Development of rapid heating cycle molding using heater and process parameters optimization

Abstract

Plastic injection molding (PIM) is a manufacturing technology to plastic products, and it is important to determine optimal process parameters for high product quality and high productivity. Weldline that are formed when two or more melt fronts meet should be reduced for high strength and high surface quality. Rapid heating cycle molding (RHCM) that the mold is heated up is an attracted PIM technology for weldline reduction, but long cycle time is generally required. In this paper, an RHCM incorporating a heater system is used, and the process parameters optimization is performed. To determine the optimal process parameters, multi-objective optimization for minimizing both weldline and cycle time is considered. The numerical simulation in RHCM is computationally so expensive that sequential approximate optimization that the response surface is repeatedly constructed and optimized is adopted for the design optimization. The pareto-frontier is identified through the numerical simulation, and the experiment using PIM machine (MS100, Sodick) is also conducted. It is found from the numerical and experimental result that the RHCM using the heater system is effective to the weldline reduction.