https://www.thingiverse.com/thing:1958296
This is actually a E3D kits for monoprice mini printer. I only print out the fan mount part. It cools hotend and print at the same time, but you might want to upgrade your fan to >6500 rpm ball bearing fan.

I print it with PLA, works great.
If you prefer the dual fan solution, connect layer cooling fan to D9 and hotend fan to fan port. Double check manual for your RAMPS board to make sure the fan port provide 5V power or 12V power and choose the fan accordingly.
http://forums.reprap.org/read.php?219,284204
(Da Vinci 1.0, Jr. 1.0 RAMPS, miniMaker) X4, (Creality CR-10S, CR-10 mini, Ender-3) X4, Anycubic MEGA X4, Anycubic Chrion X1, ADMILAB Gantry X2 (MonoPrice Maker Select V2, Plus, Ultimate)X4--Select mini X1, Anycubic photon X4, Wanhao duplicate D7 X1.
iNSTONE Inventor Pro X2, CTC Dual X2, ANET-A8, Hictop 3DP-11, Solidoodle Press, FLSUN I3 2017X1