The interaction between a high power(>10 kW), continuous wave CO2 laser beam and a material results In strong emission of radiation in the visible and infrared regions of the spectrum. This prevents the use of conventional camera systems from examining the nature of the interaction between the laser beam and the material. Utilizing a pulsed N2 laser which was synchronized with a video camera that had been filtered to the wavelength of the N2 laser light (337 nm), a series of laser welds and clads were studied. This laser-camera system was originally developed for use in the study of conventional are welding processes. The images from the camera were recorded on a video recorder for evaluation and data acquisition. Welds were made in a number of materials with variations in the power input, plasma suppression, and travel speed. The laser-camera system was also used in the evaluation of laser cladding operations.
Both qualitative and quantitative information was obtained from the study. The point of interaction between the laser beam and the material was quite visible but a small plume was still visible above the keyhole. Through a series of welds and variations in the camera set-up, an estimate of the keyhole size was made which was agreeable with the nominal spot size of the focusing optics. The effects of the welding parameters were made by measuring the size and shape of the weld pool. Cross sections of the welds were examined in an attempt to relate the laser-camera observations with the resulting weldment configuration. The laser-camera system was also used in monitoring a laser hardface cladding process development program. The information obtained from the system allowed for modification of the process to produce higher quality specimens.