Insert molding is a technique in which an item such as a threaded fastener, tube or stud, electrical component, or label is present in the mold. As the viscous plastic fills in around it and hardens, the item becomes a component of the finished part. When performing insert molding, it’s obviously critical that the insert does not move as the mold closes or as plastic is injected under pressure into the cavity — no small feat as hot resin can enter at 20k-30k psi.
Insert molding, or more accurately “plastic injection insert molding,” is a process in which viscous plastic is injected into a mold around one or more items. When the plastic cools and hardens, the result is an integrated assembly that incorporates these “inserts.” The items can be metal, ceramic, or any other type of material that can withstand the heat of the melted plastic and the pressure with which it is injected into the mold.