of the Research Laboratory of Electronics.

Joining Notaros on the paper are Sabrina Corsetti, lead author and EECS graduate student; Milica Notaros PhD ’23; Tal Sneh, an EECS graduate student; Alex Safford, a recent graduate of the University of Texas at Austin; and Zak Page, an assistant professor in the Department of Chemical Engineering at UT Austin. The research appears today in Nature Light Science and Applications.

Printing with a chip

Experts in silicon photonics, the Notaros group previously developed integrated optical-phased-array systems that steer beams of light using a series of microscale antennas fabricated on a chip using semiconductor manufacturing processes. By speeding up or delaying the optical signal on either side of the antenna array, they can move the beam of emitted light in a certain direction.

Such systems are key for lidar sensors, which map their surroundings by emitting infrared light beams that bounce off nearby objects. Recently, the group has focused on systems that emit and steer visible light for augmented-reality applications.

They wondered if such a device could be used for a chip-based 3D printer.

At about the same time they started brainstorming, the Page Group at UT Austin demonstrated specialized resins that can be rapidly cured using wavelengths of visible light for the first time. This was the missing piece that pushed the chip-based 3D printer into reality.

“With photocurable resins, it is very hard to get them to cure all the way up at infrared wavelengths, which is where integrated optical-phased-array systems were operating in the past for lidar,” Corsetti says. “Here, we are meeting in the middle between standard photochemistry and silicon photonics by using visible-light-curable resins and visible-light-emitting chips to create this chip-based 3D printer. You have this merging of two technologies into a completely new idea.”

Their prototype consists of a single photonic chip containing an array of 160-nanometer-thick optical antennas. (A sheet of paper is about 100,000 nanometers thick.) The entire chip fits onto a U.S. quarter.

When powered by an off-chip laser, the antennas emit a steerable beam of visible light into the well of photocurable resin. The chip sits below a clear slide, like those used in microscopes, which contains a shallow indentation that holds the resin. The researchers use electrical signals to nonmechanically steer the light beam, causing the resin to solidify wherever the beam strikes it.

A collaborative approach

But effectively modulating visible-wavelength light, which involves modifying its amplitude and phase, is especially tricky. One common method requires heating the chip, but this is inefficient and takes a large amount of physical space.

Instead, the researchers used liquid crystal to fashion compact modulators they integrate onto the chip. The material’s unique optical properties enable the modulators to be extremely efficient and only about 20 microns in length.

A single waveguide on the chip holds the light from the off-chip laser. Running along the waveguide are tiny taps which tap off a little bit of light to each of the antennas.

The researchers actively tune the modulators using an electric field, which reorients the liquid crystal molecules in a certain direction. In this way, they can precisely control the amplitude and phase of light being routed to the antennas.

But forming and steering the beam is only half the battle. Interfacing with a novel photocurable resin was a completely different challenge.

The Page Group at UT Austin worked closely with the Notaros Group at MIT, carefully adjusting the chemical combinations and concentrations to zero-in on a formula that provided a long shelf-life and rapid curing.

In the end, the group used their prototype to 3D print arbitrary two-dimensional shapes within seconds.

Building off this prototype, they want to move toward developing a system like the one they originally conceptualized — a chip that emits a hologram of visible light in a resin well to enable volumetric 3D printing in only one step.

“To be able to do that, we need a completely new silicon-photonics chip design. We already laid out a lot of what that final system would look like in this paper. And, now, we are excited to continue working towards this ultimate demonstration,” Jelena Notaros says.

This work was funded, in part, by the U.S. National Science Foundation, the U.S. Defense Advanced Research Projects Agency, the Robert A. Welch Foundation, the MIT Rolf G. Locher Endowed Fellowship, and the MIT Frederick and Barbara Cronin Fellowship.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

Imagine a portable 3D printer you could hold in the palm of your hand. The tiny device could enable a user to rapidly create customized, low-cost objects on the go, like a fastener to repair a wobbly bicycle wheel or a component for a critical medical operation.

Researchers from MIT and the University of Texas at Austin took a major step toward making this idea a reality by demonstrating the first chip-based 3D printer. Their proof-of-concept device consists of a single, millimeter-scale photonic chip that emits reconfigurable beams of light into a well of resin that cures into a solid shape when light strikes it.

The prototype chip has no moving parts, instead relying on an array of tiny optical antennas to steer a beam of light. The beam projects up into a liquid resin that has been designed to rapidly cure when exposed to the beam’s wavelength of visible light.

By combining silicon photonics and photochemistry, the interdisciplinary research team was able to demonstrate a chip that can steer light beams to 3D print arbitrary two-dimensional patterns, including the letters M-I-T. Shapes can be fully formed in a matter of seconds.

In the long run, they envision a system where a photonic chip sits at the bottom of a well of resin and emits a 3D hologram of visible light, rapidly curing an entire object in a single step.

This type of portable 3D printer could have many applications, such as enabling clinicians to create tailor-made medical device components or allowing engineers to make rapid prototypes at a job site.

“This system is completely rethinking what a 3D printer is. It is no longer a big box sitting on a bench in a lab creating objects, but something that is handheld and portable. It is exciting to think about the new applications that could come out of this and how the field of 3D printing could change,” says senior author Jelena Notaros, the Robert J. Shillman Career Development Professor in Electrical Engineering and Computer Science (EECS), and a member of the Research Laboratory of Electronics.

Joining Notaros on the paper are Sabrina Corsetti, lead author and EECS graduate student; Milica Notaros PhD ’23; Tal Sneh, an EECS graduate student; Alex Safford, a recent graduate of the University of Texas at Austin; and Zak Page, an assistant professor in the Department of Chemical Engineering at UT Austin. The research appears today in Nature Light Science and Applications.

Printing with a chip

Experts in silicon photonics, the Notaros group previously developed integrated optical-phased-array systems that steer beams of light using a series of microscale antennas fabricated on a chip using semiconductor manufacturing processes. By speeding up or delaying the optical signal on either side of the antenna array, they can move the beam of emitted light in a certain direction.

Such systems are key for lidar sensors, which map their surroundings by emitting infrared light beams that bounce off nearby objects. Recently, the group has focused on systems that emit and steer visible light for augmented-reality applications.

They wondered if such a device could be used for a chip-based 3D printer.

At about the same time they started brainstorming, the Page Group at UT Austin demonstrated specialized resins that can be rapidly cured using wavelengths of visible light for the first time. This was the missing piece that pushed the chip-based 3D printer into reality.

“With photocurable resins, it is very hard to get them to cure all the way up at infrared wavelengths, which is where integrated optical-phased-array systems were operating in the past for lidar,” Corsetti says. “Here, we are meeting in the middle between standard photochemistry and silicon photonics by using visible-light-curable resins and visible-light-emitting chips to create this chip-based 3D printer. You have this merging of two technologies into a completely new idea.”

Their prototype consists of a single photonic chip containing an array of 160-nanometer-thick optical antennas. (A sheet of paper is about 100,000 nanometers thick.) The entire chip fits onto a U.S. quarter.

