Inserts for Plastics allow designers to replace machined and cast metal components with plastic to achieve significant cost and weight savings without any loss of joint strength - even in demanding applications. Threaded Inserts can be installed with heat or ultrasonics, they can be molded-in, pressed-in, or tapped into the hole. The challenge is for Engineers to choose an Insert that meets the performance and assembly requirements of the application. This article describes how Inserts for Plastics work, and provides design guidelines for the plastic host components to ensure that the completed assembly meets the desired expectations.