Digital Timber Reciprocity

Digital Timber Reciprocity: Design, Manufacture and Assembly of a Freefrom Reciprocal Structure

TMHARCSDMA01 BARC0060:

Design For Manufacture Thesis Portfolio, Final Project

Students:

Fabrizio Tozzoli Alfredo Salgado Ferrer

Programme Director: Emmanuel Vercruysse Christopher Leung Tutors: Vincent Huyghe Tomass Svilans Gulio Brugnaro

Front Cover Picture by Sarah Lever

0

Contents Chapters and Sub-sections 1 INTRODUCTION 5 2 DIGITAL ASSEMBLY 10 2.0 References 11 2.1 Digital Workflows 14 2.2 Robotic Stacking 17 2.3 Robotic Assembly of Interlocking Elements 20 2.4 Robotic Joints 22 3 THE RECIPROCAL LOGIC 30 3.0 References 31 3.1 Reciprocal Framing 34 3.2 The Cantileverd Arc 39 3.3 Project Schedule 4 MATERIAL BEHAVIOUR 46 4.0 Timber Properties 47 4.1 Fabrication Issues 49 5 JOINT PROGRESSION 52 5.0 References 53 5.1 Japanese Joinery 54 5.2 Toolpath Strategies 59 5.3 Hypar Surface Joint 61 5.4 Toolpath Management 65 6 ASSEMBLING RECIPROCITY 75 6.0 References 76 6.1 Design Development 78 6.2 Fabrication Stage 82 6.3 Assembly Stage 84 6.4 Project Schedule 92 7

DIGITAL TIMBER RECIPROCITY

94

7.0 References 95 7.1 Interface Development 97 7.2 Initial Design Proposal 99 7.3 Final Design Proposal 101 7.4 Fabrication Stage 105 7.5 Project Schedule 108 8 APPENDIX 109 8.0 Design Workshops Project 110 8.1 Fabrizio Tozzoli 112 8.2 Alfredo Salgado 113

1 INTRODUCTION

Nowadays, we are witnessing to a dramatic increase in the complexity of the design of free-form architectures, however, despite this advanced digital approach, the final assembly of the generated components is not explored enough, and the on-site construction is not taking advantage of the digitalisation of the first part of the process. This lack of seamless continuity in the process inexorably drives to a massive loss of data resulting in inefficient, time-consuming and costly strategies to assembly these shapes on-site.

If we analyse the current paradigm in architecture and construction, the digital design workflow takes into account only the process until the end of the manufacture of the single elements. It is possible to argue that assembly, in architecture, is instead an issue of primary importance.

Thus, embedding the construction, from a point of view of sequence of assembly or the way in which elements are assembled together into a more significant component and try to maintain all of this inside a digital workflow, help to create a system that can react and adapt to changes at every level, reacting to the feedback even in the final part of the process.

Our research is aimed by the intention of creating a digital workflow that informs and is informed by the design, manufacture and assembly processes, and thus, can inform the manufacture of elements taking into account data that come even from the assembly part of the process.

1

Design for Assembly From digital design to material object

“B of the Bang” Heatherwick Studio- Manchester 2002

Fig1.http://www.heatherwick.com/projects/objects/b-of-the-bang/ (16.11.19)

1.

INTRODUCTION

6

1

Digitalization of the Assembly process Implementig Agumented Reality in the workflow

The Tallinn Architecture Biennale: ‘Steampunk’ Gwyllim Jahn & Cameron Newnham (Fologram, AU) Soomeen Hahm & Igor Pantic (UCL), Tallinn, Estonia 2020 The team used analogue tools, augmented with mixed reality environments to create pavilion made of steam-bent timber elements.

‘Steampunk’ rethinks applications and traditions of craft in pursuit of their evolution, and challenges visitors to reassess how they view contemporary architectural design.

Fig1.https://www.ucl.ac.uk/bartlett/architecture/news/2019/mar/ bartlett-tutors-design-winning-pavilion-tallinn-architecture-biennale (16.11.19)

1.

INTRODUCTION

7

1

Academia vs. Industry Design, Manufacture & Assembly criteria

Industry

Academia

Use of Standard elements. i.

Use of Bespoke elements.

i.

Robotic dirven assembly.

Prefabrication driven assembly. ii.

ii.

Controlled environment. iii.

The aim of this research is to achieve more efficient communication between the different stages of design, manufacture and production.

By breaking into simple points the criteria of execution between academia and industry, we intend to create a list of possibilities and complexities that the two realms face.

From the list, we can derive a potential outcome which juxtaposes the main achievements of these two and produces an innovative outcome.

On-site changing environment.

iii.

1.

INTRODUCTION

8

Picture by Sarah Lever

9

2 DIGITAL ASSEMBLY

This chapter is about the first assembly-driven approaches, where we tried to embed all the process into a continuous digital workflow using the robot as an additive digital fabrication actuator.

The digital assembly experiments are oriented to create a workflow that can inform the geometry in a continuous feedback loop driving the assembly to a “hypothetical� never ending addition of elements.

These first experiments have gradually driven us from a digital approach to fabrication and assembly to a digitally controlled fabrication able to influence the assembly.

