Effect of Overmolding Injection Parameters on Warpage of PMMA-PC Composite Board

Abstract

The influence of overmolding injection parameters such as packing pressure, racking time, melt temperature, mold temperature and the injection speed on the warpage of PMMA-PC composite boards was investigated. The result shows that the warpage of PMMA-PC composite boards exhibits the tendency of decreasing first and then increasing with the increase of packing pressure; However, the prolongation of packing time is beneficial to reduce the warpage of composite boards, increasing melt temperature and injection speed will lead to the increase of the warpage composite boards. When mold temperature increases, the composite boards bend towards the PMMA side. Asymmetrical cooling in the mold resulting in internal residual thermal stress in composite boards is the main reason of the increase of the warpage, when the mold temperature is 90℃, no warpage occurs in the composite boards. Among these parameters studied, mold temperature and packing time influence the most significantly on the warpage of the composite boards.

Keywords

• overmolding injection
• warpage
• polymethylmethacrylate
• polycarbonate