Indentation shape parameters as indicators of spot weld quality

This contribution presents a laser-based method for three-dimensional (3D) measurements of the shape of an electrode indentation. The method is based on the illumination of the indentation with structured light and the detection of the image of the illuminated indentation by means of a digital camera. Image processing algorithms are employed to determine the 3D shape of the indentation. A batch of welds obtained from an automotive production process has been measured and analysed for characteristic geometrical indentation parameters such as diameter, depth, presence of cracks, splash, etc. The potential of indentation shape parameters to serve as indicators of spot quality is discussed.