Hi Alvin and Curt,
We cut through the Home Depot Birch plywood with the filler in the middle on the 3.8W laser at 150mm/min with 5 passes. We have a shop vacuum attached down by the work surface to suck up the smoke where the cut is made. This helps with reducing the amount of char and makes the efficiency of the laser better for cutting. There will be less flare up and the laser light will not get reflected off the smoke coming off the cut. I think without the vacuum (or other air assist system) cutting hard woods is going to be difficult. The 1/8″ built up hobby plywood (multiple sheets of Birch) is going to be very tough to get through. I have seen people accomplish it, but I think they had a vacuum or air system as well.