When powered by an off-chip laser, the antennas emit a steerable beam of visible light into the well of photocurable resin. The chip sits below a clear slide, like those used in microscopes, which contains a shallow indentation that holds the resin. The researchers use electrical signals to nonmechanically steer the light beam, causing the resin to solidify wherever the beam strikes it.

A collaborative approach

But effectively modulating visible-wavelength light, which involves modifying its amplitude and phase, is especially tricky. One common method requires heating the chip, but this is inefficient and takes a large amount of physical space.

Instead, the researchers used liquid crystal to fashion compact modulators they integrate onto the chip. The material’s unique optical properties enable the modulators to be extremely efficient and only about 20 microns in length.

A single waveguide on the chip holds the light from the off-chip laser. Running along the waveguide are tiny taps which tap off a little bit of light to each of the antennas.

The researchers actively tune the modulators using an electric field, which reorients the liquid crystal molecules in a certain direction. In this way, they can precisely control the amplitude and phase of light being routed to the antennas.

But forming and steering the beam is only half the battle. Interfacing with a novel photocurable resin was a completely different challenge.

The Page Group at UT Austin worked closely with the Notaros Group at MIT, carefully adjusting the chemical combinations and concentrations to zero-in on a formula that provided a long shelf-life and rapid curing.

In the end, the group used their prototype to 3D print arbitrary two-dimensional shapes within seconds.

Building off this prototype, they want to move toward developing a system like the one they originally conceptualized — a chip that emits a hologram of visible light in a resin well to enable volumetric 3D printing in only one step.

“To be able to do that, we need a completely new silicon-photonics chip design. We already laid out a lot of what that final system would look like in this paper. And, now, we are excited to continue working towards this ultimate demonstration,” Jelena Notaros says.

This work was funded, in part, by the U.S. National Science Foundation, the U.S. Defense Advanced Research Projects Agency, the Robert A. Welch Foundation, the MIT Rolf G. Locher Endowed Fellowship, and the MIT Frederick and Barbara Cronin Fellowship.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

Layerless, all-at-once resin printing is a reality with the astonishing CAL system

The post Computed Axial Lithography: 3D Printing in Seconds appeared first on Make: DIY Projects and Ideas for Makers.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

Mobility walkers can be expensive. Build your own personalized, strength-tested version for less.

The post Walk This Way: DIY Mobility Walker appeared first on Make: DIY Projects and Ideas for Makers.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

MIT researchers have used 3D printing to produce self-heating microfluidic devices, demonstrating a technique which could someday be used to rapidly create cheap, yet accurate, tools to detect a host of diseases.

Microfluidics, miniaturized machines that manipulate fluids and facilitate chemical reactions, can be used to detect disease in tiny samples of blood or fluids. At-home test kits for Covid-19, for example, incorporate a simple type of microfluidic.

But many microfluidic applications require chemical reactions that must be performed at specific temperatures. These more complex microfluidic devices, which are typically manufactured in a clean room, are outfitted with heating elements made from gold or platinum using a complicated and expensive fabrication process that is difficult to scale up.

Instead, the MIT team used multimaterial 3D printing to create self-heating microfluidic devices with built-in heating elements, through a single, inexpensive manufacturing process. They generated devices that can heat fluid to a specific temperature as it flows through microscopic channels inside the tiny machine.

Their technique is customizable, so an engineer could create a microfluidic that heats fluid to a certain temperature or given heating profile within a specific area of the device. The low-cost fabrication process requires about $2 of materials to generate a ready-to-use microfluidic.

The process could be especially useful in creating self-heating microfluidics for remote regions of developing countries where clinicians may not have access to the expensive lab equipment required for many diagnostic procedures.

“Clean rooms in particular, where you would usually make these devices, are incredibly expensive to build and to run. But we can make very capable self-heating microfluidic devices using additive manufacturing, and they can be made a lot faster and cheaper than with these traditional methods. This is really a way to democratize this technology,” says Luis Fernando Velásquez-García, a principal scientist in MIT’s Microsystems Technology Laboratories (MTL) and senior author of a paper describing the fabrication technique.

He is joined on the paper by lead author Jorge Cañada Pérez-Sala, an electrical engineering and computer science graduate student. The research will be presented at the PowerMEMS Conference this month.

An insulator becomes conductive

This new fabrication process utilizes a technique called multimaterial extrusion 3D printing, in which several materials can be squirted through the printer’s many nozzles to build a device layer by layer. The process is monolithic, which means the entire device can be produced in one step on the 3D printer, without the need for any post-assembly.

To create self-heating microfluidics, the researchers used two materials — a biodegradable polymer known as polylactic acid (PLA) that is commonly used in 3D printing, and a modified version of PLA.

The modified PLA has mixed copper nanoparticles into the polymer, which converts this insulating material into an electrical conductor, Velásquez-García explains. When electrical current is fed into a resistor composed of this copper-doped PLA, energy is dissipated as heat.

“It is amazing when you think about it because the PLA material is a dielectric, but when you put in these nanoparticle impurities, it completely changes the physical properties. This is something we don’t fully understand yet, but it happens and it is repeatable,” he says.

Using a multimaterial 3D printer, the researchers fabricate a heating resistor from the copper-doped PLA and then print the microfluidic device, with microscopic channels through which fluid can flow, directly on top in one printing step. Because the components are made from the same base material, they have similar printing temperatures and are compatible.

Heat dissipated from the resistor will warm fluid flowing through the channels in the microfluidic.

In addition to the resistor and microfluidic, they use the printer to add a thin, continuous layer of PLA that is sandwiched between them. It is especially challenging to manufacture this layer because it must be thin enough so heat can transfer from the resistor to the microfluidic, but not so thin that fluid could leak into the resistor.

The resulting machine is about the size of a U.S. quarter and can be produced in a matter of minutes. Channels about 500 micrometers wide and 400 micrometers tall are threaded through the microfluidic to carry fluid and facilitate chemical reactions.

Importantly, the PLA material is translucent, so fluid in the device remains visible. Many processes rely on visualization or the use of light to infer what is happening during chemical reactions, Velásquez-García explains.

Customizable chemical reactors

The researchers used this one-step manufacturing process to generate a prototype that could heat fluid by 4 degrees Celsius as it flowed between the input and the output. This customizable technique could enable them to make devices which would heat fluids in certain patterns or along specific gradients.

“You can use these two materials to create chemical reactors that do exactly what you want. We can set up a particular heating profile while still having all the capabilities of the microfluidic,” he says.

However, one limitation comes from the fact that PLA can only be heated to about 50 degrees Celsius before it starts to degrade. Many chemical reactions, such as those used for polymerase chain reaction (PCR) tests, require temperatures of 90 degrees or higher. And to precisely control the temperature of the device, researchers would need to integrate a third material that enables temperature sensing.

In addition to tackling these limitations in future work, Velásquez-García wants to print magnets directly into the microfluidic device. These magnets could enable chemical reactions that require particles to be sorted or aligned.

At the same time, he and his colleagues are exploring the use of other materials that could reach higher temperatures. They are also studying PLA to better understand why it becomes conductive when certain impurities are added to the polymer.

