I Love Creating Designing Prototyping

Week 9::Mechanical Design


For a handful of travelers, especially Japanese, not only the island's scenic attractions prompt their visits but also the pleasure of Taiwanese foot massages.
Foot massage not only makes feet feel wonderful, but it also helps us entire body relax.
Most electronic massagers are excellent for general massage of the feet and for relaxation therapy.
We want to make a machine that you can set the path you want.


Acupressure for feet:

Mechanical Design


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.



Simulation with real person.




Trying to simulate on Fusion 360. It seems fine but there was a big mistake that we did not draw tool platform. Unfortunately we did not figure it out something wrong until two weeks passed.





We simply calculated the frame size in reasonable range and figured out the length of rods cannot be too long.


After alculated the frame size , we have combined and modified linear stage material with 300 mm length from Jason Wang.










Then modified rods holders and platform from Rodstack by Johann Rocholl


The platform 3D design



The carriage 3D design



The rod_side 3D design



The magnet mount 3D design



3D printing for components




Combine two separate parts



We were testing and the rods were not in the right length in this picture. And when we built with platform, it was unstable with many degrees of freedom because we misunderstood that only rods intersecting at one point can limit the mechanism to one solution.



So we bought an 1 inch iron ball (used to bearing) and magnetic ball joints to limit the rods motion within one solution.



For the tool, we bought a nose hair trimmer which would have limited area and could engrave really nice shapes.


When we assembled all the components, the shape of pyramid just fixed and cannot move anyway! This disaster came from that the platform shape should be flexible in the mechanism and also have holder nose hair trimmer vertically pointing to the triangle.