Hackaday Links: May 15, 2016

The Hackaday Overlords (or Hackaday family) are running a series of AMAs on SupplyFX. What is SupplyFX? It’s a social network for EEs. Who’s in the first AMA? [Brady Forrest], the guy who runs Highway1, a Bay Area hardware accelerator. They’re the accelerator responsible for the lustworthy Keyboardio, and the startup that is purely mechanical and has shipped zero lines of code, CoolChip. If you want to talk about hardware startups, [Brady] is your man. The AMA is tomorrow, May 16th, at 13:00 Pacific.

Makerbot is dead, or at least they will be soon. Whatever. Nothing of value was lost. Lulzbot, on the other hand, is going gangbusters. They saw eight hundred percent growth over the last two years. and $15M in revenue in 2015. They did this all with open source hardware and software, and using 3D printing in a manufacturing context. They’re the jewel of the Open Hardware movement, and a shining example of what Free Software can do.

The current generation of software defined radios started with the ubiquitous TV tuner dongles, and quickly graduated to the HackRF. You can only get so much bandwidth out of a USB 2.0 socket, and the newest and bestest SDR is the LimeSDR. They’re about halfway through their crowdfunding campaign (and halfway funded), and have finally changed out the USB A connector to a USB micro B connector. Good choice.

The ESP8266 is quickly becoming the go-to device for when you want a cheap way to put a sensor on the Internet. The only problem is programming it. No problem – here’s a bunch of Lua scripts that do 90% of everything. Need to read a PIR sensor? Light up a few LEDs? Put the data from a temperature and humidity on the Internet? There you have it.

The Vintage Computer Festival West is back on this year. We’ve gone to VCF East in New Jersey for a few years now, and had a few occasional outings to the southeast and midwest Vintage Computer Festivals over the years. This is the first time the west coast has had a Vintage Computer Festival in several years. It’s in Mountain View, on August 6th and 7th. Yes, that’s the same weekend as DEF CON.

E3D, makers of fine hot ends and 3D printer paraphernalia, have released a new kind of filament. It’s called Edge, it’s based on PET, and it prints as easily as PLA, with better mechanical properties than ABS. A few sample prints made from Edge were at this year’s Midwest RepRap Festival, and the Edge’s bridging ability is crazy. You need a heated bed for Edge and it’s sensitive to moisture, but it has some very interesting properties that can be cleverly exploited.

In other filament news, Colorfabb released a filament to print clear parts. Yes, that’s very weird. Clear parts require 100% infill, meaning it will use a lot of filament. It’s still very advanced wizardry, and I’m very interested in seeing the first print of a sanded and polished convex lens.

Holy Crap it’s the 3D printing edition of the links post. [Prusa] just released the latest version of the i3. It’s now bigger: 250x210x200mm build volume. The heated bed – [Prusa] was one of the first to experiment with PCB heated beds – is now vastly improved when looking at it through a FLIR. The Mk. 42 heated bed doesn’t have a hot center or cool corners. PEI sheet removes the need for blue painters tape, glass, aqua net, or glue sticks. The printer has self-test capabilities. The mechanics of the printer, especially the Z axis, are improved. [Prusa] will be selling this as a kit for ~19000 Czech Crowns or $699 USD, but he’s RepRap to the core. Buy a spool and start printing your next printer.


Hacklet 107 – 3D Printing Projects

3D printers have forever changed the hardware hacker movement. From the original RepRap project on up through current commercial offerings, 3D printers have become an indispensable tool for hackers, makers, and engineers. While printers may not have started a desktop manufacturing revolution, they are a desktop prototyping evolution. It’s rare for a day to go by on Hackaday without a project that uses a 3D printed part in some way shape or form. These printers also continue to evolve, with new projects pushing the technology ever forward. This week’s Hacklet is all about some of the best 3D printer projects on Hackaday.io!

reprapWe start with [TTN] and Icepick Delta. [TTN’s] passion is creating 3D printers as cheaply as possible. The Icepick definitely succeeds at this. Icepick’s frame is made of wood. The motors are commodity steppers. Control is via the long proven Ramps 1.4 board, which can be picked up with drivers and an Arduino Mega clone for under $35 these days. A few ball bearings and metal parts fill out the vitamins of this design. Just about everything else is 3D printed in true RepRap style. The printer is currently running Marlin firmware, but [TTN] plans to move to Repetier in the future.