“If we can understand the mechanism that is related to the electrical conductivity of PLA, that would greatly enhance the capability of these devices, but it is going to be a lot harder to solve than some other engineering problems,” he adds.

“In Japanese culture, it’s often said that beauty lies in simplicity. This sentiment is echoed by the work of Cañada and Velasquez-Garcia. Their proposed monolithically 3D-printed microfluidic systems embody simplicity and beauty, offering a wide array of potential derivations and applications that we foresee in the future,” says Norihisa Miki, a professor of mechanical engineering at Keio University in Tokyo, who was not involved with this work.

“Being able to directly print microfluidic chips with fluidic channels and electrical features at the same time opens up very exiting applications when processing biological samples, such as to amplify biomarkers or to actuate and mix liquids. Also, due to the fact that PLA degrades over time, one can even think of implantable applications where the chips dissolve and resorb over time,” adds Niclas Roxhed, an associate professor at Sweden’s KTH Royal Institute of Technology, who was not involved with this study.

This research was funded, in part, by the Empiriko Corporation and a fellowship from La Caixa Foundation.

Mobility walkers can be expensive. Build your own personalized, strength-tested version for less.

The post Walk This Way: DIY Mobility Walker appeared first on Make: DIY Projects and Ideas for Makers.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

MIT researchers have used 3D printing to produce self-heating microfluidic devices, demonstrating a technique which could someday be used to rapidly create cheap, yet accurate, tools to detect a host of diseases.

Microfluidics, miniaturized machines that manipulate fluids and facilitate chemical reactions, can be used to detect disease in tiny samples of blood or fluids. At-home test kits for Covid-19, for example, incorporate a simple type of microfluidic.

But many microfluidic applications require chemical reactions that must be performed at specific temperatures. These more complex microfluidic devices, which are typically manufactured in a clean room, are outfitted with heating elements made from gold or platinum using a complicated and expensive fabrication process that is difficult to scale up.

Instead, the MIT team used multimaterial 3D printing to create self-heating microfluidic devices with built-in heating elements, through a single, inexpensive manufacturing process. They generated devices that can heat fluid to a specific temperature as it flows through microscopic channels inside the tiny machine.

Their technique is customizable, so an engineer could create a microfluidic that heats fluid to a certain temperature or given heating profile within a specific area of the device. The low-cost fabrication process requires about $2 of materials to generate a ready-to-use microfluidic.

The process could be especially useful in creating self-heating microfluidics for remote regions of developing countries where clinicians may not have access to the expensive lab equipment required for many diagnostic procedures.

“Clean rooms in particular, where you would usually make these devices, are incredibly expensive to build and to run. But we can make very capable self-heating microfluidic devices using additive manufacturing, and they can be made a lot faster and cheaper than with these traditional methods. This is really a way to democratize this technology,” says Luis Fernando Velásquez-García, a principal scientist in MIT’s Microsystems Technology Laboratories (MTL) and senior author of a paper describing the fabrication technique.

He is joined on the paper by lead author Jorge Cañada Pérez-Sala, an electrical engineering and computer science graduate student. The research will be presented at the PowerMEMS Conference this month.

An insulator becomes conductive

This new fabrication process utilizes a technique called multimaterial extrusion 3D printing, in which several materials can be squirted through the printer’s many nozzles to build a device layer by layer. The process is monolithic, which means the entire device can be produced in one step on the 3D printer, without the need for any post-assembly.

To create self-heating microfluidics, the researchers used two materials — a biodegradable polymer known as polylactic acid (PLA) that is commonly used in 3D printing, and a modified version of PLA.

The modified PLA has mixed copper nanoparticles into the polymer, which converts this insulating material into an electrical conductor, Velásquez-García explains. When electrical current is fed into a resistor composed of this copper-doped PLA, energy is dissipated as heat.

“It is amazing when you think about it because the PLA material is a dielectric, but when you put in these nanoparticle impurities, it completely changes the physical properties. This is something we don’t fully understand yet, but it happens and it is repeatable,” he says.

Using a multimaterial 3D printer, the researchers fabricate a heating resistor from the copper-doped PLA and then print the microfluidic device, with microscopic channels through which fluid can flow, directly on top in one printing step. Because the components are made from the same base material, they have similar printing temperatures and are compatible.

Heat dissipated from the resistor will warm fluid flowing through the channels in the microfluidic.

In addition to the resistor and microfluidic, they use the printer to add a thin, continuous layer of PLA that is sandwiched between them. It is especially challenging to manufacture this layer because it must be thin enough so heat can transfer from the resistor to the microfluidic, but not so thin that fluid could leak into the resistor.

The resulting machine is about the size of a U.S. quarter and can be produced in a matter of minutes. Channels about 500 micrometers wide and 400 micrometers tall are threaded through the microfluidic to carry fluid and facilitate chemical reactions.

Importantly, the PLA material is translucent, so fluid in the device remains visible. Many processes rely on visualization or the use of light to infer what is happening during chemical reactions, Velásquez-García explains.

Customizable chemical reactors

The researchers used this one-step manufacturing process to generate a prototype that could heat fluid by 4 degrees Celsius as it flowed between the input and the output. This customizable technique could enable them to make devices which would heat fluids in certain patterns or along specific gradients.

“You can use these two materials to create chemical reactors that do exactly what you want. We can set up a particular heating profile while still having all the capabilities of the microfluidic,” he says.

However, one limitation comes from the fact that PLA can only be heated to about 50 degrees Celsius before it starts to degrade. Many chemical reactions, such as those used for polymerase chain reaction (PCR) tests, require temperatures of 90 degrees or higher. And to precisely control the temperature of the device, researchers would need to integrate a third material that enables temperature sensing.

In addition to tackling these limitations in future work, Velásquez-García wants to print magnets directly into the microfluidic device. These magnets could enable chemical reactions that require particles to be sorted or aligned.

At the same time, he and his colleagues are exploring the use of other materials that could reach higher temperatures. They are also studying PLA to better understand why it becomes conductive when certain impurities are added to the polymer.

“If we can understand the mechanism that is related to the electrical conductivity of PLA, that would greatly enhance the capability of these devices, but it is going to be a lot harder to solve than some other engineering problems,” he adds.

“In Japanese culture, it’s often said that beauty lies in simplicity. This sentiment is echoed by the work of Cañada and Velasquez-Garcia. Their proposed monolithically 3D-printed microfluidic systems embody simplicity and beauty, offering a wide array of potential derivations and applications that we foresee in the future,” says Norihisa Miki, a professor of mechanical engineering at Keio University in Tokyo, who was not involved with this work.

“Being able to directly print microfluidic chips with fluidic channels and electrical features at the same time opens up very exiting applications when processing biological samples, such as to amplify biomarkers or to actuate and mix liquids. Also, due to the fact that PLA degrades over time, one can even think of implantable applications where the chips dissolve and resorb over time,” adds Niclas Roxhed, an associate professor at Sweden’s KTH Royal Institute of Technology, who was not involved with this study.

