PROCESS
My partner Krithika and I wanted to integrate two mechanical movements for our midterm project! Our inspiration came from an example from a previous year where a team created a box where Mario jumps over a pipe while a cloud moves back and forth in the background.
We brainstormed and came up with the idea of having a wave move back and forth in the x-axis while a dolphin jumps up and down! The wave would utilize movement 153 and the dolphin would utilize movement 100.
To begin, we drew rudimentary concept sketches to further understand the various aspects of our movements.
We then moved forward to using Fusion360 and SolidWorks to CAD the elements to create our low fidelity prototypes. These drawings are shown to the left.
After we were able to visualize how our movements would act independently and integrated, we used our CADs to laser cut our parts out of cardboard for our medium fidelity prototypes. As you can see here, we were able to assemble the pieces together!
We didn’t have all of the necessary parts, such as spacers, rods, handles, for our medium fidelity prototype but we were still able to envision what our final prototype would look and function like.
Our next step was to move onto creating our high fidelity prototype. At first, we wanted to use wood and acrylic for our final product but then decided to make it all out of acrylic for an aesthetically pleasing and clean look.
We decided to encase our model within a box that would have a base with slots in which panels containing the two mechanisms would go, along with slots for clear front and back panels. We completed an initial kerf test of sorts, in which we tried different slot sizes to press-fit the panels into.
Unfortunately, we had issues with the auto-focus on the laser cutter while attempting to complete this test, which caused a small fire on the bed. After learning how to use the manual focus function, we were successful in identifying the right slot size and printing the base and the panels for the wave and dolphin mechanisms.
We sized down the Illustrator files to ensure they fit within a more compact box, laser cut the mechanism components, and found screws to act as the centers of rotation. Unfortunately, while trying to test the wave mechanism, we ran into many problems with sizing, spacing, friction, and positioning. Some of the laser cut, cardboard, and metal components we attempted to use are displayed below.
We began to troubleshoot the problems, but eventually decided the mechanism was too complicated to attempt to incorporate given the limited amount of time we had. We decided to move forward with only the dolphin mechanism, and incorporate stationary wave panels into our model. Once we laser cut these parts and assembled them together, our mechanism was complete!
This is what our completed prototype looked like:
Here is a video of it in motion:
ROADBLOCKS
We spent a lot of time on the wave mechanism, only to ultimately not incorporate it within our model–we determined how it worked, CADed and built it out of cardboard, refined the component sizes, laser cut them, and attempted to troubleshoot the issues. This made the decision not to move forward with the mechanism very difficult, but given the deadline we were under, it was for the best. In the future, when making low-fidelity prototypes, we should determine how and with which materials all parts of the prototype will be made, along with how it will be held together. For instance, we should have determined how the “rails” would remain in position and upright, the dimensions of each component in proportion to each other, and other details which seemed minor at the time. Further, when tasked with a project like this, we now believe that a best practice is to choose one simple mechanism, and then design an aesthetically pleasing system around it, rather than going with one or two more complicated mechanisms.
While assembling the mechanism, we faced some additional challenges. Because we laser cut over several days and we had to manually focus the laser cutter each day, there were variations in the panel sizing. The second and back wave panels were loose and did not press fit into the base, so we glued the panels in.
COST
- Machines/Equipment
- Laser cutter rental 5 hours at $25/hour: $125
- Materials
- 2 sheets of 0.25” acrylic at OEDK: $10
- Acrylic glue: $10
- Labor
- 20 hours for 2 people at $15/hour: $600
Overall – $745
This is an extremely high cost, with labor being by far the most expensive part of it. Because the two of us worked together on this project for so long, and used an expensive machine like the laser cutter, the costs associated with a project like this are prohibitively high. However, based on our lessons learned, and if we were using a less finicky laser cutter, we could significantly reduce the costs if we were to do a project like this again.
Here is the link to our design powerpoint:
https://docs.google.com/presentation/d/1tghN73y_NzNCY58-6PtPz-fE0VHHKNiJ2uXGQ5llTfQ/edit?usp=sharing
