6.2b Fabrication and Assembly

After finalizing the design and narrowing down the goal of this project, we moved on to the manufacturing of our parts. Our design consists of a geared 5 bar mechanism, which emulates the motion of a fishing rod. The first part of our design consisted of making the gears that would allow our links to recreate a sort of figure 8 motion. Originally, we attempted to out source the gears that would go into our mechanism, however, after budgeting and thinking about it, we just decided to 3D print them. PETG was used as the material for the gears with an appropriate center-to-center distance so as to allow us to show the motion of our mechanism. 

To really convert transform our project from its initial prototype, we had to convert our horizontal motion into vertical motion. We created walls with press-fit housing for our bearings to elevate our mechanism. We used 6mm rods to connect the shafts and bearings. One interesting fact is that after running out of 6mm bearings, we ended up using 8mm bearings with the 6mm shafts. We designed a sort of spacer that would be 3D printed in order to hold the shaft while also being inside the bearing. After many iterations of these spacers, they enabled us to jump over the hurdle of oversized bearings and allowed us to continue the fabrication process for our project. 

Another key part of our design process was concluding the material of our links. After seeing many projects at TIW functioning, we came across a common theme for failure. The links in some projects were too heavy to achieve the motion they wanted due to the low torque of their motors. We chose to test out both 1/4'' and 1/8'' for our prototypes. In the end, we ended up incorporating the 1/8'' acrylic links into the final assembly. 

The final assembly consisted of press-fitting bearings, shafts, and spacers into the laser cut walls and 3D printed parts. Many fasteners were used in order to hold the acrylic walls and base together, while also attaching the 3D printed mounts to the walls.