This research was funded, in part, by the Empiriko Corporation and a fellowship from La Caixa Foundation.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

MIT researchers have used 3D printing to produce self-heating microfluidic devices, demonstrating a technique which could someday be used to rapidly create cheap, yet accurate, tools to detect a host of diseases.

Microfluidics, miniaturized machines that manipulate fluids and facilitate chemical reactions, can be used to detect disease in tiny samples of blood or fluids. At-home test kits for Covid-19, for example, incorporate a simple type of microfluidic.

But many microfluidic applications require chemical reactions that must be performed at specific temperatures. These more complex microfluidic devices, which are typically manufactured in a clean room, are outfitted with heating elements made from gold or platinum using a complicated and expensive fabrication process that is difficult to scale up.

Instead, the MIT team used multimaterial 3D printing to create self-heating microfluidic devices with built-in heating elements, through a single, inexpensive manufacturing process. They generated devices that can heat fluid to a specific temperature as it flows through microscopic channels inside the tiny machine.

Their technique is customizable, so an engineer could create a microfluidic that heats fluid to a certain temperature or given heating profile within a specific area of the device. The low-cost fabrication process requires about $2 of materials to generate a ready-to-use microfluidic.

The process could be especially useful in creating self-heating microfluidics for remote regions of developing countries where clinicians may not have access to the expensive lab equipment required for many diagnostic procedures.

“Clean rooms in particular, where you would usually make these devices, are incredibly expensive to build and to run. But we can make very capable self-heating microfluidic devices using additive manufacturing, and they can be made a lot faster and cheaper than with these traditional methods. This is really a way to democratize this technology,” says Luis Fernando Velásquez-García, a principal scientist in MIT’s Microsystems Technology Laboratories (MTL) and senior author of a paper describing the fabrication technique.

He is joined on the paper by lead author Jorge Cañada Pérez-Sala, an electrical engineering and computer science graduate student. The research will be presented at the PowerMEMS Conference this month.

An insulator becomes conductive

This new fabrication process utilizes a technique called multimaterial extrusion 3D printing, in which several materials can be squirted through the printer’s many nozzles to build a device layer by layer. The process is monolithic, which means the entire device can be produced in one step on the 3D printer, without the need for any post-assembly.

To create self-heating microfluidics, the researchers used two materials — a biodegradable polymer known as polylactic acid (PLA) that is commonly used in 3D printing, and a modified version of PLA.

The modified PLA has mixed copper nanoparticles into the polymer, which converts this insulating material into an electrical conductor, Velásquez-García explains. When electrical current is fed into a resistor composed of this copper-doped PLA, energy is dissipated as heat.

“It is amazing when you think about it because the PLA material is a dielectric, but when you put in these nanoparticle impurities, it completely changes the physical properties. This is something we don’t fully understand yet, but it happens and it is repeatable,” he says.

Using a multimaterial 3D printer, the researchers fabricate a heating resistor from the copper-doped PLA and then print the microfluidic device, with microscopic channels through which fluid can flow, directly on top in one printing step. Because the components are made from the same base material, they have similar printing temperatures and are compatible.

Heat dissipated from the resistor will warm fluid flowing through the channels in the microfluidic.

In addition to the resistor and microfluidic, they use the printer to add a thin, continuous layer of PLA that is sandwiched between them. It is especially challenging to manufacture this layer because it must be thin enough so heat can transfer from the resistor to the microfluidic, but not so thin that fluid could leak into the resistor.

The resulting machine is about the size of a U.S. quarter and can be produced in a matter of minutes. Channels about 500 micrometers wide and 400 micrometers tall are threaded through the microfluidic to carry fluid and facilitate chemical reactions.

Importantly, the PLA material is translucent, so fluid in the device remains visible. Many processes rely on visualization or the use of light to infer what is happening during chemical reactions, Velásquez-García explains.

Customizable chemical reactors

The researchers used this one-step manufacturing process to generate a prototype that could heat fluid by 4 degrees Celsius as it flowed between the input and the output. This customizable technique could enable them to make devices which would heat fluids in certain patterns or along specific gradients.

“You can use these two materials to create chemical reactors that do exactly what you want. We can set up a particular heating profile while still having all the capabilities of the microfluidic,” he says.

However, one limitation comes from the fact that PLA can only be heated to about 50 degrees Celsius before it starts to degrade. Many chemical reactions, such as those used for polymerase chain reaction (PCR) tests, require temperatures of 90 degrees or higher. And to precisely control the temperature of the device, researchers would need to integrate a third material that enables temperature sensing.

In addition to tackling these limitations in future work, Velásquez-García wants to print magnets directly into the microfluidic device. These magnets could enable chemical reactions that require particles to be sorted or aligned.

At the same time, he and his colleagues are exploring the use of other materials that could reach higher temperatures. They are also studying PLA to better understand why it becomes conductive when certain impurities are added to the polymer.

“If we can understand the mechanism that is related to the electrical conductivity of PLA, that would greatly enhance the capability of these devices, but it is going to be a lot harder to solve than some other engineering problems,” he adds.

“In Japanese culture, it’s often said that beauty lies in simplicity. This sentiment is echoed by the work of Cañada and Velasquez-Garcia. Their proposed monolithically 3D-printed microfluidic systems embody simplicity and beauty, offering a wide array of potential derivations and applications that we foresee in the future,” says Norihisa Miki, a professor of mechanical engineering at Keio University in Tokyo, who was not involved with this work.

“Being able to directly print microfluidic chips with fluidic channels and electrical features at the same time opens up very exiting applications when processing biological samples, such as to amplify biomarkers or to actuate and mix liquids. Also, due to the fact that PLA degrades over time, one can even think of implantable applications where the chips dissolve and resorb over time,” adds Niclas Roxhed, an associate professor at Sweden’s KTH Royal Institute of Technology, who was not involved with this study.

This research was funded, in part, by the Empiriko Corporation and a fellowship from La Caixa Foundation.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

MIT researchers have used 3D printing to produce self-heating microfluidic devices, demonstrating a technique which could someday be used to rapidly create cheap, yet accurate, tools to detect a host of diseases.

Microfluidics, miniaturized machines that manipulate fluids and facilitate chemical reactions, can be used to detect disease in tiny samples of blood or fluids. At-home test kits for Covid-19, for example, incorporate a simple type of microfluidic.

But many microfluidic applications require chemical reactions that must be performed at specific temperatures. These more complex microfluidic devices, which are typically manufactured in a clean room, are outfitted with heating elements made from gold or platinum using a complicated and expensive fabrication process that is difficult to scale up.

Instead, the MIT team used multimaterial 3D printing to create self-heating microfluidic devices with built-in heating elements, through a single, inexpensive manufacturing process. They generated devices that can heat fluid to a specific temperature as it flows through microscopic channels inside the tiny machine.

Their technique is customizable, so an engineer could create a microfluidic that heats fluid to a certain temperature or given heating profile within a specific area of the device. The low-cost fabrication process requires about $2 of materials to generate a ready-to-use microfluidic.

