Experimental Ejection Forces of Thermoplastic Parts From Rapid Tooled Injection Mold Inserts (Preprint)

摘要

The application of rapid prototyped tools for injection molding, if technically feasible, may allow for small quantity production by reducing the cost of tooling. This work has investigated one aspect of the technical feasibility through testing and experimentation to determine ejection force requirements and coefficients of friction. Injection molding experiments were conducted using three mold insert materials, P-20 steel, laser sintered ST-100, and stereolithography SL 5170 resin. Ejection forces for cylindrical parts molded with high density polyethylene and high impact polystyrene were measured directly and compared with values calculated from an ejection force differently, depending on the materials characteristics. Results show that ST-100 is a good candidate for injection molding tools, and that SL 5170 might be a candidate for molding some thermoplastics, but only in very small quantities.