HCmaker 7 part cooler (improved)

This is an improved version of the part cooler I designed by myself.

The hot end fan's mounting is stronger, but the positions of the mounting screws are still the same. I modified the air exhaust, it's now wider (30mm) with thicker walls and closer to the hot end's aluminium radiator.
I closed the nut sleeves beneath, which are used for assembly the center fan's mounting bracket, so the nuts can't fall through the left and right assembly.
The air exhausts of the left and right assembly ar