Characterization of an Injection Molding Process for Improved Part Quality

An injection molding process was characterized with respect to certain physical characteristics of an injection molded part. The produced part, the “Triconnector”, is a planar Lego-like piece, which was shot from ABS thermoplastic on a Morgan-Press G-100T Injection Molding Machine. Using statistical design of experiments, we identified the most significant parameters affecting part quality. The parameters used fell into three main categories: machine, process, and material. Part quality was defined by part fill, sink, and flash. Predictive models of part quality were developed and tested. It was found that ram speed, mold pre-heat, and nozzle temperature most affect part fill. Similarly, it was found that barrel temperature and cycle time most affect the sink of the sprue. A reliable predictive model for flash could not be developed, as there was too much variability in the results.