I never managed to get good results with my 80W cutter on cheap grade 1/4" plywood. The problem was mainly the ply itself - mainly laminating glues don't respond well to laser cutting. There is a big difference between proper laser ply and "normal" ply. Several lighter cuts didn't improve things much. Lots of charring and it stinks badly after having been cut. The machine gets covered in stinky goo. Proper laser ply cuts very cleanly and easily.