In the beginning, our plan was to make a “hair-milling machine” in delta mechanism but not parallel. The reason why we chose delta is that for the all 3 DoF machines, xyz mechanism tool point would always vertically point to the ground or plane of axes. But, for delta structures, the tool point can follow sphere surfaces within special coordinate which could let machine have bigger working area to mill your hair.
I tried to simulate on Fusion 360. It seems fine but there was a big mistake that we did not draw end effector. Unfortunately I did not figure it out something wrong until two weeks passed.
I simply calculated the frame size in reasonable range and knew the length of rods cannot be too long.
I modified rod holders and end effector from Rodstack by Johann Rocholl to our machine system.
We were testing and the rods were not in the right length in this picture. And when we built with end effector, it was unstable with many degrees of freedom because we misunderstood only rods intersecting at one point can limit the mechanism to one solution.
For the tool, I bought a nose hair trimmer which would have limited area and could engrave really nice shapes.
The winter is coming.
When we assembled all the components, the shape of pyramid just fixed and cannot move anymore! This disaster came from that the end effector shape should be flexible in the mechanism and have holder nose hair trimmer vertically pointing to the triangle. I forgot to put end effector in simulation before or it could tell me that end effector cannot be concrete.
Though the winter is coming, we know something about it still can become a useful machine, like foot massage delta.
