Thermoforming: Shaping Curvy Grilles With No Supports

February 11, 2026 by Maya Posch 7 Comments

Making sure the heatgun is on 'low' and gloves are on while pushing on the mold. (Credit: Zion Brock) — Making sure the heatgun is on ‘low’ and gloves are on while pushing on the mold. (Credit: Zion Brock)

Although hobbyists these days most often seem to use thermoplastics as a print-and-done material in FDM printers, there’s absolutely nothing stopping you from taking things further with thermoforming. Much like forming acrylic using a hot wire or hot air, thermoplastics like PLA can be further tweaked with a similar method. This can be much less complex than 3D printing the design with supports, as demonstrated by [Zion Brock].

For this classically styled radio project the front grille was previously 3D printed with the curved shape, but to avoid an ugly edge it had to be printed with most of the grille off the print bed, requiring countless supports and hours of printing time. To get around this, [Zion] opted to print the grille flat and then thermoform its curved shape. Of course, due to the unusual shape of the grille, this required a bit more effort than e.g. a spherical form.

This is similar to what is used with sheet metal to get detailed shaped, also requiring a mold and a way to stretch the flat shape over the mold. With the flat form designed to have all the material in the right places, it was able to be printed in less than an hour in PLA and then formed with a heatgun aimed at the part while the two-section mold is slid together to create the final form.

You can find the design files and full instructions on the website for the radio project.

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Making A Hidden Door Status Sensor

February 10, 2026 by Maya Posch 29 Comments

The door sensor in its new enclosures. (Credit: Dillan Stock)

A common sight in ‘smart homes’, door sensors allow you to detect whether a door is closed or open, enabling the triggering of specific events. Unfortunately, most solutions for these sensors are relatively bulky and hard to miss, making them a bit of a eyesore. This was the case for [Dillan Stock] as well, who decided that he could definitely have a smart home, yet not have warts sticking out on every single doorframe and door. There’s also a video version of the linked blog post.

These door sensors tend to be very simple devices, usually just a magnet and a reed relay, the latter signaling a status change to the wireless transmitter or transceiver. Although [Dillan] had come across recessed door sensors before, like a Z-wave-based unit from Aeotec, this was a very poorly designed product with serious reliability issues.

That’s when [Dillan] realized that he could simply take the PCB from one of the Aqara T1 door sensors that he already had and stuff them into a similar 20 mm diameter form factor as that dodgy sensor unit. Basically this just stuffs the magnet and PCB from an existing wart-style sensor into a recessed form factor, making it a very straightforward hack, that only requires printing the housings for the Aqara T1 sensor and some intimate time between the door and a drill.

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Is That Ancient Reel Of PLA Any Good?

February 10, 2026 by Jenny List 37 Comments

When it comes to knowledge there are things you know as facts because you have experienced them yourself or had them verified by a reputable source, and there are things that you know because they are common knowledge but unverified. The former are facts, such as that a 100mm cube of water contains a litre of the stuff, while the latter are received opinions, such as the belief among Americans that British people have poor dental care. The first is a verifiable fact, while the second is subjective.

In our line there are similar received opinions, and one of them is that you shouldn’t print with old 3D printing filament because it will ruin the quality of your print. This is one I can now verify for myself, because I was recently given a part roll of blue PLA from a hackerspace, that’s over a decade old. It’s not been stored in a special environment, instead it’s survived a run of dodgy hackerspace premises with all the heat and humidity that’s normal in a slightly damp country. How will it print?

It Ain’t Stringy

In the first instance, looking at the filament, it looks like any other filament. No fading of the colour, no cracking, if I didn’t know its age it could have been opened within the last few weeks. It loads into the printer, a Prusa Mini, fine, it’s not brittle, and I’m ready to print a Benchy.

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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 12 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.

Building A Metal 3D Printer With A Laser Welder

February 1, 2026 by Aaron Beckendorf 6 Comments

The development of cheaper, more powerful lasers has always been a cause for excitement among hackers, and fiber lasers are no exception. One of the newer tools they’ve enabled is the laser welder, which can be used to weld, cut through metal, or clean off surfaces. Or, as [Cranktown City] demonstrated, you can use one to build a metal 3D printer.

The printer’s built around a 2000-Watt fiber laser welder from Skyfire, and the motion system came from a defunct secondhand 3D printer built by an out-of-business insole printing company. The frame was reinforced with steel, the welding gun was mounted in place of the hotend, and the trigger was replaced with a CNC-controlled switch. It didn’t originally use any specific shielding gas, since the welder was supposed to perform adequately with just compressed air if high weld quality wasn’t essential.

