Single-piece Tank Chassis Goes Robotic

November 27, 2023 by Donald Papp 8 Comments

[EXTREME3DPRINT] has a new version of their print-in-place tank chassis: the PiPBOT now accepts drop-in motors (in the form of 360° rotation servos), RC receiver, and battery pack to make a functional RC tank platform in no time flat. The design is entirely 3D printed with no supports needed.

This new version is a paid 3D model (and it includes STEP files, thankfully) but the original proof-of-concept print-in-place tank chassis is free and remains a highly clever piece of design that really shows off what is possible when one plays to a 3D printer’s strengths.

A better look at the design’s details can be found on the designer’s website, and a short video demonstrating assembly and operation is embedded below. We particularly like the attachment points on the top of the PiPBOT, which allows for securely mounting all kinds of customized payloads.

Interested in this style of printable RC platform, but want something a little more accessible? If race cars are more your thing, we’d like to also mention the Gamma 2.0 by [Under Engineered]. It’s a print-in-place RC car that needs minimal parts to get rolling and would make an excellent afternoon project.

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3D Printing A Nifty Sphere Without Supports

November 26, 2023 by Donald Papp 6 Comments

[DaveMakesStuff] demonstrates a great technique for 3D printing a sphere; a troublesome shape for filament-based printers to handle. As a bonus, it uses a minimum of filament. His ideas can be applied to your own designs, but his Giant Spiralized Sphere would also just happen to make a fine ornament this holiday season.

Printing two interlocking parts and using vase mode ensures a support-free print that uses a minimum of filament.

The trick is mainly to print the sphere in two parts, but rather than just split the sphere right down the middle, [Dave] makes two hollow C-shaped sections, like a tennis ball. This structure allows the halves to be printed in vase mode, which minimizes filament use while also printing support-free.

Vase (or spiral) mode prints an object using a single, unbroken line of extruded filament. The resulting object has only one wall and zero infill, but it’s still plenty strong for an ornament. Despite its size, [Dave]’s giant ball uses only 220 grams of filament.

A video (also embedded below) shows the design in better detail. If you’d like to experiment, we’ve previously covered how PETG’s transparency is best preserved when 3D printing by using vase mode, slightly overextruding, and printing at a higher temperature to ensure solid bonding between each layer. Continue reading “3D Printing A Nifty Sphere Without Supports” →

An Automated Watch Cleaner From An Older 3D Printer

November 23, 2023 by Jenny List 11 Comments

The many delicate parts in a mechanical wristwatch present a tricky cleaning problem, one that for professionals there is a variety of machines to tackle. As you might expect, such specialty equipment doesn’t come cheap, so [daveburkeaus] came up with his own solution, automated using an older 3D printer.

The premise is straightforward enough: it’s a machine with a succession of stations for cleaning, rinsing, and drying, through which the watch is moved on a set cycle. The hot end and extruder is replaced with a motor and shaft, on the end of which is a basket in which the watch sits. The basket is a commercial part for simplicity of construction, though one could certainly fabricate their own if need be. The printer gets a controller upgrade and of course a motor controller, and with a software stack built upwards from the Klipper firmware seems ready to go. There is the small matter of the heater used for drying not keeping the firmware happy as a substitute for the heated bed it thinks it’s driving, but that is fixed by controlling it directly.

We’ve remarked before that superseded 3D printers are present in large numbers in our community, and particularly now a few years since that article was written we’re reaching the point at which many very capable machines are sitting idle. It’s thus particularly good to see a project that brings one of them out of retirement for a useful purpose.

Cooking With Magnets And 3D Printing

November 18, 2023 by Al Williams 9 Comments

Have you ever wondered how induction cooking works? A rotating magnetic field — electrically or mechanically — induces eddy currents in aluminum and that generates heat. When [3D Sage] learned this, he decided to try to 3D print some mechanical rigs to spin magnets so he could try cooking with them.

We doubt at all that this is practical, but we have to admit it is fun and there are some pretty impressive 3D prints in the video, too. The cook surface, by the way, is tiny, so you won’t be prepping a holiday meal on it. But there’s something super charming about the tiny breakfast on a plate produced by a printed magnetic “stove.” We would be interested to know how much power this setup consumed and how much heat was produced compared to, say, just using a big resistor to heat things up.

We’ve heard that induction heating is efficient, but this setup is a bit unconventional. If cooking things isn’t your bag, you can use induction for soldering, too.

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Robot Hand Has Good Bones

November 16, 2023 by Al Williams 8 Comments

What do you get when you mix rigid and elastic polymers with a laser-scanning 3D printing technique? If you are researchers at ETH Zurich, you get robot hands with bones, ligaments, and tendons. In conjunction with a startup company, the process uses both fast-curing and slow-curing plastics, allowing parts with different structural properties to print. Of course, you could always assemble things from multiple kinds of plastics, but this new technique — vision-controlled jetting — allows the hands to print as one part. You can read the full paper from Nature or see the video below.

Wax with a low melting point encases the entire structure, acting as a support. The researchers remove the wax after the plastics cure.

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3D Printed Stamp Rollers

November 13, 2023 by Al Williams 3 Comments

If you have an artistic bent, you might have seen self-inking stamp rollers. These are like rotary rubber stamps that leave a pattern as you roll across a page. [Becky] wanted a larger custom roller and turned to 3D printing to make it happen. The first prototype used a modified Sharpie. However, she soon moved to an unmodified acrylic marker that had a rectangular tip.

A Tinkercad design produces a cap that fits the marker and a wheel that contains the desired pattern. Text works well, although you can easily do a custom pattern, too, of course.

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Putting 3D Printed Screw Threads To The Test

November 10, 2023 by Maya Posch 28 Comments

One of the challenges with 3D printing is seeing how far designs can be pushed before they break. This includes aspects like flexible hinges and structural components, but also smaller details such as screw threads. Often metal inserts with threads are added to FDM 3D prints by melting them into the plastic, but might 3D printed threads be sufficient for many cases? This is a question which [Adam Harig] sought to investigate in a recent video while working on parts that would connect to a rather expensive camera.

Trusting expensive camera gear to 3D printed threads... (Credit: Adam Harig) — Trusting expensive camera gear to 3D printed threads… (Credit: Adam Harig)

Rather than risking the camera, a few stand-in cubes printed in PLA+ (AnkerMake brand) were used, with these and their internal thread being exposed to destructive testing. For the measuring equipment only a luggage/fishing scale was used. The difference between the test parts was the amount of infill, ranging from 10 to 100% infill, with 0.2 mm layer height. After this the test involved pulling on the metal hook screwed into the plastic test item with the scale, up to the point of failure or the human element giving up.

The results are rather interesting, with the 100% infill version scoring better than than the 50% infill version (the next step down), with [Adam] giving up on trying to pull the test unit apart and with the scale maxed out. This gave him enough confidence to use this design to lift his entire camera off the table. What’s perhaps most interesting here is that the way the test items were printed, the layers experienced a peeling force, which as the final clips in the video show seemed to often result in the bottom layers giving away, which was the part not being held together by the metal screw inside the item. What the effect of dynamic loads are is something that should possibly also be investigated, but it does show that FDM printing screw threads is perhaps not that silly.

(Thanks to [Pidog] for the tip)

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