Case for Raspberry Pi 2 Model B.
Intended screws for attaching the board to the case are thread-forming screws PT K25, with nominal diameter of 2.5mm and length of 7mm.
This was a project to make a case for Raspberry Pi 2. It was meant to be optimised for injection moulding with simple 2-part moulding tool.
There were also some other requirements:
- The board is connected to the case with thread-forming screws
- Design for assembly and Simple assembly
- It must withhold a static load of 20kg and deformation must be smaller than 1mm and must not touch the board at any point.
- Mass less than 70g,
- Cases must be able to stack on each other
- Calculate all the joints
- Analysis of injection moulding
- Design of moulding tool
My design has some advantages. There is no visible line between two parts. I really like how I was able to hide the line between two parts on the inside of the case. Also the force applied to the top of the case is transmitted trough the ribs directly to the legs. It does not affect neither the board neither the bottom part. I was also able to use a snap fit and therefore make an assembly and disassembly quick and easy.
3d printed version is a little bit different. I had to make the top flat. I had to thicken some parts of the case (mostly ribs). I changed position of the slots on the bottom part, so you can route through a ribbon cable for camera.There were also some other minor changes to improve printability.
It can be printed without support material. There are some tricky bridges and some very thin parts, but I was able to print it without any problems.
You might need to file down or sand some parts to ensure a better fit. Mostly on the part of the case around USB connectors.
*You can't see it on the pictures, but there is supposed to be a 1mm gap between the case and the table, so it gets a little bit of air from the bottom and it also doesn't sit on ribbon cable.
Disclaimer: I do not guarantee that this case can withhold 20 kg of load or that deformation is less that 1mm.