This is to go on the intake side of the 30mm cooling fan used on the E3Dv6 hotend. It provides a grill to protect the fan, as well as a duct to try to limit intake away from the print bed. This should work fine for the intake, but I would probably not use it for the exhaust side.

I have provided the OpenSCAD script for this. It allows you to change the size of the screw holes, the height of the duct above the grill, the height of the screw standoffs, the diameter of the screw standoffs, and the thickness of the grill plate (plus anything else if you rework the script).

The standoffs make this part work better with thing: 455071. I had 25mm screws. Using a 2.5mm standoff made the screws go right about 2mm through the one part of 455071 and into the other (0.5mm for a washer, 2.5mm for the standoff, 2mm for the grill plate, 10mm for the fan, 8mm for the first part, leaving 2mm for the second part). That is just about perfect. You can adjust the plate thickness or the standoff to accommodate something else, if needed.

If necessary, set the parameters in the OpenSCAD file, compile it and export the stl. If using with thing 455071 and 25mm M3 screws, you can probably just use the included stl.

I printed it out of ABS, but PLA should work. If there is too much heat in that location for PLA, then the fan might not be long for this world. I printed with 0.2mm layer height, 2 perimeters, 50% infill.

Once printed, I just screwed the parts together.