Picture by Sarah Lever

2.0

Robotic approximation to Construction Integrative Computational Design and Construction

EXC 2120: Cluster of Excellence IntCDC University of Stuttgart- ICD -The urgent need to rethink design and construction in architecture -Shaping the future of architecture and the building industry -Towards truly integrative computational design and construction -Shaping the future of architecture and the building industry

Fig1. https://icd.uni-stuttgart.de/?p=24111 (16.11.19)

2.DIGITAL ASSEMBLY

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2.0

Stacked Tectonics

Assembly-driven tectonics

The Stacked Pavilion Gramazio Kohler Projects, Switzerland, 2009 Temporary wooden structure - Material: Planed spurce elements, wood screws.

- Fabrication: Additive assembly of dsicrete timber elements.

- Machinery: Kuka KR150 L110 on linear track.

- Production: 5 study models (1:20), 1 pavilion (1:1).

Fig1.http://gramaziokohler.arch.ethz.ch/web/e/projekte/165.html/ (16.11.19)

2.DIGITAL ASSEMBLY

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2.0

The Sequential Wall Sequencing as design strategy

The Sequential Wall Gramazio Kohler Research, ETH Zurich, 2008-2009 - Material: Planed spruce elements, Isofloc thermal insulation, nails.

- Fabrication: Additive assembly of non-standard timber walls.

- Machinery: Kuka KR150 L110 on a linear track.

- Production: 18 study models, 7 wall elements (1:1).

Fig1.http://gramaziokohler.arch.ethz.ch/web/e/lehre/148.html (16.11.19)

2.DIGITAL ASSEMBLY

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2.1

Digital Workflows

Methods diagram Design

Manufacture

Assembly

-Grasshopper, Rhino 6.0 plugin.

-Robots, Grasshopper plugin.

-Robotic Milling with KUKA robot, 6 axes of freedom. robot: Gripper.

-Robotically assembled Timber structure.

-Milling with 3 axes of freedom: TM3 Haas machine.

-CAM component of Fusion 360.

-Solid Modelling by Fusion 360 Software.

-3D modelling with Rhino 6.0 Software.

-2d modelling with Auto CAD 2019 software.

-Trotec laser, for laser cutting.

-Waterjet, metal cutting.

-Feeder (home location of structure components).

The diagram illustrates the workflow for the design, manufacture and assembly stages of our project development. it exemplifies in a diagrammatical way each step we took to obtain a result for our procedure.

-Cura software for 3D models.

-Ultimaker 2.0 3D printer for models in PLA plastic.

2.DIGITAL ASSEMBLY

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2.1

Digital Workflows Decision making diagram -Stacking Sequences: Pick and place process.

-Catalogue of Joints from santardized elements.

-Robotic Joints: Part to tool, the sequence of manufacture.

-Study of Japanese Joinery and timber structures.

-Milling with six axes of freedom: KUKA robot.

-Milling with 3 axes of freedom: TM3 Haas machine.

-Reciprocal structure: Dove-tail and tenon joints.

-3-lap Joint: tapered facilitated assembly.

-Random frame structure: Sequential & layered assembly.

-Robotic simulation for assembly of random structures.

-Adaptive technologies: sensing and tracking attributes of components.

The diagram illustrates the techniques implemented by our methods and developments in this project. It seeks to portray the line of thought we followed in our decision making towards a process that involved the study of design, manufacture and assembly, with an increase in complexity for each step.

2.DIGITAL ASSEMBLY

15

2.1

Digital Workflows Progress proposal for term 2

DESIGN

GRIPPER

FEEDER

CODE ROBOT

HUMAN

TIMBER 2X2

STACKING DRILL SCREW

GLUE GUN

NEST

TIMBER 4X4

AR / VR

OPTI TRACK

CUT

HOME

DRILL HOLE

JOINT 3D SCAN CHAIR STRUCTURE The diagram illustrates the proposed experimentations for the work throughout the term. It is subdivided into repetitive loops that keep increasing in complexity, specificity and innovation. This aim was set to compare our outcomes with our initial aims.

2.DIGITAL ASSEMBLY

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2.2

Robotic Stacking Design process for “pick and place” techinique

-2D line-drwaing from AutoCad, obtained through exporting modelf rom Rhino 6.0 software.

-Rendered 3D model from baked geometry in Grasshopper in Rhino with material attributes.

-Grasshopper definition simulated in Rhino 6.0 software.

The development of this 3D model was generated parametrically in Grasshopper. The main focus was to generate a “complex” shape from standard timber components placed in a specific location (plane). the exercise demonstrates that through parametric design in grasshopper, 3D models can be obtained in Rhino, which have a very high precision and can be easily modified.

2.DIGITAL ASSEMBLY

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2.2

Robotic Stacking

Assembly process

Assembly of the components of the timber basket 1: Picking the standard component.

2: Fastening it by closing the gripper.

3: moving the component above of its specific target plane.

4: Adding some silicone form the glue gun.

5: Placing the component in its target plane.

6: Releasing by opening the gripper with the solenoid valves.

7: Repeat each step for each piece.

Fig 1-2. Stills of the Robotic assembly process of stacking elements into a parametric basket design.

Video link: https://youtu.be/UBX4cL1HLlA 2.DIGITAL ASSEMBLY

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A i.

B

C

A ii.

C A D

iii.

C A iv.

“Pick and Place” logistics A: Timber component 20 x 20 x 150 mm.

B: Feeder C: Gripper (end effector) D: Target (Location plane in the basket).

Fig 2-3. Stills of the Robotic assembly process of stacking elements into a parametric basket design.

