3D Printed Sorter Separates Spare Hex Nuts With A Shake

October 13, 2022 by Donald Papp 14 Comments

Got a pile of mixed hex nuts? Sort them in no time by printing [jonafriendj]’s nut sorter, which has options for pretty much any nut size you’d be after (it’s labeled metric, but actually includes Imperial sizes as well.)

Something to admire about the design is the handy little raised labels on each of the sieves, and the fact that all the parts print entirely without supports. Designing a part to play to a manufacturing method’s strengths (and avoid its weaknesses) is good DFM, or Design for Manufacturing.

With 3D printing being the boon that it is to workshops and hobbyists everywhere, it certainly pays to strive for good DFM, especially for designs meant to be shared with others. Sometimes good DFM takes a page from other manufacturing methods like injection molding, and we end up with things like using crush ribs on printed parts.

Want to see a demonstration of [jonafriendj]’s nut sorting design? Check out the short video embedded below the page break. If that leaves you wanting, take a look at a motorized, automated DIY solution.

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A Raspberry Pi Phone For The Modern Era

October 10, 2022 by Bryan Cockfield 43 Comments

While it might seem like mobile phones are special devices, both in their ease of use and in their ubiquity in the modern culture, they are essentially nothing more than small form-factor computers with an extra radio and a few specific pieces of software to run. In theory, as long as you can find that software (and you pay for a service plan of some sort) you can get any computer to work as a phone. So naturally, the Raspberry Pi was turned into one.

[asherdundas], the phone’s creator, actually found a prior build based around the Raspberry Pi before starting this one. The problem was that it was built nearly a decade ago, and hadn’t been updated since. This build brings some modernization to the antiquated Pi phone, and starts with a 3D printed case. It also houses a touchscreen and a GSM antenna to connect to the cell network. With some other odds and ends, like a speaker and microphone, plus a battery and the software to tie it all together, a modern functional Raspberry Pi phone was created, with some extra details available on the project page.

The phone has the expected features — including calling, texting, and even a camera. A small WiFi USB dongle allows it to connect to the Internet too, allowing it to do all of the internet browsing a modern smartphone might want to do. The only thing that it might be pretty difficult to do is install Android apps, and although there are ways to get Android apps working in Linux, it’s not always strictly necessary to have this functionality.

Seven Segments, But Not As We Know Them

October 6, 2022 by Donald Papp 11 Comments

We’ve seen a lot of clever re-imagining of the classic 7-segment display, and proving there is still room for something new is [Jack]’s 7-segment “DigiTag” display.

This 3D printable device has a frame into which is slotted three sliders. These sliders can be adjusted individually, mixing and matching the visibility of colored and uncolored areas, to create digits 0-9. We’ve seen some unusual 7-segment-inspired displays before, using from one motor for the whole digit to ones that need one motor per segment, but nothing quite like this approach.

While this particular design relies on the user to manually “dial in” each digit, the resulting key-like assembly (and unique shape for each digit) seems like it could have some interesting applications — a puzzle box design comes to mind.

If you have any ideas of your own on how this could be used, don’t keep them to yourself! Let us know in the comments, below.

Casting Metal With A Microwave And Vacuum Cleaner

September 29, 2022 by Bryan Cockfield 38 Comments

Metalworking might conjure images of large furnaces powered by coal, wood, or electricity, with molten metal sloshing around and visible in its crucible. But metalworking from home doesn’t need to use anything more fancy than a microwave, at least according to [Denny] a.k.a. [Shake the Future]. He has a number of metalworking tools designed to melt metal using a microwave, and in this video he uses them to make a usable aluminum pencil with a graphite core.

Before getting to the microwave kiln, the pencil mold needs to be prepared. A 3D-printed pencil is first created with the graphite core, and then [Denny] uses a plaster of Paris mixture to create the mold for the pencil. The 3D printed plastic is left inside the mold and placed in the first microwave kiln, which is turned on just enough to melt the plastic out of the mold, leaving behind the graphite core. From there a second kiln goes into the microwave to melt the aluminum.

