Color switching for three-dimensional printing

摘要

By reversing the direction of a first build material fed into an extruder, the first build material can be wholly or partially evacuated from the extruder before a second material is introduced. This approach mitigates transition artifacts and permits faster, more complete changes from one build material to another.

主权项

1. A method comprising:
providing a three-dimensional printer having an extruder with a first input port, a second input port, an extrusion port, and a chamber coupling the first input port, the second input port, and the extrusion port in fluid communication; driving a first build material through the first input port until the first build material extrudes through the extrusion port; withdrawing the first build material through the first input port a predetermined amount, wherein the predetermined amount is selected to move a material transition region between the first build material and a second build material out of the chamber but not enough to completely withdraw the first build material from the extruder; and driving the second build material through the second input port until the second build material extrudes through the extrusion port.