This adapter mounting plate is designed as a replacement for the Waveshare Cobra Flex top cover plate.
 

The base outline geometry originates from the official Cobra Flex top cover provided by Waveshare available here:

https://files.waveshare.com/wiki/Cobra_Flex/Cobra_Flex_with_Cam-PT.zip (Look for “上功能扩展版:1”)

I modified it extensively to add a mounting interface for the Waveshare RoArm M2/M3 robotic arm, with new hole patterns to allow mounting the RoArm M2/M3 directly onto it, with or without the Driver Board, depending if you prefer moutning it inside the chassis or not.

Printing Material

If you are planning to drive your Cobra Flex outdoor, I highly recommend printing the mount plate in ASA. For extra strength, you can also chose to print it in ASA-CF if you'd like, especially if you plan on mounting lots equipment over it.

If your cobra share is for indoor use only, then any filament will probably do, and same rule applies if you are planning of carrying a lot of weight on it: use reinforced carbon fiber reinforced filament if that is the case.

Assembly

You have two options:

1. Using m2.5/m3 at any length + 6mm screw held with with m2.5 nut + washer on the other side, or
2. Injecting m2.5x4mm /m3x4mm heat inserts

If you'd like to use heat inserts, make sure to use m2.5mm heat inserts for the 58x49 holes for the General Driver Board, and M3mm head inserts for the RoARM pattern.

Credit: Waveshare, for publishing the original Cobra Flex cover plate CAD.
Modifications and adapter design: MeanUIThread

This design lets you securely mount the RoArm M2 or M3 onto the Cobra Flex platform.