Laser not cutting trough/not cutting evenly trough

[ThomasTP (Thomas Petersen)]

Hi
I just bought a Sculpfun S9 laser and i seem to have trouble cutting all the way trough the material when cutting out figures.
I started off by trying to cut a square in 3mm MDF - with 80% power @ 300mm/min with 5 passes, and it cuts all the way trough no problem. But when i try to cut out a more complex figure(in this case a christmas ornament) in the same sheet of MDF with the same settings, i cant get it to cut trough everywhere. The outer circle is cutting trough fine, but the decorations in the middle are not getting trough. I’ve tried to set min. power to 80% also, but that doesn’t seem to do the trick - do you guys have any tips for me?

[berainlb (PY)]

A few things to experiment with:

1. Air assist - if you don’t already have it you really need this to do any cutting
2. Focus - make sure you’re getting the best possible focus you can. When you’ve got that sorted out, you can experiment with focusing to different depths of the material. One school of thought says to aim half-way down the material for cuts. I’ve found this isn’t necessarily a universal truth but something to consider.
3. You may want to experiment with slowing down the cut at lower power depending on how the material responds, increasing the number of passes as necessary.

But candidly the air assist is probably the most significant if you want to pursue cutting vs engraving.