The process could be especially useful in creating self-heating microfluidics for remote regions of developing countries where clinicians may not have access to the expensive lab equipment required for many diagnostic procedures.

“Clean rooms in particular, where you would usually make these devices, are incredibly expensive to build and to run. But we can make very capable self-heating microfluidic devices using additive manufacturing, and they can be made a lot faster and cheaper than with these traditional methods. This is really a way to democratize this technology,” says Luis Fernando Velásquez-García, a principal scientist in MIT’s Microsystems Technology Laboratories (MTL) and senior author of a paper describing the fabrication technique.

He is joined on the paper by lead author Jorge Cañada Pérez-Sala, an electrical engineering and computer science graduate student. The research will be presented at the PowerMEMS Conference this month.

An insulator becomes conductive

This new fabrication process utilizes a technique called multimaterial extrusion 3D printing, in which several materials can be squirted through the printer’s many nozzles to build a device layer by layer. The process is monolithic, which means the entire device can be produced in one step on the 3D printer, without the need for any post-assembly.

To create self-heating microfluidics, the researchers used two materials — a biodegradable polymer known as polylactic acid (PLA) that is commonly used in 3D printing, and a modified version of PLA.

The modified PLA has mixed copper nanoparticles into the polymer, which converts this insulating material into an electrical conductor, Velásquez-García explains. When electrical current is fed into a resistor composed of this copper-doped PLA, energy is dissipated as heat.

“It is amazing when you think about it because the PLA material is a dielectric, but when you put in these nanoparticle impurities, it completely changes the physical properties. This is something we don’t fully understand yet, but it happens and it is repeatable,” he says.

Using a multimaterial 3D printer, the researchers fabricate a heating resistor from the copper-doped PLA and then print the microfluidic device, with microscopic channels through which fluid can flow, directly on top in one printing step. Because the components are made from the same base material, they have similar printing temperatures and are compatible.

Heat dissipated from the resistor will warm fluid flowing through the channels in the microfluidic.

In addition to the resistor and microfluidic, they use the printer to add a thin, continuous layer of PLA that is sandwiched between them. It is especially challenging to manufacture this layer because it must be thin enough so heat can transfer from the resistor to the microfluidic, but not so thin that fluid could leak into the resistor.

The resulting machine is about the size of a U.S. quarter and can be produced in a matter of minutes. Channels about 500 micrometers wide and 400 micrometers tall are threaded through the microfluidic to carry fluid and facilitate chemical reactions.

Importantly, the PLA material is translucent, so fluid in the device remains visible. Many processes rely on visualization or the use of light to infer what is happening during chemical reactions, Velásquez-García explains.

Customizable chemical reactors

The researchers used this one-step manufacturing process to generate a prototype that could heat fluid by 4 degrees Celsius as it flowed between the input and the output. This customizable technique could enable them to make devices which would heat fluids in certain patterns or along specific gradients.

“You can use these two materials to create chemical reactors that do exactly what you want. We can set up a particular heating profile while still having all the capabilities of the microfluidic,” he says.

However, one limitation comes from the fact that PLA can only be heated to about 50 degrees Celsius before it starts to degrade. Many chemical reactions, such as those used for polymerase chain reaction (PCR) tests, require temperatures of 90 degrees or higher. And to precisely control the temperature of the device, researchers would need to integrate a third material that enables temperature sensing.

In addition to tackling these limitations in future work, Velásquez-García wants to print magnets directly into the microfluidic device. These magnets could enable chemical reactions that require particles to be sorted or aligned.

At the same time, he and his colleagues are exploring the use of other materials that could reach higher temperatures. They are also studying PLA to better understand why it becomes conductive when certain impurities are added to the polymer.

“If we can understand the mechanism that is related to the electrical conductivity of PLA, that would greatly enhance the capability of these devices, but it is going to be a lot harder to solve than some other engineering problems,” he adds.

“In Japanese culture, it’s often said that beauty lies in simplicity. This sentiment is echoed by the work of Cañada and Velasquez-Garcia. Their proposed monolithically 3D-printed microfluidic systems embody simplicity and beauty, offering a wide array of potential derivations and applications that we foresee in the future,” says Norihisa Miki, a professor of mechanical engineering at Keio University in Tokyo, who was not involved with this work.

“Being able to directly print microfluidic chips with fluidic channels and electrical features at the same time opens up very exiting applications when processing biological samples, such as to amplify biomarkers or to actuate and mix liquids. Also, due to the fact that PLA degrades over time, one can even think of implantable applications where the chips dissolve and resorb over time,” adds Niclas Roxhed, an associate professor at Sweden’s KTH Royal Institute of Technology, who was not involved with this study.

This research was funded, in part, by the Empiriko Corporation and a fellowship from La Caixa Foundation.

Journalis, author and Boing Boing contributor Glenn Fleishman has launched a Kickstarter to fund an upcoming book, How Comics Were Made: A Visual History from the Drawing Board to the Printed Page. The book is scheduled to be released October, 2024. — Read the rest

The post Upcoming book: How Comics Were Made: A Visual History from the Drawing Board to the Printed Page appeared first on Boing Boing.

The constant hunt for more efficient and useful ways to use these 3d printers keeps turning up interesting results. For quite some time, people have speculated on various methods of arranging our 3d print layers for better adhesion and stronger results. Stefan from CNC Kitchen tackles the subject to see if there’s any validity to […]

The post Staggering Layers For Added Strength In Your 3D Prints appeared first on Make: DIY Projects and Ideas for Makers.

Kind of. Text-to-3D-model generators are here, but not optimized for printing

The post Can I Use AI To Make Models For 3D Printing? appeared first on Make: DIY Projects and Ideas for Makers.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

MIT researchers have used 3D printing to produce self-heating microfluidic devices, demonstrating a technique which could someday be used to rapidly create cheap, yet accurate, tools to detect a host of diseases.

Microfluidics, miniaturized machines that manipulate fluids and facilitate chemical reactions, can be used to detect disease in tiny samples of blood or fluids. At-home test kits for Covid-19, for example, incorporate a simple type of microfluidic.

But many microfluidic applications require chemical reactions that must be performed at specific temperatures. These more complex microfluidic devices, which are typically manufactured in a clean room, are outfitted with heating elements made from gold or platinum using a complicated and expensive fabrication process that is difficult to scale up.

Instead, the MIT team used multimaterial 3D printing to create self-heating microfluidic devices with built-in heating elements, through a single, inexpensive manufacturing process. They generated devices that can heat fluid to a specific temperature as it flows through microscopic channels inside the tiny machine.

Their technique is customizable, so an engineer could create a microfluidic that heats fluid to a certain temperature or given heating profile within a specific area of the device. The low-cost fabrication process requires about $2 of materials to generate a ready-to-use microfluidic.

The process could be especially useful in creating self-heating microfluidics for remote regions of developing countries where clinicians may not have access to the expensive lab equipment required for many diagnostic procedures.

“Clean rooms in particular, where you would usually make these devices, are incredibly expensive to build and to run. But we can make very capable self-heating microfluidic devices using additive manufacturing, and they can be made a lot faster and cheaper than with these traditional methods. This is really a way to democratize this technology,” says Luis Fernando Velásquez-García, a principal scientist in MIT’s Microsystems Technology Laboratories (MTL) and senior author of a paper describing the fabrication technique.

