Michelson Interferometer Comes Home Cheap

January 12, 2026 by Al Williams 24 Comments

We suspect there are three kinds of people in the world. People who have access to a Michelson Interferometer and are glad, those who don’t have one and don’t know what one is, and a very small number of people who want one but don’t have one. But since [Longest Path Search] built one using 3D printing, maybe the third group will dwindle down to nothing.

If you are in the second camp, a Michelson interferometer is a device for measuring very small changes in the length of optical paths (oversimplifying, a distance). It does this by splitting a laser into two parts. One part reflects off a mirror at a fixed distance from the splitter. The other reflects off another, often movable, mirror. The beam splitter also recombines the two beams when they reflect back, producing an interference pattern that varies with differences in the path length between the splitter and the mirror. For example, if the air between the splitter and one mirror changes temperature, the change in the refraction index will cause a minute difference in the beam, which will show up using this instrument.

The device has been used to detect gravitational waves, study the sun and the upper atmosphere, and also helped disprove the theory that light is transmitted through a medium known as luminiferous aether.

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EnderSpark: Convert Your Broken Creality FDM Printer Into An EDM Machine!

January 11, 2026 by Dave Rowntree 10 Comments

EDM (Electrical Discharge Machining) is one of those specialised manufacturing processes that are traditionally expensive and therefore somewhat underrepresented in the DIY and hacker scenes. It’s with great delight that we present EnderSpark, a solution to not one but two problems. The first problem is how to perform CNC operations on hard-to-machine materials such as hardened metals (without breaking the bank). The second problem is what to do with all those broken and forgotten previous-generation Creality Ender 3D printers we know you have stashed away.

To be honest, there isn’t much to a cheap 3D printer, and once you ditch the bed and extruder assembly, you aren’t left with a lot. Anyway, the first job was to add a 51:1 reduction gearbox between the NEMA 17 motors and the drive pullies, giving the much-needed boost to positional accuracy. Next, the X and Y axes were beefed up with a pair of inexpensive MGN12H linear rails to help them cope with the weight of the water bath.

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Multi-material Parts The Easy Way

January 10, 2026 by Al Williams 14 Comments

You have a part that needs different colors or different material properties — with a multi-color 3D printer, no problem. You can also laboriously switch filaments on a single-color printer. But [anonymous kiwi] points out a different way, which is surprisingly obvious once you think about it. You simply add a previously made part to another one.

If you’ve ever experimented with adding a nut or a magnet into a print in the middle, the idea is exactly the same: you print one piece and then print a second piece, pausing in the middle to insert the completed first piece. The video example shows TPU robot wheels with PLA hubs. Of course, the same idea could apply to using different colors or even multiple materials or parts. You could imagine a hub with a steel nut embedded in it, then further being embedded in a TPU wheel, for example.

With multi-material printers becoming more commonplace, this technique might seem antiquated. But even if you have one of such a printer, this technique could save time and reduce waste. Not every part would work out this cleanly, but it is something to remember for the times when it does.

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Co-Extrusion Carbon Fiber FDM Filament Investigated

January 7, 2026 by Maya Posch 7 Comments

After previously putting carbon fiber-reinforced PLA filament under the (electron) microscope, the [I built a thing] bloke is back with a new video involving PLA-CF, this time involving co-extrusion rather than regular dispersed chopped CF. This features a continuous CF core that is enveloped by PLA, with a sample filament spool sent over by BIQU in the form of their CarbonCore25 filament.

In the previous video chopped CF in PLA turned out to be essentially a contaminant, creating voids and with no integration of the CF into the polymer matrix. Having the CF covered by PLA makes the filament less abrasive to print, which is a definitely advantage, but does it help with the final print’s properties? Of note is that this is still chopped CF, just with a longer fiber length (0.3-0.5 mm).

Samples of the BIQU filament were printed on a Bambu Lab H2D printer with AMS. In order to create a clean fracture surface, a sample was frozen in liquid nitrogen to make it easy to snap. After this it was coated with gold using a gold sputtering system to prepare it for the SEM.

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A photo of the various parts for this MSLA 3D printer

Build A 2K Resolution MSLA 3D Resin Printer For Cheap

January 7, 2026 by John Elliot V 13 Comments

Have an old Android device collecting dust somewhere that you’d like to put to better use? [Electronoobs] shows us how to make a Masked Stereolithography Apparatus (MSLA) printer for cheap using screens salvaged from old Android phones or tablets.

