Architectural Clay Formworks

Cyle King Jacob Gasper

Architectural Clay Formworks Arch 490H

This body of work explores 3d printing clay as a reusable formwork for concrete applications. Additive manufacturing or 3D printing clay is a growing body of knowledge occurring at the intersection of engineering, ceramics, and design. Jenny Sabin Labs of Cornell University and Ron Rael of University of California Berkeley are two researchers at the forefront of additive clay workflows to create architectural elements and sustainable building technologies.

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This project began with a literature review and case studies to scope a research agenda and expand upon the possibility of 3D printing clay for the design and production of reusable concrete formwork. This research develops methods and mock-ups for unfired clay 3D printing, both for its geometric possibilities and limitations as a reusable architectural formwork. The hypothesis of this project is that clay can be 3D printed to produce a mold, poured into to produce a concrete cast, then dissolved, remixed, and then used to produce new prints and molds. The project methodology relies upon iterative digital fabrication to combine robotic fabrication knowledge, computational design, and ceramic knowledge. Resulting work is evaluated for replicability and aesthetics. The outcome is mock-ups of architectural elements that reduce formwork material use and demonstrate the viability of the proposed methods.

Beginning in 2019 as a series of seminars and independent studies this work began with the design and development of a pressurized air extrusion system that works with a KUKA industrial robotic arm located in the ISU Student Innovation Center. Initial iterative studies focused on clay consistency, end effector design, compressed air calculations for pressuring clay, and robotic arm travel velocity to produce clay prints.

Expected results for Spring 2021 will include material mock-ups and an 8’ concrete cast column that tests the methods developed here.

Research began amidst the COVID-19 global pandemic during the summer of 2020 and should continue through the spring semester of 2021.

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Special Thanks Shelby Doyle AIA Advisor, Associate Professor of Architecture, Co-founder of the ISU Computation + Construction Lab (CCL), Director of the ISU Architectural Robotics Lab (ARL) Erin Hunt Master in Design Studies Technology Candidate at Harvard Graduate School of Design, Former CCL Associate Nick Senske, Assistant Professor of Architecture, co-founder of the ISU Computation + Construction Lab (CCL)

Funded in part by the Iowa State University Foundation Funded in part by the Iowa State Honors College Supported by the ISU Computation + Construction Lab

Roman Chikerinets Assistant Teaching Professor, Director of Wearable Set Design Jasmine Beul Integrated Visual Arts MFA candidate Mae Murphy 4th year BArch student Cameron Wahlberg 4th year BArch student Mary Le 5th year BArch student Negar Kalantar Associate Professor of Architecture at California College of the Arts, Co-Director of the Digital Craft Lab, Founder + Director of Variable Projects Mehdi Farahbakhsh PhD Student at Texas A&M

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Presentations National Conference of Undergraduate Research April 12-14 2021 ISU Symposium on Undergraduate Research and Creative Expression April 21st 2021 2021 Iowa State Honors Capstone Poster Sessions

Exhibitions College of Design Wearables Show March 29 - 30 2021

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01 Initial Experiments 02 Extrusion System 03 Clay Consistency 04 Tool and Base Calibration Workflow 05 End Effector 06 Cylinder Test 07 Inital Lattice Tests 08 Final Column 09 Bibliography

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01 Initial Casting Experiments

Initial exploratory experiments were conducted during an honors project for Arch 433: Intro to Digital Fabrication (Gasper, Fall 2019). This work was based upon computational and material ceramic 3D printing workflows developed by Shelby Doyle, assistant professor of architecture and former Computation and Construction Lab associate Erin.

The small-scale analysis utilized Doyle and Hunt’s existing Grasshopper definitions and a Potterbot 7 to create four 8” columns with varying parametric designs and patterning. Rockite (hydraulic expansion cement) was poured into the dry clay “molds”.

For two molds, Rockite was poured directly into a freestanding clay formwork. Water from the Rockite caused rehydration of the clay and resulted in the molds cracking, however; the forms were successfully cast.

For two molds a “double formwork” of fine sand in a five-gallon bucket was used to reduce the rehydration effects and outward hydrostatic force of the poured Rockite. The double formwork reduced the clay mold cracking but undermines the goal of creating a materially efficient formwork.

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formwork

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cast

formwork

cast

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formwork

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cast

formwork

cast

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stacking column patterns

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stacking column patterns

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02 Extrusion System

The first phase of this research is based on the design and development of a pressurized air extrusion system that is able to work with a KUKA industrial robotic arm. Using the homemade extruder design by Sabin Labs in “Clay Non-Wovens: Robotic Fabrication and Digital Ceramics” as precedent, our work deviates from the original design by facing new constraints that come with a smaller robotic arm. With the extrusion apparatus unable to be connected directly to the robotic arm due to load capacities, several different extruder orientations and positions detached from the robot were tested.

