The Bolt-On Peristaltic Pump

October 27, 2018 by Lewin Day 8 Comments

With the proliferation of 3D printing in the new millennium, stepper motors are no longer those idle junkbox inhabitants you pulled out of a dot matrix in 1994 and forgot about ever since. NEMA standard parts are readily available and knocking about just about everywhere. Now, you can readily turn a stepper motor into a peristaltic pump with just a few simple 3D printed parts.

The pump consists of a bracket that fits on to a standard NEMA-14 stepper motor frame. A rotor is then fitted to the motor shaft, constructed out of a 3D printed piece fitted with a series of standard roller bearings. These bearings roll against the tubing, pumping the working fluid.

The design uses the bearings to squeeze outwards against the tube’s own elastic resistance. Frictional wear is minimised by ensuring the tube is only pressed on by the bearings themselves, avoiding any contact between the tubing and hard plastic surfaces.

While the design is in its early stages of development, we’d be interested to see a pump performance comparison against other 3D printed peristaltic designs – we’ve seen a few before!

[Thanks to Baldpower for the tip!]

3D Printed Bridge Goes Dutch

October 24, 2018 by Al Williams 18 Comments

If you’ve ever been to Amsterdam, you know there are plenty of canals and, therefore, plenty of bridges. Next year, a unique pedestrian bridge in the old city center will go into service. The stainless steel bridge will be 3D printed and also embed a number of sensors that will collect data that the printer — MX3D — and their partners Autodesk, the Alan Turing Institute, and the Amsterdam Institute for Advanced Metropolitan Studies, hope will help produce better 3D printed structures in the future. The bridge will cross the Oudezijds Achterburgwal which is near the city’s infamous red light district.

Since the bridge matches exactly with the model used to print it, scientists hope to be able to map the sensor data to a virtual twin of the bridge very easily. You can see a few videos about the bridge’s construction below. This month, during Dutch Design Week, visitors had a chance to walk across the bridge to generate some of the first live datasets.

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A Close Look At The Prusa I3 MK3

October 22, 2018 by Tom Nardi 63 Comments

The Prusa i3 MK3 is, for lack of a better word, inescapable. Nearly every hacker or tech event that I’ve attended in 2018 has had dozens of them humming away, and you won’t get long looking up 3D printing on YouTube or discussion forums without somebody singing its praises. Demand for Prusa’s latest i3 printer is so high that there’s a literal waiting list to get one.

At the time of this writing, over a year after the printer was officially put up for sale, there’s still nearly a month lead time on the assembled version. Even longer if you want to wait on the upgraded powder coated bed, which has unfortunately turned out to be a considerable production bottleneck. But the team has finally caught up enough that the kit version of the printer (minus the powder coated bed) is currently in stock and shipping next day.

I thought this was a good a time as any to pull the trigger on the kit and see for myself what all the excitement is about. Now that I’ve had the Prusa i3 MK3 up and running for a couple of weeks, I can say with confidence that it’s not just hype. It isn’t a revolution in desktop 3D printing, but it’s absolutely an evolution, and almost certainly represents the shape of things to come for the next few years.

That said, it isn’t perfect. There’s still a few elements of the design that left me scratching my head a bit, and some parts of the assembly weren’t quite as smooth as the rest. I’ve put together some of those observations below. This isn’t meant to be a review of the Prusa i3 MK3 printer, there’s more than enough of those already, but hopefully these assorted notes may be of use to anyone thinking of jumping on the Prusa bandwagon now that production has started really ramping up.

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SandBot Happily And Tirelessly Rolls Patterns In Sand

October 18, 2018 by Donald Papp 1 Comment

The patience and precision involved with drawing geometric patterns in sand is right up a robot’s alley, and demonstrating this is [rob dobson]’s SandBot, a robot that draws patterns thanks to an arm with a magnetically coupled ball.

SandBot, SCARA version. The device sits underneath a sand bed, and a magnet (seen at the very top at the end of the folded “arm”) moves a ball bearing through sand.

SandBot is not a cartesian XY design. An XY frame would need to be at least as big as the sand table itself, but a SCARA arm can be much more compact. Sandbot also makes heavy use of 3D printing and laser-cut acrylic pieces, with no need of an external frame.

