The design of the printer is not done yet but I built one of the scissor-lift joints which connects the arms with the printer. The arm in this prototype is just an old 3mm thick aluminium part. So it doesn't have the shape / thickness of the real one.

In the video you can see the joint-construction. It looks reasonably stiff.

This is a lasercut protoype of the scissor lift (arms) out of 3mm MDF. Each arm consists of two layers 3mm MDF in the real 3D printer these will be out of 3mm 7075 Aluminium. The two layers are screwed together with 10x m3 screws. Now I'm realising how small the whole printer will be. Hope that everything works as planned because every part of the printer shrank a lot compared to the old one.