There are two Front and Back Plate (or Face) in every scanner. They’re symmetrical so it doesn’t matter which is which. These oddly-shaped parts are made from 18mm Baltic Birch plywood. Their angular shape is a result of the intersection of the following design goals:
- They must support the glass at the specified 100 degree angle.
- They must place the cameras normal to the glass surface.
- They must provide adjustments for different lens-to-mount heights.
- They must provide the operator with a clean and clear view of the book
- They must support the lighting module.
- Without sacrificing strength, they must be as light as possible.
- They must attach simply and cleanly to the Side Plates.
The unusual shape of these parts was also partially inspired by Design for Manufacturing and Assembly principles, which state that you should design as much complexity as possible into one part, so that other parts and their attachment may be simplified. While I am no DFMA expert, and the work here is not done, I was able to simplify out much complexity and many fasteners using their tools.
PDF Drawing of part:
Face
STL File of Part:
Face