Engraving to cut through

Hi guys,

recently I had to cut through 15mm acrylic and got some charring on the bottom of the sheet.
I know it's been caused by a residue from other materials that I cut previously and slow speed of the cut, the residue caught fire etc.
But that made me think if it wouldn't be better to try to cut the material using less power (similar to engraving) but run the process couple of times?
If you have any suggestions what is the best way to cut 15mm material and don't get the charring effect please share it.

Thanks

So I have ran few tests and conclusion is that it is possible. The machine that I work with is SENFENG sf1326 with a laser power 130 watts.
Perfect settings are:

focal length 11.0,
speed 6 mm/sec,
temp. 30% - 45%
but have to remember that you need to run the process twice.

Also I have got very good result with settings:
f length 11.0,
speed 6
temp. 60% - 80% and it gone straight through the acrylic.

If you guys have any other settings for this sort of job please share it here.

Thanks