Even with these humble origins, Icepick manages to print at a very respectable 50 mm/s before frame flex becomes a problem.  Prints at 0.1mm layer height look great, on par with any current commercial printer.

strataNext up is  [Machinist] with 3D printer brain retrofit. Commercial 3D printers have been available for decades now. This means some of the older models are getting a bit long in the tooth. [Machinist] has a very tired 15 year old Stratasys Dimension 768. The mechanics of the Dimension are still in good shape, but the electronics have seen better days. [Machinist] is ditching all the old electronic hardware (and the DRM which goes with it) and setting this machine up with a Smoothieboard 5X. So far the Dimension has been gutted, and [Machinist] has gotten the monster stepper motors playing sweet music with his new control board. I can’t wait to see how this project progresses.

coffeeNext we have [jcchurch’s] Coffee Maker Delta 3D Printer. [jcchurch] has managed to convert an old Norelco coffee maker into a mini sized 3D printer. The warmer plate has even become a heated bed for ABS prints. Unlike Icepick up top, the aim of this design is to use as few 3D printed parts as possible. The idea is that this would be the first printer to build when you don’t have another printer handy. Think of it as a caffeinated RepStrap. According to [jcchurch], this printer has been running strong at Tropical Labs for over a year. You can even pull the delta assembly off and make a pot of coffee! The coffee maker printer is still somewhat of a teaser project. If you see [jcchurch] online, tell him to head over and give us more details!

linearFinally, we have [DeepSOIC] with linear stepper motor 3d printer. 3D printers all use good old fashioned rotary stepper motors. [DeepSOIC] is trying to eliminate all that rotary motion, along with the belts and pulleys required to convert to linear motion. Linear stepper motors can be thought of as regular stepper motors, just unrolled. They tend to be very expensive though, so [DeepSOIC] is building DIY versions. His first attempt was to print motor parts using BlackMagic3D’s ferromagnetic filament. This lead to a whole separate project to measure the permeability of the filament. Unfortunately, the filament isn’t permeable enough to act as a motor for a printer. [DeepSOIC] hasn’t given up though. This is the type of project we love – one that might not work out, but really gets people thinking. Check out the comment thread on the project to see Hackaday.io collaboration at work!

If you want to see more 3D printer projects, check out our updated 3D printer list! If I didn’t wake up early enough to catch your project, don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Fail Of The Week: My 3D Printer Upgrade

After years of cutting my hands on the exposed threads of my Prusa Mendel i2, it was time for a long overdue upgrade. I didn’t want to just buy a new printer because it’s no fun. So, I decided to buy a new frame for my printer. I settled on the P3Steel, a laser cut steel version of the Prusa i3. It doesn’t suffer from the potential squaring problems of the vanilla i3 and the steel makes it less wobbly than the acrylic or wood framed printers of similar designs.

My trusty i2. Very sharp. It... uh.. grew organically.
My trusty i2. Very sharp. It… uh.. grew organically.

I expected a huge increase in reliability and print quality from my new frame. I wanted less time fiddling with it and more time printing. My biggest hope was that switching to the M5 threaded screw instead of the M8 the i2 used would boost my z-layer accuracy. I got my old printer working just long enough to print out the parts for my new one, and gleefully assembled my new printer.

I didn’t wait until all the electronics were nicely mounted. No. It was time. I fired it up. I was expecting the squarest, quietest, and most accurate print with breathtakingly aligned z-layers. I did not get any of that. There was a definite and visible ripple all along my print. My first inclination was that I was over-extruding. Certainly my shiny new mechanics could not be at fault. Plus, I built this printer, and I am a good printer builder who knows what he’s doing. Over-extruding looks very much like a problem with the Z-axis. So, I tuned my extrusion until it was perfect.

