Absolutely brilliant! I had been trying to deal with the cooling issue for overhangs and tall, narrow things through a combination of Skeinforge Cool (which really slows down the prints and doesn't do much for overhangs) and lowering the extruder temperature (which causes delamination problems). A couple of quick test prints showed that I could up the extruder temp to 230C and still print tall features 1 x 5mm with no sagging or delamination.

It works so well that I ended up hooking it up in parallel with the stepper cooling fan on my MK6+ extruder.

Note: this is designed for a 50mm fan.

Printed mine in green ABS, required a fair bit of cleanup after, the generated toolpath seems to be quite erratic for this thing. Used a 50mm fan from Maplin (UK highstreet electronics store) and cut it out of the frame. Used superglue to hold it in place.

See my print of the small cube gears to
see what difference it makes: http://www.thingiverse.com/der...

http://www.thingiverse.com/der...

Very nice, mine is printing as we speak.

While you're at it you could stick on some LEDs to illuminate the build area.

I would have given it 5 stars if the original files where there instead of only the exported STL-mesh.

Have you though about adding screw holes to mount a standard 40mm fan?

yea, blowing on a print gets real old (and dizzying) after a minute or two.

could you show a result printing with and without it that would be great