All thermal cutting skills of Laser Cutting machines (except in rare cases) generally require a small hole to be cut through the board to be cut before continuing to cut. In the past, on the laser stamping compound machine, a hole was punched first, and then the laser was used to cut from the small hole. Huazhi sheet metal processing Factory introduced what perforation methods for steel plates in Laser Cutting?
1. Explosive perforation
The sheet is irradiated by successive lasers to form a pit in the center, and then the molten sheet is quickly removed by the oxygen flow coaxial with the laser beam to form a hole. Generally, the size of the hole is related to the thickness of the plate. The average diameter of the explosion perforation is half of the plate thickness. Therefore, the diameter of the explosion perforation for thicker plates is larger and not round. It should not be used on parts with high machining accuracy requirements. on waste.
2. Pulse perforation
Pulse laser with high peak power is used to melt or vaporize a few materials. Air or nitrogen is often used as auxiliary gas to reduce the expansion of holes due to exothermic oxidation, and the gas pressure is lower than the oxygen pressure during cutting. Only a small particle eruption occurs with each pulsed laser, which gradually deepens, so it takes a few seconds for the thick plate to perforate. Once the perforation is completed, the auxiliary gas is immediately replaced with oxygen for incision. In this way, the diameter of the perforation is smaller, and the perforation quality is better than that of the explosive perforation.
In the case of using pulse piercing, it is necessary to pay attention to the transition skills from pulse piercing when the workpiece is stopped to continuous cutting at constant speed. Theoretically speaking, the cutting conditions of the acceleration section can usually be changed, such as focal length, nozzle orientation, gas pressure, etc., but in fact, because the time is too short, the possibility of changing the above conditions is very small.