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Threadless Ballscrew for 3D Printer

[2n2r5] posted up a mechanism that we’d never seen before — a threadless ballscrew that turns rotational into linear motion with no backlash. It works by pressing the edge of three bearings fairly hard up against a smooth rod, at an angle. The bearings actually squeeze the rod a little bit, making a temporary indentation in the surface that works just like a screw thread would. As the bearings roll on, the rod bounces back to its original shape. Watch it in action in the video below.

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3D Cocooner (3D Lattice Printer)

Sometimes it feels like we haven’t yet tapped into all the possibilities of additive manufacturing. Festo, a company that loves to try innovative things (and not always bring them to market), just came up with something called the 3D Cocooner — essentially, a rostock style 3D printer on its side, with a UV cure feature to allow it to build up skeletal structures and lattice style shapes.

Similar to the MX3D-Metal 3D printer (which is currently on a mission to build a bridge end-to-end — by itself), this 3D printer specializes in printing structures as opposed to the more traditional layer approach. It’s called the 3D Cocooner as it is a bionic technology platform designed to “spin” complex lattices, very similar to naturally occurring structures.

The cool thing is, it’s not actually using plastic filament like most printers — it’s actually printing using string! The string is covered with a special UV resin which is then hardened into place as soon as it is expelled from the print head — making this more like a giant robot spider than a 3D printer.

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Stealing 3D Prints By Sound

In the open hardware world, we like to share 3D design files so that our friends and (global) neighbors can use and improve them. But we’ve all printed things from time to time that we’d like to keep secret. At least this is the premise behind this article in Science which proposes a novel method of 3D-printer-based industrial espionage: by recording the sound of the stepper motors and re-creating the toolpath.

Unfortunately, the article is behind a paywall so we’re short on the details, but everyone who’s played the Imperial March on their steppers has probably got the basic outline in their mind. Detecting the audio peak corresponding to a step pulse should be fairly easy. Disentangling the motions of two axes would be a bit harder, but presumably can be done based on different room-acoustic filtering of the two motors. Direction is the biggest question mark for us, but a stepper probably has a slightly audible glitch when reversing. Keeping track of these reversals could do the trick.

What do you think? Anyone know how they did it? Does someone with access to the full article want to write us up a summary in the comments?

[Thanks LVfire via Ars Technica]

[Edit: We were sent a copy of the full article (thanks [PersonUnknown]!) and it doesn’t explain any technical details at all. Save yourself the effort, and have fun speculating, because reading the article won’t help.]

Error Correction of 3D Printers

From the very first RepRaps to the newest and latest printers off the Makerbot assembly line, nearly every consumer 3D printer has one significant shortcoming: it cannot recover from missed steps, slipped belts, or overheating stepper drivers. Although these are fairly rare problems, it does happen and is purely a product of the closed open-loop control system used in 3D printer firmware.

[Chris Barr] has come up with a rather clever solution to this problem. He’s designed a system that will detect and correct problems with the mechanics of 3D printers. It’s technically not a closed-loop control system, but it does allow him to get the absolute position of a nozzle on the build plate, detects error states, and can automatically calculate the number of motor steps per millimeter. It’s also much simpler than other closed loop control systems we’ve seen in the past, requiring only a few bits and bobs attached to the axes and to the printer controller board.

[Chris]’ system uses a magnetic encoding strip, a single chip, and a little bit of support circuitry. It’s actually not that much different from the moving axis on a desktop inkjet printer. It’s not closed loop, though; the firmware hack is only a ‘basic error correction’ that moves the nozzle back to where it should be. Although this is somewhat of a kludge, it is much simpler than refactoring the entire printer firmware.

In the video below, [Chris] demonstrates his solution for error correcting the printer by jerking his axis around during a print. The nozzle miraculously returns to where it should be, producing a usable part.

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