Laser cutting machine has become the standard of sheet metal processing because of its high processing efficiency and high cutting quality of finished products. However, when some customers use laser cutting, there will be burrs on the front and back of the sub material. These burrs will not only affect the work efficiency of the production team, but also require more manpower to polish the burrs, which is time-consuming and laborious. This is not caused by the laser cutting machine itself, but by improper operation.
In the process of sheet metal processing, the purity of auxiliary gas and cutting data parameters of optical fiber laser cutting machine will affect the processing quality. So what is burr?
Burr is the residual particles melted and re solidified on the surface of metal materials - the energy generated by the laser beam focused on the workpiece surface will vaporize the workpiece surface and blow out the slag. Due to incorrect subsequent operations, the melt could not be removed in time and could not be "wall hung" on the surface of the sub material.
1. Auxiliary gas - air pressure, purity
When the material in the cutting line melts, the auxiliary gas will blow out the slag in the cutting groove on the workpiece surface. If no gas is used, slag will be generated after cooling slag. Therefore, the air pressure of the gas should be sufficient (too small to blow out adhesion and cut off; too large to melt large cross section lines and diagonals). The air pressure will vary from plate to plate, and the appropriate air pressure can be found through validation tests. And the auxiliary gas must be pure. Impurities cause the laser head to run at a low speed on the workpiece surface (the auxiliary gas cannot produce sufficient chemical reaction with the sub material), the speed will become slow, and the incision will be rough or cannot be penetrated. In addition, according to relevant information, it is known that the appropriate auxiliary pressure fluctuation rule is:
● When cutting carbon steel plates with oxygen (auxiliary gas):
When the thickness of the thin plate increases from 1mm to 5mm, the cutting pressure range decreases to 0.1-0.3MPa, 0.1-0.2MPa, 0.08-0.16MPa, 0.08-0.12MPa, 0.06-0.12MPa; When the thickness of medium thick carbon steel plate increases from 6mm to 10mm, the corresponding range of auxiliary gas oxygen pressure decreases to 0.06-0.12MPa, 0.05-0.10MPa, 0.05-0.10MPa;
● When nitrogen (auxiliary gas) cuts stainless steel plate:
When the thickness increases from 1mm to 6mm, the cutting pressure changes from 0.8-2.0MPa to 1.0-2.0MPa to 1.2-2.0MPa, which is high-pressure cutting.
2. Parameter setting focus position and cut in position
After the customer has prepared the laser cutting machine, it is better to let an experienced operator debug the equipment. Therefore, it is necessary to adjust the cutting parameters to the best state. The air pressure, flow rate, focal length and cutting speed must be adjusted many times. High quality workpieces cannot be cut by the parameters provided by the machine tool.
If the focus position is too high, the burr will "swell", and the burr is very hard and the side is not smooth. You also need to adjust the focus position several times.
The lead-in wire should be far away from the ionic material to prevent local overheating, and the "melting knob" appears on the back of the sub material. The import is relative to the run on hole. The arc start hole is also called the "cut start hole". The diameter of the arc striking hole is larger than the diameter of the normal slit. Therefore, in order to improve the cutting quality and save the plate, the arc starting hole should be placed at the corner of the plate. In addition, there are two methods of leading in lines: lines and arcs.
Generally, when burrs appear on the front and back of sub materials, they can be checked and solved from the following aspects:
1. The upper and lower positions of the beam focus have deviation.
2. The output power of the laser cutting machine is insufficient.
3. The cutting speed of the cutter is too slow.
4. The purity of auxiliary gas is insufficient.
5. Fatigue operation of laser cutting machine.
Fiber laser cutting machine is an accurate cutting method. Usually, data errors will cause its operation exceptions. Therefore, strict work must be carried out to reduce errors.