Effect of electrode misalignment on the quality of resistance spot welds

The quality of resistance spot welds is critical to the structural integrity of components manufactured using the process. This paper analyses the effect of electrode misalignment, referred to as electrode tilt, on the quality of resistance spot welds and their relationship. The weld quality is represented by the diameter of the weld nugget as is standard in industry. Principal Component Analysis (PCA) was used to reduce the dimensionality of the dynamic resistance signal and extract features to be used in a linear regression model for the prediction of nugget diameter. This paper found that increased misalignment of the electrodes reduced the peak resistance of the welding process resulting in smaller nugget diameters and therefore a lower weld quality.