Optimization Of Mold Process Parameters And Tooling Variables For Highest Quality Plastic Packaging

Abstract

A novel approach to understanding the impact of the large number of variables that play a role in the quality of the molded product was undertaken for very large, high pin count devices. Both mold process and tooling variables were optimized by varying 10 important input parameters in a fractional f actorial experimental design. As opposed to traditional studies, where mold process parameters are varied to select the best compromise setting for selected criteria, both process (mold temperature, transfer profile, cure time, pellet preheat temperature, and leadframe preheat temperature) and tooling (cavity depth, gate depth, gate angle, location of gate, and cull design) variations were studied and the interaction between them determined. A single plunger Per cavity mold system was utilized to allow easy tooling changes. The experimental design permitted determination of all main effects and some two factor interactions. Other interactions were confounded and required some understanding of the mold process to determine most likely effects. Package quality was judged by package warpage, diepad tilt, wiresweep, delamination, and visual defects such as voids, blisters, and porosity. The end result showed which variable effected which output characteristics and allowed determination of mold process and tooling conditions for optimum package quality with the trade-offs very well understood.