Effects of chopper on laser texturing of rolls by CO2 laser,

摘要

Abstract: The effects of chopper on laser-texturing of rolls by CO$- 2$/ laser are reported in the paper. The propagation of laser radiation through chopper can be described as four states: (1) chopping state; (2) transition state from chopping to transmitting; (3) transmitting state; and (4) transition state from transmitting to chopping. The distribution of laser energy flux on roll surface is derived from these descriptions and the assumption of Gauss beam, and the thermal physical process of laser-texturing is numerically simulated. It is true that the reflected laser radiation from state (1) and the direct laser radiation from state (3) can be superimposed to result in efficient texturing, but these effects are not so obvious as stated in published literatures. Shorter focal length will benefit in more efficient laser texturing because laser power density increase quickly with the decrease of focal length. In the case of short focal length, the superimposition effect is almost invisible, and the position of chopper because important, it should be near to the roll surface for a clear pattern of separated texturing points.!5