What is the reason of slag hanging after laser cutting

2021-05-24

We call the residual metal melt on the back of the workpiece cutting as hanging slag. Laser cutting machine will produce a lot of heat during processing. Generally speaking, the heat generated during cutting will diffuse to the whole workpiece along the cutting seam, and then the workpiece will be fully cooled. However, when cutting small hole workpiece, the outside of the hole can be fully cooled, and the heat inside the hole can be diffused because of the small space, and the heat is too concentrated, resulting in excessive slag hanging. In addition, when cutting thick plate, the molten metal accumulated on the surface of the material and the heat accumulation will make the auxiliary air flow disordered, and the heat input is too much, resulting in slag hanging.


How to solve it? After cutting slag, first from the following points to find out the reason, find out after adjustment can solve the formation of slag.


1. The output power of the laser is not high enough


When cutting thick plate, the power is not enough to melt the whole plate. If the power can be adjusted, the power can be increased to test whether it can be cut off. If the power has been adjusted to the maximum, the laser with higher power needs to be replaced.


2. The focus of laser beam deviates


Focus too close or too far will affect the cutting quality, can only be adjusted by inspection, according to its offset position.


3. The pressure of auxiliary gas is not enough


The auxiliary gas can blow off the slag and cool the heat affected zone. If the air pressure is too low, the residue can not be blown out of the workpiece or the workpiece can not be cooled in time, resulting in the formation of slag. Adjust the air pressure to the appropriate level.


4. Cutting speed too fast or too slow


If the feed speed of laser cutting is too fast, the workpiece can not be cut off in time, the cutting surface will form oblique stripes, and there will be slag hanging in the lower half area. If the feed speed is too slow, the phenomenon of over melting will occur, the overall section is rough, the cutting seam becomes wider, and the slag will hang in the upper part.





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