Weld quality inspection based on on-line measured indentation from servo encoder in resistance spot welding

Since resistance spot welding (RSW) has become the dominant way for car-body assembly, studies on spot welding quality control and on-line inspection are becoming more and more important for automobile industry. This article mainly relates an on-line weld quality inspection way based on electrode indentation measured from servo gun. In the servo spot welding system, electrode indentation is extracted from servo encoder and calibrated by a PLC data collecting system including laser displacement sensor and A/D convertor. Then a weld lobe along with indentation is determined for 0.8mm DP600 sheet. At last, on-line quality inspection is carried out according to the indentation range in the weld lobe to demonstrate that this method is reliable.