Mosaic Palette: Single Extruder Multi-Color and Multi-Material 3D Printing

Lots of solutions have been proposed and enacted for multi-color and multi-material 3D printing, from color mixing in the nozzle to scripts requiring manual filament change. A solution proposed fairly early on was to manually splice the filament together, making a custom spool. The printer would print as normal, but the filament would change color. This worked pretty well, but it was tedious and it wasn’t entirely possible to control where the color change happened on the model.

You’ll find some examples of the more successful manual splicing hacks in the pictures below. Scroll down a bit further to find our interview with Mosaic Manufacturing at Bay Area Maker Faire 2016. They have a new product that automates the filament splicing process with precision as the ultimate goal. It unlocks a single extruder printer to behave like a multi-extruder model without stopping and starting.

Mosaic pulled off a very difficult combination of two methods mentioned above. Their flagship product is a machine they’ve dubbed, “Palette”. It’s an automatic filament splicer. Up to four different filaments can feed into Palette, and it will splice them at determined intervals. This would be cool by itself, if only to save the tedium of splicing and winding a custom spool by hand.

The real killer app with Palette, however, is the software that runs alongside it. Palette can take the GCODE output of any properly prepared multi material file from any slicer, and then precisely combine and splice the filament. This can feed into any printer without modifying it, aside from sticking an encoder somewhere in the filament path. The results are indistinguishable from a dual, or quad extruder set-up.

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Hackaday Links: June 12, 2016

The Navy is doing some crazy stuff out in China Lake. They were planning to test something out that could potentially make GPS unusable from San Diego to Las Vegas to San Francisco. Those plans were cancelled for ‘internal’ reasons. They will be testing something in Indiana shortly, though. What are they doing? Who knows. That’s what idle speculation in the comments section is for.

3D Hubs, the distributed ‘3D printing service’ thing, now has 30,000 machines distributed around the globe. They also put together the definitive guide to 3D printing recently. For just about everyone reading this, a ‘introduction to 3D printing’ is old news, but this is a very good guide for telling your weird aunt what you’re building in the basement. Forward this one to your family on Facebook.

This one is amazing. Over on Hackaday.io, [Arsenijs] is working on a Raspberry Pi project. It uses a Raspberry Pi, and several accessories and components to make this Raspberry Pi project work. This Raspberry Pi project is already getting far more than the usual number of likes and follows, making this one of the most interesting Raspberry Pi projects in recent memory.

Moog is re-releasing the Minimoog, the original Moog synth from 1970. That’s cool, but what about a DIY Minimoog? That’s what [Scott Rider] is doing with the Crowminius Analog Music Synthesizer on Kickstarter. It’s an analog synth that’s more or less a Minimoog with MIDI, and one of the Kickstarter rewards is a bare PCB.

The future is dancing robots, so here’s a servo-driven Stewart platform that is sure to bring on the robot apocalypse.

What do you do when you need to get your Hackaday fix, but all you have is a laptop from 1995 and a dial-up modem? The Hackaday Retro Edition, of course. That’s a bunch of retro Hackaday posts, posted five at a time, with all the CSS and JavaScript cruft stripped. We’re always interested to see the old machines that are pulling the retro edition down, and [djnikochan] has the latest entry. He found a Thinkpad 380ED from 1997 at the Goodwill store for $15. The RAM was upgraded with a 64MB SIMM, giving this machine a total of 80MB. The Hackaday Retro Edition is viewable with IE 5.5 over a trusty PCMICA WiFi card. Awesome job, and we love to see old iron rendering the retro edition. Send some pics in if you get your old battlestation to load it.

Plastic cutter made of 3.5” floppy disk

This is so cool; an unexpected use for an antiquated digital storage medium. [DeepSOIC] built a cutter that shaves off plastics but cannot cut through metal. It’s made out of the media part of a 3.5” floppy disk. For the new kids, here’s what a Floppy Disk is.

The disk is attached to any high speed DC motor connected to a plain ol’ power supply – variable if you want to adjust speed. As you can see from the video after the break, it cuts through plastic quite well, but is unable to damage any metal that it encounters. This property makes it extremely handy for many applications. Want to strip through an old 3.5mm phono jack without damaging the wires? Want to wind a coil over a plastic former and then strip away the plastic? Want to trim some 3D printed parts? All game for this handy tool. According to [DeepSOIC], if you don’t have floppy disks, you can use other kinds of plastic films too – such as overhead transparencies or plastic printer films. If you are in a pinch, he claims even paper works, although it doesn’t last too long. Don’t throw away all of those business cards yet.

