Qidi Max 3 Printhead Magnetic Back Cover

This is a remix of qidi_back_v4_3. I increased the diameter of the screw holes a bit as I couldn't get magnets to fit in the holes without taking a drill bit to them. I removed the layer between the magnets and the screws, and rounded the inner edges of the screw mounts. I also removed half of the material from the top where the USB cable enters. I did this because every time I removed the ptfe filament tube it moved the USB cable and knocked my printhead cover off. Lastly, I increased the depth of the holes, for three reasons. (1) I have a BLTouch and the magnet on the bottom right side interfered with it (not much, but it does have an effect). (2) I didn't want to print with the top down because the supports would impact the appearance. I printed with the bottom down a couple times and  lost prints because I couldn't get the supports off, or if I increased the distance of the supports the vents looked terrible. (3) Without a fourth magnet the cover wouldn't stay on the back of my printhead. With more depth you can leave the screws partially unscrewed as shown in the attached image (around 5 mm on top and 3.5 mm on bottom), which holds the cover in place much better. The best way to do it is to unscrew the screws more than you need to so there is a gap between the cover and the base when the cover is attached. Then remove the cover and make minor adjustments to the screw until there's no gap. You can print this model on the side, which minimizes support contact - improving the appearance and you're no longer unable to remove the supports or risk breaking your print. Removing the layer between the screw and magnet also allows you to insert the magnets after the print is complete. I used an Allen wrench to hold them in the right orientation and press them in. It's a pretty tight fit so there was no need for glue (this could potentially differ depending on your print settings). 

I printed in ABS, .6mm nozzle, .24 layer, 100% infill, organic supports. I also printed with a .4mm nozzle, .16 layer, and it looks very nice. In the slicer, flip the model with the screw holes facing down, then add support blocking cylinders to fill the entirety of the screw holes so no supports are printed inside of the screw holes - make sure that no part of the support blocker is on the inside of the model or it could interfere with supports for the mounts. Then flip the model on its side and slice. It should turn out like the attached image. I sanded it down after printing to improve the appearance. 

Increased the diameter of the screw holes
Increased the diameter of the screw holes, removed the layer between the magnets and the screws, rounded the inner edges of the screw mounts
Removed half of the material from the top where the USB cable enters
Increased the depth of the screw holes