Nozzle adapter for K40 laser cutter engraver

thingiverse

Increase size by 3% before printing (1.03 on 'scale XYZ'), all three axis - since plastic shrinks. This is male to male adapter for K40 laser so that air assist nozzle can be attached to the head. Use 20 mm lens with 50.8 mm focal length (2 inch lens). Please use Cloudray CVD lens which has low dispersion and less absorption. Original (stock) 12 mm diameter lens is not the best quality and on high power can be hot and deform 3D printed plastic. I am using PETG, orange. 0.1 mm layer, 25% infill. 240C head and 70C bed. Since there is M22 x 1 mm thread, it should be relative precise, so use 0.1 mm for layer in order to reproduce that thread. Nozzle should has few turns of nylon thread in order to be able to adjust position of the air inlet. It can work without that thread, but during tightening the screw, air inlet may end at wrong place, so adding thread on black thing (nozzle) helps unscrew little bit while maintaining airtight connection. Adjust laser head precisely since orifice is just 2.5 mm wide. Avoid 'ghostinig' due to reflection of the laser from that opening. Ghosting is manifested by half burn area next to cut. With this setup, focus is at 5 mm from the end of the nozzle. This way good flow of air is assured to remove smoke as soon as possible, clean cut without tar. For engraving, use minimum air flow to avoid returning back of the smoke and tar to the surface. Just to protect lens. If you cut acrylic and the lens is dirty - use acetone and cotton swab to gently remove residue from the lens.