Multi-material polymer filament for three-dimensional printing

Abstract

A thermoplastic filament comprising multiple polymers of differing flow temperatures in a geometric arrangement is described. A method for producing such a filament is also described. Because of the difference in flow temperatures, there exists a temperature range at which one polymer is mechanically stable while the other is flowable. This property is extremely useful for creating thermoplastic monofilament feedstock for three-dimensionally printed parts, wherein the mechanically stable polymer enables geometric stability while the flowable polymer can fill gaps and provide strong bonding and homogenization between deposited material lines and layers. These multimaterial filaments can be produced via thermal drawing from a thermoplastic preform, which itself can be three-dimensionally printed. Furthermore, the preform can be printed with precisely controlled and complex geometries, enabling the creation of a filament or fiber with a wide range of applications. A method is also described for including an interior thread that adds structural reinforcement or functional properties, such as electrical conductivity or optical waveguiding, to the filament.