When screws or bolts are threaded directly into plastic components, failures can occur due to stripped threads or plastic creep. Metal threaded inserts provide serviceable threads for situations when joint strength and the ability to assemble and disassemble the parts without degrading them are required.
Threaded inserts can be installed during the molding process or afterwards. In the latter case, inserts can be screwed in or pressed in, with or without the addition of heat or ultrasonic energy. Installation of inserts after molding shortens molding time. Post-mold installation also reduces the chance of scrap and mold damage resulting from dislodged inserts.