Hands On With Filament Splicing Robots

The future of 3D printing, it seems, is in multimaterial filament printers. The Prusa I3 multimaterial upgrade exists, and this weekend at MRRF E3D announced their amazing multihead printer. Multimaterial printing will get you mechanical parts with the properties you want, like wheels with grippy treads and strong hubs. It will give you easily removable support material. The most popular use, though, is bound to be multicolor prints. It’s easier to do, as you’re really only working with either ABS or PLA, and if you’re really clever, you can squeeze everything through a single nozzle.

While there are some very ingenious ways of printing in multiple colors of filament, one technique that hasn’t gotten a lot of attention is automated filament splicing. With this, a piece of software analyzes a model, and combines multiple spools of filament into one long strand. A machine that’s getting a lot of attention is the Palette+ from Mosaic Manufacturing. There were a few of these on hand at this weekend’s Midwest RepRap Festival, and here anyone could get a hands-on with this machine without spending $800.

When it comes to multicolor and multimaterial prints, the first question that comes to mind is the toolchain and the process of turning an STL file into a physical object. The Palette+ uses a piece of software called Chroma that takes STL files as its input. Each color in the object to be printed is actually a separate STL file, combined on Chroma’s build platform. The Charmander print shown above is actually four different prints; the white eyes are one STL, the orange body is a second, the yellow belly is a third, and the red flame on the tail is a fourth STL. In the Chroma app, these STLs are assembled, colors are assigned, and a file generated that’s stored on an SD card and shoved in the Palette robot. The Palette then assembles a custom length of filament with the right colors in the right places. Combine this with some G-code from your favorite slicer, and you have everything you need for multicolor printing with the printer you already own.

The results are fantastic, and the best I’ve ever seen from a multicolor filament-based printer, whether it’s a dual-extrusion head, Prusa’s Multimaterial upgrade, or a bizarre machine with multiple toolheads.

Of course, there are downsides. Because the Palette is designed for single-extruder printers, you’re not going to be able to combine ABS and PLA filament. Combining fancy engineering plastics and colorful PLA is right out. This is a machine that can only use one type of plastic at a time.

That said, we’re getting very, very close to an era of true multicolor printing. Of course, this machine costs as much as a good 3D printer, but if you just want to print some colorful blobs of plastic, I haven’t seen anything better.

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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