This is a simple frame to mount the MKS Robin Nano v3.1 3D printer mainboard to just about anything.

It features recessed areas on the back of the frame to capture (4x) M3 nuts so that the frame sits flush against the mounting surface when the stand-offs are in place.

The design expects that you use some sort of metal or nylon standoff, as this frame is not meant to be a low-profile surface mount frame, but rather still elevate the board to allow for air flow across top and bottom of the board in enclosures.

The frame is 4mm thick to allow for more than adequate stiffness, and to allow space for the M3 nuts to sit flush against the back side of the frame.

To save on materials and print time, the frame has been skeletonized (so to speak) with cutouts in non-structural areas.

There are 4 general mounting holes to allow for a few different options to mount the plate to your intended surface. For my particular use case I was mounting the frame to the inside of an MDF enclosure beneath a production CNC machine.