yes, a few observations on those results;
- add air, it will make a huge difference with penetration, and thus less passes needed. Search this forum for low cost solutions. I use my shop air system because its available dry air supply, but the volume of air through a 6mm tube at 40PSI has got to be fairly low based on how infrequently my compressor cycles on/off, perhaps 0.5 SCFM or less.
- double check fine focus, it should be near 0.1mm for a diode laser. Also read about the effect of lens position for your specific laser, my laser’s lens position is adjustable by 1-2mm, screw in/out, changing the focal length by 10mm or so, and its position changes the conical shape of the beam, which effects the focal length and depth of field. Ideally for cutting, you want a narrow conical shape which also increases depth of field, if I recall all that correctly.
- consider you may be running into the tough glue. For instance, I’ve laser etched some cutting boards where the laser did not damage/burn at all the glue lines between the wood planks, it just left a micro thin vertical wall in the etching. Glue matters.
- and check your lens for clarity, since you’re not using air assist, you may have collected smoke and soot on the lens over past uses and that can diminish effective optical power delivered at the focal point. You may be able to clean it with Dawn soap and water solution, be careful with solvents as the lens could be plastic.
Relax with a pot of coffee and watch this video, it will blow your mind. Among other tid bits of info, the vid demos optical physics proof that one lens position can have more that one focal length.
Finally, when I mention above that I’ve run into some luan that my laser won’t penetrate no matter how many passes, you have ‘forced’ me to clarify ‘no matter how many’, which is about 6 passes in my case as I don’t have the patience for more passes 