Weld Quality Inspection Based on Online Measured Indentation From Servo Encoder in Resistance Spot Welding

Since resistance spot welding has become the dominant method for car body assembly, studies on spot welding quality control and inspection are becoming more and more important and urgent for the automobile industry. Compared to the traditional air gun, the servo gun spot welding system has the advantages of precise control and feedback of electrode position and pressure. Therefore, it provides the possibility of controlling and inspecting weld quality online. By using the electrode position feedback function of the servo gun, this paper proposes a method for online weld quality inspection based on weld indentation. During a welding process, a weld indentation is extracted from a servo encoder under various welding failures. Then, a weld lobe, which is based on indentation, is built to identify the range for good welds. Finally, experimental data are presented to prove that this method can effectively achieve online weld quality inspection.