16.2.3 Iteration Documentation
We started with a simple sketches to get a feel for the four-bar linkage geometry and figure out the link lengths. A few members tested various designs on paper, or in sketches in On-Shape
Then we built a small 1:10 scale prototype using cardboard and popsicle sticks to test how the mechanism would move. This helped us confirm that the linkage gave us the vertical motion we wanted without any interference.
After that, we made a second sketch to clean up the motion path and add a 3:1 input gear ratio for smoother movement. Once that was done, we started CAD modeling to define link proportions, joint alignment, and motion range before building the next version. Since the 3D printers at TIW were full, we built the next prototype out of recycled wood and metal parts instead. We used a small lazy Susan for the rotating base and super glue instead of wood glue so we could assemble it faster
The wooden prototype was a lot sturdier and gave us a better idea of how the real thing would perform. Each step helped us improve the motion, materials, and overall design as we moved from sketches to CAD to a working physical mechanism
Finally, we used CAD models to check our travel and fine tune the final details of the design