Frequency analyses of a signal of IR radiation from the cutting front and surface profile height in laser cutting of austenitic stainless steel

Efficient control of laser cutting processes is closely related to knowledge of heat effects in the cutting front and its surroundings. Similar to other machining processes using high power densities, in laser cutting processes it is very important to monitor the heating phenomena in the specimen material due to heat input. The processes in the laser cutting front were monitored in three ways, i.e., by a voltage signal of infrared (IR) radiation from the cutting front by measuring surface profiles of laser cuts, and by macrographs of laser cut surfaces. In the paper it is shown that an analysis of macrographs showing surface-profile corrugation of the laser cut at austenitic stainless steel as well as at low-carbon steel can be used to confirm and analyse thermal phenomena in the cutting front. A comparison is given between the power spectra of the voltage signal of the IR radiation and those of the surface-corrugation profile for different steel grades, different specimen thicknesses, and various input energy. High frequency in the voltage signal of IR radiation and in the surface profile height were appreciated with a coefficient of high frequency in the voltage signal.