Monitoring Nd:YAG and CO2 Laser Weld Quality

Automated laser welding can be improved by developing sensors that accurately record the weld characteristics and provide a feedback signal to control the laser output appropriately. A number of solutions to this problem have been developed [1,2]. An indicator or set of indicators, representing the weld quality, have to be measured during the weld process and optimised in real time so that constant quality is guaranteed. The main indicators of a good weld are its symmetry, general regularity of the weld bead and the relative spacing between the solidified pool ripples along the bead. Discontinuities such as cracks and porosity characterise a poor weld.