3D printing objects in two colors using a dual extrusion setup; many makers dream of doing that in the comfort of their own home, without having to fear the dreaded ooze (i.e. colors dripping where they don’t belong). While that kind of dual extrusion FDM 3D printing is becoming increasingly available, Microsoft is already looking to take things one step further. They have just patented a new 3D printing technique that creates mixtures of 3D printable materials with a 2D printer’s CMYK colors plus white, allowing it to 3D print objects in any and full-color.

 Of course patents don’t always translate into 3D printing hardware immediately; it could take years before such a 3D printer sees the light of day, while Microsoft could even just be heading off a competitor by filing for a patent. Nonetheless, the concept is brilliant and approved as US patent 9,434,108. It was filed by Yulin Jin, Emmett Lalish, Kris N. Iverson, Jesse McGatha and Shanen J. Boettcher on behalf of Microsoft Technology Licensing. “It demonstrates a persistent investment by Microsoft to improve the state of the art in the 3D space,” Iverson said to 3ders.org.
So how does it work? In a nutshell, this patent covers various techniques for mixing CMYKW (cyan, magenta, yellow, key or black and white) 3D printable materials and expressing the design from computer software to a physical device – from CAD model to 3D printed object.

A number of existing techniques already allow users to produce 3D printed objects in multiple colors, but these lack the ability to represent the full gamut of colors in a color space – unlike a 2D color printer. “In addition, none of the conventional technologies are capable of determining exactly which color to produce because they are not capable of translating a full-color model into machine instructions to 3D print them,” the Microsoft team writes. “Limitations imposed by such conventional technologies inhibit full color three-dimensional object fabrication.”

While technology patents are necessarily very broad to cover all bases, the Windows team seems to overcome this problem by attaching color information to each and every sliced layer and polygon. As a result, they will generate two-dimensional polygons on each layer based on colors on faces, colors on textures, and/or gradient colors. Their technique further determines a tool path for fabricating those color schemes from colored but unspecified 3D printable materials (could be plastics, could be resins). All polygons of one color are 3D printed before switching colors, while it also smooths down exterior layers of full colors. What’s more, transitional material is deposited in an infill area and also used for support structures.