He is joined on the paper by lead author Jorge Cañada Pérez-Sala, an electrical engineering and computer science graduate student. The research will be presented at the PowerMEMS Conference this month.

An insulator becomes conductive

This new fabrication process utilizes a technique called multimaterial extrusion 3D printing, in which several materials can be squirted through the printer’s many nozzles to build a device layer by layer. The process is monolithic, which means the entire device can be produced in one step on the 3D printer, without the need for any post-assembly.

To create self-heating microfluidics, the researchers used two materials — a biodegradable polymer known as polylactic acid (PLA) that is commonly used in 3D printing, and a modified version of PLA.

The modified PLA has mixed copper nanoparticles into the polymer, which converts this insulating material into an electrical conductor, Velásquez-García explains. When electrical current is fed into a resistor composed of this copper-doped PLA, energy is dissipated as heat.

“It is amazing when you think about it because the PLA material is a dielectric, but when you put in these nanoparticle impurities, it completely changes the physical properties. This is something we don’t fully understand yet, but it happens and it is repeatable,” he says.

Using a multimaterial 3D printer, the researchers fabricate a heating resistor from the copper-doped PLA and then print the microfluidic device, with microscopic channels through which fluid can flow, directly on top in one printing step. Because the components are made from the same base material, they have similar printing temperatures and are compatible.

Heat dissipated from the resistor will warm fluid flowing through the channels in the microfluidic.

In addition to the resistor and microfluidic, they use the printer to add a thin, continuous layer of PLA that is sandwiched between them. It is especially challenging to manufacture this layer because it must be thin enough so heat can transfer from the resistor to the microfluidic, but not so thin that fluid could leak into the resistor.

The resulting machine is about the size of a U.S. quarter and can be produced in a matter of minutes. Channels about 500 micrometers wide and 400 micrometers tall are threaded through the microfluidic to carry fluid and facilitate chemical reactions.

Importantly, the PLA material is translucent, so fluid in the device remains visible. Many processes rely on visualization or the use of light to infer what is happening during chemical reactions, Velásquez-García explains.

Customizable chemical reactors

The researchers used this one-step manufacturing process to generate a prototype that could heat fluid by 4 degrees Celsius as it flowed between the input and the output. This customizable technique could enable them to make devices which would heat fluids in certain patterns or along specific gradients.

“You can use these two materials to create chemical reactors that do exactly what you want. We can set up a particular heating profile while still having all the capabilities of the microfluidic,” he says.

However, one limitation comes from the fact that PLA can only be heated to about 50 degrees Celsius before it starts to degrade. Many chemical reactions, such as those used for polymerase chain reaction (PCR) tests, require temperatures of 90 degrees or higher. And to precisely control the temperature of the device, researchers would need to integrate a third material that enables temperature sensing.

In addition to tackling these limitations in future work, Velásquez-García wants to print magnets directly into the microfluidic device. These magnets could enable chemical reactions that require particles to be sorted or aligned.

At the same time, he and his colleagues are exploring the use of other materials that could reach higher temperatures. They are also studying PLA to better understand why it becomes conductive when certain impurities are added to the polymer.

“If we can understand the mechanism that is related to the electrical conductivity of PLA, that would greatly enhance the capability of these devices, but it is going to be a lot harder to solve than some other engineering problems,” he adds.

“In Japanese culture, it’s often said that beauty lies in simplicity. This sentiment is echoed by the work of Cañada and Velasquez-Garcia. Their proposed monolithically 3D-printed microfluidic systems embody simplicity and beauty, offering a wide array of potential derivations and applications that we foresee in the future,” says Norihisa Miki, a professor of mechanical engineering at Keio University in Tokyo, who was not involved with this work.

“Being able to directly print microfluidic chips with fluidic channels and electrical features at the same time opens up very exiting applications when processing biological samples, such as to amplify biomarkers or to actuate and mix liquids. Also, due to the fact that PLA degrades over time, one can even think of implantable applications where the chips dissolve and resorb over time,” adds Niclas Roxhed, an associate professor at Sweden’s KTH Royal Institute of Technology, who was not involved with this study.

This research was funded, in part, by the Empiriko Corporation and a fellowship from La Caixa Foundation.

Kind of. Text-to-3D-model generators are here, but not optimized for printing

The post Can I Use AI To Make Models For 3D Printing? appeared first on Make: DIY Projects and Ideas for Makers.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

MIT researchers have used 3D printing to produce self-heating microfluidic devices, demonstrating a technique which could someday be used to rapidly create cheap, yet accurate, tools to detect a host of diseases.

Microfluidics, miniaturized machines that manipulate fluids and facilitate chemical reactions, can be used to detect disease in tiny samples of blood or fluids. At-home test kits for Covid-19, for example, incorporate a simple type of microfluidic.

But many microfluidic applications require chemical reactions that must be performed at specific temperatures. These more complex microfluidic devices, which are typically manufactured in a clean room, are outfitted with heating elements made from gold or platinum using a complicated and expensive fabrication process that is difficult to scale up.

Instead, the MIT team used multimaterial 3D printing to create self-heating microfluidic devices with built-in heating elements, through a single, inexpensive manufacturing process. They generated devices that can heat fluid to a specific temperature as it flows through microscopic channels inside the tiny machine.

Their technique is customizable, so an engineer could create a microfluidic that heats fluid to a certain temperature or given heating profile within a specific area of the device. The low-cost fabrication process requires about $2 of materials to generate a ready-to-use microfluidic.

The process could be especially useful in creating self-heating microfluidics for remote regions of developing countries where clinicians may not have access to the expensive lab equipment required for many diagnostic procedures.

“Clean rooms in particular, where you would usually make these devices, are incredibly expensive to build and to run. But we can make very capable self-heating microfluidic devices using additive manufacturing, and they can be made a lot faster and cheaper than with these traditional methods. This is really a way to democratize this technology,” says Luis Fernando Velásquez-García, a principal scientist in MIT’s Microsystems Technology Laboratories (MTL) and senior author of a paper describing the fabrication technique.

He is joined on the paper by lead author Jorge Cañada Pérez-Sala, an electrical engineering and computer science graduate student. The research will be presented at the PowerMEMS Conference this month.

An insulator becomes conductive

This new fabrication process utilizes a technique called multimaterial extrusion 3D printing, in which several materials can be squirted through the printer’s many nozzles to build a device layer by layer. The process is monolithic, which means the entire device can be produced in one step on the 3D printer, without the need for any post-assembly.

To create self-heating microfluidics, the researchers used two materials — a biodegradable polymer known as polylactic acid (PLA) that is commonly used in 3D printing, and a modified version of PLA.

The modified PLA has mixed copper nanoparticles into the polymer, which converts this insulating material into an electrical conductor, Velásquez-García explains. When electrical current is fed into a resistor composed of this copper-doped PLA, energy is dissipated as heat.

