An MRI-Safe 3D Printed Pneumatic Stepper Motor

July 26, 2018 by Tom Nardi 33 Comments

You will no doubt have seen those videos where MRI machines suck up all sorts of metallic objects with hilariously disastrous results. The magnetic field in one of these machines can easily pull in metal objects from across the room, exerting a force of several hundred pounds on any ferrous object unlucky enough to wander too close. As you can probably imagine, designing mechanical devices that can operate in such an intense magnetic field is exceptionally difficult.

But this fully 3D printed pneumatic stepper motor designed by [Foad Sojoodi Farimani] might one day change that. The PneuAct, which he presented at the recent International Conference on Robotics and Automation (ICRA) in Brisbane, Australia, manages to run at up to 850 RPM with full position control using bursts of air rather than electronic pulses. Made entirely of plastic and without any electronic components, the PneuAct can not only operate in intense magnetic fields but also areas with flammable gases where sparks could potentially cause an explosion.

We often say that a design is “fully” 3D printable, even though it might require screws or other bits of hardware. But in the case of the PneuAct, it’s truly all printed. It has to be, or else the whole thing would be ripped apart when it got to close to the MRI machine. Each and every piece of the motor is printed in ABS, and can be used without any additional machining or cleanup. No lubrication is required, and [Foad] mentions that the whole thing is so cheap that it can be disposable. Which is a huge advantage in medical environments where contamination could be a concern.

Design-wise the PneuAct is essentially an expanded version of the 3D printed air motors we’ve seen previously, but it would be fair to say that none has ever been studied so closely before.

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This Cetus Printer Is Rigged For Silent Running

July 26, 2018 by Dan Maloney 9 Comments

The entry-level 3D-printer market is a rich one, with offerings from many vendors that are surprisingly good. But nothing is perfect, and to hit the $200 price point some compromises are inevitable. That doesn’t mean you have to live with those engineering choices, of course, which makes these cheap printers a great jumping off point for aftermarket mods.

[Linas K] took this route and in the process made his Cetus 3D-printer essentially silent. The first part of the video below reviews the shortcomings of the stock machine and the mechanical changes [Linas] made, including new brackets for the Z-axis slide, relocating the WiFi antenna to someplace sensible, and adding limit switches for each slide. Inside the case, the electronics get a complete reworking, with a custom PCB to house Trinamic stepper drivers for ultraquiet operation. The new board also supports the limit switches as well as thermostatic control of the extruder fan and pads for a platform heater. As a bonus, the new PCB is much smaller than the original, leaving room to tuck the power supply into the case, which is a nice touch. It wasn’t cheap, and it meant basically gutting the printer, but the results are impressively quiet.

We’re tempted to try these silencing mods on our own Cetus, if [Linas] ever publishes the BOM and PCB designs (hint, hint). And Cetus hacking is becoming quite a thing around here. From a trio of Cetus pro-tips to turning a Cetus into a PCB machine, the little printer has a lot to offer.

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Monoprice Mini Converted To Pick And Place (Kinda)

July 25, 2018 by Tom Nardi 15 Comments

Would you believe that you can take a cheap 3D printer and easily convert it into a full function pick and place machine to help assemble your PCBs? No? Well good, because you can’t. A real pick and place needs all kinds of sensors and logic to identify parts, rotate them, make sure everything is aligned, etc, etc. There’s no way you could just bolt all that onto a cheap 3D printer, and let’s not even talk about the lack of closed loop control.

But if you have a very specific use case, namely a PCB that only has a relatively large single part that doesn’t need to be rotated, [Connor Nishijima] might have a solution for you. He bought a $150 USD Monoprice Mini, and with the addition of a few printed parts, was able to build a machine that drastically cuts down the time it takes for him to build his LED boards. Best of all the modification doesn’t involve any permanent changes to the printer, he can just pop off the vacuum attachment when he wants to print something.

