When you need to mold two relatively small plastic parts together nothing beats ultrasonic welding but...when it comes to large applications consisting of dissimilar material and/or of varying planes, HEAT STAKING is the way to go.

The attachment of metal to plastic is the most commonly used application.

A hole in the metal parts is combined with a pre-molded plastic boss. A thermal tip makes contact with the plastic boss and creates localized heat. The light pressure from the thermal tip configuration melts the plastic boss into a predetermined shape. When localized heat is removed, the plastic material solidifies and the different material are fastened together.