I purchased an affordable PWM controller from my electronics supplier (see photos) to control a fan in my DIY server cabinet. For this controller, I needed an enclosure that could be mounted and closed using M3 screws.

To create the 3D design, I used FreeCAD 1.0.

Board dimensions: 30x26mm

Inserts: M3x5.7mm

Let me know if you are interested in FreeCad file - i will upload then.