Made primarily of plumbing parts from Lowes and Grainger, the extruder is cost effective and parts are easily replaceable. The use of pressurized air simplifies the process further by forgoing the need for a stepper motor and Arduino board, a conventional extrusion system for clay. By creating a pressurized 3’ tall chamber, extrusion speed can easily be controlled by a psi gauge on the air compressor below the robot table.

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5” x 5” Plywood

Air Compressor Hose Coupling

2” x 1/2” Bushing PVC Fitting

3” x 2” PVC Flexible Coupling

3’ x 3” Polycarbonate Tube

End Cap Assembly

Extruder Pricing Threaded Steel Rod 3/8”

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Iteration One: Horizontal In the first trials, the extrusion system sat horizontal on the table beside the robotic arm. A 10’ x 3/4” threaded hose connected the chamber and the end of the robot.

Notes - the horizontal position allowed the pressurized air to travel around the clay in the tube, thus not allowing for enough pressure to extrude - gravity is needed to pack the clay under its own weight to avoid large air pockets which may cause small clay explosions.

- extrusion was only achieved once with watery clay, too watery to build with.

Iteration Two: Vertical In the second iteration, the extrusion system sat vertical on the robot table. The same 10’ x 3/4” threaded hose was used as the previous iteration. From the first tests we learned the clay needed gravity to assist in packing, to avoid air pockets, and extrusion, to lower the psi needed from the air compressor.

Notes - the clay packed much better, resulting in fewer to zero air pockets - although more efficient, it is much more work to unscrew the chamber from the table for clay reloading - the first few trials produced successful extrusions, but as the threaded hose became more full of clay, higher psi was needed until none was able to come out.

- cleaning the threaded hose between trials yielded more successful extrusions - more gravity is needed to allow clay to flow through the 10’ hose to the robot

Iteration Three: Vertical Detached from Table The most current iteration raises the vertical clay extruder off the table and onto a 2”x4” pole. The height allows gravity to work on the extruder and threaded hose, a problem noticed in the previous interation. The hose was also shortened from 10’ to 5’, decreasing the distance the clay traveled to the robot lessening the required psi for extrusion.

Notes - successful extrusion at 40 psi - shorter hose, 5’, allows for robot’s full range of motion

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03 Clay Consistency

In collaboration with Jasmine Beul, a ceramics student at Iowa State University applying for her MFA in Integrated Visual Art, an ideal ratio of water to clay was sought out through trial and error.

This clay would be initially mixed in the ceramics department in the basement of the College of Design, brought to the Computation + Construction Lab for examination and exchange, and then finally to the Student Innovation Center to be loaded into the extrusion tubes for testing.

These tests were our first attempts of printing clay through our assembled apparatus. Initially, the success of the clay was only determined by its ability to be extruded.

Eventually two ratios were agreed upon to further study, 1:2 and 3:5 water to clay ratios. These experiments were performed by simply extruding the clay onto baseplates to analyze the two ratios visually, textually, and stackability from layer to layer. (this was done my moving the nozzle by hand due to an unclear connection to the robot at the time as well as a developing grasshopper script)

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2:5 Water:Clay

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3:5 Water:Clay

1:2 Water:Clay

2:5 Extrusion

3:5 Extrusion

1:2 Extrusion

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04 Tool and Base Calibration Workflow

In the form of a workflow, carefully detailed diagrams and images layout the steps to calibrate a new tool and base plane on a KUKA industrial robotic arm. The workflow was developed on the premise that it would be utilized by ARL seminars and studios for ease of use. In the parameters of our research, producing a detailed documentation aided in understanding new skills on a new machine. Several workshops led by Shelby Doyle and Nick Senske covered tool and base plane calibration, basic jogging, and x y z coordinate system. The included images are selected diagrams and images produced from these workshops. A comprehensive workflow can be found at the Computation and Construction Lab’s website.

TOOL

BASE PLANE

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Architectural Robotics Lab Robotic Axis

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Tool Calibration: 4 Point Calibration Images

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Base Calibration: Origin

Base Calibration: X-Axis

Base Calibration Images

Base Calibration: Y-Axis

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05 End Effector

Attaching the extrusion system to the robot requires an “end effector” or custom tool. The main goal of the tool is to hold the threaded hose through perpendicular to the base plane and maintain a stable nozzle while printing. The ability to easily remove the printhead is also important for changing out different nozzles and cleaning the threaded hose after every print. The base of the print head design is the threaded hose, which carries the extruded clay from the pressurized chamber to the robot, and a ¾” cam and groove coupling, which allows for nozzles to be changed out. The manner in which these elements attached to robots changed dramatically through several iterative designs.