Video link: https://youtu.be/UBX4cL1HLlA 2.DIGITAL ASSEMBLY

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2.3

Robotic Assembly of Interlocking Elements Layering a frame

Fig 1-2. Robotic assembly process of stacking elements into a parametric planar frame design.

Fig. 3. CNC milling of the connections

2.DIGITAL ASSEMBLY

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2.3

Robotic Assembly of Interlocking Elements Layering of a Hashtag frame structure

Fig 1 to 5. Assembly sequence.

2.DIGITAL ASSEMBLY

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2.4

Robotic Joints Sequence of steps for robotic joint manufature

Joint 1

Joint 2

Joint 3

C A B

i.

C

C i.

A B

A B

i.

A

B A

E

ii.

E

ii.

D

ii.

C

A

B

B

E

iii.

E

iii.

A iii.

B

A G

B

B

C

iv.

E

iv.

E

iv.

C

B

A

A A: Timber standard component 20 X 20 x150 mm.

B: Timber standrad component 20 x 20 x 150 mm.

C: Gripper KUKA robot (end effector).

D: Spot drill (point), drill bit 3mm diameter.

E: Drill (hole and pocket), drill bit 3mm diameter.

F: Zip Tie, hand fastened.

G: Diall Carbon Steel Wood Screw (Diameter 4mm length 30mm.

v.

A v.

F F

vi.

vi.

22

Joint 4

Joint 5

Joint 6

C

C i.

A B

C

A B

i.

A

i.

A

A

D

ii.

A B

E

ii.

ii.

C B

B

B

A iii.

H

iii.

iii.

B B

G B

A

F

iv.

A

A

iv.

iv.

A: Timber standard component 20 X 20 x150 mm.

B: Timber standrad component 20 x 20 x 150 mm.

C: Gripper KUKA robot (end effector).

D: Spot drill (point), drill bit 3mm diameter.

E: Drill (hole and pocket), drill bit 3mm diameter.

F: Dowel wooden joint.

G: Diall Carbon Steel Wood Screw (Diameter 4mm length 30mm.

H: Band saw for cutting component.

B

G A v.

v.

23

Joint 7

Joint 8

C

C A B

i.

A: Timber standard component 20 X 20 x150 mm.

B: Timber standrad component 20 x 20 x 150 mm.

C: Gripper KUKA robot (end effector).

D: Spot drill (point), drill bit 3mm diameter.

E: Drill (hole and pocket), drill bit 3mm diameter.

F: Dowel wooden joint.

G: Zip-Tie hand fastened.

H: Band saw for cutting component.

A B

i.

C A

A E

ii.

E

ii.

C A

B E

iii.

E

iii.

B

A H

iv.

E

iv.

F

A

A

H

v.

B

v.

B

C

A

A

vi.

vi.

B

2.DIGITAL ASSEMBLY G A

vii.

F vii.

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2.4

Robotic Joints Comparison of the joint atributes

Manufacture

Characteristics

Assembly

Process

Strength

Complex

Easy Joint No. 1

2

3

4

5

6

7

Complexity

Strong

Complex

Weak

Easy

8

1

2

3

4

5

6

7

8

1

2

3

Speed Good

3

4

5

6

7

8

6

7

8

Adaptable

Bad 2

5

Sequencing

Fast

Slow Joint No. 1

4

6

7

8

Limited 1

2

3

4

5

6

7

8

1

2

3

4

5

2.DIGITAL ASSEMBLY

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Constraints

Complexity

Joint 3

Strength

Speed

6.5

Process

Constraints

Complexity

Joint 2

Strength

Speed

3.7

Process

Constraints

Complexity

Joint 1

Strength

Speed

Process

Constraints

Complexity

Strength

Speed

Process

2.4 Robotic Joints

Joint Grading

Joint 4

6.3

3.3

Manufacture Characteristics Assembly

2.DIGITAL ASSEMBLY

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Constraints

Complexity

Joint 7

Strength

Speed

3.0

Process

Constraints

Complexity

Joint 6

Strength

Speed

Process

Constraints

Complexity

Joint 5

Strength

Speed

Process

Constraints

Complexity

Strength

Speed

Process

Best Joint 8

5.8 5.3

3.5

Poor

Manufacture Characteristics Assembly

2.DIGITAL ASSEMBLY

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2.4

Robotic Joints Grasshopper definition for the Girpper set up

The screenshot of the grasshopper file show the definition used for the gripper set-up for the assembly of the robotic timber joints. This step is crucial to our development process since by the calibration of the gripper allows the picking and placing of the timber components to be as precise as possible for our physical prototyping.

2.DIGITAL ASSEMBLY

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2.4

Robotic Joints Sequencing of part to tool manufacture

Sequence of the manufacture and assembly of timber joints using a KUKA programmed robot.

Fig1-2. Photographs of the robotic manufacture of joints.

Video link: https://youtu.be/VjzCvX6gZXk 2.DIGITAL ASSEMBLY

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3 THE RECIPROCAL LOGIC

Reciprocal Frame structures have been used for centuries in the construction sector, where identical elements are used to compose a connected self-bearing structure.

Therefore, this exploration seeks a top-down approach in the design of a reciprocal frame structure, where the connections have a bespoke design for individual elements. The panorama is set to interpret a specific freeform surface into a reciprocal logic, dissecting it into smaller levels for the generation of unique components specifically designed for a determined assembly strategy of a larger self-supporting system. Consequently, computational design and digital fabrication tools in conjunction are used to carry out subtractive manufacturing techniques to attain precise jointing and fit.