[Electronoobs] wanted to revisit his earlier printer with all the benefits of hindsight, and this is the result. The tricky bit, which is covered in depth in the video below the break, is slicing up the model into graphics for each layer, so that these layers can be rendered by the LCD for each layer during the print.

The next tricky bit, once your layer graphics are in hand, is getting them to the device. This build does that by installing a custom Android app which connects to a web app hosted on the ESP32 microcontroller controlling the print, and the app has a backchannel via a USB OTG adapter installed in the device. [Electronoobs] notes that there are different and potentially better ways by which this full-duplex communication can be achieved, but he is happy to have something that works.

If you’re interested in resin printer tech, be sure to check out Continuous Printing On LCD Resin Printer: No More Wasted Time On Peeling? Is It Possible? and Resin Printer Temperature Mods And Continuous IPA Filtration.

A bed of metal powder is visible through a green-tinted window. A fused metal pattern, roughly square, is visible, with one corner glowing white and throwing up sparks.

Printing In Metal With DIY SLM

January 3, 2026 by Aaron Beckendorf 5 Comments

An accessible 3D printer for metals has been the holy grail of amateur printer builders since at least the beginning of the RepRap project, but as tends to be the case with holy grails, it’s proven stubbornly elusive. If you have the resources to build it, though, it’s possible to replicate the professional approach with a selective laser melting (SLM) printer, such as the one [Travis Mitchell] built (this is a playlist of nine videos, but if you want to see the final results, the last video is embedded below).

Most of the playlist shows the process of physically constructing the machine, with only the last two videos getting into testing. The heart of the printer is a 500 Watt fiber laser and a galvo scan head, which account for most of the cost of the final machine. The print chamber has to be purged of oxygen with shielding gas, so [Travis] minimized the volume to reduce the amount of argon needed. The scan head therefore isn’t located in the chamber, but shines down into it through a window in the chamber’s roof. A set of repurposed industrial servo motors raises and lowers the two pistons which form the build plate and powder dispenser, and another servo drives the recoater blade which smooths on another layer of metal powder after each layer.

As with any 3D printer, getting good first-layer adhesion proved troublesome, since too much power caused the powder to melt and clump together, and too little could result in incomplete fusion. Making sure the laser was in focus improved things significantly, though heat management and consequent warping remained a challenge. The recoater blade was originally made out of printed plastic, with a silicone cord along the edge. Scraping along hot fused metal in the early tests damaged it, so [Travis] replaced it with a stainless steel blade, which gave much more consistent performance. The final results looked extremely promising, though [Travis] notes that there is still room for redesign and improvement.

This printer joins the very few other DIY SLM machines we’ve seen, though there is an amazingly broad range of other creative ideas for homemade metal printers, from electrochemical printers to those that use precise powder placement.

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Why Can’t I 3D Print With Rubber?

December 31, 2025 by Jenny List 59 Comments

A friend of mine and I both have a similar project in mind, the manufacture of custom footwear with our hackerspace’s shiny new multi-material 3D printer. It seems like a match made in heaven, a machine that can seamlessly integrate components made with widely differing materials into a complex three-dimensional structure. As is so often the case though, there are limits to what can be done with the tool in hand, and here I’ve met one of them.

I can’t get a good range of footwear for my significantly oversized feet, and I want a set of extra grippy soles for a particular sporting application. For that the best material is a rubber, yet the types of rubber that are best for the job can unfortunately not be 3D printed. In understanding why that is the case I’ve followed a fascinating path which has taught me stuff about 3D printing that I certainly didn’t know.

The extruder unit from a Prusa Mini 3D printer — Newton strikes back, and I can’t force rubber through this thing.

A friend of mine from way back is a petrochemist, so I asked him about the melting points of various rubbers to see if I could find an appropriate filament His answer, predictably, was that it’s not that simple, because rubbers don’t behave in the same way as the polymers I am used to. With a conventional 3D printer filament, as the polymer is fed into the extruder and heated up, it turns to liquid and flows out of the nozzle to the print. It ‘s then hot enough to fuse with the layer below as it solidifies, which is how our 3D prints retain their shape. This property is where we get the term “plastic” from, which loosely means “Able to be moulded”.

My problem is that rubber doesn’t behave that way. As any casual glance at a motor vehicle will tell you, rubber can be moulded, but it doesn’t neatly liquefy and flow in the way my PLA or PET does. It’s a non-Newtonian fluid, a term which I was familiar with from such things as non-drip paint, tomato ketchup, or oobleck, but had never as an electronic engineer directly encountered in something I am working on. Continue reading “Why Can’t I 3D Print With Rubber?” →