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Iteration One: The first iteration simply sought to connect the print head to the robot as simply as possible. The design takes precedent from marker holders designed by Erin Hunt for Intro to Architectural Robotics.

Notes: - The print head did not maintain a perpendicular position to the baseline. The instability stemmed from the thin offset of the print.

- Once the cam and groove coupling barb is inserted into the threaded hose, the assembled print head is unable to be removed from the tool.

- Needs fasteners

Iteration Two: The second iteration builds directly from the first by including fasteners, nuts and bolts, and a thicker offset to increase tool strength. These new adjustments were hoping to fix the printhead’s instability.

Notes: - The print head is still able to move out of being perpendicular. The malleability of the tube needs a more stiff connection to maintain stability.

- This design allows for the printhead to be removed, the nuts and bolts work well - The cam and groove coupling needs to be supported

Iteration Three: The third iteration focuses on the need for the cam and groove coupling to be supported to counteract the flexibility of the threaded hose.

Notes: - It successfully held the print head stable, however, the threaded hose easily flopped around causing worries that it might break the tool off of its base - The nozzle needs to be lowered 3.5” or the bottom of Axis 5 of the robot will slam into the baseplan and table. The next iteration needs to take this into account

Iteration Four:

Current End Effector Iterations

The most current iteration solves the problems brought up in iteration three. It maintains the base that braces the cam and groove coupling with an added vertical support that keeps the threaded hose from moving around erratically. The threaded hose support also drops the nozzle down the required 3.5” need to clear the robot from hitting the table.

Notes: - Uses an excessive amount of plastic, it can be overall economized.

- The tool has successfully printed several accurate tool paths with the increased stability.

- The amount of bolts and nuts holding the pieces together can be decreased from 6 to 4

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The parametric nozzle allows for several different nozzle sizes, shapes, and diameters to be tested. These different parameters affect the clay bead size, print texture, and structural capacities.

In initial tests, a slightly flared 6mm hexagon nozzle produced a thick and imprecise tool path that had difficulties adhering to the plywood base plane. A second nozzle, a 6mm tapered hexagon, created a more exact tool path that adhered to the base plane with more success. Further investigations will involve testing smaller and more tapered nozzles and their connection to accurate clay tool paths.

3D Printed Nozzles

Nozzle Inserting into Cam and Groove Coupler

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Clay Nozzle Grasshopper Script

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06 Cylinder Tests

These initial cylinder experiments put to test our composed grasshopper script and its specific increments. Examples of these include a 6 mm (nearly half the diameter of the interior of our current nozzle allowing the above layer to compress and adhere to the bottom layer more effectively) as well as two skirt rings that provide us time to prime both the robot and the air compressor to ideal conditions before the cylinder is ready to print. These initial tests were put in place strictly to test the effectiveness of these factors.

Through progression of this research, experiments will begin to aim towards discovering the limits of height these scripts will be able to produce. Additional structural tests may be performed studying different lattice formations for stronger vertical performance.

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Skirt Generation

Cylinder Generation

Base Layer Speed

Offset from Baseplane

Skirt Speed

Cylinder Radius

Number of Skirts

Layer Height

Prepping for the Robot

Distance from Base Circle Nozzle Diameter

Print Speed

Overall Height Simulation

Layer Generation

Print Speed Offset from Baseplane

Layer Speed Division

Tool Geometry

Print Speed

Subsequent Layer Speed

File to Robot

Cylinder Tests Grasshopper Script

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80 mm

80 mm

10 mm skirt distance

2 skirt layers

80 mm

2 skirt layers

2 skirt layers

1:2 Clay : H20

1:2 Clay : H20

80 mm

10 mm skirt distance

1:2 Clay : H20

2 skirt layers 1:2 Clay : H20 10 mm skirt distance

10 mm skirt distance

40 psi 40 psi

40 psi

5 mm layer height 6 mm layer height

Notes: - 10 mm/s robot velocity - failure after 8 layers - ran on T1 (manual control)

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8 layers

Notes: - 10 mm/s robot velocity - failure after 16 layers - ran on T1 (manual control)

16 layers

4 mm layer height

24 layers

Notes: - 10 mm/s robot velocity - failure after 24 layers - tallest print at 100 mm - ran on auto - resulted in less user error

40 psi

3 mm layer height

28 layers

Notes: - 10 mm/s robot velocity - failure after 28 layers - although having more layers, the overall cylinder was the same as 4mm - ran on auto - resulted in less user error

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07 Lattice Tests

To print at the lowest and safest PSI, a higher portion of water to clay is utilized. As a result, this softer clay requires more support than harder clay. These series of experiments are testing the structural qualities of additional framework or lattice in supplement to the interior cylinder to increase its strength during the concrete pouring in order to reach greater heights and diameters. This additional framework is also necessary due to the viscosity of our clay. These tests are valuing the number of triangular supports and the clay bead diameter all while hypothesizing a final structure that utilizes the least amount of clay while reaching the needed height.

