This work by Nervous System is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. If you plan to use the design for commercial purposes you can purchase a license: commercial license.
The nozzle design makes three changes to the stock nozzle. One, it is slightly closer to the work piece, so it's important to realize there is less clearance (about 4mm). Two, it has a sharp opening at the exit of the air, which is supposed to reduce turbulence as the air escapes. Three, it features thin channels meant to columnate the air and create laminar flow. The columns have a cone removed from them to make space for the laser beam, which narrows as it exits the nozzle due to the lens. This cone is designed for a 2" lens and may not be the same as other lenses.
We printed the nozzle on a Form 2 3D-printer in the Rigid 10K material at 50 micron resolution. You want the result to be as smooth as possible, since that also reduces turbulence. We have also tested it in standard clear resin, which works fine but the opening of the nozzle tends to degrade quickly from air pressure and heat.
We have exclusively tested this on Trotec Speedy 360 lasercutters with external compressed air running at around .2MPa or 30 psi, which is significantly higher than the stock internal air compressor. One of the advantages of this nozzle is you can increase the air assist pressure without blowing out the kerf. Also this does not help with flashback, where the laser reflects off the bed and burns the underside of the piece. It can also make rasters less clean, since if you are not cutting through the piece you are simply blowing smoke more forcefully into the top.
Do you have any other tips about getting the best cuts out of your lasercutter? Leave them in the comments