Influence of Injection Molding Process Parameters on Part Quality

Abstract

A case study to determine the influence of injection molding process parameters on part quality is performed. Part quality is evaluated based on deflection rate, volumetric shrinkage, and sink mark depth results. Considered process parameters are mold temperature, melt temperature, injection time, pack time, pack pressure and cooling time. A thin walled butterfly valve flap and a thick walled butterfly valve shaft are analyzed separately. Polypropylene is used as molding material. A design of experiment based on the Taguchi method is generated for both parts and a computer simulation to solve the case matrixes is executed. Relative process parameter influence on each individual quality criteria is determined by analysis of variance. Importance of process temperatures as well as parameter impact dependence on characteristic part shape is reveled.