Patent ID: 8827684

Claim:
A fused filament fabrication printhead unit comprising: a fixture; a plurality of stepper motors mounted to the fixture, each stepper motor of the plurality of stepper motors having a motor shaft and a filament drive gear mounted to the motor shaft; portions of the fixture forming a plurality of filament guide paths, each of the plurality of filament guide paths arranged to guide a filament through the fixture and into engagement with one of the filament drive gears, such that rotation of the filament drive gear drives the filament along one of the plurality of filament guide paths; an extrusion module mounted to the fixture in filament receiving relation to the filament guide paths, the extrusion module further comprising: at least one insulating standoff having a thermal conductivity of less than 5 W/(m·K) mounted to the fixture and supporting a nozzle block with a thermal conductivity greater than 25 W/(m·K); a heating element arranged in thermal contact with the nozzle block for heating the nozzle block; wherein portions of the nozzle block form a plurality of heated guide paths, each heated guide path leading to portions of the nozzle block forming a nozzle with a print tip; a plurality of thermally insulating filament guides having a thermal conductivity of less than 5 W/(m·K), each of the thermally insulating filament guides connecting one of the filament guide paths to one of the heated guide paths.