3D Printing a Sake Tokkuri - Clay Printing With CoilCAM and PotterBot

This 3D clay printing project was partly inspired by the tea set created by Sam from the CoilCAM paper. I wanted to create a custom Tokkuri set (sake serving bottle and cups).

I think the shape of the Tokkuri is quite elegant and unique. For the cups, I wanted to use the Difference component from CoilCAM to shape them and make them conform to the shape of the Tokkuri.

I saw this printed ceramic sake set. It is similar to my idea, but I just didn't like the surface texture that much.

Rhino/Grasshopper

CoilCAM plugin

3D PotterBot

Obsidian clay

Water & other clay crafting supplies

For the main body of the tokkuri, I used 4 CoilCAM components together to create its profile shape.

The Linear, Sinusoidal, and Exponential components are all in additive mode, so I think the order they're applied should be interchangeable.

I want to keep the bottom of the tokkuri straight-ish, so I used 2 Sinusoidal components with different parameters together to smooth as well as exaggerate different parts of the profile curve. The Linear component narrows the top of the tokkuri, including the neck of the bottle. The Exponential component was used to make the top of the bottle more flared.

I didn't add any surface texture to the tokkuri because I wanted to keep it relatively smooth.

For the cups, I want to create a flower-like shape, and add some interesting textures.

The Square component adds some protrusion to the radius. The Linear and Sinusoidal components shapes the profile of the cup. The Staircase component rotates and "twists" the shape of the cup.

Next, I moved the cup's position to partially overlap the tokkuri. Using the Difference component, I removed the intersecting volume from the cup, creating a concave surface.

I made a copy of the originally circular cup, and differenced it with the first cup. It resulted in a more textured concave surface.

Troubleshooting the base layers:

When I designed my geometries in grasshopper initially, I used the default parameters for nozzle size and layer height, which would not have worked during the lab printing session. Because the obsidian clay loaded in the PotterBot tube was unusually dry, the nozzle size needed to be changed to 8mm, and layer height to ≤4mm.

I ended up changing the layer height to 3.5mm for more compression of the clay coils to get the base to stick. I think I could've gotten away with ~3.75mm, since I did have to babystep up Z during the print when the nozzle was pressing on the tokkuri on top a bit too much.

With all the physical requirements of clay printing in mind, I needed to tweak a lot of parameters accordingly. Thus, the final shapes for the tokkuri and the cups were modified. For some reason, the difference component stopped working after the changes. I'm not really sure why because the wire connections look good aka the same as what I did before.

Other issues:

The box size in the CoilCAM example was different from the actual print bed size. So the centering was quite off and the PotterBot started printing in the upper right corner. We were able to fix that thanks to Bryan :D

Another issue was that I didn't know how to check/estimate the height of my tokkuri and cups. So in Rhino, you can use the distance tool to measure the length of your geometries with physical units. (Also thanks to Bryan!)

After the troubleshooting, my tokkuri printed pretty much without any issue. I did have to monitor and babystep Z especially towards the top of the print. I was worried that the top flare would be too heavy and collapse, or that the nozzle was pushing down on the clay too much (there was some temporary tilting). The result was great!

The 8mm nozzle meant the walls were pretty thick (which helped with overhangs). I probably should've picked the smaller PotterBot for these more delicate pieces, though I did also try to print my cups. The surface texture was not really there. Some layers towards the top de-adhered and got kinda of deformed. I didn't like how the cups turned out.

After printing, I manually shaped the clay to create a pouring spout on my tokkuri. Alejandro suggested that I could add some water to the underside of the top most layer, so that it stick better and would reduce/eliminate gaps.

For the cup, I chopped off the top bit because I thought it looked really, really ugly. The bottom layers are more consistent. You can see some small protrusions. It might become something more like a pen or paintbrush holder than a cup to drink from.

After letting the clay dry, the tokkuri is bisque fired, and then glazed (and re-fired).

The little one actually turned out pretty cool looking, much better than I expected.

The tokkuri itself has a very nice weight to it as well. I'm super happy about this project. :D