Week 6: 3D Printed Clay Cup (MAT238)

In this project, I created a 3D printed clay cup with an embedded spiral design.

• Rhino (Grasshopper)
• Potterbot Micro 10

I started with a Grasshopper file that defined a parametric cup with a base and edited the code. I played with polar equations on Desmos to find the profile I wanted for my cup. The equation I landed on for the profile was

r = R + abs(A*sin(n*theta))

This function allows me to define the radius of the cup, how many bumps there are in the profile, and how deep the bumps are. I implemented the equation in Grasshopper so I could adjust these parameters with sliders.

I created the wavy spiral pattern on the surface of the cup by having the Z-axis oscillate on a sine wave. Each layer, the wave was offset by a phase shift which created the spiral. This phase shift by layer introduced a seam between the layers, so I made sure that the seam would be in one of the corners of the profile so it would be hidden. This worked well.

I also gradually transitioned the Z-axis oscillation for the first 5 layers, so there would be no gaps between the layers. This also seemed to work well

The GCode was generated from the sample Grasshopper file. I copied this data into VSCode to save it as a GCode file for the Potterbot to print.

I was initially conservative with the amplitude of the sine wave on the first cup (with Amplitude = 0.5mm), so I made a second cup and doubled the amplitude. I also switched up the profile of the cups between prints, so the first cup had four bumps and the second one had 3. The pattern was much more apparent on the second cup, but I kind of like the subtlety of the first. I am very happy with how this project turned out, the result was very similar to how I imagined it. I plan on glazing these pieces in the coming weeks so I can drink out of them.