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How to solve the burr in laser cutting fabrication

When some customers use laser cutting machines, the cut workpieces have many burrs. Is there a way to avoid this?

The answer is yes. In the process of sheet metal cutting processing, the parameter setting, gas purity and air pressure of the fiber laser cutting machine will affect the processing quality. It needs to be set reasonably according to the processing material to achieve the best effect.

Burrs are actually excessive residue particles on the surface of metal materials. When the metal laser cutting machine processes the workpiece, the laser beam irradiates the surface of the workpiece, and the generated energy vaporizes the surface of the workpiece to achieve the purpose of cutting. When cutting, an auxiliary gas is used to quickly blow off the slag on the metal surface, so that the cutting section is smooth and free of burrs. Different auxiliary gases are used to cut different materials. If the gas is not pure or the pressure is not enough to cause a small flow, the slag will not be blown cleanly and burrs will be formed.

If the workpiece has burrs, it can be checked from the following aspects:

1. Whether the purity of the cutting gas is not enough, if it is not enough, replace the high-quality cutting auxiliary gas.

 

2. Whether the laser focus position is correct, you need to do a focus position test, and adjust it according to the offset of the focus.

2.1 If the focus position is too advanced, this will increase the heat absorbed by the lower end of the workpiece to be cut. When the cutting speed and auxiliary air pressure are constant, the material being cut and the melted material near the slit will be liquid on the lower surface. The material that flows and is melted after cooling will adhere to the lower surface of the workpiece in a spherical shape.

2.2 If the position is lagging. The heat absorbed by the lower end surface of the cut material is reduced, so that the material in the slit cannot be completely melted, and some sharp and short residues will adhere to the lower surface of the board.

 

3. If the output power of the laser is enough, check whether the laser is working normally. If it is normal, observe whether the output value of the laser control button is correct and adjust accordingly. If the power is too large or too small, a good cutting section cannot be obtained.

 

4. The cutting speed of the laser cutting machine is too slow or too fast or too slow to affect the cutting effect.
4.1 The effect of too fast laser cutting feed speed on cutting quality:

It may cause inability to cut and sparks.

Some areas can be cut off, but some areas cannot be cut off.

Causes the entire cutting section to be thicker, but no melting stains are generated.

The cutting feed speed is too fast, causing the sheet to be unable to be cut in time, the cutting section shows an oblique streak road, and melting stains are generated in the lower half.

 

4.2 The effect of too slow laser cutting feed speed on cutting quality:

Cause the cut sheet to be over-melted, and the cut section is rough.

The cutting seam will widen accordingly, causing the entire area to melt at the smaller rounded or sharp corners, and the ideal cutting effect cannot be obtained. Low cutting efficiency affects production capacity.

4.3 How to choose the appropriate cutting speed?

From the cutting sparks, the speed of the feed speed can be judged: Generally, the cutting sparks spread from top to bottom. If the sparks are inclined, the feed speed is too fast;

If the sparks are non-spread and small, and condensed together, it means that the feed speed is too slow. Adjust the cutting speed appropriately, the cutting surface shows a relatively stable line, and there is no melting stain on the lower half.

 

5. Air pressure

In the laser cutting process, the auxiliary air pressure can blow off the slag during cutting and cool the heat-affected zone of the cutting. Auxiliary gases include oxygen, compressed air, nitrogen, and inert gases. For some metallic and non-metallic materials, inert gas or compressed air is generally used, which can prevent the material from burning. Such as the cutting of aluminum alloy materials. For most metal materials, active gas (such as oxygen) is used, because oxygen can oxidize the metal surface and improve cutting efficiency.

When the auxiliary air pressure is too high, eddy currents appear on the surface of the material, which weakens the ability to remove the molten material, which causes the slit to become wider and the cutting surface to be rough;
When the air pressure is too low, the molten material cannot be completely blown away, and the lower surface of the material will adhere to the slag. Therefore, the auxiliary gas pressure should be adjusted during cutting to obtain the best cutting quality.

 

6. Long running time of the machine tool causes the machine to be unstable, and it needs to be shut down and restarted to allow the machine to rest.

 

By adjusting the above settings, I believe you can easily get a satisfactory laser cutting effect.