| 摘要 |
A rapid prototyping system has a liquifier carried by a extrusion head. The liquifier is formed of a single piece of thin-wall tubing preferably made of metal, encased in a heating block. The thin-wall tube has a inlet end for receiving a filament of molding material and an outlet end for delivering the material in liquid form. A first section of the tube adjacent the inlet end functions as the entrance or cap zone. This first section of the tube is exterior to the heating block. The tube has a second section which passes through the heating block forming a heating zone. A nozzle can be formed by swaging the outlet end of the tube to a nozzle geometry, or, a nozzle may be brazed or welded to the outlet end of the tube. The heating block preferably contains a heating element in heat exchange relation to the second section of the tube to heat the filament to a temperature just above its solidification temperature. The extrusion head may alternatively carry two liquifiers that share a common nozzle, for receiving and dispensing two different materials.
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