Beyond the 3D printed parts (which were made on the printer itself), the only thing you need to make the modification is the vacuum pump. [Connor] is using a hot air station that includes a vacuum pump for picking up SMD components, but he mentions that you’d probably better off just modifying an aquarium pump and using that. A printed holder snaps over the cooling fan of the Monoprice Mini to hold the vacuum pickup tool, and another printed piece holds the strip of LEDs and the PCB. It’s worth noting that the machine has no ability to control the vacuum pump, and doesn’t need to. The pickup tool is so weak that when the LED lands in the solder paste it sticks to the board well enough that the tool can’t lift it back off.

The real genius in this build comes from the manually written G-Code. You load it from the printer’s built in menu system as if it was a normal 3D print, and it instructs the printer to move the vacuum tool over the line of LEDs, pick one up, and drop it in place on the PCB. It then uses a small peg built into the vacuum tool holder to advance the line of LEDs before starting the cycle all over again. Incredibly, it does this whole complex dance 20 times for each PCB without ever having any kind of feedback or alignment check. It only works because [Connor] was willing to go through the trial and error of getting the calibration and G-Code down as close to perfect as can be expected for such a cheap machine.

This isn’t the first time we’ve seen the Monoprice Mini converted into something a bit more impressive than a cheapo 3D printer. Seems that for whatever the machine lacks in the printing department, it more than makes up for in hackability.

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3D Printing, Cybersecurity, And Audio Fingerprinting

July 24, 2018 by Al Williams 18 Comments

We all understand the risk of someone taking over our computers or phones for nefarious purposes. But remote access to printers and fax machines was something most people took a little less seriously. After all, you might get some obscene printouts or someone wasting some paper, but in general, those are not big deals. Some researchers however have lately been pondering what might happen should someone break into your 3D printer. Of course, you could bring a printer down to deny service, or cause things to malfunction — maybe even in ways that could be dangerous if the printer didn’t have sufficient safety features. But these researchers are more crafty. They are studying how you know what you’ve printed hasn’t been subtly sabotaged. They also think they have an answer.

If you are printing another Benchy at home this probably isn’t a real concern. However, according to the paper, 3D printing now accounts for over $6 billion of revenue with 33.8% of all parts having some function. This includes a recent FAA approval for a 3D-printed fuel nozzle for a jet engine. So indulge us in a little science fiction. You are about to fly your drone to take video of an important social function. You are worried about one of your props, so you 3D print a new one. Too bad your competitor has hacked your computer with a phishing e-mail and modified your STL files so that the new prop will have built-in weak spots internally. The prop will look fine and you’ll be able to install it. But it is going to fail right when you are taking those critical shots.

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Failed 3D Print Saved With Manual Coding

July 20, 2018 by Al Williams 20 Comments

Toast falls face down. Your car always breaks after the warranty period. A 3D print only fails after it is has been printing for 12 hours. Those things might not always be true, but they are true often enough. Another pessimistic adage is “no good deed goes unpunished.” [Shippey123] did a good deed. He agreed to make a 3D printed mask for his friend to give as a gift. It was his first print he attempted for someone else after about four months’ experience printing at all. After 20 hours of printing, he noticed the head was moving around in the air doing nothing — a feeling most of us are all too familiar with. But he decided not to give up, but to recover the print.

Luckily, he’s a CNC machinist and is perfectly capable of reading G-code. The first thing he did was to shut everything down and clear the head. Then he rehomed the printer and used the head to determine what layer the printer had been working on when it failed. He did that by moving over a hidden part of the print and lowering the head by 100 microns. Then he’d move the head a few millimeters in the X direction to see if the head was touching.

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A Farewell To Printrbot

July 19, 2018 by Tom Nardi 71 Comments

It’s with a heavy heart that we must report Printrbot has announced they are ceasing operations. Founded in 2011 after a wildly successful Kickstarter campaign, the company set out to make 3D printing cheaper and easier. Their first printer was an amalgamation of printed parts and wood that at the time offered an incredible deal; when the Makerbot CupCake was selling for $750 and took 20+ hours to assemble, the Printrbot kit would only run you $500 and could be built in under an hour.

