Mileage may vary. My birch was.23 inches
I cut out small squares, from 200 to 100 speed at full power (glowforge plus) . The first one to cleanly cut is 150 Here are all the cuts from 150 to 100. The last one is 100 x 2. Notice the edges
Here are the backs
Cleaned up 150
150 next to 100 x 2 passes
This is a good test to run for various materials. Birch plywood from various sources is quite variable and I believe testing is necessary on every batch I get. The testing is time consuming, but wasting material is too costly to just “wing” it.
That 150 looks so clean! My 1/4" birch ply is coming out so dark and so dirty (lots of black soot on my hands when handling). I just tried your settings and it didnt even cut through!
At the time this post was written, a Glowforge Plus had a 45W tube.
If you have a post-October-2019 Glowforge Plus or a Glowforge Basic made at any time, you have a 40W tube and would need much lower cut speeds for this material.
The settings would work with a 45W Glowforge Pro. 1/4" baltic birch cuts clean at 140/full for me on that. IIRC something like 120 or 110 is needed to cut it on a 40W Glowforge.
Keep in mind Baltic birch and birch are two quite different products. The most common issue with plywood is that the glue they used isn’t laser cuttable, or there are voids/fills that aren’t laser cuttable. Cleaning the edge will always have to happen - your using fire to cut wood - but it sounds like your issue may be the material as well as the 40 vs 45W tube.
