3D Printing Additive Manufacturing Introduced to Engineering, Architecture and Construction Complex

3D PRINTING INTRODUCED TO THE BRAZILIAN COMPLEX OF ENGINEERING, ARCHITECTURE, CONSTRUCTION (AEC)

3D PRINTING

ADDITIVE MANUFACTURING INTRODUCED TO ENGINEERING, ARCHITECTURE AND CONSTRUCTION COMPLEX (AEC) IN BRAZIL

Caroline Afonso Manolio Advisor professor: Arthur Hunold Lara

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3D Printing: Additive Manufacturing introduced to the Engineering, Architecture and Construction Complex (AEC) in Brazil Caroline Afonso Manolio

Double Degree Student School of Architecture and Urbanism of University of São Paulo (FAU-USP) Master of Science Built Environment - Politecnico di Milano carolinemanolio@usp.br / caroline.afonso@mail.polimi.it

Advisor: Arthur Hunold Lara

Associate Professor at the Department of Architectural Technology Coordinator of the Didactic and Research Laboratory Architectural Materials and Structures (LABMAT) School of Architecture and Urbanism of University of São Paulo (FAU-USP) arthurlara@usp.br

Abstract New techniques that emerge in the complex of Engineering, Architecture, Construction and Works Management (AEC) demand new ways of building, different from traditional construction. In recent years, Additive Manufacturing (AM) - commonly called 3D Printing (3DP) - has emerged as one of the Industry 4.0 supplies with promising technological advantages in various industry sectors. Companies, startups, universities and other organizations have experimented with the application of AM in the building construction complex, historically associated with archaic construction methods, especially in Brazil. The prototypes and constructed works have shown that the sector can benefit from the application of this technology, either in the optimized production of constructive components, or, on a more ambitious scale, in the construction of entire buildings, bearing in mind that it can bring gains of productivity, cost savings, greater precision in production and design and formal freedom. In addition to that, it points to more environmentally sustainable construction processes.

The adoption of technology has, however, a series of challenges to be overcome so that it can be adopted independently or in association with conventional construction methods in the AEC complex.

Keywords: digital fabrication; additive manufacturing; technology; 4.0 industry;

This research was developed with the support of the International Exchange Scholarship Program - Entrepreneurship and Innovation, by AUSPIN - Innovation Agency of the University of São Paulo (USP), with the purpose of developing projects that promote the improvement of practices associated with innovation, technological development and entrepreneurship at University of São Paulo. This research was developed in parallel with the Double Degree program at Politecnico di Milano, Italy, during the Master of Science course in Built Environments, between September 2022 and February 2023.

3D PRINTING INTRODUCED TO THE BRAZILIAN COMPLEX OF ENGINEERING, ARCHITECTURE, CONSTRUCTION (AEC)

SUMMARY

Acronym Index: 3DP - 3D printing AEC – Architecture, Engineering and Construction Industry, BJ - Binder Jetting BIM - Building Information Modeling BD - Building Printing CNC - Computer Numerical Control DDM - Direct Digital Manufacturing DF – Digital Fabrication FDM or FFF - Fused Filament Fabrication FF – File to factory IOT - Internet of things LM - Layers Manufacture MA - Additive manufacturing R&D – Research and Development RP - Rapid Prototyping SLA - Stereolithography SLS - Selective Laser Sintering

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Introduction Reserach aim

06 07

Definitions 3D Printing definition Historical line and evolution of technology Industry 4.0 and the relevance of 3DP in the current context

09 15 19

Processes 3D printing techniques Printing process Printer types Printing materials and required attributes

23 28 30 32

Application in AEC Most adopted methodologies in civil construction Opportunities in the application of 3DP in the AEC complex Disadvantages and challenges to overcome in the application of the 3DP in AEC Experiences and case studies Possibilities of the application of 3DP in the AEC complex in Brazil

37 50 52 54 77

Conclusions Bibliography

87 90

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3D PRINTING INTRODUCED TO THE BRAZILIAN COMPLEX OF ENGINEERING, ARCHITECTURE, CONSTRUCTION (AEC)

The Interrelationships between architecture and digital technologies, initially confined to the sphere of representation and then reviewed and directed to the sphere of cognitive and design processes, present nowadays other possibilities for the manufacturing processes [...].

