A much lighter weight, more efficient, and quieter fan duct for the Creality CR-10. It is designed to fit the stock Mk8 style red heatsink hot end. It works with the stock cooling fan. It keeps air flow from blowing on the heater block or going anywhere it shouldn't.
Printed as I did it weighs 7g where the stock metal shroud weighs a porky 44g.
The stock bolts that hold the heatsink to the X carriage are not quite long enough. I used M3x20mm button head screws I had on hand. The stock screws that hold the cooling fan in place will thread nicely into the holes of the printed shroud as they are sized for M3 screws.
I printed with no layer fan as I'm working on a redesign for that also and it came out fine with a few small blobs on the inner support structure and overhangs at the top of the fan opening.
PSA: It has come to my attention that a few people, including myself, experienced the screws going through the shroud loosening over the time of hours worth of printing. Which allows the entire hot end to shift slightly. Make sure you tighten the screws good and tight! And it's not a terrible idea to use a very small amount of BLUE / low strength thread lock on them.
So because I've seen a fair amount of commentary going around that this shouldn't be printed out of PLA...that's incorrect. PLA is just fine. If your heatsink is getting hot enough to hit the glass transition temperature of PLA then there is seriously something wrong. If the heatsink is getting that hot, you will be experiencing lots of jams because the filament will get swollen and melted inside the tube above the heatbreak. With that said, feel free to print out of whatever you want. Keep in mind that most PLA experiences around 2-3% shrink rate so it will fit nice and tight, which is good. Printing it out of PETT or PETG should shrink roughly 1% so it may be a bit more loose.
EDIT: Adding some fan info because there's a LOT of discussion about which fans to replace the super loud stock fan. Here's the thing folks, there has to be both enough CFM (airflow) AND enough static pressure generated to actually be capable of forcing the air through all those fins of the heat sink! Reducing the air flow pathway of a tiny 40x10mm fan hurts them very badly! This is why manufacturers don't care about noise level, they care about a cheap fan that pushes hard enough and fast enough to cool. I highly suggest people stop trying to use Noctua fans for this application. They simply don't push enough CFM or pressure for it. They are quiet, but will quickly lead to clogs and other problems. The BEST option of a Noctua would be a 20mm thick variety as it would produce the most static pressure, but that's not the best option overall.
Here are my recommendations (`30dB noise for these while the stock fan runs close to 70dB. Noctua are mostly 17- 28dB FYI):
For 10mm thick fan
For a 20mm thick fan
For a 15mm thick fan
Super quiet Sunon 10mm, but only 7 CFM and pressure is pretty low at ~30Pa, but still better than a Noctua.
An even better option if you're willing to take a slight bit more noise
I also want to add some options for the control box for 50mm and 60mm as they are very noisy and there's a lot of questions floating around about what fans to use there. The following are very quiet, push a lot of air and are good brands. Outperform Noctua and likely far cheaper even in countries outside the USA. Although those across the ponds may have to source via Newark/Element14, Mouser, Jaycar or something besides Digikey.
So for 50mm this is a good option
Also this one