Laser cutting of thick sheet metals: Effects of cutting parameters on kerf size variations

Laser cutting of thick sheets, in general, results in poor end product quality due to excessive thermal erosion from the kerf sites. In the present study, laser melting of thick mild steel sheets is considered and effect of cutting parameters on the percentage of kerf width variation is examined. The cutting parameters considered include laser output power, cutting speed, and oxygen assisting gas pressure. A factorial analysis is carried out to identify the main effects and interactions of the parameters. Thermal efficiency of cutting and liquid layer thickness is formulated. Optical microscopy and scanning electron microscopy (SEM) are carried out to examine the cutting defects and the kerf size variation. It is found that laser output power and oxygen gas pressure have significant effect on the percentage of kerf width variation.