RecapThis is the clay extruder. It is sold by 3D Potter. It's their 2000ml model. Really simple: a 3" diameter tube, a stepper motor, gear box, acme screw, piston and a nozzle.
The clay needs to be softened a bit for use by adding 16 ounces of water to 25 pounds of clay:
Here's the first test of extruding clay:
A wood fixture holds the extruder, fixed in space. The robot moves a flat board beneath the extruder to generate the form. Another stand holds the electronics and computer.
The motion of the robot follows a 3D modeled form, is a continuous helix. This is the actual speed of the robot:
Early FormsSome of my early work was straight forward geometric forms. These are modeled in the CAD software Rhino.
Code GenerationThe code for the robot is generated generated directly out of the CAD software. Rhino has a feature called Grasshopper which let's you program geometry visually. That is, you don't need to write code - you can simply wire nodes together on the screen and that creates the program. There's a plug-in called Kuka|prc that generates code for the robot and simulates the robot's motion in the viewport.
To contour a form and have the robot follow that path is very simple. You can see the overall complexity below:
New Form GeneratorSome of the new forms are generated using a simple but interesting algorithm. The basic idea is to have a polygon sided cylinder, make a circular array of these such that they overlap a bit, union them together, then twist and taper the final form.
The parameters are listed below:
Here are some computer renderings of type types of form you can generate:
Pattern MethodsThere are several pattern methods used:
- Generating random, but repeating perturbations to the surface
- Bumping out the surface at repeating intervals
- Bumping out the surface using an image
- Sculpting a high resolution mesh and using that as the form to extrude
Random, Repeating PatternsAnother technique involves using "noise" to randomly bump out the points, but then repeat those bumps so they produce a noticeable pattern. If you look carefully you can see the pattern swirling around this form:
Bumping Out the SurfaceThis technique involves bumping out points on the surface at controlled intervals. You can bump out every N points on every N levels. The vase below has every 4th point bumped out on every 2nd level.
There is also a "basket weave" effect. This one uses a sine wave to push the points out and pull them in. You can control how many repetitions of the wave occur in each level, and how many levels to skip between pushing points out. And you can control how far they push out. In the example below it is every other level. Note how the algorithm shifts the pattern alternately between levels. That's what gives it the basket weave effect.
Image Based Alterations to the SurfaceYou can use an image to map onto the surface. The lighter the pixels the more the surface is pushed out. This one was made by Taubman College student Julia Hunt using an image of a leaf.
The image map can be combined with the bumping. So areas which are white are bumped a lot and area which are black are not bumped at all. The following vases were created by Taubman College students Jasmine Almomar, Teruaki Hara, Jad Ismail, Akshay Srivastava:
By slowing the robot motion as the bumps are pushed out loops of clay can be generated: