抄録
At cutting speed faster than 3 m/min surface roughness of kerf of thin steel plates cut with CW CO2 laser (having power ripple) has a close relation to the fluctuation in intensity distribution at focal point.
Measurements were made to determine intensity distribution of focused laser beam and laser power ripple in terms of amplitude and frequency. The kerf width was found to be approximately equal to a critical beam diameter, at which power density correspond to 1-1.5×105 W/cm2, and is 1/30 to 1/40 of peak value of beam profile. A thermal conduction model was proposed to predict the surface roughness, in which the surface roughness is equal to the amplitude of change in the critical radius up to frequency of 1 kHz, and decreases at frequencies higher than 1 kHz. It was found that the surface roughness can be predicted by this model, when the intensity profile of the focused laser beam and laser power ripple are given.
