A MATHEMATICAL MODEL FOR DETERMINING THE ROUGHNESS OF LASER-MACHINED SURFACES

Abstract

The paper aims to determine the influence of input parameters on surface roughness in CO₂ laser cutting. The material used is Hardox 450 steel in the form of plates with a thickness of 12 mm. Adjustment parameters that ensure cutting, laser power (3700,3900) W, pressure (0.55,0.75) bar, and cutting speed (1250,1650) mm/min were identified through trial tests.Based on the current state of research in the field, a mathematical model is proposed to describe the relationship between roughness and input parameters. The designed model is validated with statistical methods. The results show that the pressure of the assistant gas is the most influential factor with regard to surface roughness. The laser surface treatment of manganese steel is a promising technique for increasing roughness if the pressure is used at the minimum input level of 0.55 bar. For low production costs, the combination of 3700 W power, 1250 mm/min speed, and 0.55 bar pressure is recommended for cutting Hardox 450 steel.