In the process of using laser cutting machine, there are always various small problems, most of which are burrs and edges. How can we solve this situation?
First of all, we need to understand the principle and process of laser cutting: laser beam irradiates the surface of the workpiece, high energy makes the irradiated part of the workpiece vaporize and evaporate, and auxiliary gas is used to remove the residue and cool the plate to achieve the cutting effect. This cutting process belongs to a hot processing type.
What are the causes of burrs?
In the process of sheet metal processing, the gas purity and parameter settings of the laser cutting machine will affect the processing quality. If the equipment+gas+parameters are adjusted properly, the workpiece will be free of burrs.
How are burrs produced?
1. Gas purity. The auxiliary gas used in the cutting process will affect the cutting effect. Generally, the cutting gas needs to have a purity of 99.999, etc., which is the best. If the purity is not high, there will be bad sections, burrs and other phenomena in the cutting process.
2. Cutting parameters; Cutting parameters are based on cutting speed, cutting focus and air pressure to achieve a good cutting effect. Therefore, if there are burrs in the cutting, these three cutting parameters need to be readjusted until they are optimal.
Practical solutions for cutting burrs:
a. The output power of the laser cutting machine is not enough.
Solution: Check whether the laser cutting machine works normally. If it is abnormal, timely repair and maintenance are required. If it is normal, check whether the output value is correct.
b. The upper and lower positions of the beam focus deviate.
Solution: Adjust the focus position according to its offset position.
c. The gas purity of the cutting machine is not enough.
Solution: Change the gas.
d. The wire cutting speed of the cutter is too slow.
Solution: Adjust the wire cutting speed in time.
e. The addition point of the laser beam of the cutting machine has shifted.
Solution: Conduct focus debugging and timely adjustment
How does burn edge come about?
Laser cutting machine processing is a process of thermal processing. Normally, part of the heat generated by cutting is taken away by the protective gas, and the other part is diffused to the workpiece through the cutting seam. During the processing of small holes by laser cutting machine, the outer side of the hole can be fully cooled, while the inner side of the single hole has a small space for heat diffusion, and the heat energy is too concentrated to cause overheating, slag formation, etc. In addition, during thick plate cutting, the molten metal accumulated on the material surface during perforation and the heat accumulation will lead to the disorder of auxiliary air flow and excessive heat input, which will lead to over burning.
The solutions to overburning of laser cutting machine are as follows
Solution to overburning during laser cutting of carbon steel pinholes: In carbon steel cutting with oxygen as the auxiliary gas, the key to solving the problem is how to suppress the occurrence of oxidation reaction heat. The method of assisting oxygen during perforation and lagging switch to assist air or nitrogen for incision can be adopted. This method can process the small hole of 1/6 thick plate at most.
The pulse cutting conditions with low frequency and high peak output power can reduce the heat output, which is helpful to optimize the cutting conditions. Setting the conditions as single pulse laser beam, high peak output of energy intensity, and low frequency conditions can effectively reduce the accumulation of molten metal on the material surface during the piercing process and suppress the heat output.
Solution for laser cutting aluminum alloy and stainless steel: nitrogen is used as the auxiliary gas in the processing of such materials, and no edge burning will occur in the cutting. However, because the temperature of the material inside the small hole is very high, the slag hanging on the inside will be more frequent.
The useful solution is to increase the pressure of auxiliary gas and set the conditions as high peak output and low frequency pulse conditions. When auxiliary gas is used with air, it is the same as when nitrogen is used, and overburning will not occur, but it is easy to form slag at the bottom. It is necessary to set the conditions as high auxiliary gas pressure, high peak output, and low frequency pulse conditions.