preheating bolt for heat staking


The objective of this application is to simultaneously preheat stainless steel bolts in multi-position coil up to 175 °F (79 °C) for a heat staking process. This will help an automotive manufacturer achieve more precise insertion of parts, faster production times, and the ability to automate the process. 


UltraHeat SM – 5 kW induction heating system was the most suitable choice for this application because of its advanced digital communication features which allowed complete automation of the induction preheating process. When the workpieces placed within the coil reach a certain temperature, a robot picks them up and brings them to an assembly. The induction heating system is started remotely and when the cycle is over, it sends a signal to the robot to perform the same process over again.  


A custom induction coil was designed to evenly distribute the heat between the four workpieces. Key process requirement was to heat the bolts in the thread sections 0.3’’ (7.62 mmOD threads at 0.577’’ (14.6 mm) thread length. The desired temperature of 175 °(79 °C) was reached within 10 seconds at the power of 2 kW. The bolts were heated above this temperature to prevent rapid cooling before the heat staking takes place.  

Industry: Automotive Industry 

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Reference Info: Application Note 3463-6739