In this way, since the organisation of the system is self-sustainable, it is possible to build a long-spanning frame-like shell without the need of falsework and using just a limited number of scaffoldings on-site.

3.0

Concrete Shells: Hyperbolic Paraboloid Construction using timber as Scaffolding and falsework

Palmira Chapel Felix Candela, Cuernavaca,1959.

-Minimizing scaffolding -Minimal surfaces -Double curvature structures

F i g 1 . h t t p s : / / w w w. m i t p re s s j o u r n a l s. o rg / d o i / p d f / 1 0 . 1 1 6 2 / grey_a_00240 (16.11.19)

3.THE RECIPROCAL LOGIC

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3.0

Digital Formations with Timber Creating freeform structures in wood

Lamella Flock KADK, CITA , Knippers Helbig Engineers & Trebyggeriet, 2010 The project contributes to the future use of Wood as one of the few truly renewable building materials - in terms of both materiality and contemporary digital production process. The research has shown that complex wood structures can be efficiently made and assembled using short straight beams.

Fig1. https://kadk.dk/en/case/lamella-flock (16.11.19)

3.THE RECIPROCAL LOGIC

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3.0

Reciprocal Structures Self sustaining structures by mutually supported elements

Bamboo Pavilion at Tongji University Shigeru Ban Architects, Shanghai, 2018 Commonly used as flooring materials in China, bamboo flooring (thickness: 17mm, width: 130mm, length: 1,100mm ) with bolt fasteners form a reciprocal frame structure. This dome was collaboratively constructed by Ban laboratory in Keio University and Tongji University.

Fig1.http://www.shigerubanarchitects.com/works/2018_bamboo/ index.html (16.11.19)

3.THE RECIPROCAL LOGIC

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3.1

Reciprocal Framing

Tesselated Pattern

Figure1. This frame is made by small poplar sticks with almonst no friction between the contact points. The reciprocal nature allow the frame to be cohesive if deformed.

Figure 2. Laser-cut Playwood prototype 6.0 x 6.0 mm sections.

3.THE RECIPROCAL LOGIC

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3.1

Reciprocal Framing

Assembly sequence

Figure 1 to 8. Assembly sequence of a reciprocal component

3.THE RECIPROCAL LOGIC

35

3.1

Reciprocal Framing Assembly logic and considerations 1 1

1

A

2 3

1 3

4

A A

1.2

1.2

2 3

3

2

4 5

3

B

6 7

4

A+B

1

B

Side View

Top View

Figure 4. Specular addition of two components.

4

3

1

1

2 4

4

3

5 3 Figure 1to 3. Basic interlocking of three beams.

Figure 5. Triple weaving constraint.

Figure 6 to 10. Radial aggregation of components

36

3.1

Reciprocal Framing

Conncetion patterns

1 4

2

3

3

2

4

3

1

1 2

1 2 3

1

2

4

2

4

4 3

3

3 2

1 4

4

4 3 2

1 3 4

3

2

1

4 1 2

1 2 3

2

2

3

4

3

1 2

4

4

1 1

3

1

1: Multiple components connections pattern.

2: Beam topology.

3: Single component conncetion pattern.

3.THE RECIPROCAL LOGIC

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3.1

Reciprocal Framing Computational design process 1: Basic unit frame represented in lines.

2: A face of the BREP is created using the guide surface curvature and the lines.

3: BREP creation through extrusion following a normal vector.

4: BREP intersection.

5: Solid intersection.

6: Generation of co-planar interfaces and extruded through a normal vector in both directions.

7: Boolean subtraction.

8: Inverted boolean subtraction.

9: BREP intersection through co-planar interface.

1

4

7

2

5

8

3.THE RECIPROCAL LOGIC 3

5

5 38

3.2

The Cantilevered Arc

Geometry generation, mesh analysis and reciprocal frame application

1

6

11

2

7

12

3

8

13

4

9

14

1: The flat surface is converted into a mesh.

2: Horizontal mesh relaxation.

3: Forces diagram generation.

4: Vertical mesh relaxation (first iteration).

5: Vertical mesh relaxation (final iteration).

6: Principal stresses on the surface.

7:V-direction stress lines.

8: U-direction stress lines.

9: Juxtaposed stress lines.

10: Mesh pattern derived from stress lines.

11: Simplified stress lines.

12: Quadrangular mesh generation.

13: Reciprocal pattern application to the single mesh.

14: Reciprocal pattern application.

15: Optimized reciprocal pattern.

3.THE RECIPROCAL LOGIC

5

10

15

39

3.2

Reciprocal Arc fabrication data generation From lines to BREPs

1

3

5

2

4

6

1: Face generation from lines.

2: BREP generation.

3: Ground connection optimisation.

4: V-direction beam generation.

5: U-direction beam generation.

6: Final geometry.

3.THE RECIPROCAL LOGIC

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3.2

The Cantilevered Arc Project Assembly sequence

Fig 1 to 18. Assembly sequence of the Cantilivered Arc

3.THE RECIPROCAL LOGIC

41

3.2

The Cantilevered Arc Robotic milling of beam components

Fig 1-2. The beams are fabricated though robotic milling.

3.THE RECIPROCAL LOGIC

42

3.2

The Cantilevered Arc

Assembled Prototype

Fig 1-2. Pictures of the assembled Cantilivered Arc.

