NOTE: This is a cross-posted remix model from Printables site, which can be found here

Here is my remix of the hotend/coldend fan adapter for the Neptune 3 Pro / Plus / Max based on design from @MaximBorodkin (from Printables). I decided to modify the fan position, and mount to give an option to have the fan mounted with pure friction, while still giving an option to mount with screws. Works for me, but your mileage may vary. Has been tested on both Winsinn and Sunon 5015 fans. 

I recommend adding a buck converter near the mainboard set to a lower voltage, as these fans outperform the stock 4015 fans while being quieter. Alternatively if running Klipper firmware, change the fan speed and cycle times to a lower value and perform a PID_CALIBRATE

Printed with Elegoo Rapid PETG 0.28mm height with supports