How Mixee Mes are Made: adventures in fullcolor 3d printing

Mixee Me is the most popular product on Mixee Labs, and recently a top product on Fab.com. Let’s take a look at the magic behind how these little mini-me figures are produced.

About the Material

Mixee Mes are 3d printed in color. All the details—the facial features, shirt patterns—are already on the model when it comes out of the printer. This material, commonly called “fullcolor sandstone,” is a formulation of gypsum. It is not technically sandstone, but it is named such because it feels like sandstone—a little rough and sandy. Some people call it full color plaster, others call it ceramics. Just like ceramics, if you drop it on the ground, it might crack and break.

The Printing Process

The printing process begins with the printer spreading a fine layer of powder on the print-bed. Then print heads—which are very similar to the type found in your 2d inkjet printers—drop bits of glue and pigment ink onto this layer, glueing pieces of the powder together. After one layer is finished, another layer of powder is spread out on top. Rinse. Repeat. Actually scratch that. DO NOT RINSE! Because the print head use inkjet printer ink, if your Mixee touches water, the ink will run and the colors will get ruined. It is basically the same effect as if you were to expose 2d inkjet printed papers to water.

Ok. Where we we? Oh yes, layer by layer your the model is glued together. After a few hours, you get solid models buried in a block of powder. 3d printing technicians carefully dig out the models and recycle all excess powder so there is little waste.

In the photo above, a technician is digging a 3d printed model from the print tray. Next, the Mixees are dipped into cyanoacrylate, the same chemical used to make superglue. This chemical dries quickly, brightening and sealing in the color on the models. Last, a thin layer of wax is applied to the Mixees to give them a more polished finish.

Digression, a bonus trivia fact

Did you know that this is actually 3d printing? Nowadays, “3d printing” is a term used for many different processes which can convert digital files to physical objects. But 3d printing, in the original sense, applies to a very specific process—one in which inkjet printhead(s) deposit glue on powder one layer at a time. The most well-known “3d printer” MakerBot, as well as that of many other desktop printers use a process called Fused Filament Fabrication, which is technically not even 3d printing! But now, the term 3d printing is used more broadly, so let’s go with that. Even Wikipedia defines 3d printing broadly, and thus it must be so.

What’s next?

There are very few processes on the market these days that can actually print different colors directly onto the model. Our process, which utilizes ZCorp machines, can do it. There’s also a company called MCor that makes printers that 3d prints in color. But that’s about it.

This is a ripe area for 3d printing research. I look forward to the day when I can use a 3d printer that (a) prints in a wide range of colors (b) on a durable material with (c) high details and (d) smooth finishing, and (e) can produce models that are reasonably priced. Whoever hits all five of these challenges will take the industry to a whole new level.

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