Partial Solidification Ejection Criteria for Injection Molding Production to Reduce Cycle Time

Productivity is essential in the injection molding process, especially for plastic parts featuring thick walls. However, for this process, product elastic and plastic deformations after in-mold cooling impose severe constraints on productivity enhancement. Due to the complexity of the molding process, producing high-quality plastic parts in less cycle time is still difficult even with the help of advanced molding simulation packages. The authors propose a new ejection criteria model based on a recently published concept of partial solidification for early ejection in plastic part molding and investigate the general time determination model targeting to reduce the cycle time tremendously. A real industrial case study has been provided to show the procedure and its verification. Compared to the traditional ejection criterion which the plastic parts need to be fully solidified by in-mold cooling, with the new criteria, the cycle time could be significantly reduced if the plastic parts are ejected earlier with qualified and controlled partial solidification.