Once the molten aluminum is ready, it is removed from the kiln and poured in the still-warm pencil mold. This is where [Denny] has another trick up his sleeve. He’s using a household vacuum cleaner to suck the metal into place before it cools, creating a rudimentary but effective vacuum forming machine. The result is a working pencil, at least after he wears down a few razor blades attempting to sharpen the metal pencil. For more information about how [Denny] makes these microwave kilns, take a look at some of his earlier projects.

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When 3D Printing Gears, It Pays To Use The Right Resin

September 26, 2022 by Donald Papp 9 Comments

There are plenty of resins advertised as being suitable for functional applications and parts, but which is best and for what purpose?

According to [Jan Mrázek], if one is printing gears, then they are definitely not all the same. He recently got fantastic results with Siraya Tech Fast Mecha, a composite resin that contains a filler to improve its properties, and he has plenty of pictures and data to share.

[Jan] has identified some key features that are important for functional parts like gears. Dimensional accuracy is important, there should be low surface friction on mating surfaces, and the printed objects should be durable. Of course, nothing beats a good real-world test. [Jan] puts the resin to work with his favorite method: printing out a 1:85 compound planetary gearbox, and testing it to failure.

The results? The composite resin performed admirably, and somewhat to his surprise, the teeth on the little gears showed no signs of wear. We recommend checking out the results on his page. [Jan] has used the same process to test many different materials, and it’s always updated with all tests he has done to date.

Whether it’s working out all that can go wrong, or making flexible build plates before they were cool, We really admire [Jan Mrázek]’s commitment to getting the most out of 3D printing with resin.

3D-Printable Sculpture Shows Off Unpredictable Order Of Chains

September 25, 2022 by Donald Papp 7 Comments

[davemoneysign] designed this fascinating roller chain kinetic sculpture, which creates tumbling and unpredictable patterns and shapes as long as the handle is turned; a surprisingly organic behavior considering the simplicity and rigidity of the parts.

3D-printed, with a satisfying assembly process.

The inspiration for this came from [Arthur Ganson]’s Machine With Roller Chain sculpture (video, embeded below). The original uses a metal chain and is motor-driven, but [davemoneysign] was inspired to create a desktop and hand-cranked manual version. This new version is entirely 3D-printed, and each of the pieces prints without supports.

According to [davemoneysign], the model works well with a chain of 36 links, but one could easily experiment with more or fewer and see how that changes the results. Perhaps with the addition of a motor this design could be adapted into something like this chains-and-sprockets clock?

You can see [Arthur Ganson]’s original in action in the video embedded below. It demonstrates very well the piece’s chaotic and unpredictable — yet oddly orderly — movement and shapes. Small wonder [davemoneysign] found inspiration in it.

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Filament Cutter Uses Unusual (But Effective) 3D-Printed Spring Design

September 23, 2022 by Donald Papp 12 Comments

When one needs a spring, a 3D-printed version is maybe not one’s first choice. It might even be fair to say that printed springs are something one ends up making, rather than something one sets out to use. That might change once you try the spring design in [the_ress]’s 3D-printed filament cutter with printed springs.

The filament cutter works like this: filament is inserted into the device through one of the pairs of holes at the bottom. To cut the filment, one presses down on the plunger. This pushes a blade down to neatly cut the filament at an angle. The cutter is the device’s only non-printed part; a single segment from an 18 mm utility knife blade.

The springs are of particular interest, and don’t look quite like a typical spring. They take their design from this compliant linear motion mechanism documented on reprap.org, and resemble little parallel 4-bar linkages. These springs have limited travel, but are definitely springy enough for the job they need to do, and that’s the important part.

Want a more traditional coiled spring? Annealing filament wound around a mandrel can yield useful results, and don’t forget the fantastic mechanisms known as flexures; they have clear similarities to the springs [the_ress] used. You can see her design in action in the short video, embedded below.

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