Low cutting capacity NEJE Master 2s plus

Hi community,
I’m trying to cut 3 mm MDF.
Settings I use: 400 mm/min, 100% power, 22 passes, additional air assist (a compressor with 250 l/h flow). It does not cut through all the times (I mean sometimes it does, sometimes there are uncut areas, sometimes it does not go through at all), on the same piece of the material.
Any ideas what could possibly go wrong?

You don’t say what power your laser head is. That is pretty important…

Thanks for pointing that out. It is 30 W (optical output 7.5 W).

Have you checked that you are focus correctly for cutting? Having the correct focus will make cutting easier.

I’ve been using a ‘Ramp technique’ for focusing (this one: Easy and precise Laser Focusing!! NEJE 30W laser Module - Ramp technique - YouTube) in a single pass. I fully screwed the lens in, then did five clicks to unscrew it, then found the best focal distance by engraving a single line on a ramp and finding the narrowest spot on it.
For that setting it turned to be 30.25 mm between the surface and the laser aluminum radiator.
For cutting purposes I try to focus the laser in the middle of the material, it turns to be 30.25 - 3 / 2 = 28.75 mm.
I 3D-printed a template for 3 mm thick material, so it wasn’t a measurement with a ruler or a caliper.