Colored fused filament fabrication

Fig. 1. Our technique enables color printing with precisely controlled gradients using a filament printer. Le : The printer is equipped with an o -the-shelf nozzle that inputs multiple filaments (three in the picture) and outputs molten mixed plastic through a single exit hole. Such devices cannot directly be used to print gradients: the transition between mixtures takes time, and this timing varies unpredictably. Middle: Using our technique, a user can 3D paint a virtual model and print an accurate, colored physical realization of her design. Printing uses standard, widely available materials (PLA, PET, ABS). Right: Our approach deposits sublayers of varying heights to reproduce colors. We optimize the choice of colors to reduce defects such as color fringes (a) and color stripes (b). These optimizations are especially important as filament printers produce relatively thick layers, visible to the eye. (a, le ) Color fringes appear due to interferences between colored sublayers across layer boundaries. (a, right) We optimize sublayer ordering to minimize this defect. (b, top) Without optimization, prints have visible color stripes as target color and sublayer colors mismatch. (b, bo om) We further optimize prints to minimize stripes.