Reverse alignment tool for K40 laser cutter

thingiverse

This is a simple reverse alignment tool that holds a 12mm diameter red laser module (the kind with a lens) on the laser head of a K40 laser cutter. To use it, you remove the lens and its holder from the laser head and push it onto the remainder of the head. The laser module is powered by 3 AA batteries in a battery holder. If you have access to a lathe, the function can be improved by making a12mm diameter ~5mm thick Delrin insert to go above the laser and using the tailstock of the lathe to drill a 1.5mm hole through the insert. The insert can then be press fitted into the 3d printed part above where the laser module will sit. However, the tool will function without the insert. Reverse alignment will not mean your K40 is perfectly aligned. This is because the red laser light may not exit mirror #1 at the same angle that the IR light from the CO2 laser tube enters it. However, it should not be far out and using the 'burn the tape technique' should quickly bring the K40 into alignment. It's a good tool for when things are miles out of line and unlike the burn technique it can safely be used with the lid of the machine open (as long as the main laser is off!!). After printing some judicious sanding may be required to ensure a snug but not too tight fit to the laser head - ditto for the laser module. Note the diameter of the laser head of the K40 should be about 26mm - this may vary from manufacturer to manufacturer. See https://petermobbs.wordpress.com/2022/03/22/the-k40-laser-commissioning-part-1/. The holes are for 3mm bolts - these are only useful if the part comes out a little too big or your laser head is a bit smaller than mine.