Design and build, or think and make, the built environment both critically and synchronous to the transformations of each age is one of the greatest challenges of architecture in its history and this condition remains with digital manufacturing (SPERLING, 2015).

1. INTRODUCTION It is undeniable that new techniques that emerge in the complex of Engineering, Architecture and Construction Complex (AEC) demand new ways of building, different from traditional construction. In recent years, Additive Manufacturing (AM) - commonly called 3D Printing (3DP) - has emerged as one of the Industry 4.0 topics with promising technological spillovers in various industry sectors. Recently, companies, startups, universities and other organizations have undertaken experiments with the application of AM in the building construction complex, historically associated with archaic construction methods, especially in Brazil. The prototypes developed and the works built have shown that the sector can benefit from the application of this technology, either in the optimized production of constructive components, or, on a more ambitious scale, in the construction of entire buildings, bearing in mind that it can bring gains of productivity, cost savings, greater precision in production and design and formal freedom, in addition to pointing to more environmentally sustainable construction processes. However, the adoption of the technology has a series of challenges to be overcome so that it can be adopted independently or associated with conventional construction methods in the AEC complex.

DEFINING THE TECHNOLOGY

>> To define what additive manufacturing is - commonly called 3D printing - as well as other concepts from the same universe: file to factory, digital manufacturing, subtractive manufacturing, building printing, for example.

SITUATING CHRONOLOGICALLY THE TECHNOLOGY AND ITS RELEVANCE TODAY

>> To trace historically the evolution of technology to the current context of Industry 4.0, pointing out its relevance today

2. RESEARCH AIM The objective of this research is to analyze the current state of development of the 3D Printing applied to civil construction worldwide, and discuss the possibility of insertion in the Brazilian context. It seeks to draw, firstly, a historical line of evolution of this technology, from the initial stage in the mid-80s, to the current moment of industry 4.0, placing it within the various techniques of Additive Manufacturing and demonstrating the relevance of the topic in the global industrial economy. Next, it seeks to unravel the varieties of methodologies and techniques associated with AM, in view of the diversity of the range of processes, types of systems and printers, materials and characteristics of the printed object associated with the technology.

Through the explanation about the printing process, as well as the description of the most adopted types of printers, the aim is to describe the 3DP methodologies most commonly adopted in civil construction, also explaining the opportunities and challenges to be overcome in the use of technology in the building construction complex. Experiences and works undertaken in recent days are analyzed with the intention of pointing out promising aspects of the application of the technique in this industry. Finally, it is provided an analysis of the current state of civil construction in Brazil and the possibilities of applying the 3DP in the AEC complex nationwide.

The intention of this research is, therefore, to analyze, systematize, organize and transmit information about Additive Manufacturing technology in Architecture and Civil Engineering.

The intention is, shortly, to collaborate through research, with the transition process of Civil Construction to a digital and circular economy, through the study of an innovative solution, with possibilities of competitiveness, sustainability and productivity. It is believed that the scientific study focused on the 3DP technology can help future research and processes in the context of the entrepreneurial ecosystem and the creative economy linked to the construction industry.

DESCRIBING AND CLASSIFYING ITS PROCESSES

POINTING OPPORTUNITIES AND CHALLENGES

ANALYZING CASE STUDIES AND CONSTRUCTED WORKS

SETTING PARALLELS WITH THE INDUSTRY IN BRAZIL

>> To explain the 3D printing techniques, the printing process, the most used types of printer, the necessary attributes of the printing materials, as well as the most adopted methodologies in civil construction

>> To discuss the opportunities that the technique offers in relation to conventional methods, in addition to the disadvantages and challenges to be overcome for the adoption of the technique in the context of Architecture and Civil Engineering

>> To analyze projects undertaken by companies, startups, universities and other organizations that have built prototypes or produced building components or entire buildings with additive manufacturing.

