This is my cooling solution for a BMG style extruder and V6 hotend combo. I made up this carriage for my EMT8 (modded A8), and needed a cooling solution for both the hot end and the parts fan. Initially I tried several designs and all had their ups and downs. I took the best from parts from the ones I liked and rolled them into one to make this... lol It works very well, and looks good on the printer too!
The duct for cooling the hot end is this great design by DaVinchi2000 - https://www.thingiverse.com/thing:3590309 It's pretty much untouched, other than hanging the 5015 radial fan off the side of it. I retained the ability to use an M3 screw/nut, or zipties to attach it to the hot end. Personally I prefer the screw/nut option so it's more secure and supports the weight of the radial fan better. The 30mm fan that comes with the V6 hotend screws to the duct and exhausts out the right side under the stepper motor for free unrestricted flow and better cooling. (At least in my particular setup)
The mount for the radial fan comes from this similar design by Tom114 - https://www.thingiverse.com/thing:1746358 Unfortunately his design didn't allow clearance for the BMG, hence my remix here... I used the flat plate behind the radial fan and cut off everything else. The plate is thicker (5mm) so the radial fan is attached with M4x20 screws that thread directly into the printed part. I printed the parts in PETG and they thread in and hold great. The duct is the same as his, from the Prusa i3 MK2.
These parts should work with most designs using the E3D V6 hot end, as long as there's sufficient clearance for everything obviously. This is the carriage I'm using it on with this printer - https://www.thingiverse.com/thing:3781552 If you're using an A8 or similar, I really suggest checking out this upgrade as well as the one listed for the Y axis using rollers instead of linear bearings, it helps a LOT. :)
I printed this with the face for the 30mm fan down against the bed so it needed no supports. I used PETG for the temperature resistance and flexibility to clip around the hot end. The excellent layer adhesion of PETG resulted in a strong part, though other materials may need to be printed in a different orientation using supports so the hot end duct doesn't break between the layers when attached to the hot end. I'd love to hear your experiences if you print it with something other than PETG, or even with PETG... lol It's working great for me though.