METHOD OF MOLDING COMPLEX STRUCTURES USING A SACRIFICIAL MATERIAL
A number of processes are described herein that can be used to form complex parts with undercuts and the like. In one embodiment, a multi-shot process is used to form the sacrificial component and inject the PIM feedstock. The processes described herein may reduce the number and/or severity of defects in the final part.
1 . A method of molding a part comprising:
molding a sacrificial component;
molding the part over the sacrificial component; and
wherein the sacrificial component is molded in one or more shots in a molding press and the part is molded over the sacrificial component in one or more additional shots in the molding press.
2 . The method of claim 1 wherein the sacrificial component is molded in one or more shots in a molding press and the part is molded over the sacrificial component in one or more additional shots in the molding press.
3 . The method of claim 1 comprising debinding the part.
4 . The method of claim 3 wherein debinding the part includes catalytically debinding the part.
5 . The method of claim 3 wherein debinding the part includes thermally debinding the part.
6 . The method of claim 3 wherein debinding the part includes chemically debinding the part.
7 . The method of claim 1 comprising sintering the part.
8 . The method of claim 1 wherein the part includes a binder and the sacrificial component and the binder have at least substantially the same composition.
9 . The method of claim 1 wherein the sacrificial component includes polyacetal based material.
10 . The method of claim 1 wherein the part is made of injection molded plastic.
11 . A multi-shot process for powder injection molding a part comprising:
molding a sacrificial component in one or more shots in a molding press; and
molding the part over the sacrificial component in one or more shots in the molding press.
12 . The multi-shot molding process of claim 11 wherein the part includes a binder and the sacrificial material and the binder are capable of being removed simultaneously from the part.
13 . The multi-shot molding process of claim 11 comprising debinding the part.
14 . The multi-shot molding process of claim 13 wherein debinding the part includes catalytically debinding the part.
15 . The multi-shot molding process of claim 11 comprising sintering the part.