I needed to cut 6.4mm oak with a 50w machine. Two passes doesn’t reliably cut thru. Below describes how to cut from both sides using mirror horizontal.
First laser cut a straight piece of thin wood or poster board that’s clamped or held with magnets to the table. Include a tick mark in the center of the new cut line. Jog the origin +Y slightly an reset origin. Reset Z focus for the cut piece.
Upload the first pattern with the origin set at the lower center
Put a notch in the cut wood and align it to the mark on the wood strip
So the notch in the wood strip should align with the notch in the cut piece which should be just below the current machine origin. You can check by test firing.
Cut the first patten then upload a horizontal mirror of the pattern. cut the second pattern after flipping the wood and aligning to the notch.
Don’t change origin between cuts.
Since everything is aligned you can take more passes by simply relocating the wood to the strip and above the notch.
I’ve done fast, clean, straight cuts on 1" hardwood (oak, paduak) and literally 2x4’s. On a 2" lens.
That really shouldn’t be possible, and has given me a lot of thought. This laser is a really powerful build but even still it can’t be in focus that far out. I believe the air assist is being superheated past the decomposition point of wood and jetting right through.
It’s actually quite simple and repeatable, on this machine.
Anyhow, the effect disappeared when I did 2 passes each twice as fast. Nowhere near a cut. One-pass or bust.
For this, I had the air assist cone- normally 6mm from focal point- moved as close to the surface as I dared. Roughly 1mm. That puts the focal point inside the material, and also forces the air assist to jet into the wood.
So I finally got my controller (AWC708C or LO-X7) to perform that print and copy function. The goal would be to burn from one side then burn from the opposite side and cut thru. The problem with that tool in a thick cut is that you have to penetrate the wood from the first side so you know where to pick up the reference marks on the back side. Since you can’t penetrate the wood your left with drilling the reference marks, in order to target them on the back side.
I just think flipping the wood against a straight edge and locating it off a band sawed notch is more accurate then finding the center of two drilled holes with a laser beam. I know some of your machines have visible lasers in the beam but that seems to add another potential error that the visible beam isn’t perfectly in line with the invisible cutting beam. And those 5mw lasers can have a fairly thick beam.
Anyway It would be interesting of anyone else has a technique for thick wood.
