Adventures!

I got the inspiration for my midterm project from NO.327 in 507 mechanical movements. As shown in the figure below, the rotational motion is transferred into a vertical translational motion. This process is easier to understand by taking a look at https://www.youtube.com/watch?v=sqL2LfmT66Y, in which the animated model is shown. 

Based on this model, I used adobe illustrator to make the preliminary 2D file as shown in the following drawing.

First iteration model

The hardest part about this structure is that components need to coordinate appropriately so that the translational movement could be smooth. To improve the 2D file and make it more precise, I took measurements of the rollers, wood sticks and plywood. The design of sword was not just for aesthetics, but was also used as a load to make the moving part more balanced. Furthermore, I changed the steering wheel to a rudder’s look. The second version of 2D design is presented in the following drawing.

Although everything seemed to be fine on the 2D design, I recognized that the design was still incomplete when I started to build the low-fid prototype. I laser cut the components out of cardboard and used either hot glue or pressure fit to assemble them. In testing this prototype, I found three major problem.

First, I didn’t consider the 3D spacing of the components while doing 2D design. As a result, when I built the prototype, I found that the wheel had structural conflict with the guide bars’ extruding supporting sticks. Additionally, I found that rollers need to be squeezed a little bit by the guide bars, or it would be very easy for rollers to get off track. Moreover, the sword didn’t add enough weight to the roller system and the roller system was not balanced. When I turned the wheel, influenced by the force from cross head, the roller system tilted to one side instead of doing translational movements.

Considering these factors, I adjusted my 2D model and added several parts to the design. First, I added extra support for the frame itself by adding a heavier piece of wood as the base and two supporting pieces perpendicular to the frame. Second, I plasma cut two aluminum water drop pieces and added them to each side of the roller system to balance the roller. Third, I redesigned the guide bars to minimize structural conflicts.

In building the final prototype, I made the frame and wheel thicker to prevent the possible deformation resulted from the loads on the roller system. I cut out some wood pieces that had inner diameter that was slightly smaller than the one of the wood stick and used them to hold components in place through pressure fit.

Most wood components are colored with wood stain to get a nice texture, but I didn’t have time to finish it. The prototype is functionally satisfying, and I might add more aesthetics element to it.

Cost estimation:

labor cost: I am actually not sure about how long I spent on the project, as I edited the model and experimented a lot. Assuming I spent one week, 4h a day on the project, labor cost~$9*4*7=$252

metal pieces: ~$10

spray paints: 4 cans, (grey, black, red, clear), $3.98 per can on Home Depot, $15.92 in total.

wood stain: $8.98 (Home Depot)

Without considering the machines I used, the project costs $286.9.

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