>> To describe the current state of incorporation of technology in Brazil, drawing parallels with the characteristics of the building construction industry, analyzing the experimental initiatives and explaining the possibilities of adopting the 3DP in Brazil

Image 01: Scheme: objective and division of research topics

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3. DEFINITION OF ADDITIVE MANUFACTURING - 3D PRINTING

DEFINITIONS :: Definition of 3D Printing :: History and evolution of technology :: Industry 4.0 and the relevance of 3DP in the current context 8

The automation process in the manufactured objects industry has developed at an exponential pace in the last century. In the last decade, in particular, the emergence of new technologies has promised to generate a true revolution in the design and in the way we build our buildings, bringing the same principle used in post-industrial production to the construction site, the file to factory (FF), linking directly the digital design and its manufacturing process. In this scenario, “the distance between the manufacturing logic of industrialized objects and buildings seems to tend to be overcome” (FLORÊNCIO, 2016).

A few years ago, Digital Fabrication (DF), the production of physical objects from digital models, has emerged as one of the great innovations within the Engineering, Architecture, Construction and Works Management (AEC) complex. DF is the result of the integration of design and industrial production through information and digital communication techniques (BALLERINI, 2018).

Among the technologies related to DF, Additive Manufacturing (AM) is included, the process of producing an object from a three-dimensional model, generating successive stacked layers. AM is known by a number of other names, such as Rapid Prototyping (RP), Direct Digital Manufacturing (DDM), Layered Manufacturing (LM) and the name that has became more commonly known - 3D Printing (3DP).

AM is configured as the opposite of the classic subtractive manufacturing that starts from a volume of material to be adapted to form the desired object through different methods, such as cutting, crushing and drilling.

In relation to subtractive manufacturing, additive manufacturing proves to be advantageous in terms of material use: while subtractive manufacturing, as it involves the subtraction of a volume producing also waste, AM executes the object as it was configured in the digital model, using only the necessary material. Although there may be waste in AM, it is minimized, representing efficiency, economy and sustainability. Another advantage of additive manufacturing is the customization of the object: it is possible to execute the desired object in a single session, unifying several stages of the object’s production in a single process, which also points to the reduction of lead time. Additive techniques do not, therefore, imply that several parts are produced with the subsequent need for assembly, which can be an advantage from the point of view of production planning and control (LOPES, 2016).

It is important to point out, however, that, currently, 3D printing is not as advantageous as subtractive printing for the production of massive objects, which subtractive manufacturing can ensure.

Lead time is the time spent by the production system to transform raw materials into finished products.

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FORMATIVE MANUFACTURE

SUBTRATIVE MANUFACTURE

3D PRINTING IS A TECHNIQUE OF ADDITIVE MANUFACTURE

ADDITIVE MANUFACTURE

Image 02: Scheme: types of manufacturing | Adapted from “The 3D Printing Handbook”

COST PER PART

FORMATIVE MANUFACTURE SUBTRATIVE MANUFACTURE ADDITIVE MANUFACTURE

Initially applied to rapid prototyping and the production of mockups and models on reduced scales, Additive Manufacturing, in the last decade, in particular, has been the target of experiments in the Engineering, Architecture and Construction complex (AEC), with the use of 3DP for computerized production not only of construction components, but also for printing entire buildings, the so-called -building printing (BP), the context in which this research focuses.

Analyzing the automated production methods used in AEC, one can categorize them according to their purpose, the number of axes they work with and the way they produce objects (PUPO, 2008).

