Ender 3 (Pro) - MKS Gen L Case

This design replaces the stock Ender 3 (Pro) mainboard case with one that fits the MKS Gen L. You can find very good information about this mod in [Teaching Tech's](https://www.youtube.com/channel/UCbgBDBrwsikmtoLqtpc59Bw) video guide. The aim of this design was to have a clean look (no fan at top or front) and still provide adequate cooling for TMC stepper motor drivers. In my setup, the 4010 fan blows air out of the box so that fresh air is sucked in directly above the stepper motor drivers.