Clay 3D Printed Cup

This week I used Coil Cam to design and print a 3D printed clay cup.

I first looked for inspiration for what I wanted to make, and my initial idea was to design a matching cup and pitcher which could fit together like a water carafe. I found a lot of inspiration from glassware, like this pink vintage set and these retro double layered vases. I liked the idea that a 3D printer could create fine details and narrower shapes on a vessel than I would be able to produce by throwing on a wheel. I landed on a design for a cup with a horizontal ridged detail at the bottom which flairs out to the mouth. I thought the ridged detail could be reproduced on a carafe to indicate that they are a matching set. I also liked the promise of clay 3D printing to match geometry to the same size for the opening of the cup and carafe so they can be stacked together like the pink set I found.

Coil Cam is a Grasshopper plugin which allows the design of tool paths for 3D printing parametric forms and surface textures for ceramics. I used Coil Cam to design a cup and matching vessel. For the cup, I first designed a basic curved shape using an exponential curve to determine the profile of the cup. Since I wanted the cup to flair outward towards the top but then curve back gently to make a comfortable lip, I added a sin wave with a long period to shape the radius. I then had a cup shaped how I wanted it, but no surface decoration. I knew I wanted to use a sin wave with a smaller period to add ridges at the bottom of my cup. Since Coil Cam primarily uses mathematical functions which affect the whole height of the vessel, I had to specify which areas of the cup I wanted the sin wave to be applied to. I did this using a square wave, setting the amplitude to 1, the period to the number of layers in the vessel, and the number of bumps to the number of layers I wanted the sin wave to be applied to (in my case, 25). I then multiplied the sin wave function by the output of the square wave, which functioned as a boolean and multiplied the sin wave by 1 for the first 25 layers and 0 for the remaining. This gave me the decoration around the bottom that I wanted.

I then quickly designed a matching vessel, which I haven't yet printed. It has the same sin wave decoration at the bottom, using the same technique of a square wave x sin wave. I created a taller vessel using sin waves with a longer period, then boolean joined it with a simple circular vessel of the same height. I was able to get a design for a vessel with alternating curved and straight geometry, with the small sin wave decoration at the bottom.

See my grasshopper files here: https://drive.google.com/file/d/1bZStNyqhk7l264_2BmStgHqI6WBkn1qu/view?usp=sharing, https://drive.google.com/file/d/1bpp6gt4_ooXvVgqlfqmnOWIxqDnPv0dQ/view?usp=sharing

I then was able to print my cup...after about an hour of loading clay into the printer. Clay 3D printing takes a lot of prep work, as well as fine tuning parameters on the geometry of the model after seeing how the clay was behaving. I initially had more bumps with larger amplitude at the bottom of my design, but with the nozzle I was using, there wasn't enough overlap between layers for this to be structurally sound. I also had to adjust the speed of the printer, extrusion rate, and babystep the z-axis as the print started to get a compressed base and layers.

After removing my print from the board, it will be fired soon and hopefully will survive the kiln!