Research on thermal stress, deformation, and fatigue lifetime of the rapid heating cycle injection mold

Rapid heating cycle molding (RHCM) is a novel plastic injection molding process. It can be used effectively to prevent many defects of products produced in conventional injection molding process. In this paper, the panel of large-size liquid crystal display TV was taken as an example. Thermal, deformation, and fatigue analysis models for RHCM injection mold were established. Firstly, by analyzing the heat transfer process of the RHCM mold, the temperature distributions on the mold cavity surface were studied. Secondly, through numerical simulation, the tendency of the stress and deformation of the RHCM mold was obtained. It showed that the fixing mode between the stationary mold insert and the stationary mold plate had a great influence on the thermal stress and deformation of the mold. As a result, a new fixing mode for the stationary mold insert was proposed which could effectively decrease the deformation caused by the temperature changing. Lastly, the lifetime of the mold under different fixing modes was evaluated, and reasonable suggestions which could improve the lifetime of RHCM mold were also proposed. Application in engineering proved that it was a very effective way to improve the lifetime of RHCM mold by using the suggested fixing mode.