Induction Heating a Steel Shaft for Metal-to-Plastic Insertion

A client came to THE LAB at Ambrell with a heat staking application involving heating a knurled steel shaft prior to staking into plastic. This shaft is used in the hinge of a consumer device. Controlling heat to the lower portion of the shaft was critical to this client, as they needed to preserve the lubricant applied to the unheated end. 

THE LAB determined an Ambrell EASYHEAT^TM 2 kW, 150-400 kHz induction heating system would be the right solution for this heat staking application. Initial testing was performed to optimize the power delivered to the part. A single-turn channel style coil was used to generate the required heating pattern. The knurled end of the shaft was heated to the required temperature in just three seconds. The lower portion of the shaft did not exceed 200 °F (95 °C), which was the desired result. This successfully preserved the lubricant on the unheated end. 

As mentioned, localized heating prevented temperature drift, which was critical for this application. Another benefit was rapid heating, as it took just three seconds with our smallest power supply. Additionally, induction offers an even distribution of heat, and the heating process is extremely repeatable. Finally, induction delivers hands-free heating that is not dependent on operator skill, and there is also no open flame, resulting in a safer work environment. 

If you have a heating application, be sure to take advantage of complimentary feasibility testing from THE LAB at Ambrell. With our new Virtual Lab Service, you can observe testing live from our laboratory in your office. Contact us today if you'd like to get started.