12. Mechanical Design (Machine Week)

Song of the Sea

Link to group work here

Overview

This week our group built Song of the Sea — a joystick-controlled tilting platform made up of three stepper-driven arms holding a laser-cut ring, with a cloth stretched across it and a marble on top. Tilting the ring with the joystick steers the marble across the surface. Mechanically it is a three-motor parallel manipulator, similar in principle to self-leveling platforms.

Perosnal Contribution

My contributions focused on the conceptual and mechanical side of the project. I worked on the initial mechanism sketches and 3D design, ran the first stepper motor tests to understand how the motors behave under load, and made the first iteration of the electronics layout — mapping out how the three driver boards, the Barduino, and the external power supply would connect together.

I then contributed to the board design and wiring, designing a carrier board to hold the bardiuno and organize the connections.

One of the most important problems we encountered was that the stepper motors were generating enough heat under sustained load to soften and eventually melt the PLA 3D-printed joints connecting the motor shafts to the arms. The fix was to reprint those contact parts in resin, which handles heat significantly better than PLA and held up reliably under the same conditions. This was a direct lesson in material selection for functional mechanical parts — thermal performance matters as much as geometry.

Other key lessons from the project was test how much the stepper can handle in terms of load early.Our first CNC-milled ring was too heavy for the motors to lift and had to be redesigned in laser-cut MDF