NUMBER OF PARTS

Image - 03 | Costs per part x number of parts in relation to manufacturing types | Adapted from“The 3D Printing Handbook”

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AUTOMATED PRODUCTION METHODS Architecture, Engineering & Construction complex (AEC)

REDUCED SCALE

SCALE 1:1 2D

STUDIES MODEL

EVALUATION

MANUFACTURE WAY OBJECTS ARE PRODUCED

DIMENSIONS

AIM

PRESENTATION

2,5D

3D

FINAL PRODUCTION

BUILDING PRINTING

PARTS OF THE BUILDING

SUBTRATIVE

FORMATIVE

ADDITIVE

MOLDS

MASS PRODUCTION

ONE PIECE

SMALL SERIES

Image 04: Scheme: automated production methods | Adapted from PUPO, 2008

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4. HISTORICAL LINE AND EVOLUTION OF TECHNOLOGY Architecture and Civil Engineering have changed radically in the 20th and 21st centuries, due to the development of new materials and technologies. As punctuated by Kolarevic (2003), materials that allow free and moldable shapes, such as concrete and plastics, created special interest in the 1950s and 1960s. The greatest innovations related to new materials and production methods, however, occurred in the 21st century, based on computer use applied to building construction and digital fabrication in industry.

The principle that gives rise to 3D printing is stereolithography (SLA), outlined by Charles Hull in 1984, seen as the first additive manufacturing process created. SLA uses a liquid polymeric resin as raw material, deposited on a vat. A membrane spreads a layer of this material that is subsequently solidified by the action of an ultraviolet (UV) laser. This process is repeated for each layer until the desired object is obtained.

After SLA, Selective Laser Sintering (SLS) and Molten Material Deposition Modeling (FDM) technologies were milestones in the development of Additive Manufacturing. The evolution of AM continues to progress in its processing speed, in the complexity of the design, and in the variety of materials used. In the last decade, in particular, additive manufacturing machines also began to be used in everyday life and the purchase of 3D printers, for example, became possible for the same price as a smartphone. According to Hager [2], thanks to open source systems, the prototyping of new products, as well as the application of 3D Printing in various fields are available in an increasingly democratic way. In the last decade, Additive Manufacturing techniques were part of the phenomenon related to the emergence of Fab Labs and Tech Shops that spread across cities, workshops and laboratories that stimulated the use of digital manufacturing tools.

Initially, the concept of automated production and Digital Fabrication were applied more extensively to manufacturing, but there was a spread to other sectors - such as agriculture, medicine and, more recently, the complex of Engineering, Architecture, Construction and Construction Management.

From the beginning of the 2010s, projects seeking large-scale application in the construction of buildings began to be developed more intensively:

Image 05: FAB LAB Barcelona | Source: Institute for Advanced Architecture of Catalonia (IAAC)

Like makerspaces and hackerspaces, FabLabs and Tech Shops are spaces - workshops and labs - that have fostered the culture of digital fabrication by offering public and shared access to cutting-edge manufacturing equipment.

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Image 05: Chart - Production of 3D printed works in Construction/Architecture Field per year | Adapted from ALVARADO, 2021

[1] Izabela Hager in “3D printing of buildings and building components as the future of sustainable construction?”. 2016.

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Dutch 3D printing company MX3D builds a steel bridge

The BBC reported the first family that moved into a 3D-printed house in Nantes, France.

2021

BioHome3D builds the first 3D printed house with all elements produced with biomaterials, wood fibers and bio-resins,100% recyclable

Decree No. 24 of 2021 regulates the use of 3D printing in the construction sector in Dubai

2022

Chinese company WinSun builds 10m multi-storey building in Shanghai

3D Home Construction built the first printed house in Brazil

2020

Dubai Government Offices are 3D Printed in China

by WinSun

2016

2015

A plot of 10 houses is built

by Winsun in China

2013

2009

Makerbot introduces 3D Printing to everyday life through do-it-yourself kits for people who want to build their own 3D printer

2010

Pegna [3] suggests the use of AM in the manufacture of large structures for civil construction by Selective Aggregation (SA)

2006

3D Systems ships first SLA machine

1997

1992

Fraunhofer Institute develops the first Selective Laser Melting (SLM) machine

1995

First 3D printer patent [2]

1989

Stratasys markets first Fused Deposit Modeling (FDM) printer

1986

1983

Charles Chuck Hull develops the stereolithography, first 3D printing technique

Dr. Behrokh Khoshnevis launches the Contour Crafting System, a huge 3D printer designed for printing buildings on site

