Measurement of weldpiece distortion during pulsed laser welding using rapid laser profilometry

The present paper reports a new setup for acquisition of shape data for weldpieces during pulsed laser welding. The setup is based on illumination of the weldpiece surface by laser light, which is structured as multiple light planes, and acquisition of the image of the illuminated surface by a digital camera. The position of the optical system is fixed relative to the measured weldpiece. The acquired image is fed into a personal computer where it is processed to obtain the three-dimensional shape of the part of the weldpiece surface that was imaged by the camera. A setup that allows up to 20 shape measurements per second was developed based on this principle. The setup was applied to examine distortion of weldpieces during laser welding of low carbon thin steel sheets. According to the results the setup allows a rapid and accurate temporally and spatially resolved evaluation of weldpiece distortion.