Wanhao D9 Fan Duct Reworked - After initially using Tiny Machines 3D's flipped version, I decided to remodel it from scratch with the exception of the vary top fan insert; no sense re-inventing the wheel and his design there works well for the myriad of available fans out there.
I'll add a couple images of it installed soon.
The big changes were internal rounding of the cavity to better direct flow, some edges tweaked to accommodate sloppy fabrication holes in the heat sink bottom and to some degree, variations in your print quality. I used 0.15 since I dont concern myself with time and printing at 0.20 should work if you desire to go that route.
This duct uses the stock cooling port on the bottom- all that's needed is to print it and add spacers to tweak your height from the nozzle zero. I included 3 sizes of spacers and aside from just making your own adjustments, once you are happy you can simply merge them into the main duct part and reprint. I haven't bothered and theres no air leakage that I can detect.
You will need (3) M3X25mm set screws if your spacer choices require it. One note however, since the mount uses Wanhao's default that means there are screws in the top side of the extruder holding the top box fan down, and may have to shorten them.
The fan is a standard 5015 BUT you MUST note the voltage with your choice- the replacement you use MUST be 24v @ 0.10 amps - anything other than that and you run the risk of damaging your printer, so be warned.
Lastly, when installing, check the wire colors on the stock fan, and compare them to the replacement and note which pins are red and black. I had to swap them on the fans I ordered. This is also important.
Enjoy- Earl @Wanhao University