Using fiber optic sensors to monitor the quality of resistance spot welding joints

Resistance spot welding (RSW) is a widely used technique in the automotive industry. The weld size is the critical parameters for evaluating the quality of RSW. In this study, an innovative non-destructive inspection method based on fiber-optic sensing was proposed. The relationship between the change of the fiber optic sensor signals during the welding process and the weld size is established. The results show that there is a strong correlation between the maximum wavelength change of the fiber optic sensing signal during the welding process and the weld size. The method shows good generalizability to different welding parameters and materials. In addition, the signal vibration difference can accurately predict the occurrence of expulsion.