Printrbot got their foot in the door early, but the competition wasn’t far behind. The dream of Star Trek style replicators fueled massive investment, and for a while it seemed like everyone was getting into the 3D printing game. Kit built machines gave way to turn-key printers, and the prices starting coming down. Printrbot’s products evolved as well, dropping wood in favor of folded steel and pioneering impressive features like automatic bed leveling. In 2014 they released the Printbot Simple Metal, which ultimately became their flagship product and in many ways represents the high water mark for the company.

Eventually, overseas manufacturers saw an opportunity and started flooding the market with 3D printers that were cheaper than what many would have believed possible only a few years earlier. Today you can go online and buy a perfectly serviceable starter printer for under $200, even less if you’re still willing to build it yourself. For an American company like Printrbot, competing at this price point was simply an impossibility.

Rather than give up, Brook decided to take things in a different direction. If he couldn’t compete with imported machines on price, he would start building high end printers. A new version of the Simple Metal was introduced in 2016 with premium features such as linear rails and cloud-based slicing, complete with a premium price. From that point on, most new Printrbot products would release at over $1,000; putting them more in line with “prosumer” machines from companies like Ultimaker. For hacker types who got their first taste of 3D printing thanks to a cheap wooden Printrbot kit, this was something of a bittersweet moment.

At the same time, Brook’s natural hacker spirit and love of the open source community lead to a number of interesting side projects that never quite got off the ground. Most recently, he’d been putting the finishing touches on the Printrbelt, a 3D printer with a conveyor belt in place of a traditional bed. Such a machine could finally bridge the gap between desktop 3D printing and true small scale production capability.

When we saw Brook at the East Coast RepRap Festival, he brought along a new machine that the more cynical observer might have taken as foreshadowing. The Printrbot Easy was going to be a modified and rebranded FlashForge Finder, a final acknowledgement that the only way to compete with the Chinese manufactured 3D printers was to sell one of your own.

It’s always sad to see a tech company go under, but seeing the end of Printrbot is especially hard. Built in America with locally sourced components and with a commitment to keeping their machines open source, there was a lot to love about the plucky little 3D printer company from Lincoln, California. Printrbot was the quintessential hacker success story, and we’re proud to say we’ve been in their corner from the start. Here’s to wishing Brook Drumm and the entire Printrbot team success in their future endeavors; we’ll be keeping an eye out.

ERRF 18: The Start Of Something Great

July 18, 2018 by Tom Nardi 7 Comments

For years, the undisputed king of desktop 3D printing conferences has been the Midwest RepRap Festival (MRRF). Hosted in the tropical paradise that is Goshen, Indiana, MRRF has been running largely unopposed for the top spot since its inception. There are other conferences focused on the industrial and professional end of the 3D printing spectrum, and of course you’d find a Prusa or two popping up at more or less any hacker con; but MRRF is focused on exploring what the individual is capable of once they can manifest physical objects from molten plastic.

But on June 23rd, 2018, MRRF finally got some proper competition. As the name might indicate, the East Coast RepRap Festival (ERRF) is an event very much inspired by its Hoosier State predecessor. Held in Bel Air, Maryland, hackers on the right side of the United States for the first time had the opportunity to attended a true 3D printing festival without having to get on a plane. Not to say it was a neighborhood block party; people from all over the country, and indeed the globe, descended on the APG Federal Credit Union Arena for the two-day celebration of everything plastic.

This inaugural ERRF was, to put it mildly, a massive success. A couple of Hackaday Field Agents were in attendance, and we definitely came away impressed with the event considering it was the first attempt. We saw evidence that the RepRap dream of printable printers is still going strong, a gaggle of new printers and products that will be prying at your wallet this year, and an American-made hotend that challenges traditional wisdom. Of course we also saw a huge number of 3D printing fanatics who were eager to show off their latest creations.

We have no doubt that ERRF will return again next year, but until then, you’ll have to settle for the following collection of selected highlights from this year’s show.

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