Sensing and control system of process quality in CO2 laser deep penetration welding

摘要

A sensing and control system of process quality in C02 laser deep penetration welding has been developed, including plasma photo sensor (PS) and plasma charge sensor (PCS), signal processing circuit, personal computer and optimization and controlsoftware. By using the information of plasma radiation and plasma charge, the focusing lens is adjusted to the optimum focal point position (at which the maximum penetration can be achieved ) and closed-loop control is realized to assure the focal pointposition and penetration depth constant. In laser welding of the workpiece aslant placed with larger angle, the variation of focal point position is less than 0.2mm and the fluctuation of penetration depth is less than 0.05mm. The control system has beenpreliminarily applied in laser precision welding of 2.5m long zircaloy fuel channel used in nuclear heat-supply reactor.