3.THE RECIPROCAL LOGIC

43

3.2

The Cantilevered Arc

Assembled Prototype

Fig 1-2. Pictures of the assembled Cantilivered Arc.

3.THE RECIPROCAL LOGIC

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3.3

Cantilevered Arc

Project schedule Venue: 3rd Term Final Critics at Here East Opening: 13th June 2019 Status:

Built and disassembled

Design time:

3 weeks

Development time:

2 weeks

Fabrication time:

2 weeks

Sssembly time:

2 days (off-site)

Elements:

n째 15 beams n째 1 metal plate with 2 connections

Ground connection:

Through a metal fins bolted to the beams and welded to a metal plate

Dimensions Height: 2.10 meters Width: 2.10 meters Depth: 1.60 meters Manufacture method Beams (n째 15): KUKA Robot KR60 Metal base: Waterjet cutting machine Materials:

Pine 80x40mm (15 beams) Mild iron plate 5mm

Beams connection:

Straight lap joints with 45째 cut edges

3.THE RECIPROCAL LOGIC

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4 MATERIAL BEHAVIOUR

The organic nature of wood, today, is again understood as a significant advantage, predominantly in the virtue of the future environmental challenges within the building sector, thus placing timber construction on the vanguard of digital fabrication processes.

There is a substantial undergoing research for subtractive numerically controlled technologies that precisely and efficiently produce elements which can be then assembled into more significant components.

Compared with other materials, it is possible to state that timber differs from any other material used in construction: it is a naturally grown biological tissue energy efficient, naturally renewable, fully recyclable, anisotropic and with a hierarchical structure. Thus, it is easily predictable that wood has complex proprieties and behaviour.

This chapter then illustrates the characteristics and adaptations we implemented in order to use timber in an intensive digital fabrication process.

4.0

Timber Properties Sawn and Lamellas variations

Plain Sawn

Quarter SawnR

ift Sawn

Waste wood Usable wood Quarter sawn

Fig2-3. Images of variations in growth rings on yellow pine

-Smoother surface due to less distinct grain -Decreased expansion and contraction on the plank’s width -Twisting, cupping, and warping resistance -Ages evenly over time -Chances of surface checking are significantly reduced -More resistant to moisture penetration

Quality Wood with closer growth rings has a better quality, tends to be stronger and better for machining.

4.MATERIAL BEHAVIOUR

47

4.0

Timber Properties Fabrication Finish and Breakouts

Fig 1. Different timber essencies milled using the same toolpath can give us a first idea over the manufacturability of the wood, showing a range of different finishes.

Fig 2. The result after testing with an aggressive toolpath.

Fig 3. The tool sharpness is important for a good finish and precision evene with hardwood.

4.MATERIAL BEHAVIOUR

48

4.1

Fabrication Issues Fabrication Constraints for Robotic Milling

A y

z x

B

m

.0 m

150

m

.0 m

100

Fig1. Adjustable vice proposal for milling with a Tool to part approach., vice fixed on the rotary table.

Fig 2. Maximum distances for milling from vice centre to avoid material deflections and accumulation of vibrations.

Fig 3. Pocket sequence for milling strategy.

4.MATERIAL BEHAVIOUR

49

4.1

Fabrication Issues

Material Deformation y x

a. Spring a.

b. Bow

y x b.

c. Cip

y x c.

d. Twist y x d.

Fig 1. Timber deformations.

Fig 2-3. Maximum deformation allowed for Robotic Milling

Fig 4. MAccounting for Warping in wood.

4.MATERIAL BEHAVIOUR

50

51

5 JOINT PROGRESSION

This chapter explains all the process of improvement and development of the interface between the elements, starting from the first approach with complex timber connections up to the full-contact hypar surface that defines the last improvement.

This complex geometry needs complex management of the fabrication toolpath in order to be fabricated with the high degree of precision to reduce tolerance and obtain a perfect match between the connections.

We have developed a series of joints that have different and specific performances, trying to improve the utilisation of the two machines and reach the limit they can offer in terms of optimisation and performance of the different milling processes.

5.JOINT PROGRESSION

5.0

Complex Timber Connections

Assembly planning

La Seine Musicale Shigeru Bam Architects/ Design to production, Paris, 2016 Design-to-Production implemented a fully parametric 3D-CAD-model detailed up to the last screw and containing both the raw and final geometries of the almost 1,300 doubly curved timber pieces and provided both gluing and machining data for all segments, solid models for the 3,300 faรงade subconstruction elements and a full set of individual workshop drawings and assembly plans.

Fig 1. Shigeru Ban Architects, Works. http://www.shigerubanarchitects.com/works/2017_ileseguin/index. html (18.11.19) Fig 2-3. Design to Production- Projects: La Seine Musicale http://designtoproduction.com/en/ (16.11.19) 5.JOINT PROGRESSION

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5.1

Japanese Joints Geometry and Material Study

A study of some Japanese joints was made throughout the term. The purpose of this study was to analyse the different characteristics of the joints such as strength, efficiency, complexity and of course machinability with both the TM3 Haas CNC machine for milling compared to the 6 axes of freedom KUKA robot.

Hence, before creating the respective milling toolpaths, we did some prototypes in the Ultimaker 3D printing machine in PLA plastic (fig1.), and some plywood laser cuts (fig2.), before actually machining another prototype in the TM3 Hass machine in timber.