This isn’t the only trick up his sleeve. He’s documenting a whole series on his project page at Hacks and Tricks. And if you like these, then also checkout [RoGeorge]’s bag of tricks over at The Devil is in the Details.

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3D Internal Structure For Better 3D Printed Objects

Makerbot is in the gutter, 3D Systems and Stratasys stock is only a shadow of their 2014 glory, but this is the best year 3D printing has ever had. Machines are now good and cheap, there’s a variety of various thermoplastic filaments, and printing useful objects – instead of just plastic trinkets – is becoming commonplace.

Gradient-Grid
The standard rectilinear infill from Slic3r

There’s one area of 3D printing that hasn’t seen as much progress, and it’s the software stack. Slicing, the process of turning a 3D object into a Gcode file for a printer has been basically the same for the last few years. Dual extrusion is still a mess, and automated bed leveling is still in its infancy.

One aspect of slicing that has been severely overlooked is infill. Obviously, you don’t want to print plastic trinkets completely solid – only the outside surface matters, and a part with 100% infill is just a waste of plastic. Different slicers have come up with different ways of filling the inside of a print, usually with a grid of squares, triangles, or hexagons.

While the most popular methods of filling in a 3D printed objects do the job of adding a little bit of strength to a print and supporting the top layers of a print, it’s not an ideal solution. The desired strength of the finished part is never taken into account, print artifacts are sometimes visible through the side of a print, and the spacing of the infill grid is completely arbitrary. You can only set a percentage of infill, and telling a slicer to make an internal support grid with 10mm spacing is impossible.

Type A Machines just changed all of this. With the release of their public beta of Cura Type A, the infill for a 3D printed part is also 3D. The dimensions of the infill are predictable, opening the door to stronger and better looking parts.

From the Type A press literature and white paper, this new type of ‘infill’ isn’t; it’s more properly referred to as ‘internal structure’, with proper dimensions between infill features. Instead of a grid of squares or triangles stacked one layer on top of each other, it’s a true structure, with the infill following the perimeter of the 3D printed object.

Generating 3D Infill

3D
Infill generated from Type A Machine’s Cura beta. Note the 3D structure of the infill.

Right now, infill is generated in a slicer by specifying a percentage. Zero percent infill means a hollow object, and 100% infill is a completely solid part. These two edge cases are easy, but anything else means the slicer must fill the part with filament in a grid of tessellating shapes, either rectangles, triangles, or hexagons. With current slicers, the dimensions of this internal structure are, for all practical purposes, random. Printing an object with 20% infill might mean a grid of squares with 5mm or 2mm spacing. Telling the slicer to infill a part with a grid of squares spaced 10mm apart is impossible.

Type A Machine’s latest Cura release changes all of this, allowing a designer to set a precise distance between rows and columns of infill. By defining infill in absolute dimensions, this allows for stronger parts using less infill.

Absolute dimensioning is only one feature of the Type A Machine’s latest release of Cura. Even more exciting is the development of 3D internal structure. Instead of stacking layers of squares, triangles, or hexagons on top of each other, Type A Machine’s Cura uses an infill of cubes turned on their side. While each individual layer of infill looks like a series of triangles and irregular hexagons, when assembled into a printed 3D object, this infill forms a true 3D structure.

The closest comparison to this sort of structure is the difference between graphite and diamond. Both of these materials are made out of the same element, carbon. The physical structure of graphite is just, 1-atom-thick layers of graphene, producing a relatively weak material. Diamond, on the other hand, has a true 3D structure and is one of the hardest materials known to man. While adding 3D structure to the infill of 3D printed objects won’t make the objects any stronger, it will drastically reduce delamination, and be much more resistant to stresses in all three dimensions.

While Type A Machines has done some great work here, it does mean there’s yet another version of Cura to deal with. Type A Machine’s Cura, in addition to the LulzBot edition and the original are now the defacto standard for turning 3D objects into printed parts. Having an open source solution is great, but forking the development this much surely can’t be ideal.

