I have been doing some experimentation with laser cutting parts from 3 mm baltic birch. What is the general consensus on power, speed, and # passes. For example, at 100% is it better to make more passes at a higher speed or a single pass at a lower speed?
The technological limit on Diode lasers are around 5-6w. OptLasers has a true 15W using three diodes and collaminating lens setup PLH3D-15W Engraving Laser Head - Opt Lasers. 40w sounds like "marketing" So assuming a 6w - with plywood the issue is going to be the resin glue layers. 445nm doesn't absorb well into non-organics so its not very effective against the glue soaked sections of each layer. Going with 100% power, and lots of faster passes should prevent charring a little better than going slow. No need to dial back the power - effective cutting power is a combination of optical power * time spent - so upping the feedrate drops the "power" being put into the cut already.
Thanks Peter, I agree with the marketing aspect of your comment. I have carried out numerous experiments thus far changing all the variables to see the effect and have yet to establish a baseline. I shall keep experimenting.
Plywood is a challenge for a 40w laser although you should be able to cut 3mm. The more layers (and probably the type of glue used) the more difficult it is. obviously the choice of lens, alignment and how effective your air supply is also matters. So short engraving lens are less effective compared to longer focal length lenses. Double passes, like they do with diode lasers, tends to char and burn the wood. Sometimes it won't even cut thru. You can always flip the material and cut from the back side if all else fails. 40w CO2 lasers use to be the standard for hobby lasers but I got tired of knifing out uncut areas and upgraded to bigger tubes that have far more power.