A reinforced concrete bench is printed using the methodology of Concrete Printing through researches in Freeform Construction, at Loughborough University

2018

Enrico Dini patents the D-Shape printer

The New York Post has reported the first 3D-printed home for sale on Long Island

Image 06: Additive Manufacturing Timeline | Elaborated by the author

[2] Charles Hull in “Apparatus for Production of Three-dimensional Objects by Stereolithography” 1986 [3] Joseph Pegna in “Exploratory investigation of solid freeform construction, Automation in Construction”. 1997,

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5. INDUSTRY 4.0 AND THE RELEVANCE OF 3DP IN THE CURRENT CONTEXT

The theme of Digital Fabrication is part of the technological dynamism of Industry 4.0 — with themes related to Big Data, 5D, BIM (Building Information Modeling), Internet of Things (IOT), Machine Learning, cloud computing, cybersecurity, among other topics. Industry 4.0 is considered the result of the 4th Industrial Revolution and reveals a new form of production, oriented towards digital connectivity. It proposes the integration between automation systems, cyber-physical systems and the internet, to optimize production processes (MAZZAFERRO, 2018).

Image 08: Main application areas of 3D printing and preferred attributes | Source: Deloite

Image 07: Concept cloud related to Industry 4.0 | Source: BEYHAN, 2018

The reason why the use of 3D printers is currently very common in other areas — medicine, biology, food production, motorsport and mechanical engineering, for example — is not unusual because there are a series of advantages that this technology presents to different sectors. A study developed in 2018 by Deloitte, a consultancy with a tradition in the creation of content and publications that address relevant topics in the world economy, points to three attributes as the main preferred attributes of the application of 3D printing in different sectors: cost savings, speed and efficiency, and, finally, customization.

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Goldman Sachs, a large group in the banking sector, conducted a study in 2013 that pointed to 3D printing as one of the eight technologies that would change business in the coming years. Also according to projections by the consultancy Grand View Research, this market should register an annual growth of 100.7% from 2022 to 2030. 3D printing technology is also mentioned among a list of 12 potentially economically disruptive technologies in a McKinsey report Global Institute, research institute on the evolution of the global economy.

In addition, NASA, the National Aeronautics and Space Administration of the United States, has developed a technology assessment tool, the “TRL”, or technology readyness level, which describes the technological readiness of a product or company. TRL rated 3DP as a technology level 9, the highest on the scale.

In this direction, NASA developed the Relevant Environment Additive Construction Technology (REACT) project, a collaboration to develop technologies for lunar surface constructions. It awarded the construction company ICON — a company that has undertaken a series of works and experiments with 3D Printing in the construction of houses — a contract of US$ 57 million to develop 3D printing technology with the objective of building roads, launch pads and houses in the moon surface.

More recently, a 3D Hubs 2021 3D Printing Trends Report predicted that the 3D printing market will more than double its current size over the next five years, reaching an estimated value of $37.2 billion by 2026.

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Image 09: Predictions for the 3DP market | Source: McKinsey Global Institute

It is therefore seen that 3D printing has great relevance in the current context of Industry 4.0 and 3D printing markets are expected to grow rapidly. A growth within the scope of the Brazilian complex of Engineering, Architecture, Construction and Works Management, according to previous forecasts, could represent a series of gains in the construction of buildings, of new spaces and of infrastructures in cities as well.

