I would like to make an updated calibration stick for setting up the laser cutter height. At a minimum, the new version would include commonly cut / etched materials (e.g. 3.2 mm ply). It would also be interesting to have a few heights for making purposefully de-focused lines.
Does anyone know how the existing calibration stick was designed? As far as I can tell, the height should be based on the focal length of the focus lens, and offset by the distance from the lens to the bottom of the nozzle. I haven’t been able to find the focal length of the lens.
Any guidance or suggestions for improvements would be appreciated.
I think I made the last one. (the files can be found here, if you assume the focus distance hasn’t changed).
‘zero’ height was determined entirely empirically - putting a flat piece of wood in at an angle, and then lasing a line along the material. Found the sharpest point of focus on the line, stacked card stock/blocks from there to the laser head, and then used callipers to measure the stack.
That gave the initial height to work off, then the material thickness heights were done based on the idea of the laser being focussed half way through them.
The pain in the ass was mainly just manufacturing - sides should be reasonably parallel, which the laser itself is bad at, so I added a lot of parallel offset, and sanded it down. Would be cool to mill a metal one, now that it’s an option.