Robotic Extrusion Research

KU ROBO-LAB SPRING 2017 Our research team assembled a clay extruder tool that attaches to a KUKA robotic arm with which we produced over 50 unique tests from three different types of clay. A variety of parameters were explored such as: air pressure, water content, tool path speed, nozzle diameter, and layer spacing. After achieving optimal deposition parameters our goal became to explore ways in which to utilize the KUKA’s nine points of rotation in conjunction with traditional 3D printing techniques.

There are a number of reasons why clay extrusion is different than t r a d i t i o n a l 3 D printing. Since the cartridge is pressurized the extruder is constantly outputting force in the direction of the tool path orientation. Also, since there is currently no way to augment the flow from the extruder, the clay will extrude continuously until the air pressure is turned off or disconnected. Our GH scripts took these findings into account in order to create optimal contact between layers while also exploring ways in which to utilize all 9 points of rotation on the robot arm.

AIR COMPRESSOR KUKA ROBOT ARM CHASSIS

CLAY EXTRUDER COMPUTER BLAST SHIELD

WORK SURFACE

AIR COMPRESSOR ATTACHMENT CARTRIDGE HOUSING

CARTRIDGE CAP PISTON

MOUNT

CARTRIDGE

CARTRIDGE TIP

METAL FITTING

COPPER NOZZLE

Geometry Input Script

1

2

1. Input geometry

2. Generate Contours

Weave curves for tool path

Path Extrusion Script

1

2

3

4

5 1. Input curve geometry

2. Array curve along vector

3. Shift list to create undulation

4. Create circles at points

5. Weave tool path between points on circle

Formwork Script

1

2

3 1. Input surface geometry

2. Offset mesh from formwork

3. Create overlapping contours

Flip every other curve to form continuous tool path

Orient tool for optimal material deposition

Circle Script 90 psi none 15% med.

3.5

A-4 Our initial tests sought to find optimal settings for 3d printing clay. Once we were able to 3d print in a traditional layer by layer method, we wanted to push the limits of 3d printing by utilizing the 9 points of rotation on the robot arm and also some of the aspects of 3d printing clay that are unique such as testing tensile strength and the effect of gravity on the tests. We also began to explore ways to create larger modular forms through our Scripts.

Rotating Polygon 100 psi none 12% med.

3.5

A-5

Twisting - Triangle 96 psi none 10% med.

3.5

A-8

Rotated Square 95 1 oz.

10% med.

3.5

A-11

C - Channel 95 psi none 10% med.

3.5 mm

A-7

Rotating Stellated Hexagon 100 psi none 10% med.

3.5 mm

A-9

Triangulated Cylinder 100 psi 1 oz.

10% med.

3.5 mm

A-10

Parabolic Teardrop 100 psi 2 oz.

31% med.

3.2 mm

A-17

Structural Path Extrusion 105 psi none 10% med.

3.5 mm

C-2

Catenary Curve 50 psi none 20% sml. n/a

B-4

Formwork Orthogonal 100 psi 2 oz.

10% med. n/a

B-8

Formwork 45 Degree 105 psi none 10% med. n/a

B-10

Formwork Modular 105 psi 2 oz.

10% med. n/a

B-11

Implementation Our best

findings way

to

concluded apply

this

that

the

research

to

c o n s t r u c t i o n t e c h n i q u e s would

be

to

take

a

modular

approach. Since the robot’s strength is in doing

repetitious

actions,

a

building

system could be panelized in a way that the robot is able to fabricate individual pieces that make up a larger whole. We also concluded that the clay is extremely brittle and should not be used in tension, but works very well in compression – especially after firing in a kiln.