Fan mount, wind duct

2018/12/20
Per makers' request, I added 4020 cooling fan version as a remix of this design. If your cooling fan is of 4020 size, please refer to
https://www.thingiverse.com/thing:3302224

2018/12/05
The STL files begin with "famo" are 1 heat sink cooling fan + 1 filament cooling blower
The STL files begin with "du" are 1 heat sink cooling fan + 2 filament cooling blower
The STL files begin with "crx" are especially for CR-X
The STL files ended with "mo" are with add-on mounting holes

2018/12/04
A well designed fan mount + wind duct + add on provision for many 3d printer hot ends.

A good design must

1. Efficient on cooling
§ Hot end cooling duct conformed from fan blade circle to heat sink rectangle, making 100% air go through heat sink.
§. Filament cooling fan partially share duct wall with hot end cooling duct to shorten the distance from fan to duct outlet so not to lost too much pressure.
§ The filament cooling duct pointing bullseye to hot end t