Fig1-3. Japanese Joinery prototypes.

5.JOINT PROGRESSION

54

5.1

Japanese Joints

Manufacture study

Fig 1-2. Stills of the Robotic assembly process of stacking elements into a parametric basket design.

Video link: https://youtu.be/UBX4cL1HLlA 5.JOINT PROGRESSION

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5.1

Japanese Joints

Manufacture study

Fig 1-2. Stills of the Robotic assembly process of stacking elements into a parametric basket design.

Video link: https://youtu.be/UBX4cL1HLlA 5.JOINT PROGRESSION

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5.1

Japanese Joints

Dovetail Joints

Milling timber processes can achieve better precision for the assembly of timber structures, with implemented intelligence into the self-aligning joints. Modelling in Fusion 360 and milling in the Haas TM3 machine was efficient, even though breakouts in the Timber milling, due to faulty design of the toolpaths can be improved in order to attain better results.

Fig1. Design of Milling toolpaths in Fusion CAM component from exported Rhino 3D model.

Fig2. Standard timber component after milling in the manufacture process in Haas TM3 machine.

Fig3. Assembly process (pick and place) from Feeder to KUKA robot.

Fig4. Assembled Dove-tail tapered joint type.

5.JOINT PROGRESSION

57

Fig 1. Toolpath created with Fusion360.

Fig 2. Self-aligning dovetail joint.

5.JOINT PROGRESSION

58

5.2

Toolpath Strategies Flank milling - Tool to part

Figure 42. Tip milling with KUKA KR60 robot.

Template of Toolpath 1 (Downcutter End Mill 12 mm) ---- Standard Pocket: 4 mm stepover 10 mm Stepdown ---- Tapper: 6 mm stepover 3 mm Stepdown

Feedrate: 1.8 cm/s

Spindle speed: 11,963 rpm

Figure 42. Tip milling with KUKA KR60 robot.

Template of Toolpath 1 (Downcutter End Mill 12 mm) ---- Standard Pocket: 4 mm stepover 10 mm Stepdown ---- Tapper: 6 mm stepover 3 mm Stepdown

Feedrate: 1.8 cm/s

Spindle speed: 11,963 rpm

5.JOINT PROGRESSION

59

5.2

Toolpath Strategies Tip milling - Tool to part

Figure 1-3. Flank milling with KUKA KR60 robot.

Template of Toolpath 2 (Downcutter End Mill 12 mm).

---- Standard Pocket: 4 mm Stepover 1 mm Stepdown.

---- Tapper - - - Final pass: Finishing of the face(1mm)

Feedrate: 1.8 cm/s

Spindle speed: 11,963 rmp

Figure 30. Bill of material for the Assembling Reciprocity project - 58 components

5.JOINT PROGRESSION

60

5.3

Hypar Surface Joint

Computational design process

1

4

7

2

5

8

3

6

9

1: BREP intersection.

2: Identifing intersection plane.

3: Application of surface template.

4: Solid application.

5: Surface trim operation on solid BREP. 6: Solid trim operation on surface template.

7: Pocket template application to the basic unit.

8: Trim operations to all the BREPs. 9: Final solid geometry.

5.JOINT PROGRESSION

61

62

5.3

Hypar Surface Joint Tapered lap joint optimisation

1

2

3

4

1: Base tapered geometry.

2: Optimisation to reduce undercuts.

3: Dynamic remeshing.

4: Surface generation.

5.JOINT PROGRESSION

63

5.3

Hypar Surface Joint

Joint typologies

1

3

2

4

1: Prismatic lap jont.

2: Hypar surface lap joint.

3: Male/female tapered lap joint.

4: Male/femal snap joint.

5.JOINT PROGRESSION

64

5.4

Toolpath Management CNC milling the Hypar Surface joint

Figure 1-3. Template of Toolpath -TM3 Haas Machine.

Downcutter End Mill: Ballnosed Cutter :

12 mm 12 mm

---- Pocket Clearing: 4 mm Stepover 4 mm Stepdown.

1mm Radial & Axial Stock to leave ---- 3D Contour: 1.5 mm Finishing

---- Helix plunge - - - Retract

Feedrate: 1761 mm/min Spindle speed: 6,000 rmp

5.JOINT PROGRESSION

65

Figure 1-3. Template of Toolpath -TM3 Haas Machine.

Downcutter End Mill: Ballnosed Cutter:

20 mm 20 mm

---- Pocket Clearing: 4 mm Stepover 4 mm Stepdown.

1mm Radial & Axial Stock to leave ---- 3D Contour: 1.5 mm Finishing

---- Helix/Plunge - - - Retract

Feedrate: 1761 mm/min Spindle speed: 6,000 rmp

5.JOINT PROGRESSION

66

3

1

2

4

1: Roughing Pass Pocket Clearing, 1 mm stock to leave.

2: Finishing Pass, 3d Contour, 1.5 Ball-Nosed Finishing.

3: Joint Alignment 4: Component assembled 5.JOINT PROGRESSION

67

68

Picture by Sarah Lever

69

5.4

Toolpath Management Robotic Milling of the Hypar Surface joint

Fig 1. Toolpath as exported fromFusion360.

Fig 2. The toolpath is then edited in Rhino to respond to different performances.

Fig 3. The toolpath is inserted into the algorithm and oriented to the correspondent pocket with Grasshopper.

