CUTTING OF THIN METAL SHEETS USING ND:YAG LASERS WITH DIFFERENT PULSE DURATION

An experimental investigation on the laser cutting of thin metal sheets using a Q-switched diode pumped Nd:YAG laser and a conventional lamp pumped Nd:YAG laser with pulse duration of 150 ns and 0.3 ms respectively is described in this paper. Using the laser with short pulses the lower single pulse energy was not sufficient to remove the material along the entire thickness of the sheet in a single laser scan and multi-passes were required. However, short pulses with higher peak power densities allowed to produce precise cuts with a smaller width than long pulses. These two cutting processes by a multi-passes laser scan (using short pulses of 150 ns) and by a single laser scan (using long pulses of 0.3 ms) were compared in terms of laser energy, machining time and process performance. It was also observed that, when using short pulses, the groove geometry was different depending on the number of passes and the material removal rate due to the laser scan significantly decreases when the groove depth.