Experimental Study of Back Wall Dross and Surface Roughness in Fiber Laser Microcutting of 316L Miniature Tubes

Laser cutting is a key technology for the medical devices industry, providing the flexibility, and precision for the processing of sheets, and tubes with high quality features. In this study, extensive experimentation was used to evaluate the effect of fiber laser micro-cutting parameters over average surface roughness (Ra) and back wall dross (Dbw) in AISI 316L stainless steel miniature tubes. A factorial design analysis was carried out to investigate the laser process parameters: pulse frequency, pulse width, peak power, cutting speed, and gas pressure. A real laser beam radius of 32.1 μm was fixed in all experiments. Through the appropriate combination of process parameters (i.e., high level of pulse overlapping factor, and pulse energy below 32 mJ) it was possible to achieve less than 1 μm in surface roughness at the edge of the laser-cut tube, and less than 3.5% dross deposits at the back wall of the miniature tube.