The first few tests were promising, but did reveal quite a few problems. Heat buildup was an early issue which threatened to warp the build plate, and which eventually welded the build plate to the Z-axis gantry. Adding a strong cooling fan and putting a gap between the build plate and the gantry solved this. The wire also kept getting stuck to the build surface, which [Cranktown City] solved by pausing the wire feed and pulling it away from the part when a layer finished. Simply using compressed air led to a weak deposit that cracked easily, and while a nitrogen stream improved the print somewhat, argon shielding gas gave the best results. For his final print, [Cranktown City] made a vase. The layers were a bit crude, but better than most welder-based metal printers, and the system shows some real promise.

We’ve seen a few printers built around welders before, and a few built around lasers, but this seems to be the first to use both.

A wooden frame is shown with a scale pulling down on a 3D-printed part held in the frame. A phone on a stand is taking video of the part.

Changing Print Layer Patterns To Increase Strength

January 31, 2026 by Aaron Beckendorf 2 Comments

Dy default, the slicing software used for 3D printers has the printer first create the walls around the edges of a print, then goes back to deposit the infill pattern. [NeedItMakeIt], however, experimented with a different approach to line placement, and found significant strength improvements for some filaments.

The problem, as [NeedItMakeIt] identified with a thermal camera, is that laying down walls around a print gives the extruded plastic time to cool of. This means new plastic is being deposited onto an already-cooled surface, which reduces bonding strength. Instead, he used an aligned rectilinear fill pattern to print the solid parts. In this pattern, the printer is usually extruding filament right next to the filament it just deposited, which is still hot and therefore adheres better. The extrusion pattern is also aligned vertically, which might improve inter-layer bonding at the transition point.

To try it out, he printed a lever-type test piece, then recorded the amount of force it took to break a column free from the base. He tried it with a default fill pattern, aligned fill, and aligned fill with a single wall around the outside, and printed copies in PLA, plain PETG, and carbon fiber-reinforced PETG. He found that aligned fill improved strength in PLA and carbon fiber PETG, in both cases by about 46%, but led to worse performance in plain PETG. Strangely, the aligned fill with a single outside wall performed better than default for PLA, but worse than default in both forms of PETG. The takeaway seems to be that aligned fill improves layer adhesion when it’s lacking, but when adhesion is already good, as with PETG, it’s a weaker pattern overall.

Interesting, [MakeItPrintIt]’s test results fit in well with previous testing that found carbon fiber makes prints weaker. Another way to get stronger print fill patterns is with brick layers.

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Need A Curved Plastic Mesh? Print Flat, Curve Later

January 30, 2026 by Donald Papp 10 Comments

Need a plastic mesh in a custom pattern? 3D print it, no problem. But what if one needs a curved plastic mesh? That’s considerably harder to 3D print, but [Uncle Jessy]’s figured out a simple approach: 3D print the mesh flat, then break out a mold and a heat gun.

Of course, there are a few gotchas, but [Uncle Jessy] shares his tips for getting the most reliable results. The important part is to design and 3D print a mold that represents the final desired shape. Then print the mesh, and fit it into a frame. Heat things up with a heat gun, and press into the mold to deform the mesh while it’s still soft. It’s much easier seen than explained, so take a few moments to check out the video, embedded below the page break.

Because the plastic in a mesh is so thin, [Uncle Jessy] says to keep the heat low and slow. The goal is to have the mesh stretch and deform, not melt.

Speaking of heat, when thermoforming, one usually needs to make the mold out of heat-resistant material. But the thermal mass of a mesh is so small that it really doesn’t matter much — there just isn’t enough heat trapped in the mesh to really damage a mold. As long as the mold is reasonably dense, there’s no need to go overboard with making it heat resistant.

The whole process takes a little practice, but since the meshes are so fast to print and use so little plastic it’s easy to experiment a little.

As for the meshes themselves, a simple way to print a mesh is just to print a disc with no top or bottom layers, only infill. Set the infill pattern to honeycomb, for example, for an easy hexagon mesh. We’ve seen a variant of this “exposed infill” idea used to create a desiccant container, and using it to print a mesh pattern easily is a neat trick, too.

Why might one need to reshape a mesh into a curve? Perhaps to custom-fit a costume piece, or make custom eye inserts for masks, as shown here. In any case, it’s a good technique to keep in the back of one’s mind, and if you put it to good use, drop us a tip!

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