Abstract: With the analysis of the stud plunge process, the control of stud plunge depth in the stepping arc stud welding is studied. The relative displacement between the stud and the workpiece during welding process is acted as the controlled variable. Through the acquisition of the compression displac- ement of spring in the welding gun by displacement sensor, the contact state between the stud and the workpiece is gained. Based on that, the control of stud plunge depth is realized. It is indicated from the test results that the autocontrol of stud plunge depth can be realized in stepping arc stud welding. The stud plunge depth need not be preset before welding. When the different stud lift heights are adopted in welding, the corresponding adjustment can be done by the control system to guarantee the adaptive stud plunge depth. That adopting the control method of stud plunge depth in penetration welding decreases the effects of gap on welding process, which ensures the trouble-free realization of penetration welding.

Key words: Arc stud welding, Autocontrol, Displacement, Plunge depth