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6. 3D PRINTING TECHNIQUES Many Additive Manufacturing techniques have been developed to produce 3D structures with desired shapes and properties. Below is a classification according to the American Society for Testing and Materials (ASTM F42):

:: Material Jetting: parts are printed in layers by depositing material that is cured using ultraviolet (UV) light. :: Binder Jetting: Thin layers of powdered material are deposited sequentially and are bonded by means of a liquid binding agent. After printing, the pieces, usually made of metal or ceramics, are subjected to post-processing (firing) to achieve the necessary resistance. :: Material Extrusion: printable material is extruded through a nozzle that travels on rails. This material is deposited in layers to form the final object. :: Powder Bed Fusion: powder-based selective materials are melted and fused using a laser or electron beam. :: Sheet Lamination: the object is made up of molding “sheets” that, depending on their material, are glued together using methods such as adhesive bonding, ultrasonic welding or brazing. :: Direct Energy Deposition: process usually associated with repairing or adding new parts to objects that already exist. In this process, a metal or powder-based material is deposited through a nozzle onto an existing object surface, associated with the application of heating sources such as laser or electron beam. :: Vat Photopolymerization: process based on the use of a liquid-based resin (photopolymeric resin) which is hardened using a laser.

PROCESSES :: Three-dimensional printing techniques :: Printing process :: Types of printer :: Printing materials and required attributes :: Most adopted methodologies in civil construction 22

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PROCESS

DESCRIPTION

RELATED TECHNOLOGIES

DESCRIPTION

RELATED TECHNOLOGIES

BINDER JETTING

MATERIAL EXTRUSION Material is deposited selectively through a nozzle

Fused Filament Fabrication (FFF), also known as Fused Deposition Modeling (FDM)

A liquid binding agent selectively binds regions of a powder bed

DIRECT ENERGY DEPOSITION

VAT POLYMERIZATION A photopolymeric liquid in a vat is selectively cured through light-activated polymerization

Estereolitografia (SLA), Direct Light Processing (DLP)

Binder Jetting (BJ)

Concentrated thermal energy is used to melt materials by melting them as they are deposited

Laser Engneering, Net Shaping (LENS), Laser Based Metal Deposition (LBMD)

Sheets of material are joined together to form a part

Ultrasonic Additive Manufacturing (UAM), Laminated Object Manufacturing (LOM)

SHEET LAMINATION

POWDER BED FUSION

Thermal energy selectively melts regions of a powder bed

Selective Laser Sintering (SLS), Direct Metal Laser Sintering (DMLS), Selective Laser Melting (SLM), Electron Beam Melting (EBM)

Image 10: Tables of three-dimensional printing techniques | Adapted from: “The 3D-Printing Handbook”

MATERIAL JETTING

Drops of material are selectively deposited and cured onto a build plate

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PROCESS

Material Jetting (MJ), Drop on Demand (DOD)

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ADDITIVE MANUFACTURING PROCESSES IN THE CONSTRUCTION INDUSTRY

Binder Jetting

Extrusion

VAT - Photopolymerization

Contour Crafting

Fused Deposit Modeling

D-Shape

Concrete Printing

Freeze-form Extrusion Fabrication

Three-Dimensional Printing

3D Foam Printing

Cellular Fabrication

Stereolithography

Sheet Lamination

Material Jetting

Multi-Jet Modeling PolyJet

Powder Bed Fusion

Laminated Object Manufacturing

Direct Energy Depsition

Selective Laser Sintering

Laser Metal Deposition

Selective Laser Melting

Electron Beam Melting

Image 11: Additive Manufacturing Processes in the Construction Industry | Adaptation of KOSTETSKYI, 2021

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7. PRINTING PROCESS

and can be exported to most CAD software packages, such as Autodesk Fusion 360.

4. With the .stl file, it is sent to the computer installed on the machine and its configuration.

5. The operation of the presses is therefore controlled by a computer, in a process known as Computer Numeric Control (CNC), which was already widely used in other automated manufacturing methods.

The 3D Printing application process follows the same application principles, even at different scales and the use of different materials. The printing process on concrete and cementitious compounds, materials most associated with construction with Additive Manufacturing at the AEC complex, for example, is similar to that used by printers that use polymers to print small prototypes.

Operating system of conventional 3D printers: 1. The 3D printer hardware interprets the “G-code” generated by the slicer and proceeds to generate layers that create the object.

2. Printing takes place by pumping the print material stored in a reservoir through an extrusion nozzle. This extrusion nozzle is coupled to shafts moving in XYZ directions and is controlled via a computer.