The Hacker is The Future of the Prosthetic: Hackers Helping Those In Need

Rush_valley
Even the city’s welcome sign is held high by two prosthetic arms.

In the show Full Metal Alchemist, there’s a city called Rush Valley whose main and only business are the high performance prostheses called Automail. Engineers roam the street in Rush Valley; the best have their own shop like that of the high-end clothiers in Saville Row. Of course; it’s all fantasy set in a slightly ridiculous Japanese cartoon, but while walking through this year’s Maker Faire I began to wonder if is a future that may come to be.

The problem with prosthetics is the sheer variety of injuries, body types, and solutions needed. If an injury is an inch higher or an inch lower it can have a big effect on how a prosthetic will interact with the limb. If the skin is damaged or the nerves no longer function a different type of prosthesis will be needed. Some prostheses are to replace a lost limb, others are to assist an ailing body in order to return it to normal function. More than a few are simply temporary aides to help the body along in its healing efforts. Unfortunately, this means that it’s often the case that larger companies only sell the prostheses people are most likely to need; the rarer cases are often left without a solution.

The e-Nable project doesn't mess around.
The e-Nable project doesn’t mess around.

However, we see hackers stepping up and not just working on the problems, but solving them. One of our semifinalists last year, openbionics, inspired one of the projects we’ll be talking about later. There are robotic legs. We met a guy at MRRF who has been 3D printing hands for his son from the E-nable project.

Along these lines, we saw two really cool projects at Maker Faire this year: The first is the Motor-Assistive Glove, or MAG. MAG is designed to help people with Peripheral Neropathy regain some use of their hands while they go through the lengthy road to recovery. Perhipheral Neuropathy is a disease, usually resulting from diabetes, toxin exposure, or infection, where the nerves are damaged in such a way that typically the hands and feet are no longer mobile or feel sensation in a useful way. Once the disease is in full swing, a previously able person will find themselves unable to do simple things like hold a can of soda or grasp a doorknob firmly enough to open it.

The Motor Assistive Glove
The Motor Assistive Glove

We had a chance to interview one of the members of the MAG team, [Victor Ardulov], which you can see in the following video. [Victor] and his group started a research project at the University of Santa Cruz to develop the Motor-Assistive Glove. The concept behind it is simple. People with Peripheral Neuropathy typically have some movement in their hands, but no strength. The MAG has some pressure sensors at the tips of the fingers. When the user puts pressure on the pad; the glove closes that finger. When the pressure is off; the glove opens. The concept is simple, but the path to something usable is a long one.

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Hexapod Tank from Ghost in the Shell Brought to Life

Every now and then someone gets seriously inspired, and that urge just doesn’t go away until something gets created. For [Paulius Liekis], it led to creating a roughly 1:20 scale version of the T08A2 Hexapod “Spider” Tank from the movie Ghost in the Shell. As the he puts it, “[T]his was something that I wanted to build for a long time and I just had to get it out of my system.” It uses two Raspberry Pi computers, 28 servo motors, and required over 250 hours of 3D printing for all the meticulously modeled pieces – and even more than that for polishing, filing, painting, and other finishing work on the pieces after they were printed. The paint job is spectacular, with great-looking wear and tear. It’s even better seeing it in motion — see the video embedded below.

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Feeding The Cat, Reinventing the Wheel

There are few projects that we see as many iterations of as the pet feeder or the plant waterer. (What is it with you people? Are you all as forgetful as we are?) Still, the fun is in the details of the implementation. Or at least that’s the case with [Emmaanuel]’s cat feeder.

The writeup is split into three parts: the worm-drive, the electronics, and the housing (here in English: worm, electronics, housing). And of course, there’s a video inlined below.

The auger and motor housing make great use of PVC pipe and 3D printing, and the dispenser unit looks quite professional. There’s not all that much to say about the electronics — an Arduino clone, an LCD, and a cheap gear motor do just about what you’d expect.

The CNC’ed case with spring-fit tabs steals the show, however. It’s made out of MDF, which doesn’t take well to screwing or glueing. With carefully routed pins and tabs that have a little spring in them, [Emmaanuel] was able to take the pieces off the mill table and just snap them together. Awesome.

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