5.JOINT PROGRESSION

70

5.4

Toolpath Management

Toolpath Families

Fig 1. Combination of 2 toolpaths used when milling process is driving to a collision between the collet and the beam.

Fig 2. Toolpath used for a very deep pocket.

Fig 3. Basic Toolpath 5.JOINT PROGRESSION

71

5.4

Toolpath Management Embedded Collision Simulation

72

5.4

Toolpath Management

Results

Fig 1-2. Close-ups pics of pockets as milled by the robot using different families of toolpaths.

5.JOINT PROGRESSION

73

74

6 ASSEMBLING RECIPROCITY

The pavilion is the result of the development of self-aligning joints.

The surfaces that define interfaces between the elements profoundly influence the final design.

The joints have all different orientations that can drive to undercuts but are milled with a three axes CNC machine.

The assembly process has been taken into particular consideration considering the short time frame available for the on-site installation.

The beams are connected to the ground through a beam-like platform to reduce deformations and improve the overall stiffness.

6.0

Subtractive Robotic Fabrication Multi-axis Robotic milling

Research Pavilion ICD/ITKE, Stuttgart 2011 Employing custom programmed routines the computational model provided the basis for the automatic generation of the machine code (NC-Code) for the control of an industrial seven-axis robot. This enabled the economical production of more than 850 geometrically different components, as well as more than 100,000 finger joints freely arranged in space. Following the robotic production, the plywood panels were joined together to form the cells.

Fig1. https://icd.uni-stuttgart.de/?p=6553 (16.11.19)

6.

ASSEMBLING RECIPROCITY

76

6.0

Shell structures in Compression Balancing Computation and traditional Craft

The Armadillo Vault Block Research Group, ETH Zurich, 2017 Holds hundreds of limestone slabs with no glue. The whole installation is a structure that achieved equilibrium state by adopting a mechanism of a ‘right’ geometry corresponding to the applied loads. Known as funicular geometry, it is not a new concept. Medieval vault builders have done a number of similar complex forms carefully balanced in compression.

Each considered today a masterpiece and yet none of them was made without cement.

Fig1. Philippe Block, M. R. (2017). The Armadillo Vault: Balancing computation and traditional craft. In A. M. Philip f. Yuan, Digital Fabrication (pp. 100-111). Shanghai: Tongji University Press.

6.

ASSEMBLING RECIPROCITY

77

6.1

Design Development Design for a public venue

78

6.1

Design Development

Structural model

Fig 1 to 3. Structural model.

6.

ASSEMBLING RECIPROCITY

79

6.1

Design Development

Assembly sequence

Fig 1 to 12. Assembly sequence of the pavilion.

6.

ASSEMBLING RECIPROCITY

80

6.1

Design Development Bill of material

a. 40 x 40 mm

b. 40 x 80 mm

c. 80 x 80 mm

Fig 1. Bill of Materials.

Fig 2. Axonometric exploded.

Fig 3. The two structural systems.

6.

ASSEMBLING RECIPROCITY

81

6.2

Fabrication Stage

CNC Milling

82

83

6.3

Assembly Stage

Base assembly

Fig 1-2. Assembly at Here East, using Zip-ties for fixing.

6.

ASSEMBLING RECIPROCITY

84

6.3

Assembly Stage

On-site

6.

ASSEMBLING RECIPROCITY

85

6.

ASSEMBLING RECIPROCITY

86

6.

ASSEMBLING RECIPROCITY

87

6.

ASSEMBLING RECIPROCITY

88

89

90

91

6.4

Assembing Reciprocity

Project schedule Venue: London Design Festival at OXO Tower Courtyard Opening: 18th September 2019 Status:

Built and disassembled

Design time:

1 month

Development time:

3 weeks

Fabrication time Beams: 10 days Platform: 3 days Assembly time Platform: Beams:

2 days 8 hours (on-site)

Elements n° 59 beams

n° 11 box-like fins 2° platform layers

Ground connection: Through a beam-like platform Dimensions Height: 2.80 meters Width: 3.70 meters Depth: 2.20 meters Manufacture method Beams: Hass TM-3P CNC milling machine Platform: Piranha CNC router Materials:

Tulipwood 80x80mm (17 beams) Tulipwood 80x40 mm (36 beams) Tulipwood 40x40 mm (6 beams) Pine plywood 18mm (platform) OSB 18 mm (lower platform)

Beams connection:

Hypar surface lap joints with SPAX screws 6.

ASSEMBLING RECIPROCITY

92

Picture by Sarah Lever

93

7 DIGITAL TIMBER RECIPROCITY

As final project we decided to take to improve the reciprocal relationship that underlies the previous projects, augment the cohesion between the beams and get over some of the problems related to global geometry.

To reduce the edges on the geometry and obtain a complete reciprocal structure, we decided to create a funnel shape. Also we implemented an evolved workflow that involves the use of both CNC milling machine and the KUKA robot.

The interfaces between elements are the result of a more efficient fullcontact surface made through a “three axes milling� logic to achieve precision and reduce material breakouts.

The fabrication data are entirely managed inside Grasshopper in order to reduce errors and control further fabrication issues making the process adaptable.

Picture by Sarah Lever

7.0

Additive Robotic Fabrication Robotic pre-fabrication and Assembly

Complex Timber Stuctures Gramazio Kohler Research, ETH Zurich, 2012-2017 -Material: Planed spurce elements, wood screws, Nails, PUR adhesive.

