Condition monitoring of laser systems: Monitoring the cover slide

Laser systems are high investment production machines that require a high level of availability in order to be amortized. Laser condition monitoring methods can be used to avoid breakdowns and maintain a consistent quality. In particular elements such as the cover slide, which protect the focusing optics from getting splashed through the welding process, need to be monitored. The effects of dirt on the cover slide are detrimental to the beam quality reaching the workpiece and can cause a spontaneous failure of the cover slide. By using a laser based calorimetric test the absorption and thereby the state of the deterioration of the cover slide can be measured. In order to make this test practical in an industrial situation the method must be simplified and the indirect cooling through the head accounted for. With this simplified absorption test an objective measurement of the state of the cover slide can be done between each weld. By monitoring the deterioration of the cover slide spontaneous breaks and low quality processes can be avoided.