Analysis and optimization of surface quality of stainless steel miniature gears manufactured by CO₂ laser cutting

This paper reports the results of investigation conducted on CO₂ laser cutting of miniature gears of stainless steel 304. In this work, analysis of the effects of important laser parameters such as power, cutting speed, focal position, and gas pressure on average surface roughness (R_a) has been investigated. Stainless steel spur gears having 9.04 mm outside diameter and 4.5 mm face width have been cut using a CO₂ laser system with nitrogen as assisted gas. A total of twenty nine experiments have been conducted based on BBD (Box-Behnken Design) technique of response surface methodology where aforementioned laser parameters varied at three levels each. ANOVA study found focal position as the most significant parameter. Further, the Desirability based optimization of laser parameters obtained best values of R_a- 0.43 μm at laser power- 2407 W, cutting speed- 1.25 m/min, focal position- (-) 2.4 mm, gas pressure- 12.5 bar. A scanned electron microscopy study also revealed the good surface morphology of the miniature gear machined at optimum parameters.