Cause of occurring of burr when cutting machine – Laser cutting machine has become the standard for metal sheet processing due to its high processing efficiency and high cutting quality of finished products. However, when some customers use laser cutting, there are any burrs on the front and back surfaces of the sub-material. These burrs will not only affect the production team’s work efficiency but also need to inject more manpower to polish the burrs. It is time-consuming and laborious. This situation is not due to the laser cutter itself but improper operation.
In the process of plate processing, the purity of the auxiliary gas and the cutting data parameters will affect the processing quality. So what is a burr?
Cause of occurring of burr is the residue particles that melted on the surface of the metal material and re-solidified. The energy from the laser beam focused on the surface of the workpiece to vaporize the surface of the workpiece and blow out the slag. Due to improper follow-up operations, the melt “wall-mounted” on the surface of the sub-material.
Cause of occurring of burr when cutting machine
1. Auxiliary gas-air pressure, purity
When the material in the cut line is melted, the auxiliary gas will blow out the slag in the cutting groove on the surface of the workpiece. If no gas to use, slag will generate after cooling the slag. Therefore, the air pressure of the gas should be sufficient. The air pressure varies depending on the plate, you can find the appropriate air pressure through the proof test. And the auxiliary gas must be pure. Impurity causes the laser head to run at a reduced speed on the surface of the workpiece. If the rate becomes slow, the cut is rough. Or it cannot cut through. Besides, according to relevant information, we all know that the suitable auxiliary pressure fluctuation rule is:
● Use oxygen (auxiliary gas) to cut the carbon steel sheet:
When the thickness of the thin plate is increased from 1mm to 5mm, the cutting pressure range is sequentially reduced 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 sheet will increase from 6mm to 10mm. The corresponding auxiliary gas-oxygen pressure ranges sequentially reduce to 0.06-0.12MPa, 0.05-0.10MPa, 0.05-0.10MPa;
● When nitrogen (auxiliary gas) cuts stainless steel plate:
When its thickness increase from 1mm to 6mm, the cutting pressure transitions from 0.8-2.0MPa to 1.0-2.0MPa to 1.2-2.0MPa. It is a high-pressure cutting.
2. Parameter setting-focus position, cutting lead-in position
After the customer prepared the laser cutter, it is best to let the experienced operator debug the equipment. Therefore, it will adjust the cutting parameters to the best. Air pressure, flow rate, focal length, and cutting speed must adjust several times. High-quality workpieces cannot cut by the parameters provided by the machine.
If the focus position is too high, the burr will “swell”. And the burr is very hard and the sides are not smooth. It is also necessary to adjust the focus position multiple times.
The lead-in line should be far away from the sub-material to prevent local overheating. And “melt knobs” appear on the back of the sub-material. The lead-in is relative to the pilot arc hole. The arc-starting hole also called “cutting starting hole”. The diameter of the arc-starting hole is larger than the normal slit. Therefore, to improve the cutting quality and save sheet material, the arc-starting hole should place at a scrap of the sheet material. Besides, there are two ways to introduce lines: straight lines and circular arcs.
In general, when the burr appears on the front and back of the sub-material, we can check and resolve from the following aspects:
1. There is a deviation in the up and down position of the focus of the beam.
2. The output power of the laser cutting machine is not enough.
3. The cutting speed of the cutting machine is too slow.
4. The purity of auxiliary gas is not enough.
5. Fatigue operation of laser cutting machine.
Fibre laser cutting machine is a precise cutting method. Usually data errors will cause their operations to behave abnormally.