“It is amazing when you think about it because the PLA material is a dielectric, but when you put in these nanoparticle impurities, it completely changes the physical properties. This is something we don’t fully understand yet, but it happens and it is repeatable,” he says.

Using a multimaterial 3D printer, the researchers fabricate a heating resistor from the copper-doped PLA and then print the microfluidic device, with microscopic channels through which fluid can flow, directly on top in one printing step. Because the components are made from the same base material, they have similar printing temperatures and are compatible.

Heat dissipated from the resistor will warm fluid flowing through the channels in the microfluidic.

In addition to the resistor and microfluidic, they use the printer to add a thin, continuous layer of PLA that is sandwiched between them. It is especially challenging to manufacture this layer because it must be thin enough so heat can transfer from the resistor to the microfluidic, but not so thin that fluid could leak into the resistor.

The resulting machine is about the size of a U.S. quarter and can be produced in a matter of minutes. Channels about 500 micrometers wide and 400 micrometers tall are threaded through the microfluidic to carry fluid and facilitate chemical reactions.

Importantly, the PLA material is translucent, so fluid in the device remains visible. Many processes rely on visualization or the use of light to infer what is happening during chemical reactions, Velásquez-García explains.

Customizable chemical reactors

The researchers used this one-step manufacturing process to generate a prototype that could heat fluid by 4 degrees Celsius as it flowed between the input and the output. This customizable technique could enable them to make devices which would heat fluids in certain patterns or along specific gradients.

“You can use these two materials to create chemical reactors that do exactly what you want. We can set up a particular heating profile while still having all the capabilities of the microfluidic,” he says.

However, one limitation comes from the fact that PLA can only be heated to about 50 degrees Celsius before it starts to degrade. Many chemical reactions, such as those used for polymerase chain reaction (PCR) tests, require temperatures of 90 degrees or higher. And to precisely control the temperature of the device, researchers would need to integrate a third material that enables temperature sensing.

In addition to tackling these limitations in future work, Velásquez-García wants to print magnets directly into the microfluidic device. These magnets could enable chemical reactions that require particles to be sorted or aligned.

At the same time, he and his colleagues are exploring the use of other materials that could reach higher temperatures. They are also studying PLA to better understand why it becomes conductive when certain impurities are added to the polymer.

“If we can understand the mechanism that is related to the electrical conductivity of PLA, that would greatly enhance the capability of these devices, but it is going to be a lot harder to solve than some other engineering problems,” he adds.

“In Japanese culture, it’s often said that beauty lies in simplicity. This sentiment is echoed by the work of Cañada and Velasquez-Garcia. Their proposed monolithically 3D-printed microfluidic systems embody simplicity and beauty, offering a wide array of potential derivations and applications that we foresee in the future,” says Norihisa Miki, a professor of mechanical engineering at Keio University in Tokyo, who was not involved with this work.

“Being able to directly print microfluidic chips with fluidic channels and electrical features at the same time opens up very exiting applications when processing biological samples, such as to amplify biomarkers or to actuate and mix liquids. Also, due to the fact that PLA degrades over time, one can even think of implantable applications where the chips dissolve and resorb over time,” adds Niclas Roxhed, an associate professor at Sweden’s KTH Royal Institute of Technology, who was not involved with this study.

This research was funded, in part, by the Empiriko Corporation and a fellowship from La Caixa Foundation.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities. 

MIT researchers have used 3D printing to produce self-heating microfluidic devices, demonstrating a technique which could someday be used to rapidly create cheap, yet accurate, tools to detect a host of diseases.

Microfluidics, miniaturized machines that manipulate fluids and facilitate chemical reactions, can be used to detect disease in tiny samples of blood or fluids. At-home test kits for Covid-19, for example, incorporate a simple type of microfluidic.

But many microfluidic applications require chemical reactions that must be performed at specific temperatures. These more complex microfluidic devices, which are typically manufactured in a clean room, are outfitted with heating elements made from gold or platinum using a complicated and expensive fabrication process that is difficult to scale up.

Instead, the MIT team used multimaterial 3D printing to create self-heating microfluidic devices with built-in heating elements, through a single, inexpensive manufacturing process. They generated devices that can heat fluid to a specific temperature as it flows through microscopic channels inside the tiny machine.

Their technique is customizable, so an engineer could create a microfluidic that heats fluid to a certain temperature or given heating profile within a specific area of the device. The low-cost fabrication process requires about $2 of materials to generate a ready-to-use microfluidic.

The process could be especially useful in creating self-heating microfluidics for remote regions of developing countries where clinicians may not have access to the expensive lab equipment required for many diagnostic procedures.

“Clean rooms in particular, where you would usually make these devices, are incredibly expensive to build and to run. But we can make very capable self-heating microfluidic devices using additive manufacturing, and they can be made a lot faster and cheaper than with these traditional methods. This is really a way to democratize this technology,” says Luis Fernando Velásquez-García, a principal scientist in MIT’s Microsystems Technology Laboratories (MTL) and senior author of a paper describing the fabrication technique.

He is joined on the paper by lead author Jorge Cañada Pérez-Sala, an electrical engineering and computer science graduate student. The research will be presented at the PowerMEMS Conference this month.

An insulator becomes conductive

This new fabrication process utilizes a technique called multimaterial extrusion 3D printing, in which several materials can be squirted through the printer’s many nozzles to build a device layer by layer. The process is monolithic, which means the entire device can be produced in one step on the 3D printer, without the need for any post-assembly.

To create self-heating microfluidics, the researchers used two materials — a biodegradable polymer known as polylactic acid (PLA) that is commonly used in 3D printing, and a modified version of PLA.

The modified PLA has mixed copper nanoparticles into the polymer, which converts this insulating material into an electrical conductor, Velásquez-García explains. When electrical current is fed into a resistor composed of this copper-doped PLA, energy is dissipated as heat.

“It is amazing when you think about it because the PLA material is a dielectric, but when you put in these nanoparticle impurities, it completely changes the physical properties. This is something we don’t fully understand yet, but it happens and it is repeatable,” he says.

Using a multimaterial 3D printer, the researchers fabricate a heating resistor from the copper-doped PLA and then print the microfluidic device, with microscopic channels through which fluid can flow, directly on top in one printing step. Because the components are made from the same base material, they have similar printing temperatures and are compatible.

Heat dissipated from the resistor will warm fluid flowing through the channels in the microfluidic.

In addition to the resistor and microfluidic, they use the printer to add a thin, continuous layer of PLA that is sandwiched between them. It is especially challenging to manufacture this layer because it must be thin enough so heat can transfer from the resistor to the microfluidic, but not so thin that fluid could leak into the resistor.

The resulting machine is about the size of a U.S. quarter and can be produced in a matter of minutes. Channels about 500 micrometers wide and 400 micrometers tall are threaded through the microfluidic to carry fluid and facilitate chemical reactions.

Importantly, the PLA material is translucent, so fluid in the device remains visible. Many processes rely on visualization or the use of light to infer what is happening during chemical reactions, Velásquez-García explains.

