Condition monitoring and lifetime estimation of a CO2 laser

Lasers are being successfully applied to a variety of manufacturing processes, including cutting, welding, cladding, and free forming. Part of their success is due to the high quality beam that is directly related to the condition of components involved in the lasing process. However, maintaining the requisite beam quality requires frequent and time-consuming intervention by maintenance operators, specifically, for dismounting, inspection, servicing, and reassembly. Preventive maintenance, targeting reduction of machine downtime by prevention of faults, is the de facto maintenance program for lasers in industry. In this work, condition monitoring and lifetime estimation have been proposed to enable predictive maintenance programs for CO2 lasers. Specifically, the cooling system of a CO2 laser is monitored to infer its health condition, which is then used to statistically predict its lifetime. A Weibull distribution has been used to model the hazard function that depends on the operating parameters and the condition of the machine. The monitoring and estimation strategy has been verified using simulation. Results of tests conducted at Applied Research Laboratory (ARL) at the Pennsylvania State University to exemplify the proposed approach are also presented. (C) 2003 Laser Institute of America.