A8 "EvenFlow" fan duct

thingiverse

This fan duct should be particularly useful for PETG printing, where you need less of cooling, but much more control over it. Irecommend to adjust your end G-code so the fan would run at least on 20% after print is finished, but nozzle still very hot, else the duct could deform from radiated heat. This is what I use as part of my end G-code, after parking extruder head: M106 S204 ;fan to 80% to prevent duct melting and cool dow hotend M109 R50 ;wait for hotend temperature to drop to 50°C M104 S0 ;hotend off M107 ;fan off Many fan ducts increase flow velocity, but this comes at cost of flow restriction. Being inspired by original Prusa i3 MK3S fan duct, where you can see little "flap" that directs the flow in level with platform, but there is virtually no flow restriction, I came out with my own design. This should provide better flow control. V1 is simple shape and seems to work just fine V2 has wider outlet and inner slat to direct more flow to the lower layer. V3 improved inner shape to make smooth transition frm fan to the shroud V12 only lower channel with smmoth transition from fan outlet, good for PLA When Z = 0, the duct is nearly touching platform, so depending on your print quality, you might need to use sand paper and sand the bottom of the duct flat.