Our newly updated design guide, titled the Heat Staking Design Guide: Inserting Metal into Plastic with Induction by Dr. Girish Dahake, is now available for download. Heat staking of threaded metal inserts into plastic (also known as metal-to-plastic insertion) is a common induction heating application, and this design guide will help you get started. With heat staking, the insert is preheated with induction and then pressed into a hole in the plastic part. This is accomplished by positioning the induction coil over the hole and then holding the insert in the coil for a short period of time. When the correct temperature is achieved, the insert is pressed into the plastic.

Heat staking, which is also known as metal-to-plastic insertion, involves preheating an insert with induction and then pressing it into a hole in a plastic part. This is accomplished by positioning the induction coil over the hole and then holding the insert in the coil for a short period of time. When the correct temperature is achieved, the insert is pressed into the plastic. A narrow zone of plastic then melts and flows into the knurls of the insert. The plastic re-solidifies resulting in a complete assembly that often has much better mechanical properties than what results from alternative heating methods. The inserts are often brass or steel. 

An organization had been using a torch for this metal-to-plastic insertion application involving heating a brass shaft, however it required multiple torches to meet their growing throughput requirements. Consequently, they wanted to see if induction heating could offer them a more efficient solution. They turned to THE LAB at Ambrell and took advantage of complimentary application testing.

A supplier to an engine manufacturer needed to heat magnetic steel inserts for a metal-to-plastic insertion (also known as heat staking) application. The parts needed to heat to 500 ^°F (260 ^°C) within five seconds prior to being placed into an injection mold. Due to it taking the robot a few seconds to place the parts in the mold, it was also important that it maintain the temperature for a few seconds after heating concluded.