I am brand new to laser engraving and am learning.
I am trying to cut 1/4" baltic birch which is approximately 6mm.
The instruction book with the laser indicated to use a speed of 400, 100% power, and 1 pass.
That did not work. I got close to the piece being cut out using a speed of 450 and 8 passes but am getting pretty significant burning on the top. I do have the air assist on and open all the way. Is this normal or do I have something setup wrong?
Welcome to the Lightburn Community? Visit often, even when you do not have problems. There is a goldmine of experience in this user forum.
Focus has to be spot on to get these results, plus you must have the same material they used. It varies a lot.
Focus you can control. Use the Laser Tools Focus test to get it dialed in. Use the lowest power you can to prevent over burning the wood.
My chart (10w) says 480mm/min for 3mm and 180mm/min for 6mm ply. As you can see, there is not a 1:1 relationship (6mm would be 240mm/min).
I know this will not help you, but I saw a video where my S30 Pro laser cut 18mm ply in one pass. I currently cut 3mm Baltic ply at 800mm/min, 65% power, and 4 passes. That reduces the blowtorch scorch effect a lot.
For your 6mm ply and 20w machine, I would start at 750mm/min and 70% power. That should get you in the ballpark. And quit trying to keep up with those 1-pass miracles. 
Thank You for the response.
I tried 750mm and 70%, but it did not go through.
I am cutting a 5/15in wide grove that is 1 1/2in long.
When I went to 7 passes it would cut the 1 1/2in length all the way through but not the width.
When I went to 9 passes it seemed perfect and piece popped out and I did NOT have significant burning.
This is all new to me and in my opinion, I was not very happy with the documentation that came with the two trees laser especially the part regarding the auto focus.
I ran the auto focus on the birch plywood with the defaults - speed=118.1in/m, max power 20%, steps=20, high power laser mode was off.
Does that sound right? When should auto focus be used - everytime the thickness of the material changes?
Again, appreciate the help.
Yes. A mm or 2 makes a big difference in the power delivered to the spot. Focus means we are trying to get the spot as small as possible. This will give maximum heat in the spot.
I do not have auto-focus, so I can not give any pointers for that.
You might run the Lightburn Focus Test to see how it compares to what auto-focus does.
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.