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4” diameter initial tests

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4” diameter initial tests

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print

clay formwork

removing formwork from cast

finished cast

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These images illustrate our first casting attempt with lattice structure. First, the cylinders are printed while analyzing their qualities. The clay is then left to dry 1-2 days in order to reach a leather hard state. At this point, the clay is both wet enough to resist the pressure of the poured concrete, and dry enough to not bind with the mixed concrete. The completed cast reveals undesigned moments where the nozzle pushes and pulls the clay creating a final undulating cast.

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70 psi

6 Lattice Points 10”

Final Clay Formworks

Final Clay Formworks

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08 Final Clay Formworks Column

The final outcome exists as a myriad of our variables. Within the 6 feet of the final column, different textures and heights of each cast are celebrated in the chronological assortment showcasing the process of work from start to finish. Regardless of the consistency of these variables, discrepancies occur due to the uncontrollability of clay as an architectural formwork.

This research challenges the current conceptions of digital fabrications and its inherited perceptions of perfection. With the collaboration of robotic software and constructed variables with the malleability of clay as a material, a new awareness of fabricated aesthetics is assumed. Clay has proven to be a relatively unreliable material against gravity and requires human touch and attention.

Our project explores these clay limitations and chooses to rather celebrate them as a digitally fabricated aesthetic appearance.

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2.

1. Student Innovation Center (SIC) 2. College of Design (COD) 3. Computation + Construction Lab (CCL)

1.

3.

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Final Clay Formworks

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Final Clay Formworks

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29 March 2021

26 March 2021

25 March 2021

23 March 2021

20 March 2021

16 March 2021 Final Clay Formworks Printing Schedule

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Casting the clay formwork: Edges are sealed with slab clay to ensure no concrete leaks. This method also applied to fixing falling formwork sides. PVC piping is placed in the middle to use less concrete material and reduce the overall weight of the module. Smaller PVC creates slots for the vertical rebar to slide through and provide overall support.

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Final Clay Casts

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Final Cast Variable Analysis

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Final Cast Variable Analysis 68 | Architectural Clay Formworks

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Final Column Assembly

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Wearables Show Exhibition

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Wearables Show Exhibition

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Wearables Show Exhibition 74 | Architectural Clay Formworks

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2019Dissolvable 3D Printed Formwork: exploring additive manufacturing for reinforced concrete Shelby Doyle and Erin Hunt

Bibliography

Explores the potentials, limitations, and advantages of 3D printing water-soluble formwork for reinforced concrete applications.

Anton, Ana, Patrick Bedarf, Angela Yoo, and Timothy Wangler. “Concrete Choreography.” dbt, 2019. https://dbt.arch. ethz.ch/project/concrete-choreography/.

Bieg, K., Briscoe, D., and Odom, C. (Eds.) Ubiquity and Autonomy: Paper Proceedings of the 39th Annual Conference of the Association for Computer Aided Design in Architecture ACADIA, October 24-26, 2019, Austin, Texas (pp. 178-188)

Computationally designed series of concrete columns arranged into an ensemble of variation. The final exhibition included nine, individually designed, 2.7m tall columns. Each column is concrete 3D printed at full height in 2.5 hours with the process developed at ETH Zurich, with the support of NCCR DFAB.

- Similar to Melting, this paper looks at the capabilities of a dissolvable formwork to create more complex shapes when compared to previous casting methods. Can clay also be beneficial in this way?

Doyle, Shelby, Erin Hunt, and Kelly Devitt. “Custom 3D Printed Nozzles for Ceramic 3D Printing.” Erin Linsey Hunt.

Accessed May 12, 2020. https://erinlhunt.com/custom-3d-printed-nozzles-for-ceramic-3d-printing

2019Melting: Augmenting Concrete Columns with Water Soluble 3D Printed Formwork Shelby Doyle and Erin Hunt

Series of custom printed 3D printed nozzles as the independent variable, studying their printing variations through ceramic printing utilizing the same code as the dependent variable.

