One-piece Geared Hinge Can Take The Weight

January 24, 2022 by Donald Papp 31 Comments

3D printers have come a long way from cranking out things like bottle openers and coat pegs, and [E. Soderberg]’s Print in Place Geared Hinge is a pretty nifty demonstration of that. This hinge is designed as a print-in-place part, meaning it is 3D printed as a single piece, requiring no assembly. Not only that, but the herringbone gears constrain the sturdy device in a way that helps it support heavy loads.

Of course, hinges — even strong ones — are not particularly hard to find items. They’re available in a mind-boggling array of shapes and sizes. But what’s interesting about this design is that it shows what’s easily within the reach of just about any hobbyist nowadays. Not that long ago, designing and creating an object like this would not have been accessible to most home enthusiasts. Making it without a modern 3D printer would certainly have been a challenge in its own right.

It doesn’t always matter that a comparable (or superior) off-the-shelf part is available; an adequate part that can be created in one’s own workshop has a value all its own. Plus, it’s fun to design and make things, sometimes for their own sake. After all, things like 3D-printed custom switch assemblies would not exist if everyone were satisfied with the ability to just order some Cherry MX switches and call it a day.

Printing In Silicone

January 22, 2022 by Al Williams 22 Comments

When you think of making something out of silicone, you usually think of using a mold and injecting it with the material. Can you 3D print it? [Kimberly Beckett] answers that very question in a recent post. The short answer is yes, but you need specialized printing equipment.

Most consumer or hobby printers use either filament deposition or photoresin. Neither of these processes are good for printing silicone. For one thing, silicone doesn’t melt and reform like a thermoplastic. After all, that is why we like making hotend socks and oven utensils with the material. If you do melt silicone, you get a gooey mess, not a nice fluid you can push through an extruder nozzle. As for resin printing, silicone is resistant to UV so the chances of coming up with UV curable silicone are pretty small.

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Pen Plotter From PCB Panels

January 21, 2022 by Chris Lott 6 Comments

Hacker [12344321A] has built a clever open-source pen plotter having a frame made from odd-shaped PCB panels (Chinese). It holds an ordinary drafting pen and draws on a small writing platform 8 x 8 cm square. This is barely enough space to draw a business card, depending on which country you’re from. The motion appears to be provided by DVD stepper motor head positioning assemblies, and the controller is an ESP32-based GRBL 3-axis board. User control is via WiFi and the plotter can be seen in operation being driven from the user’s smartphone (see video on the project page above).

Linear Motion Assemblies from a DVD player?

This looks like it would be an inexpensive build, and seems sturdy enough despite being literally held together by solder and paper clips. But be forewarned, the project is documented on an open-source hardware sharing site sponsored by EasyEDA called OSHWHub — the Chinese equivalent of their similar English-language OSHWLab. Hence all the notes are in Chinese, although Google translate can help here. [12344321A] provides all the engineering design files under GPL 3.0 license.

Thanks to [J. Peterson] for finding this project and bringing it to our attention via the tip line.

3D Printing Copper

January 20, 2022 by Al Williams 28 Comments

People really want to 3D print metal, but while true metal printers exist, they still are expensive and out of reach of most hackers. However, even if you can afford an exotic printer or use metal-impregnated polymer, you don’t often see copper as a print material. Copper has high electrical and thermal conductivity which makes it very useful. But that thermal conductivity also makes it very difficult to print using any process that involves heating up the material and copper reflects common lasers used in the 3D printing process. However, a German company, Infinite Flex, is claiming a breakthrough that will allow printers that use a standard IR laser to produce copper parts. The material, Infinite Powder CU 01 is suitable for selective laser sintering and several other laser-based techniques.

The powder has 99.5% copper and particle sizes of between 10 and 45 microns. There are some copper alloys that reduce thermal conductivity to allow printing, but often the reason you want a copper part is for its thermal properties. A kilogram of the powder will set you back nearly $100, so it isn’t dirt cheap, but it isn’t astronomical, either.

