Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3899683.
New nozzles uploaded for dual blower configuration The nozzles with "2" in the name are better for the dual-blower configuration, as the original (smaller) ones are too restrictive and cause the blowers to stall. The smaller ones may still be better for the single-blower configuration.
QMB == Quiet, Modular, Blower-based Ender 3 hot-end and part cooler (if you have an idea of a catchier name, feel free to suggest it!)
Work in progress I've only tested the single-blower version at this point, and it works great. This was designed for the Ender 3. I don't know if it will fit an Ender 5 or a CR10 or not (I've heard parts are swappable, but don't have access to try). Please let me know the results if you test it on one!
I designed this with several things in mind: 1. Forced air through the hotend heatsink. I'm amazed at how well the Ender 3 works with fans only blowing at the heatsink with no exit ductwork. I wanted to correct this and have air ducted to, through, and away from the heatsink. 2. No spillage of air from the heatsink to the part. This is important for when you don't want airflow on your part, such as when printing with materials that like to shrink. The air is forced behind the heatsink, through back-to-front and straight up and away. 3. Larger openings for the part cooler ducts. Far too many coolers put a high restriction on the fans with very small duct nozzle openings, and fans typically do not flow well through restrictions. 4. Blowers instead of fans. Fans are great at airflow. Blowers are much better at (an designed for) maintaining pressure through restrictions. 5. Low noise. Axial fans with the intake facing forward produce a lot of noise. They were by far the noisiest parts of my printers. I've found that 4020 and even 4010 blowers are a lot quieter than 4010 fans, while moving more air through restrictions. The largest source of noise from blowers is the intake. I aimed the intake away from the room to help mitigate this. This is far from perfect, I believe a shroud can be attached to further quiet the intakes down (I may design one in the future), but at this point, the power supply and mainboard fans are by far the loudest part of my printer. 6. Airflow to the part with a place to go. I've angled the airflow coming out of duct nozzles from both sides so the air flows across the extruder nozzle at an angle to the rear. This will draw in air from the front as well, pulling air across the tip of the extruder nozzle, where you want it. Many part coolers do this, but many simply blow straight at the nozzle from both sides, leaving a dead-zone in the middle with no airflow. 7. Swappable/adjustable/removable duct nozzles I made the duct nozzles very simple for remixing in case anyone wants to experiment with different shapes, angles, opening sizes, etc. The two sides are mirror images of each-other, so you really only need to design one (you can mirror a part in cura with a mouse-click). The nozzles in the uploaded picture (of just two nozzles) are actually an earlier version, the uploaded model is an improvement on that. Printing variations on the design is quick and uses very little material. You can trim the duct top (or simply slice it with it lowered slightly through the built plate) if you want it raised higher once pressed all the way in, or lower it easily just by pulling it down a little (it should fit snugly enough to hold, more on that in the Assembly section). The duct nozzles can be removed if you're not using the part cooler while printing materials prone to shrink when cooled, providing even more visibility to your work. 8. Modular for different fan arrangements. The back plate forms a duct for cooling the heatsink, and acts as a platform for the front plate which holds the part cooler fan(s) and ductwork. The front can easily be remixed for different blowers. I provided a model for a single 4020 blower and another for dual 4020 blowers for part-cooling. 9. Open view of the nozzle for remote viewing I didn't want the part cooler making it difficult to see the nozzle from a camera. 10. Good clearance from the heat-block. My favorite part cooler melted while printing at 280C recently (yes, with an all-metal insert in the hot-end) because it was too close to the heat-block. The single-blower front housing has decent clearance, and the dual-blower front housing has a very open area shaped to allow convection up from the heat-block. Note: I've not yet tried printing at 280C with this cooler! It should hold up, but I can't say for certain yet. 11. Access to service the bowden tube Both front housings provide full access to the bowden tube fitting. The dual-blower front housing also has a full relief for the set-screw (grub-screw) holding the heatbreak into the heatsink.
Backplate octolapse: https://youtu.be/zC_PO1anxJs
<iframe width="560" height="315" src="https://www.youtube.com/embed/zC_PO1anxJs" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>Single-blower front housing octolapse: https://youtu.be/bAtzbjC3eqs
<iframe width="560" height="315" src="https://www.youtube.com/embed/bAtzbjC3eqs" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>Dual-blower front housing octolapse: https://youtu.be/Z1cdWggT7Hg
<iframe width="560" height="315" src="https://www.youtube.com/embed/Z1cdWggT7Hg" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>Duct nozzle octolapse: https://youtu.be/qX8zVnqQ4UM
<iframe width="560" height="315" src="https://www.youtube.com/embed/qX8zVnqQ4UM" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>Large opening duct nozzles octolapse: https://youtu.be/KrtulF2xaNU
<iframe width="560" height="315" src="https://www.youtube.com/embed/KrtulF2xaNU" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> ----------------------------------------------------------------------------------------------------------------------October 6th, 2019, 2pm: Uploaded fixed version of dual-blower front housing (was missing attachment points for 2nd blower - d'oh!).
October 6th, 2019, 6pm: Uploaded slightly improved version of the dual-blower front housing.
October 13, 2019, 9:40pm Uploaded version 2 of the duct nozzles. These are far more open and a bit further away from the heater block. These are good for the dual blower version, as the smaller ducts nozzles restricted the blowers to the point of stalling.
Things I may change / possible improvements
As mentioned above, I may create a shroud to quiet the fans even further. Right now they're quiet enough that I can't hear them over the obnoxious stock main-board fan or the power supply fan (upgrading those will come first).
I may add a bit more clearance around the heatsink fins (but not at the top and bottom) to provide for a bit of air to bypass the fins (since they're so close together) allowing the 4010 blower to operate a bit more efficiently. It'll be interesting to see if it still cools as well (or better).
I may put some finishing touches on the single-blower front housing that you can see on the dual-blower front housing. Aside from aesthetic tweaks, I may add a relief for accessing the set-screw (grub-screw) to the single-blower front housing.
I may experiment with and upload some more duct nozzles. Those are easy to swap and very economical to print.
I have a Chinese all-metal hotend I've been thinking about trying. I will likely make a remix/variant of this that will work with that hotend.
I have uploaded remixed thing 3947323 that supports a Microswiss clone hotend.