-Fabrication: Spatial Assembly of complex timber structures.

-Machinery: Universal robots UR5 ABB IRB 4600 on mobile platform, ABB IRB 6650 (BUAS).

-Production: 8 study models (1:10), 2 structural prototypes (1:1).

Fig1. http://gramaziokohler.arch.ethz.ch/web/e/forschung/184.html (16.11.19)

7.DIGITAL TIMBER RECIPROCITY

95

7.0

Parametric design in Timber structures Complexity apportion to design and manufacture

Cambridge Mosque: A Paradise Garden from Timber Marks Barfield Architects/ Design to production/ Blumer Lehmann, Cambridge, 2017 Design-to-Production was commissioned by timber contractor BlumerLehmann to optimize the geometry, develop a pre-fabrication and assembly concept in close collaboration with the engineers of SJB Kempter Fitze and implement a detailed 3D-model of the structure.

Based on fabrication data generated directly from this parametric digital model, 2746 timber parts were pre-fabricated in Switzerland and assembled on-site in only a few weeks.

Fig 1. Marks Barfield Architects, Cambridge Mosque http://www.marksbarfield.com/projects/cambridge-mosque/ (16.11.19) Fig 2-3. Design to Production- Projects: Cambridge Mosque http://designtoproduction.com/en/ (16.11.19) 7.DIGITAL TIMBER RECIPROCITY

96

7.1

Interface Development BREP Dual manufacture diagram

TM3 Haas

Template Surface

CAM Fusion Software

CNC Beam

Reciprocitree Assembly

Toolpath Generation KUKA KR60

Robotic beam

7.DIGITAL TIMBER RECIPROCITY

97

7.1

Interface Development Joint connections workflow

1

2

3

4

5

6

7

8

9

10

11

12

Fig 1. V-direction BREP. Fig 2. U-direction intersecting BREPs. Fig 3-4. Solid difference between BREPs. Fig 5. Guide plane.

Fig 6 to 8. Template surfaces oriented to the guide plane Fig 9. Creation of the final geometry for V-direction BREP.

Fig 10-11. Creation of final geometry for U-direction BREPs. Fig 12. Final connection between elements.

7.DIGITAL TIMBER RECIPROCITY

98

7.2

Initial Design Proposal Concept design of a Hypar reciprocal structure

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

Fig 1. Surface Generation.

Fig 2. Structural analysis.

Fig 3 to 5. Iso-surface subdivision iterations.

Fig 6. Pattern application.

Fig 7 to 15. Assembly sequence.

Fig 16. Complete structure.

Fig 17-18. Final paneling.

7.DIGITAL TIMBER RECIPROCITY

99

7.2

Initial design proposal

Renders of Hypar reciprocal Proposal

7.DIGITAL TIMBER RECIPROCITY

100

7.3

Final Design Proposal

Geometric development

1

3

2

4

5

1: Curve guide.

2: Surface generation.

3: Iso-surfaces subdivision (first iteration).

4: Iso-surfaces subdivision (final iteration).

5: Iso-surfaces optimisation for fabrication.

7.DIGITAL TIMBER RECIPROCITY

101

7.3

Final Design Proposal

Geometry Definition

1

3

2

4

5

1: Discontinuity points from pattern application.

2: Lines generation from points.

3: Lines optimisation.

4: Application of timber sections.

5: Final outcome variant.

7.DIGITAL TIMBER RECIPROCITY

102

7.3

Final Design Visualisations for installation on Gordon Street

Fig 1-2. Renderings of the Reciproci-tree Project.

7.DIGITAL TIMBER RECIPROCITY

103

Fig 1-2. Renderings of the Reciproci-tree Project.

7.DIGITAL TIMBER RECIPROCITY

104

7.4

Fabrication Stage CNC and robotic milling

105

106

107

7.5

Digital Timber Reciprocity

Project schedule Venue:

Fifteen Exhibition at The Bartlett

Opening: 3rd December 2019 Status:

Ready to be installed

Design time:

2 months

Development time:

15 months

Fabrication time:

8 days

Assembly time:

3 days (off-site)

Elements:

n° 65 beams

Ground connection:

Direct

Dimensions Height: 3.00 meters Diameter: Base 1.00 meter Min 0.50 meters Max 4.00 meters Manufacture method V-direction (n°35): Hass TM-3P CNC milling machine V-direction (n° 30): KUKA Robot KR60 Materials:

Tulipwood 80x40mm (25 beams) Tulipwood 40x40 mm (40 beams)

Beams connection:

Full-contact hypar surface lap joints

7.DIGITAL TIMBER RECIPROCITY

108

8 APPENDIX

8.0

Design Workshops Project

The EGG Oeuf Project

Fig 1. Components of Oeuf Gimbal mechanism

Fig 1 to 3. Manufacture and Assembly of Oeuf project.

8.

APPENDIX

110

8.0

Design Workshops Project

The EGG Oeuf Project

Fig 1 to 3. Manufacture and Assembly of Oeuf project.

8.

APPENDIX

111

8.1

Fabrizio Tozzoli

Robot management

Fig 1-2. Robotic milling and simulation Picture by James Tye

8.

APPENDIX

112

8.2

Alfredo Salgado

CNC management

Fig 1-2. CNC milling and simulation Picture by Dr. Christopher Leung

8.

APPENDIX

113