Influence of injection velocity and joint geometry on quality of insert molding

A study of the influence of the injection velocity and the joint geometry on the quality of insert molding is presented. The proposed approach was based on the rheological concept, and the optimal injection velocity of insert molding was determined through calculations of the relative viscosity with corresponding injection velocities. In addition, the influence of the joint geometry between two different materials on the adhesion performance was also evaluated experimentally. A newly designed wafer cassette storage box that consisted of a cover (polybutylene terephthalate) with a transparent window (polycarbonate) and a base was given to demonstrate how to implement the methodology. Besides injection velocity, this study shows that the joint geometry is also a significant factor in improving the adhesion strength between the cover and the transparent window.POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers