Laser cutting A36

[grayseal]

We use a Trump L 3030 laser to cut up to 5/8" A36 hot rolled steel. Our current cuts on 5/8" are good but our cuts on 1/2" A36 vary (incomplete cuts) from one side of the sheet to the other. The 5/8" material has more scale than the 1/2". The 1/2" almost has a cold rolled appearance. Niether have excessive oil on the surface. We use the standard tech tables. Could material chemistry affect the cut or could it be related to surface finish?

 

[serguei]

Hi!
1)If you have different cutting conditions on different sides of sheet - the most likely is internal alignment( you may check it - do nozzle alignment at x=0 y=0 and after that - check it at the far end of the table.
2) It is not easy to say which material is good for laser cutting which is not. It may be not bad idea to remember the supplier of material which was cut good and use his material in complex cases.
Of course surface is important - no rust, no paint, it should be green or blue.

 

[grayseal]

serguei,

Thanks for the response. I'll have the nozzle alignment checked. I'm a little confused on the surface condition of green or blue. Our plates come in either black (heavier scale) or gray (less scale).

grayseal

 

[msandoval]

When you are cutting plate, the quality of the material makes up about 75% to 80% of the application. You must have good material quality (free or rust, scale, paint marks), beam-mode, external optics aligned, low gas pressure (0.5 Bar or kg), and last but not least your lens must be in good conditions.

A36 is usually a lower quality steel in comparison to A572. This doesn't mean you can't cut it, but sometimes depending on the material composition, some may cut faster than others (taking away the other factors mentioned by Serguei and above). You may have to slow down.

The green surface that Serguei talks about sounds like a Cold Rolled Plate or Hot Rolled Pickled and Oiled to prevent rust. Try slowing down the feedrate by 15% and remember to also tune the power down to avoid overheating. Use an average of 2500-3000 Watts which should be more than plenty.

If you have the time, check the resonator for leaks, the power output using a power meter (if available), double check your external optics to make sure they are in good condition, and last but not least, double check your lens for heat stress using a pair of circular polarizing lenses.

Best of Luck

 

[grayseal]

msandoval,

Thanks for the info. Sounds like good advice.

grayseal