Our project for the final was to create a kinetic sculpture. When we started looking for ideas, we started with some that were a bit unrealistic, like an entire orrery. However, eventually we saw one that created a sin wave-like motion with a cam shaft. Additionally, we heard teams have had very good luck using cam shafts to create movement, and we thought the wave would be interesting as a kinetic sculpture.
The instructable we found did not have cad files along with it, so we made our own. The cam shaft was simple as we only needed to cut out cardboard circles with a set diameter hole towards one side. Then we designed levers with an off-center axis. Lastly, we designed supports and the base. We had to account for double thick cardboard when trying to make joints for our pieces, and later we had to account for stacking double thick cardboard.
1st cardboard construction
Our first cardboard construction had only 3 wheels and levers to generally test the feasibility of our design. We quickly found that we would need spacers, and that quite a few of the pieces would need to be stacked for more support.
2 cardboard model (not adhered in any way – proof of concept)
After this assembly, we made changes such as the pattern for levers and changing the fishing line to string in final model. We made the base and remade a lot of the pieces to look better. After testing the laser cutter settings on our previous pieces, we decided to end up making two passes on the Epilog Pro at a speed of 65 and a power of 100. This allowed the cuts to cut through the thick, double layered cardboard while preventing fires from starting. Next we super glued the stacks of the same part together.
For the etching, we etched through one layer of cardboard on our base to label the project
For post processing, we decided to make our piece fun and give the pieces doing the motion rainbow coloring. We did two coats of color on each cam wheel stack and lever stack. With cam wheels and levers having matching colors.
For supporting pieces, we decided we didn’t want colors taking away from the main rainbow, so we kept it its neutral brown color (also there was no more white spray paint). We went over it with enamel spray to make it a bit more resistant to moisture.
When the parts were dry, we assembled our entire system. We were pretty happy with it, but found some issues that needed to be addressed.
First, The cam shaft supports were leaning back from the levers from the force of the fit. Because of this, we added braces that connected the two vertical supports to each other.
Next, The stringed nuts acting as our pendulums were not at a constant height to make the wave visible. So we adjusted the strings until at the same point, they were all an equal length.
Lastly, the spin of the cam shaft adjusting the levers had a lot of friction and was hard to turn. We ended up adding tape to the bottom of the levers to reduce friction and ended up with a very pleasant spin.
It took us a while to decide what we wanted for our vinyl sticker, but eventually we settled on a cute oscilloscope to add to our base. https://static.thenounproject.com/png/886638-200.png
Costs:
Cardboard:
- Cost = negligible
Hot Glue:
- negligible
Laser Cutter:
Labor:
- Time: 7hrs
- Lab Assistant Wage = $70/hr
- Cost = $70
Total Cost = $8070
