Improved Fan Duct for Nimble print head for Creality type

thingiverse

NEW IMPROVED V2 AND V3 ADDED! I recently mounted a Zesty Nimble extruder to my Ender 3 Pro and so I downloaded and printed Zesty's geometry "Nimble print head for Creality type" (https://www.thingiverse.com/thing:3558524) to mount the new extruder and try out their cooling solution. I'm pretty happy with the geometry, I like the compact size and clean design of the heat brake fan shroud and I really like the mount for the BLTouch, but I wasn't particularly thrilled with the geometry for the 4010 part cooling fan duct. My problems with the part cooling duct in that design are (1) with the fan mounted on the side, it unevenly distributes air pressure to the two nozzles, (2) it's a relatively bulky fan duct, and (3) the mount for the stock 4010 fan was a poor fit. (At least it was when I printed it. Your experience may vary.) I previously had used a Petsfang Bullseye (https://www.thingiverse.com/thing:2759439) which I was quite happy with and so I thought I'd see if I couldn't incorporate the elements that I liked from that duct into a design that would fit Zesty's hot end shroud geometry. This is what I've come up with. (It's not really a remix; more of a replacement part; but I thought I'd label it a remix to make sure it got linked back to the original design.) It moves the part cooling fan to the front, centered on the hot end so as to provide a perfectly even air flow distance to the left and right duct nozzles. The ducts provide really even and directed air flow and the mounting slots offer plenty of room to adjust the ducts up or down to get them perfectly aimed. The ducts are quite short which keeps the entire shroud very light (much lighter than my old Bullseye duct was). The part fan is mounted at a 45 degree angle so as to give the heat brake fan unimpeded air flow, which also gives an added bonus of giving clear access to the upper right and lower left mounting screws. (Two screws is plenty to hold that fan secure.) All in all, I'm super happy with this design so I thought I'd share it in case anyone else wanted to try it too. The duct prints very easily in its upright orientation but you will need to use support (from the bed only). I recommend that you use PETG or ABS as PLA has a low melting temp and can be prone to cracking. I printed mine in PETG and I'm very happy with it. UPDATE: I've added a second version (NimbleDuctV2.stl) that is even more compact and which should work with the EZABL probe as well as the BLTouch. This version also moves the duct nozzles so that they are 180 degrees opposite one another. (V1's ducts are just a little less than 180 degrees.) Like the first version, it also has a perfectly symmetrical duct path but it's even more compact and about 5% lighter. If you liked the first one, I think you'll like this one even more. FINAL UPDATE: I've added a THIRD version (NimbleDuctV3.stl) that has less restricted air flow and moves the ducts so that they're almost 120 degrees offset. I also slightly improved the aim of the air jets. THIS CHANGE IS THE RESULT OF ACTUAL AIRFLOW TESTING! I ran smoke through the ducts to observe airflow behavior and I found two things: (1) that I wasn't getting as much air flow as I thought I was, and (2) that with the ducts facing directly into one another, the air flow around the nozzle became quite turbulent. Offsetting them 120 degrees apart allows the air streams to collide just at the bottom of the nozzle and vent cleanly toward the back of the machine. In my tests, this has resulted in significantly improved overhangs and bridging. (Your mileage may vary.) By the way, the bottom of the ducts should be just under 3 mm above the bottom of your nozzle. To adjust mine, I drop the nozzle until it's right where I would print my first layer and then I slip a 3mm spacer (two of the small metal wrenches that come with the ender 3 stacked should do) under each duct while I tighten the mounting screws. This third version also should not collide with any of the bed probes.