Based on the same principle responsible for transition lenses in glasses, researchers at MIT Computer Science and Artificial Intelligence Laboratory (CSAIL) have made 3D printed objects capable of changing color.
The idea is that the chameleon-like properties could one day be added to jewelry and clothes so, instead of buying a sweater in 10 different colors, you could have just one that changes to suit the weather (and your mood.)
How does a chameleon object change its color?
CSAIL’s color changing method is called ColorFab (not to be confused with Dutch filament maker colorFabb). ColorFab’s secret ingredient is a selection of light-reactive “photochromic” inks in red, yellow and blue.
Each color is inkjet 3D printed as a 3D pixel, or voxel, across the surface an object. By exposing these pixels to a projector, they are activated or deactivated, changing the overall color. The ink’s unique solution means that the process can be repeated multiple times.
The process can simply be done in on a PC. A photochromic surface is automatically added to a given .stl file before it is 3D printed. Then, when the user wants to change the color, they can simply “paint” the object, and the program determines how long the object must be exposed to light .
The concept behind the CSAIL study is that color changing objects could help reduce the amount of things people purchase. Such qualities could be added to almost anything, from phone cases to clothes and shoes.
Professor Stefanie Mueller, a member of the CSAIL team explains, “Largely speaking, people are consuming a lot more now than twenty years ago, and they’re creating a lot of waste,”
“By changing an object’s color, you don’t have to create a whole new object every time.”
In the next stages of development the team will be looking at how to reduce the size of pixels to give colors a better resolution, and make the ColorFab process more mobile. “Our long-term goal,” explains the study’s conclusion, “is to allow users to recolor objects while on the go using a smart phone with an integrated micro-projector and UV light.”
Multimaterial 3D printing and voxels at CSAIL
The study of inkjet technology and pixels/voxels is also key to a number of multimaterial 3D printing studies at MIT.
Another group at CSAIL demonstrated how voxels can be used to make metamaterial objects, and Neri Oxman’s Mediated Matter Group has patented a method that translates point-cloud data into a material jetting operation.
The paper for “ColorFab: Recoloring 3D Printed Objects using Photochromic Inks” can be found online here. It is co-authored by Parinya Punpongsanon, Xin Wen, David Kim and Stefanie Mueller.
Nominate award-winning research in the 2018 3D Printing Industry Awards here.
Featured image shows MIT’s color changing ring. Image via MITCSAIL on YouTube