Daniel G Sander

US Patent:

55143105, May 7, 1996

Filed:

Mar 25, 1994

Appl. No.:

8/217553

Inventors:

Daniel G. Sander - Grand Island NY

International Classification:

B29C 4402

US Classification:

264 37

Abstract:

An injection molding machine or extruder 10 for injecting a foamed thermoplastic material 82 into a mold 12 for forming a shaped article at a relatively low pressure. The injection molding machine comprises a barrel 20 housing a screw 22 disposed in a relatively loose clearance with respect to an inner surface 24 of the barrel. This loose clearance provides for churning a molten thermoplastic material into a foamed condition, which is then introduced into a mold. As the thermoplastic material cools, its foamed characteristic retards shrinkage of the thermoplastic material.