We Can Now 3D Print Slinkys

March 9, 2017 by Brian Benchoff 32 Comments

A mark of a good 3D print — and a good 3D printer — is interlayer adhesion. If the layers of a 3D print are too far apart, you get a weak print that doesn’t look good. This print has no interlayer adhesion. It’s a 3D printed Slinky, the kind that rolls down stairs, alone or in pairs, and makes a slinkity sound. Conventional wisdom says you can’t print a Slinky, but that didn’t stop [mpclauser] from trying and succeeding.

This Slinky model was made using a few lines of JavaScript that output a Gcode file. There is no .STL file, and you can’t edit this CNC Slinky in any CAD tools. This is also exceptionally weird Gcode. According to [mpclauser], the printer, ‘zigzags’ between an inner and outer radius while constantly increasing the height. This is the toolpath you would expect from a 3D printed Slinky, but it also means the usual Gcode viewers throw a fit when trying to figure out how to display this thing.

All the code to generate your own 3D printable Slinky Gcode file is up on [mpclauser]’s Google Drive. The only way to see this print in action is to download the Gcode file and print it out. Get to it.

Innovating A Better Printing Platform

March 7, 2017 by James Hobson 29 Comments

Just because you have a fancy new 3D printer doesn’t mean that innovation should stop there. Almost everyone has had a print go foul if the first layer doesn’t properly adhere to the printing platform — to say nothing of difficulty in dislodging the piece once it’s finished. Facing mixed results with some established tricks meant to combat these issues, [D. Scott Williamson] — a regular at Chicago’s Workshop 88 makerspace — has documented his trials to find a better printer platform.

For what he had (a printer without a heated plate), painter’s tape and hairspray wasn’t cutting it, especially when it came time to remove the print as the tape wouldn’t completely come off the part. How then, to kill two birds with one stone? Eureka! A flexible metal covering for the printing plate.

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Stop Printing Air With A Filament Sensor

March 4, 2017 by Al Williams 21 Comments

If you have had a 3D printer for awhile, you know the heartbreak of coming in to check on an 8-hour print only to find that in hour 7 you ran out of filament (or the filament broke) and your printer has been dutifully moving around for no reason. [Chuck Hellebuyck] knows and he decided to make a filament sensor he found on Thingiverse.

Finding a part on Thingiverse and printing it probably doesn’t warrant much attention. But if you watch the video, below, it is a good example of how things from Thingiverse don’t always meet your needs. The microswitch [Chuck] had was bigger than the design used. So he loaded the STL file into TinkerCAD and fixed it. He shows you exactly how he did it. That’s a useful skill because you never know when you’ll need to modify some part you’ve found on the Internet.

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Making Laser Cutter Designs Work In A 3D Printer

March 3, 2017 by Al Williams 18 Comments

The main mechanical tools in a hacker’s shop used to be a drill press and a lathe. Maybe a CNC mill, if you were lucky. Laser cutters are still a rare tool to find in a personal shop, but today’s hackers increasingly have access to 3D printers. What happens when you have a design for a laser cutter (2D parts) but only have access to a 3D printer? You punt.

[DIY3DTECH] has a two-part video on taking a 2D design (in an SVG file) and bringing it into TinkerCad. At that point, he assembles the part in software and creates a printable object. You can see the videos below.

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Speech To Sign Language

March 2, 2017 by Al Williams 20 Comments

According to the World Federation of the Deaf, there are around 70 million people worldwide whose first language is some kind of sign language. In the US, ASL (American Sign Language) speakers number from five hundred thousand to two million. If you go to Google translate, though, there’s no option for sign language.

[Alex Foley] and friends decided to do something about that. They were attending McHack (a hackathon at McGill University) and decided to convert speech into sign language. They thought they were prepared, but it turns out they had to work a few things out on the fly. (Isn’t that always the case?) But in the end, they prevailed, as you can see in the video below.

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Unique Planetary Gearbox Can Be Custom Printed For Steppers

March 2, 2017 by Dan Maloney 44 Comments

Stepper motors are a staple in all sorts of projects, but it’s often the case that a gearbox is needed, especially for applications like the linear drives in CNC machines and 3D printers. In those mechanisms, a high-torque, low backlash gearbox might be just the thing, and a 3D printable split planetary harmonic drive for the popular NEMA 17 motors would be even better.

Right up front, we’ll say that we’re skeptical that any plastic gearbox can stay as backlash free as [SirekSBurom] claims his creation is. But we can see the benefits of the design, and it has some nice features. First off, of course, is that it’s entirely 3D printed, except for a few screws. That it mates perfectly with a NEMA 17 motor is a really nice feature, too, and with the design up on Thingiverse it shouldn’t be too tough to scale it up and down accordingly. The videos below show you the theory: the stepper drives a sun gear with two planet gears orbiting, each of which engages a fixed ring of 56 teeth, and an output ring of 58 teeth. Each revolution of the planets around the fixed ring rotates the output ring by one tooth, leading to almost 100:1 reduction.

We think the ‘harmonic’ designation on this gearbox is a little of a misnomer, since the defining feature of a harmonic drive seems to be the periodic deformation of a flex spline, as we saw in this 3D-printed strain wave gear. But we see the resemblance to a harmonic drive, and we’ll admit this beastie is a little hard to hang a name tag on. Whatever you call it, it’s pretty cool and could be a handy tool for all kinds of builds.

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That Time I Spent $20 For 25 .STL Files

March 1, 2017 by Brian Benchoff 72 Comments

Last weekend I ran out of filament for my 3D printer midway through a print. Yes, it’s evidence of poor planning, but I’ve done this a few times and I can always run over to Lowe’s or Home Depot or Staples and grab an overpriced spool of crappy filament to tide me over until the good, cheap filament arrives via UPS.

The Staples in my neck of the woods was one of the few stores in the country to host a, ‘premium, in-store experience’ featuring MakerBot printers. Until a few months ago, this was a great place to pick up a spool of filament that could get you through the next few hours of printing. The filament cost about three times what I would usually pay, but it was still good quality filament and they usually had the color I needed.

This partnership between MakerBot and Staples fell through a few months ago, the inventory was apparently shipped back to Brooklyn, and now Robo3D has taken MakerBot’s space at the endcap in Staples. Last weekend, I picked up a 1kg spool of red PLA for $40. What I found next to this filament left me shocked, confused, and insatiably curious. I walked out of that store with a spool of filament and a USB thumb drive loaded up with twenty-five STL files. This, apparently, is the future of 3D printing.

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