3. With the printed object, in some cases, cleaning and post-processing are also necessary.

Before printing: 1. The 3D model is made in CAD three-dimensional modeling software. At this stage, the possibility of using BIM software also plays an important role, which can optimize a series of aspects regarding the construction of the object.

2. The model is layered by another piece of software, called “slicer”. The “slicer” will determine the thickness and number of layers.

3. With the sliced file, it is necessary to generate a file with “G-code”: this is the code that will give printing instructions to the 3D printer. The final file must be in .stl (stereolithography, similar to the first printing process created) or .amf format (additive manufacturing format)

PRINTING PROCESSES 3D PRINTING

DESIGN AND MODELING IN CAD/BIM The 3D model is produced using CAD or BIM software

SLICER + G-CODE

The model is transformed into layers by the “slicer” software.

G-CODE READING AND PRINTING

FINAL 3D OBJECT

The file with the G-Code is sent to the computer installed in the machine and its configuration, and the printing process takes place

Eventually, in some cases, cleaning and post-processing are required.

Image 12: 3D Printing Process | Adapted from My3DConcepts.com

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8. PRINTER TYPES Among the models of 3D printers currently used in companies and organizations that have been experimenting with 3D printing in the field of Engineering, Architecture, Construction and Works Management (AEC) complex, models based on two movement systems have stood out: 1. gantry system and 2. robotic arm system.

The gantry model epresents, shortly, a giant 3D printer. The concrete extrusion nozzle performs translation movements defined by the X, Y and Z axes in Cartesian coordinates. This type of printer has some limitations, such as transport, installation and size, but it has also proven to be the most economical model.

Advantages: In the gantry printer system, the biggest advantage is the extended printing range. Even without the need to move the printer, it is possible for an entire house to be printed continuously. According to Formiga (2021), using a gantry printer, a complete two-story building can be printed without the printer being moved. Furthermore, it is noted that this type of printer has been more extensively used in the Architecture and Civil Engineering complex.

Disadvantages: for a component to be produced on a large scale, it is necessary for the gantry system to be larger than the component being built, which can generate a series of transport and installation difficulties. In addition, for orthogonal deposition a good control system is needed to ensure the generation of smooth trajectories when the robot approaches singular configurations (ROMDHANE, 2020).

Cylindrical Robotic Arm Model - Printers with one or more robotic arms require less space than gantry systems and can be assembled on a transportable platform, making it easy to assemble on construction sites. However, they have a print space limitation, compared to gantry cranes, as their range is limited by the high moments generated at the base when the robot arm reaches its maximum extension (ROMDHANE, 2020). Robotic arms make circular paths more easily, and in the case of more complex structures, more than three degrees of freedom can be employed. In addition to material extrusion, robotic arms can perform auxiliary tasks related to construction, such as painting, finishing activities and assemblies (LABONNOTE, 2016).

Advantages: In printers with robot arm principles, the extruder head is generally more flexible for printing. It is also possible to print components with greater precision and the robotic arm can help with other construction tasks. When the robotic arm is mounted on a mobile structure, the scale of the print can be increased considerably, without the need for a large 3D printer.

Disadvantages: Robotic arms usually do not reach more than three meters, limiting the size of printed objects. Printing an entire house with this technology might not be possible due to this limitation. In this case, it would be necessary to print out sections of the building and then assemble or move the robotic arm around the building to construct the different parts of the building.

Image 14: 3D printer with robotic arm system | Source: APIS COR Image 13: 3D printer with gantry system | EL SAYEGH, 2020

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9. PRINTING MATERIALS AND REQUIRED ATTRIBUTES Unlike conventional subtractive manufacturing processes, 3D printing performs additive means of production. For this reason, 3D printers are able to work with a wide variety of different types of materials, in different states: powder, filament, pellets, granules, resin, etc.

A great advantage pointed out in the use of AM is that the vast majority of recyclable materials available on the market, such as glass, plastic, thermoplastic polymers (ABS), metals, ceramics, and other materials can be used in the printing process (BEYHAN, 2018).