[rob]’s writeup is chock full of excellent detail and illustrations, and makes an excellent read. His previous SandBot design is also worth checking out, as it contains all kinds of practical details like what size of ball bearing is best for drawing in fine sand (between 15 and 20 mm diameter, it turns out. Too small and motion is jerky as the ball catches on sand grains, and too large and there is noticeable lag in movement.) Design files for the SCARA SandBot are on GitHub but [rob] has handy links to everything in his writeup for easy reference.

Sand and robots (or any moving parts) aren’t exactly a natural combination, but that hasn’t stopped anyone. We’ve seen Clearwalker stride along the beach, and the Sand Drawing Robot lowers an appendage to carve out messages in the sand while rolling along.

Just In Time For Halloween: Another Talking Skull

October 16, 2018 by Al Williams 4 Comments

It isn’t a unique idea, but we liked [Eric Wiemers’s] take on the classic animated skull for Halloween. In addition to showing you the code and the wiring, the video spends some time discussing what the audio looks like and what has to happen to get it into a format suitable for the Arduino. You can see the spooky video, below.

Of course, this is also a 3D printing project, although the skull is off-the-shelf. We wondered if he felt like a brain surgeon taking the Dremel to the poor skull. To fix the two parts of the device, he used brass threaded inserts that are heat set, something we’ve seen before, but are always surprised we don’t see more often.

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Life Imitates Art: 3D Printed Banksy Frame “Shreds” Oeuvre, Prints Money

October 16, 2018 by Adam Fabio 14 Comments

[Dave Buchanan] is giving the world his own take on the now famous shredding Banksy frame. This version has a few extra features though – like reverse shredding and printing money! Like many of us, [David] was impressed with the Banksy art auction shredding last week. We’re still not sure how he pulled it off, and the jury is still out if it was real, or all some sort of stunt involving the auction house.

[David] took his inspiration straight to CAD software, and designed a miniature version of the frame. A quick trip to the 3D printer and he had the actual frame in hand. He even hand-painted his own copy of Girl with Balloon on canvas. Assembly didn’t quite go as planned, a few parts had to be adjusted — i.e. cut off and hot-glued together. But in the end, the hack worked – the frame would shred and un-shred the painting whenever someone cranked the handle.

If you haven’t guessed yet, [David’s] frame is a version of the classic money printing trick. What looks like two rollers is actually a simple belt drive. The mechanism pulls in one piece of paper while pushing out a hidden piece. It creates the illusion of printing money – or of shredding art. Given Banksy’s sense of humor, we can’t help but wonder if his frame worked the same way.

[David] is working on a re-design of his piece which will be easier to build — so keep an eye on his Reddit thread if you’d like to print your own.

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Wind Turbine Pushes Limits Of Desktop 3D Printing

October 15, 2018 by Tom Nardi 36 Comments

There was a time, not so long ago, when hype for desktop 3D printing as so high that it seemed you could print anything. Just imagine it, and your handy dandy magical 3D printer could manifest it into reality. But now that more people have had first hand experience with the technology, the bubble has burst. Reality has sobered us up a bit, and today we’ve got a much better idea of what can and cannot be printed on a traditional desktop 3D printer.

But that doesn’t mean we aren’t surprised from time to time. As a perfect example, take a look at this almost entirely 3D printed wind turbine designed and built by [Nikola Petrov]. Outside of the electronics, the pole it’s mounted to, and some assorted bits and bobs, he produced all the parts on his own large-format TEVO Black Widow printer. He mentions there are a few things he would do differently if he was to build another one, but it’s hard to find much to complain about with such a gorgeous build.

To be sure, this one isn’t for the 3D printing novice. First of all, you’ll need a printer with a bed that’s at least 370 mm wide just to print the blades. [Nikola] also recommends printing the parts in ABS and coating them with acetone to smooth and harden the outside surfaces. We’d be surprised if you could print such large objects in ABS without a heated enclosure as well, so plan on adding that to your shopping list.

On the flip side though, the electronics are about as simple as they come. The blades are spinning a standard NEMA 17 stepper motor (through a 1:5 gearbox) to produce AC power. This is then fed into two W02M rectifiers and a beefy capacitor, which gives him DC with a minimum of fuss. In theory it should be capable of producing 1A at 12V, which is enough to light LEDs and charge phones. In this design there’s no battery charging circuit or anything like that, as [Nikola] says it’s up to the reader to figure out how to integrate the turbine into their system.

If you don’t think your 3D printing skills are up to the task, no worries. In the past we’ve seen wind turbines built out of ceiling fans, and occasionally, even less.