Additionally I’d advise that you’ve chosen a fairly challenging material and operation (cutting) as a beginner with a relatively low power diode laser.
You’ll need to have a number of factors fairly dialed in to get a quality cut including:
- material holding - you’ll need to ensure that you can hold the material down flat and secure across the entire plane of your planned cut. Any material vibration or movement across a fairly long burn time will result in misalignment or incomplete burn. Flatness directly affects focus which is critically important
- focus - this is hypercritical especially for diode lasers to get any level of high performance and there are various strategies for where to focus (depth wise) based on your operation, material, lens type, and desired effect. For now I’d suggest learning how to get a really tight focus on the surface of your work material
- lens - different lenses are good for different operations. Typically lenses with longer and narrower focal beams (G7 or G8 lens) have been suggested for cutting operations while lenses with shorter and wider focal beams (think G2) have been suggested for engraving operations. I’ve seen a trend to fixed-focus non-replaceable lenses in newer laser modules so you’ll need decide up-front in those cases what you want to do with those.
- air assist - as @killrob has indicated this is really important for cutting operations especially. This is probably the single biggest factor in getting clean burns (ie less scorching). The importance of this goes up the deeper you try to cut.
- material choice - any composite wood material including plywood will be harder to cut than a single-ply natural wood even at the same overall thickness. I think the combination of glues and the cross orientation of the wood fibers makes cutting harder. And of course different woods cut differently.
- cut settings - speed, power, passes - there’s a lot of art here that you’ll have to experiment through. In general you want to be able to do everything as quickly as the combination of all your equipment can support but there’s a cost to that in terms of quality or equipment wear. I’d prefer one more pass to blowing out my laser from running at full load but YMMV. Keep in mind that there’s a direct correlation with high power and reduced working life of the diode.
As you’re learning through this I’d suggest starting with engraving, then moving to cutting easier materials, and then progress to more challenging materials as you refine your skills. Having said that, I’ve seen some people with very tuned diode systems cutting through plywood > 10mm in 1 or 2 passes. That is by no means normal but 3mm birch plywood is certainly achievable.
Hope you enjoy your new toy.