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We’ve remarked before that superseded 3D printers are present in large numbers in our community, and particularly now a few years since that article was written we’re reaching the point at which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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It’s A Marble Clock, But Not As We Know It

November 6, 2023 by Donald Papp 28 Comments

[Ivan Miranda] is taking a very interesting approach to a marble clock. His design is a huge assembly that uses black and white marbles to create a (sort of) dot matrix display. It’s part kinetic art and part digital clock, all driven by marbles.

Here’s how it works: black and white marbles feed into a big elevator. This elevator lifts marbles to the top of the curved runs that make up the biggest part of the device. The horizontal area at the bottom is where the time is shown, with white and black marbles making up the numerical display. But how to make sure the white marbles and black marbles go in the right order?

The solution to that is simple. Marbles feed into the elevator in an unpredictable order. An array of sensors detects the color of each marble. Solenoids simply eject any marble that isn’t in the right place. For example, if the next marble for track n needs to be white, then simply kick out any black marbles in that position until there’s a white one. Simple, effective, and guarantees plenty of mesmerizing moving parts.

Of course, this means that marble ejection and marble color sensing need to be utterly reliable, and [Ivan] ran into problems with both. Marble ejection took some careful component testing and selection to get the right solenoids. Color sensing (as well as detecting empty spaces) settled on IR-based sensors commonly used in line-following robots.

You can watch the clock in action in the video embedded below just under the page break. We recommend giving it a look, because [Ivan] does a great job of showing all of the little challenges that reared their heads, and how he addressed them. There are still a few things to address, but he expects to have those licked by the next video. In the meantime, [Ivan] asks that if anyone knows a source for high quality glass marbles in bulk, please let him know. Low quality ones vary in size and tend to get stuck.

Marble clocks are great expressions of creativity, especially now that 3D printing is common. We love clock hacks, so if you ever create or run across a good one, let us know about it!

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Reducing Poop On Multicolor Prints

November 5, 2023 by Bob Baddeley 25 Comments

While multicolor printing eliminates painting steps and produces vibrant objects, there are two significant downsides; filament consumption and print time. A single-nozzle filament printer needs to switch from one color to another, and doing so involves switching to the other filament and then purging the transition filament that contains a mixture of both colors, before resuming the print with the clean new color.

[teachingtech] tests out a variety of methods for reducing print time and waste. One surprising result was that purging into the infill didn’t result in significant savings, even when the infill was as high as 50%. Things that did have a positive effect included reducing the amount of purge per transition based on light to dark color changes, and printing multiple copies at once so that even though the total amount of waste was the same as a single part, the waste per part was reduced.

All of the tests were with the same model, which had 229 color changes within a small part, so your mileage may vary, but it’s an interesting investigation into some of the deeper settings within the slicer. Reducing filament waste and print time is an admirable goal, and if you make your own extruder, you can turn all of that purge waste into various shades of greenish brownish filament. Continue reading “Reducing Poop On Multicolor Prints” →