Continued research from 2019 Dissolvable 3D Printed Formwork: exploring additive manufacturing for reinforced concrete, this proposal aims to simultaneously print polyvinyl alcohol (PVA) and steel PLA tensile reinforcement to produce water soluble concrete formwork with integrated reinforcement.

- These nozzles will be used in our ceramic clay printing on the Potterbot. Further testing may lead to manipulating existing nozzles.

Knauß, Michael, Ammar Mirjan, and Anastasia Pistofidou. “Robotic Clay Molding.” Gramazio Kohler Research, 2012. https://gramaziokohler.arch.ethz.ch/web/e/lehre/235.html.

This workshop researches the potential of clay as a reusable molding material to fabricate unique building elements in concrete with a minimum of waste resulting from the formwork.

- This article served as the basis for experimental approach number three in Methodology.

“Facade Panel Prototypes.” XtreeE, April 2018. http://www.xtreee.eu/project-facade-panels/.

Enables the optimal use of 3D printing to produce complex shapes for various architectonic elements. Studies the architectural potential of integrated formwork aiming to allow for a significant reduction of waste and shorten production time.

- This article serves as the basis for experimental approach number two in Methodology.

Fellabaum, Alyssa, Wiskur, Austin. 2020. “Topology Formwork Optimized Concrete Components: Utilizing 3D Printed Clay” Masters Thesis, University of Michigan.

Student work as a precedent for printed clay and poured concrete relationships. Utilizes printed clay as a formwork for poured concrete masonry with the intention that the “formwork” will be left in place for a more sustainable formwork option.

- This thesis contains ideas about “leave in place” formwork and selective concrete pouring which expands upon the notion of clay as a more sustainable formwork option.

2019 Optimization of Clay Mould for Concrete Casting Using Design of Experiments Sihan Wang, Zack Xuereb Conti, andn Felix Raspall Intelligent & Informed, Proceedings of the 24th Annual International Conference of the Association for Computer-Aided Architectural Design Research in Asia CAADRIA, April 15 - 18, 2019, Wellington, New Zealand (pp. 283–92) Through a series of experiments, the paper explains the benefits of using smaller layer heights, and pouring into “leather hard” clay. Not wet and not dry. When the clay is “leather hard” the mold automatically starts cracking off the concrete object when it is dry.

This paper also has interesting diagrams on clay 3d printing using a KUKA industrial arm.

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Bieg, K., Briscoe, D., and Odom, C. (Eds.) Ubiquity and Autonomy: Projects Catalog of the 39th Annual Conference of the Association for Computer Aided Design in Architecture ACADIA, October 24-26, 2019, Austin, Texas (pp. 92-97) - This study is another example of more efficient formwork technologies using additive construction methods. The results of this study could be discussed comparatively to the clay additive construction methods in formwork.

2018Elemental | Ornamental Asa Leland Peller and Wes McGee Anzalone, P., Del Signore, M., and Wit, A. (Eds.) Recalibration: On Impreceision and Infidelity: Projects Catalog of the 38th Annual Conference of the Association for Computer Aided Design in Architecture ACADIA, October 18 - 20, 2018 Mexico City, Mexico (pp. 198 - 203) This study is supplemental knowledge in the use of ceramic molds, this time with poured molten metal. Objects created are non - structural. This experiemnt also gives glimpses into large scale ceramic 3d printing workflows. Attaching a “potterbot” tube to the end and synchronizing extrusion and robot movement.

2018EndlessColumns T. Shan Sutherland, William Marshall, and Dave Lee Anzalone, P., Del Signore, M., and Wit, A. (Eds.) Recalibration: On Impreceision and Infidelity: Projects Catalog of the 38th Annual Conference of the Association for Computer Aided Design in Architecture ACADIA, October 18 - 20, 2018 Mexico City, Mexico (pp. 204 - 209) This study is supplemental knowledge in the use of ceramic molds, this time with poured molten aluminum. Unlike Elemental | Ornamental, this study quantifies the structural capacities of the resulting casts.

Doyle, Shelby, and Nick Senske. “Polycasting: Multi-Material 3D Printed Formwork for Reinforced Concrete.” Architectural Research Centers Consortium, September 30, 2019. http://www.arcc-arch.org/wp-content/uploads/2019/10/ARCCPolycasting-final-report.pdf.

Casted three clay 3d printed columns with Rockite on top of a Sonotube. The main problems again are with the rehydration of the clay as the Rockite is poured. This creates cracking and possible breakage. Positives include the possible reuse of the clay for future molds and faster printing time when compared to PLA printing.

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