I did some thinking and researching regarding focus and have found some useful tips regarding getting the best out of the laser:
1. When focusing initially, focus past the smallest point on either side, which should give you a good idea of the midpoint, and hence best focused position
2. The focus tool is about 51.5mm long, but 1.4mm thick, which puts the focus at 50.1mm away from the heatsink. I have found that this is not always represented by the thickness of the focus tool from the laser shroud away from the surface. In fact, the front of the shroud on my emblaser is pretty much touching the surface for it to cut optimally.
3. At optimal focus, I have been able to cut Bunnings 3mm pine 3ply in 6 passes (5 with a bit of coaxing) @2.1A
, 300mm/min, 100% power. Even a 1mm deviation in depth means that more passes will be needed to cut through.
4. I've been trialling pressure fit junctions and am currently working on a remix of a Parallel Laser Pressure fit gauge seen on Thingiverse. Current pressure fit junctions are around 0.1mm to 0.2mmhttp://www.thingiverse.com/thing:41999