Molded-In Inserts: Precautions and Guidelines

When end use considerations preclude complete utilization of the multifunctional design capabilities of DuPont engineering plastics, components can be joined through a variety of relatively quick and inexpensive assembly techniques. Among them: press and snap fits, cold heading cementing self-tapping screws, heat staking and spin, vibration and sonic welding. There is still another method of joining engineering plastic components to a final assembly that can solve critical problems. Molding metal inserts into a part, often considered a last resort because of the difficulties associated with it, may pay off in some outstanding advantages when adequate safeguards are taken in the design stage. It is the purpose of this article to suggest some of those precautions and some guidelines for successful insert molding. The three principal reasons for using metal inserts are: