<title>Evaluation of secondary contamination in laser cutting of surface-contaminated metals</title>

We investigated the mixing of simulated surface contamination in the cut surfaces of laser-cut stainless steel. A 10 micrometers layer of molybdenum was coated by wire explosion spraying of 8mm-thick 304L stainless steel to serve as the simulated contaminated metal plate. The cutting was done with a CO2 laser using a nitrogen and oxygen gas mixture as cutting assist gas. The mixing of the molybdenum into the cut walls was evaluated by EPMA surface analysis and fluorescent x-ray analysis. The result revealed that the degree to which the molybdenum was mixed into the cut surfaces decreased as the concentration of oxygen in the assist gas increased. Also, the result of contaminant removal from the cut piece by chemical oxidation reduction decontamination processing was that the greater the oxidation, the less the molybdenum that remained after the processing. Thus, to reduce the mixing of simulated surface contaminants in the cut surfaces, a cutting assist gas that has a high concentration of oxygen should be used.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.