The idea is to make these fabrication blocks as modular as possible. CADing these is a good way to take good ideas and turn them into bad ideas. The method of binding the sections together with M3 threaded rod works for the linear sections that follow one after the other. A problem arises when joining at right angle, or at any angle, as the rods cannot now be in the same plane. The top section works as there is plenty of meat and they can be moved down, was thinking about doing that anyway as that would reduce the torque in the mold. But, at the bottom extra 5mm needs to be added which might no be to bad....... maybe.

 Thinking thinking thunck

There clearly is going to be an increase in complexity of the molds, but with the above mold this is not a problem. The only major change is with the bottom mold pieces as the above pieces just have two extra holes in an area with plenty of plastic.

Probably the piece that will contain the most complexity is the centre piece that all other sections will attach and the air inlet will be. The more I think about this section the more I think this is the right solution. Normally the air hose is attached to the back, but if there is going to be a section on it then that will be blocked.

As a generic section the one with all sides open would only need the holes sealed, easier than attaching the flexure.