A small plastic object can be seen in front of the tip of a hypodermic needle. The object is made of clear, slightly purple-tinted plastic. It is roughly circular, with edges thicker than the center.

The Latest From RepRapMicron – Nail Gel, First Objects, And More

February 1, 2026 by Aaron Beckendorf 11 Comments

We’ve been following [Vik Olliver]’s progress on the μRepRap project with interest for some time now. The project’s goal is to build a 3D printer that can print feature sizes down to about 10 microns – the same feature size used in the Intel 4004 processor. At the recent Everything Open 2026 conference, [Vik] presented an overview of all the progress he’s made in the last year, including printer improvements, material woes, and the first multi-layer prints (presentation slides).

The motion stage has undergone some fundamental improvements recently. The original XY motion table was supported on four flexures which allowed movement in X and Y, but also introduced slight variations in Z – obviously a problem in a system that needs to be accurate down to the microns. The latest version now uses complementary flexures to maintain a constant Z height, and eliminates interference between the X and Y axes. The axis motion drivers were also redesigned with parallel-bar linear reducers inspired by a pantograph, increasing their usable range from two to eight millimeters.

Rather than extruding material, the μRepRap uses an electrochemically-etched needle point to deposit UV-curable gel on the build surface. [Vik] found that a bit of nitric acid in the needle etching solution gave the edges of the probe a bit of a rough texture which let it hold more resin. He started his test prints using normal 3D printer resin, but it turns out that dissolved oxygen inhibits curing – quite a problem for small, air-exposed droplets. Fortuitously, UV nail gel does cure in air, and the next set of tests were printed in nail gel, including the first layered prints (one of which can be seen above, on top of a hypodermic needle). The μRepRap can’t yet print large numbers of layers, but [Vik] did print some hinged parts that could be folded into shape.

There’s much more in the presentation than can be covered here, including some interesting thoughts about the possibility of 3D printing electrochemical memory cells in ionic gel. Near the end of the presentation, [Vik] listed some pieces of related work, including necroprinting and this homemade micro-manipulator.

RepRapMicron Promises Micro-fabrication For Desktops With New Prototype

August 22, 2025 by Donald Papp 15 Comments

3D printing has transformed how hobbyists fabricate things, but what additional doors would open if we could go even smaller? The µRepRap (RepRapMicron) project aims to bring fabrication at the micron and sub-micron scale to hobbyists the same way RepRap strove to make 3D printing accessible. New developments by [Vik Olliver] show a promising way forward, and also highlight the many challenges of going so small.

How exactly would a 3D printer do micro-fabrication? Not by squirting plastic from a nozzle, but by using a vanishingly tiny needle-like effector (which can be made at any workbench via electrochemical erosion) to pick up a miniscule amount of resin one dab a time, curing it with UV after depositing it like a brush deposits a dot of ink.

By doing so repeatedly and in a structured way, one can 3D print at a micro scale one “pixel” (or voxel, more accurately) at a time. You can see how small they’re talking in the image in the header above. It shows a RepRapMicron tip (left) next to a 24 gauge hypodermic needle (right) which is just over half a millimeter in diameter.

Moving precisely and accurately at such a small scale also requires something new, and that is where flexures come in. Where other 3D printers use stepper motors and rails and belts, RepRapMicron leverages work done by the OpenFlexure project to achieve high-precision mechanical positioning without the need for fancy materials or mechanisms. We’ve actually seen this part in action, when [Vik Olliver] amazed us by scribing a 2D micron-scale Jolly Wrencher 1.5 mm x 1.5 mm in size, also visible in the header image above.

Using a tiny needle to deposit dabs of UV resin provides the platform with a way to 3D print, but there are still plenty of unique problems to be solved. How does one observe such a small process, or the finished print? How does one handle such a tiny object, or free it from the build platform without damaging it? The RepRapMicron project has solutions lined up for each of these and more, so there’s a lot of discovery waiting to be done. Got ideas of your own? The project welcomes collaboration. If you’d like to watch the latest developments as they happen, keep an eye on the Github repository and the blog.

Up Close And Personal With A MEMS Microphone

December 20, 2023 by Dan Maloney 14 Comments

If you’ve ever wondered what lies beneath the barely visible hole in the can of a MEMS microphone, you’re in luck, because [Zach Tong] has a $10 pair of earbuds to sacrifice for the cause and an electron microscope.

For the uninitiated, MEMS stands for microelectromechanical systems, the tiny silicon machines that power some of the more miraculous functions of smartphones and other modern electronics. The most familiar MEMS device might be the accelerometer that gives your phone a sense of where it is in space; [Zach] has a deep dive into MEMS accelerometers that we covered a while back.

MEMS microphones seem a little bit easier to understand mechanically, since all they have to do is change vibrations in air into an electrical signal. The microphone that [Zach] tore down for this video is ridiculously small; the SMD device is only about 3 mm long, with the MEMS chip under the can a fraction of a millimeter on a side. After some overall views with the optical microscope, [Zach] opened the can and put the guts under his scanning electron microscope. The SEM shots are pretty amazing, revealing a dimpled silicon diaphragm over a second layer with holes etched right through it. The dimples on the diaphragm nest into the holes, forming an air-dielectric capacitor whose capacitance varies as sound waves vibrate the diaphragm.

The most visually interesting feature, though, might be the deep cavity lying behind the two upper surfaces. The cavity, which [Zach] says bears evidence of having been etched by the deep reactive ion etching method, has cool-looking corrugations in its walls. The enormity of the cavity relative to the thin layers covering it suggests it’s a resonating cavity for the sound waves.

Thanks to [Zach] for this in-depth look at a device that’s amazingly complex yet remarkably simple.

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Scanning electron micrograph of a microfabricated lens array

Getting A Fly’s-Eye View With Microfabricated Lens Arrays

September 7, 2021 by Dan Maloney 11 Comments

Atomic force microscopy, laser ablation, and etching with a witches brew of toxic chemicals: sounds like [Zachary Tong] has been playing in the lab again, and this time he found a way to fabricate arrays of microscopic lenses as a result.

Like many of the best projects, [Zach]’s journey into micro-fabrication started with a happy accident. It happened while he was working on metal-activated chemical etching (MACE), which uses a noble metal catalyst to selectively carve high-aspect-ratio features in silicon. After blasting at a silver-coated silicon wafer with a laser, he noticed the ablation pits were very smooth and uniform after etching. This led him to several hypotheses about what was going on, all of which he was able to test.

The experiments themselves are pretty interesting, but what’s really cool is that [Zach] realized the smooth hemispherical pits in the silicon could act as a mold for an array of microscopic convex lenses. He was able to deposit a small amount of clear silicone resin into the mold by spin-coating, and (eventually) transfer the microlens array to a glass slide. The lenses are impressively small — hundreds of them over only a couple hundred square microns — and pretty well-formed. There’s always room for improvement, of course, but for an initial attempt based on a serendipitous finding, we’d call it a win. As for what good these lenses are, your guess is as good as ours. But novel processes like these tend to find a way to be useful, and the fact that this is coming out of a home lab doesn’t change that fact.

We find this kind of micro-fabrication fascinating. Whether it’s making OLED displays, micro-machining glass with plasma, or even rolling your own semiconductors, we can’t get enough of this stuff.

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