This thing is a remix of thruit00's PLA cooling ducts, a remix of funbart's PLA ducts.
I was really a huge FAN (pun-intended) of thruit00's v2 PLA fan clip duct design, but on the CTC Creator I noticed that the vent outlet was actually rubbing/touching very snugly against the heating blocks causing sagging and warping of the vents after 10+ hours of printing.
Tested after 20+ hours of printing, same excellent results, no melting duct-ends.
UPDATE 2014/12/6: Two people have recently mentioned issues where the screws can no longer reach the block after flipping the fans on certain Creator Pros. It seems that the fan screws on their Creator Pros are only 34mm long VS the older designs with 40mm screws on the Dual.
Also with Creator Pros I've heard scattered reports of a deeper carriage preventing the fan duct from contacting the fan surface.
Be sure to verify these aspects before attempting to install this remix. Creator Pro owner's may want to try Repurposer's" remix of these clips, and if you do, DO PLEASE report back on the fitment, or leave a comment if you find ducts that match fitment more closely on the Creator Pro that way Thingiverse explorers who've found their way here can find the part they need faster. Many thanks to KrisRoberts1121 for updated details!
I imported thruit00's v2 design (slightly structurally better than v1) into Blender and made tweaks to lengthen vent's upper clearance by around 1-1.5 mm and recessed the vent outlet by around 1.5 mm to accommodate CTC/Flashforge Creator machines.
Installation is super-simple. Flip your fans so they pull air across the heatsinks instead of pushing it. It's perfectly OK to leave them like this. When you want to print PLA, slide these bad boys on till they 'click' flush against the fan frame.
*Align the print(s) oriented front to back.
*Avoid making barriers in front, keep faces exposed/open to airstream.
*Remove for ABS printing.