How thick can a 20W diode actually cut?

Comfortably: 3mm basswood and plywood in 3–4 passes, 6mm in 6–8, veg-tan leather and cork with ease. The practical ceiling for clean product-grade edges is about 8–10mm softwood with patience, masking, and strong air assist.

Hardwood and glue-heavy plywood shrink those numbers; clear acrylic is off the menu entirely (wavelength, not power). When your product needs one-pass 6mm cuts daily, that is the CO2 signal.