An company came to THE LAB at Ambrell needing to insert brass threaded inserts into seven locations on a plastic thermostat housing. THE LAB determined that an Ambrell EASYHEAT^TM 3.5 kW induction heating system would be the right solution for their heat staking application. Three different coils for varying patterns were designed by Ambrell's team of applications engineers and used during testing.

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.