Here's my simple way to add an adjustable and easy-to-aim funnel that channels air from a 40mm fan onto the print nozzle specifically to help cool extruded plastic quickly after it leaves the nozzle. This is helpful with overhangs and bridging and whenever the layer time is too short for the previous layer to completely cool before the next layer begins.
You probably won't need nuts because the adjustment / attachment hole is just a bit too small for an M3 screw. If you turn it in there, it'll be self-tapping and won't require a nut. So, all you need is several M3 screws or bolts.
THERE ARE TWO VERSIONS of the FUNNEL! I strongly recommend the updated/improved one as it is much less likely to interfere with your binder clips on the right side of the bed. If you go with the original version of the funnel, you have to use the SMALLEST binder clips possible on the right hand side of your print bed (when holding the glass on). If you get too large of a binder clip, the cooling fan will interfere or get hung up on your binder clips. Even with the smallest sort of bind clips, I fear that you'll have trouble with the original design. So, try the updated/improved on first!
Check out all my Folger Tech i3 2020 fixes and enhancements in this collection.
Use this link to quickly Order a 40mm fan on Amazon.
Place the funnels such that they are like cones with wide part on bed and it narrowing as it goes up. No supports necessary!