Analysis of Welding Defects in Spot Welding Process U-I Curves

High speed collecting and managing system of spot welding signal can achieve the A/D conversion and data collection. The data of welding current, electrode voltage as well as welding cycle has been collected. Subsequently, they were processed with data acquisition and memory module, wavelet filtering of digit signal module, U-I curves and energy analyzing module, respectively. Based on the collections of welding current and electrode voltage, a criterion splash occurrence and the defective of loose weld by U-I curves change and acreage were proposed. The results prove that the criterion can decipher the welding splash and defective of loose weld accurately.