Enhancing the joining strength of injection-molded polymer-metal hybrids by rapid heating and cooling

The design of a variotherm injection mold and the corresponding temperature control system for metal-polymer joining was reported. Due to the importance of understanding the heat transfer process and metal temperature variation during the molding cycle for developing the above method of polymer-metal hybrid (PMH) formation, the thermal response of the metal surface was evaluated. The existence of a correlation between metal surface temperature and tensile lap shear force was revealed, and the surface temperature resulting in the best mechanical performance was determined. Finite element simulation was used to investigate the effect of metal surface temperature on the behavior of the melt flow thereon, revealing that air retained in the metal surface microstructures significantly affected PMH bonding strength. The fracture surfaces of PMH samples molded at different metal surface temperatures were examined, and the underlying fracture mechanism was explained.