Injection Molding Process Optimization of Polypropylene using Orthogonal Experiment Method Based on Tensile Strength

Abstract

The process parameters have direct influence on the performance and quality of final products of polypropylene (PP) in injection molding. In order to optimize injection molding process of PP and obtain expected tensile strength, tensile tests designed according to orthogonal experiment method of 7 factors at 3 levels were carried out on the injection molding machine, and relevant data were analyzed by range analysis method. The results show that, in the scope of given experiment, the process parameters affecting tensile strength of PP from high to low are injection pressure, melt temperature, cooling time, packing time, packing pressure, mold temperature and injection rate, and the optimal values of injection molding process parameters are melt temperature 200°C, injection pressure 5 MPa, injection rate 200 mms−1, packing pressure 3 MPa, packing time 40 s, cooling time 40 s and mold temperature 40°C, which is further verified by additional test.