Ender3Pro Duct for 4020 Blower

This is a simple means to mount a 4020 blower to an Ender 3 Pro.  Unlike many other designs, performance has NOT been verified with CFD :)  But, I can confidently say that cooling is improved over stock and this machine will print bridges and overhangs better than my Prusa Mk3S+.

I recommend not printing it of PLA (I used PETG) as it will be near heat sources.  Orient the part as shown in the photo.  No supports necessary, though there will be some considerable bridging.  I had success, but be mindful of your own machine's abilities.

How to wire the new 4020 blower is your discretion, but the steps below are how I performed the modification.

As always with this type of mod, PID tuning the hotend is recommended after install.

Requires:

• 4020 blower
• 3x M3 heat-set inserts
  • I used these: https://www.amazon.com/gp/product/B09TNK8GD6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
• 3x M3 x 18 socket head cap screws

Steps:

1. Print the blower duct part.  
2. Heat the inserts and press into the print as shown in the photos.
3. Unscrew the stock blower from the extruder.  Keep the screws – they'll be used again.
4. Cut the stock blower wires approx .5" from the case.
5. Using the 4x screws from step 2, attach the new blower duct to the hotend shroud.
6. Using the 3x M3 x 18 screws, attach the new 4020 blower to the new fan duct.
7. Solder the new 4020 blower wires to the pigtails remaining from step 4. Insulate appropriately.
8. The hotend shroud can be loosened and canted slightly to raise/lower the duct tip (mine is fully raised in the photos).
9. Turn on the machine and enable the fan to verify it spins the correct direction and forces air out of the duct.