Physical laws governing the processing of metals by pulse-periodic CO2 laser radiation

It was found experimentally and theoretically that an increase in the pulse repetition frequency increased the crater depth in laser drilling and reduced the specific energy consumption. A comparison of the maximum depths of welds and craters obtained by drilling and of their dependences on the laser radiation parameters demonstrated that the mechanisms of the maximum penetration of a pulse-periodic CO₂ laser beam into a metal were identical for drilling and welding. The screening influence of a plasma jet decreased as the crater depth increased and this led to a nonmonotonic variation in the rate of growth of a crater on increase in the number of pulses. It was found experimentally that the use of pulse-periodic CO₂ lasers for cutting metals makes it possible to obtain high-quality cuts at low workpiece velocities of 1–3 mm/sec.