1) Cutting and punching technique
Thermal cutting technique, except in a few cases can start from the edge of the board, generally in the board through a small hole.Previously, in the laser stamping compound machine, a punch was used to punch out a hole, and then a laser was used to start cutting from the hole.There are two basic methods of perforating laser cutters without a stamping device:
Material is irradiated by a continuous laser to form a pit in the center, and then the molten material is quickly thrown away by a stream of oxygen coaxial with the laser beam to form a hole.The size of the general hole is related to the thickness of the plate, the average diameter of the blasting hole is half of the thickness of the plate, so the hole size of the thicker plate blasting hole is larger, and not round, should not be used in the processing precision requirements of higher parts, can only be used on waste.
A small amount of material is melted or vaporized by a pulse laser with peak power. Air or nitrogen is commonly used as a common gas to reduce hole expansion due to exothermic oxidation. The gas pressure is lower than the oxygen pressure during cutting.Each pulse of laser produces only small particles, which go deeper and deeper, so it takes a few seconds for a thick plate to perforate.Once the perforation is complete, the gas is replaced with oxygen for cutting.The perforation diameter is smaller, and the perforation is smaller than the blasting perforation.The laser used for this purpose should not only have high output power;The time and space characteristics of the beam are important, so the general cross flow CO2 laser cannot meet the requirements of laser cutting.
2) Deformation of small holes in machining
Instead of blasting and perforating the holes, the equipment USES pulse perforation, which makes the laser energy too concentrated in a small area and burns the non-processed areas, resulting in the deformation of the holes and affecting the processing quality.At this time, we should change the mode of pulse perforation to the mode of blasting perforation in the processing program.
3) Burr occurs when cutting low carbon steel
According to the principle of work and design, the analysis is the main reason for the burr of the workpiece produced by e: the upper and lower positions of the laser focus are incorrect, so the focus position needs to be tested and adjusted according to the offset of the focus;Output power of the laser is not enough, so it is necessary to check whether the laser generator works normally. If so, observe whether the output value of the laser control button is correct and adjust it.Linear speed of cutting is too slow, so it is necessary to increase the linear speed during operation control.Ppurity of cutting gas is not enough, high quality cutting working gas should be provided.Laser focus shift needs to be measured and adjusted according to the focus shift;Machine running time too long instability, the need to shut down and restart at this time.
4) Burrs will be generated by cutting stainless steel and aluminum plates
Considering the burr factor when cutting low carbon steel, but can not simply speed up the cutting speed, because the increase in speed will sometimes appear the plate cutting not through the situation, this situation in the processing of aluminum zinc plate.At this time should be integrated into the other factors to solve the machine, such as whether to change the nozzle, guide motion is not stable.
5) Laser cannot cut through the workpiece
Main cases of machining instability after analysis are as follows: the selection of laser head nozzle does not match the thickness of machining plate;Linear speed of laser cutting is too fast, so operation control is needed to reduce the linear speed.Nozzle induction is not allowed to lead to the laser focus position error is too large, need to re-test the nozzle induction data, is easy to appear in cutting aluminum.
6) Abnormal spark occurs when cutting low carbon steel
Will affect the cut section finish processing quality.At this point, under the condition that other parameters are normal, the following conditions should be considered: loss of laser cutting head, cutting head should be replaced in time.When there is no new cutting head, increase the working gas pressure of cutting;Screw loose at the connection between the nozzle and the laser head.At this point, the cutting should be suspended, check the connection state of the laser head, and rethread.