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Monowheel Mayhem: When Good Gyroscopic Precession Goes Bad

January 19, 2022 by Ryan Flowers 11 Comments

Since the dawn of the age of the automobile, motorheads have been obsessed with using as few wheels as possible. Not satisfied with the prospect of being incompletely maimed by a motorcycle, the monocycle was born. Gracing the covers of Popular magazines and other periodicals, these futuristic wheels of doom have transfixed hackers of all kinds. [James Bruton] is one such hacker, and in the video below the break you can see his second iteration of a 3d printed monowheel.

[James]’ wonderful monowheel is beautifully engineered. Bearing surfaces, gears, idlers, motors, and yes, twin gyroscopes are all contained within the circumference of the tire. The gyroscopes are actuated by a rather large servo, and are tied together by a gear that keeps their positions in sync. Their job is to keep the monowheel balanced at all times.

But as [James] discovered, the chief difficulty of only having one wheel isn’t lateral balancing. Ask any monocyclist and they’ll assure you that it’s possible. The real trick is balancing the machine fore and aft. Unlike a two wheeled velocipede, the monowheel has nothing to exert torque against save for a bit of gravity.

As [James] found out the hard way, it was within this fore-aft balancing act that the gyroscopic precession reared its ugly head. The concept is explained well in the video. We won’t spoil the surprise ending because the explanation and conclusion are quite good so make sure to watch to the end!

If you’d like to look at [James]’ first version, we covered it here. And if you’re the daredevil type, perhaps we can interest in you in a two stroke human sized monowheel that will probably end in an ER visit. At least they wore a helmet. Thanks to [Baldpower] for the tip!

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Extreme Thermal Mods For 3D Printing Exotic Materials

January 19, 2022 by Dan Maloney 15 Comments

For general everyday use, there’s nothing wrong with the standard selection of plastics that most 3D printer filaments are available in. PLA, ABS, PETG — they’ve all got their place, and they’re all pretty easy to work with. But if you need to work with more exotic materials, you might need to go to extremes and modify an off-the-shelf printer for high-temperature work.

For the team led by [Andreas Hagerup Birkelid] at the Norwegian University of Science and Technology, the standard menu of printer chow wasn’t up to the jobs they had in mind. They wanted to print using polyether ether ketone, or PEEK, a high-performance thermoplastic with useful mechanical and thermal properties, in addition to chemical resistance. Trouble is, the melting point of PEEK is a whopping 343°C (649°F), making it necessary to turn up the heat — a lot. A standard Creality CR-10 printer was upgraded to withstand not only the 500°C max temperature of the new hot end and 200° printed bed, but also to survive operating in what amounts to an oven — a balmy 135° in a chamber made from IKEA cabinets. That entailed replacing plastic parts with metal ones, upgrading belts, pulleys, and wires, and moving all the electronics outside the enclosure. Even the steppers got special treatment, with water cooling to keep their magnets from reaching the Curie point.

The mods seemed to do the trick, because a Benchy printed in a carbon-fiber PEEK filament came out pretty good. It seems like a long way to go and kind of pricey — $1,700 for the printer and all the mods — but if you have a need to print exotic materials, it’s way cheaper than a commercial high-temp printer.

[via 3D Printing Industry]

Giant 3D Prints Piece-by-Piece

January 16, 2022 by Al Williams 18 Comments

While FDM printers have gotten bigger lately, there’s almost always going to be a part that is bigger than your bed. The answer? Break your design into parts and assemble them after printing. However, the exact method to do this is a bit of a personal choice. A mechanical engineering student wrote:

After researching the state of the art as well as your ideas here on reddit, I realized, that there are almost no universal approaches to divide a large part and join the pieces which maintain mechanical strength, precisely position each segment, and also counteract tolerances due to the FDM-process.

Therefore I tried to develop a universal method to segment large trim parts, additively manufacture each segment and finally join those segments to form the desired overall part.

The result is a research paper you can download for free. The method focuses on thin parts intended as automotive trim, but could probably be applied to other cases.

You can read about the thought process, but the final result was a joggle — a joint made with a rabbet and tongue. Adhesive holds it together, but the joint offers advantages in constraining the final product and the transmission of force in the assembly. Judging by the picture, the process works well. It would be interesting to see slicer software develop the capability to segment a large model using this or a similar technique.

Of course, you can just build a bigger printer, at least to a point. It seems, though, that that point is pretty big.