Customizable chemical reactors

The researchers used this one-step manufacturing process to generate a prototype that could heat fluid by 4 degrees Celsius as it flowed between the input and the output. This customizable technique could enable them to make devices which would heat fluids in certain patterns or along specific gradients.

“You can use these two materials to create chemical reactors that do exactly what you want. We can set up a particular heating profile while still having all the capabilities of the microfluidic,” he says.

However, one limitation comes from the fact that PLA can only be heated to about 50 degrees Celsius before it starts to degrade. Many chemical reactions, such as those used for polymerase chain reaction (PCR) tests, require temperatures of 90 degrees or higher. And to precisely control the temperature of the device, researchers would need to integrate a third material that enables temperature sensing.

In addition to tackling these limitations in future work, Velásquez-García wants to print magnets directly into the microfluidic device. These magnets could enable chemical reactions that require particles to be sorted or aligned.

At the same time, he and his colleagues are exploring the use of other materials that could reach higher temperatures. They are also studying PLA to better understand why it becomes conductive when certain impurities are added to the polymer.

“If we can understand the mechanism that is related to the electrical conductivity of PLA, that would greatly enhance the capability of these devices, but it is going to be a lot harder to solve than some other engineering problems,” he adds.

“In Japanese culture, it’s often said that beauty lies in simplicity. This sentiment is echoed by the work of Cañada and Velasquez-Garcia. Their proposed monolithically 3D-printed microfluidic systems embody simplicity and beauty, offering a wide array of potential derivations and applications that we foresee in the future,” says Norihisa Miki, a professor of mechanical engineering at Keio University in Tokyo, who was not involved with this work.

“Being able to directly print microfluidic chips with fluidic channels and electrical features at the same time opens up very exiting applications when processing biological samples, such as to amplify biomarkers or to actuate and mix liquids. Also, due to the fact that PLA degrades over time, one can even think of implantable applications where the chips dissolve and resorb over time,” adds Niclas Roxhed, an associate professor at Sweden’s KTH Royal Institute of Technology, who was not involved with this study.

This research was funded, in part, by the Empiriko Corporation and a fellowship from La Caixa Foundation.

An intricate, honeycomb-like structure of struts and beams could withstand a supersonic impact better than a solid slab of the same material. What’s more, the specific structure matters, with some being more resilient to impacts than others.

That’s what MIT engineers are finding in experiments with microscopic metamaterials — materials that are intentionally printed, assembled, or otherwise engineered with microscopic architectures that give the overall material exceptional properties.

In a study appearing today in the Proceedings of the National Academy of Sciences, the engineers report on a new way to quickly test an array of metamaterial architectures and their resilience to supersonic impacts.

In their experiments, the team suspended tiny printed metamaterial lattices between microscopic support structures, then fired even tinier particles at the materials, at supersonic speeds. With high-speed cameras, the team then captured images of each impact and its aftermath, with nanosecond precision.

Their work has identified a few metamaterial architectures that are more resilient to supersonic impacts compared to their entirely solid, nonarchitected counterparts. The researchers say the results they observed at the microscopic level can be extended to comparable macroscale impacts, to predict how new material structures across length scales will withstand impacts in the real world.

“What we’re learning is, the microstructure of your material matters, even with high-rate deformation,” says study author Carlos Portela, the Brit and Alex d’Arbeloff Career Development Professor in Mechanical Engineering at MIT. “We want to identify impact-resistant structures that can be made into coatings or panels for spacecraft, vehicles, helmets, and anything that needs to be lightweight and protected.”

Other authors on the study include first author and MIT graduate student Thomas Butruille, and Joshua Crone of DEVCOM Army Research Laboratory.

Pure impact

The team’s new high-velocity experiments build off their previous work, in which the engineers tested the resilience of an ultralight, carbon-based material. That material, which was thinner than the width of a human hair, was made from tiny struts and beams of carbon, which the team printed and placed on a glass slide. They then fired microparticles toward the material, at velocities exceeding the speed of sound.  

Those supersonic experiments revealed that the microstructured material withstood the high-velocity impacts, sometimes deflecting the microparticles and other times capturing them.

“But there were many questions we couldn’t answer because we were testing the materials on a substrate, which may have affected their behavior,” Portela says.

In their new study, the researchers developed a way to test freestanding metamaterials, to observe how the materials withstand impacts purely on their own, without a backing or supporting substrate.

In their current setup, the researchers suspend a metamaterial of interest between two microscopic pillars made from the same base material. Depending on the dimensions of the metamaterial being tested, the researchers calculate how far apart the pillars must be in order to support the material at either end while allowing the material to respond to any impacts, without any influence from the pillars themselves.

“This way, we ensure that we’re measuring the material property and not the structural property,” Portela says.

Once the team settled on the pillar support design, they moved on to test a variety of metamaterial architectures. For each architecture, the researchers first printed the supporting pillars on a small silicon chip, then continued printing the metamaterial as a suspended layer between the pillars.

“We can print and test hundreds of these structures on a single chip,” Portela says.

Punctures and cracks

The team printed suspended metamaterials that resembled intricate honeycomb-like cross-sections. Each material was printed with a specific three-dimensional microscopic architecture, such as a precise scaffold of repeating octets, or more faceted polygons. Each repeated unit measured as small as a red blood cell. The resulting metamaterials were thinner than the width of a human hair.

The researchers then tested each metamaterial’s impact resilience by firing glass microparticles toward the structures, at speeds of up to 900 meters per second (more than 2,000 miles per hour) — well within the supersonic range. They caught each impact on camera and studied the resulting images, frame by frame, to see how the projectiles penetrated each material. Next, they examined the materials under a microscope and compared each impact’s physical aftermath.

“In the architected materials, we saw this morphology of small cylindrical craters after impact,” Portela says. “But in solid materials, we saw a lot of radial cracks and bigger chunks of material that were gouged out.”

Overall, the team observed that the fired particles created small punctures in the latticed metamaterials, and the materials nevertheless stayed intact. In contrast, when the same particles were fired at the same speeds into solid, nonlatticed materials of equal mass, they created large cracks that quickly spread, causing the material to crumble. The microstructured materials, therefore, were more efficient in resisting supersonic impacts as well as protecting against multiple impact events. And in particular, materials that were printed with the repeating octets appeared to be the most hardy.

“At the same velocity, we see the octet architecture is harder to fracture, meaning that the metamaterial, per unit mass, can withstand impacts up to twice as much as the bulk material,” Portela says. “This tells us that there are some architectures that can make a material tougher which can offer better impact protection.”

Going forward, the team plans to use the new rapid testing and analysis method to identify new metamaterial designs, in hopes of tagging architectures that can be scaled up to stronger and lighter protective gear, garments, coatings, and paneling.

“What I’m most excited about is showing we can do a lot of these extreme experiments on a benchtop,” Portela says. “This will significantly accelerate the rate at which we can validate new, high-performing, resilient materials.”

This work was funded, in part, by DEVCOM ARL Army Research Office through the MIT Institute for Soldier Nanotechnologies (ISN), and carried out, in part, using ISN’s and MIT.nano’s facilities.