LAUSR

A combined in-mold decoration and microcellular foaming injection molding process (IMD/Mucell) is proposed to improve the surface quality of foamed parts. Through theoretical inference, the mathematical models of temperature field, velocity profile and forces on bubble were established with combining traditional mathematical models and the different heat transfer coefficient of the mold inner surface. The effects of the non-isothermal mold on the bubble structure and forming process of inter bubble were investigated with experiments and numerical simulation. Results showed that the critical pressure of the cavity existed in the melt filling and bubble expanding stage, and it affected the cells structure obviously at the filling stage. The lift force took the bubbles to the film side based on the velocity profile of viscous fluid, and maximal bubble was closer to the transition layer with film due to higher temperature. In the combined process, the evolution rule of superficial bubbles was analyzed, and results showed that the surface quality was improved in the film side.