That remains to be seen with the analysis of enterprises and experiments with Additive Manufacturing at the construction site, that the material most used in the development of research and application of the technique in the field of AEC has been concrete, mortars and cementitious compounds, already historically associated with the production of prefabricated components.

The necessary properties in the composition of the mixture of printing material aiming at the success of three-dimensional printing are, according to ROMDHANE, 2020: 1. Fluidity: ability of the material to move in the idealized way through the print nozzle.

2. Extrusion capability: output capacity of the extrusion nozzle mix with the idealized characteristics of width and thickness. Refers to the way the material will be pumped and printed.

Image 15 - Material performance affecting 3D printing on concrete | Adapted from ELFATAH, 2019

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3. Building capacity: ability of the material to retain its shape and maintain its characteristics for printing. It is necessary that the layers develop enough bond between them.

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4. Resistance: the printed mix must also have some adequate compressive strength.

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5. Open time: as, in three-dimensional printing, the work is with fresh material, based on the flow of the material, the open time refers to the interval that the material will remain in the fresh state and, therefore, the time necessary to start the next layer. The material mix needs to allow enough time for the material to print. According to Elfatah (2019), the behavior of the material in a fresh state is currently a focus point in concrete printing research.

50 40 30 20 10

4

7

2

0 ROCK DUST

PLASTIC

CLAY

1 SALT

CEMENT/ CONCRETE

1

2

4

SAND

POLIESTIRENO

SOIL

Image 16 - Chart with the list of materials most used in works printed by 3DP. Source: ALVARADO, 2021

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Printer path optimization Printer limitations 3D Model generation Model slicing .STL file

PREPRINTING

Fluidity Extrusion Capacity Construction Capacity Resistance “Open time”

Print Height and Filament Nozzle dimensions MATERIAL PERFORMANCE

PRINTING PROCESS

Extrusion rate Print speed Print path

Image 17 - Parameters that affect 3D printing | Adapted from ELFATAH, 2018

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3D PRINTING INTRODUCED TO THE BRAZILIAN COMPLEX OF ENGINEERING, ARCHITECTURE, CONSTRUCTION (AEC)

10. MOST ADOPTED METHODOLOGIES IN CIVIL CONSTRUCTION Currently, there are 3D printing methodologies that stand out in the current context of embryonic application of technology in AEC: Contour Crafting, D-Shape and Concrete Printing (Free Form Construction) Contour Crafting (Robotic arm extruder) - It is a multi-layer extrusion (LOM) method, it is one of the oldest 3D printing methodologies and also, currently, the most widespread option for 3D printers in the production of full-scale buildings and structures. It is a method created by Professor Dr. Behrokh Khoshnevis of South California University (Koshnevis, 1998). In 2012, he was responsible for the production of a giant 3D printer on the construction site structured from an overhead crane. The technology was specifically designed for on-site construction automation. The printer is mounted on a gantry frame and can be quickly installed or removed.

It is one of the oldest projects under development and is configured as a mixed method: there is an extrusive process in the construction of the external surfaces of the object, the “contour” that gives the technique its name, and also a injection process, which fills and, thus, builds the core of the object. The contours have a modeling function, that is, they function as molds, but with a definitive character. The material to be deposited for filling, however, must have specific characteristics, as it is responsible for supporting the structure.

The printer works under the principle that gave rise to the methodology of WinSun, the largest company currently in the field of application of 3DP in Civil Construction. The extrusion mouth has several holes, which can extrude different materials. The holes at the ends are responsible for the outline of the object and the inner holes for filling. End holes can extrude plastic into the contours, while interior holes can extrude concrete into the object’s core.

APPLICATION IN AEC

The holes at the ends have a spatula at the top and another at the side, with the function of flattening the material throughout the extrusion process, leaving it smooth. Layers therefore acquire a different appearance compared to other technologies. The surface quality with the presence of spatulas is remarkable and allows it to be painted without the need for extra treatment (LOPES, 2016). The side spatulas can also be tilted to create non-orthogonal surfaces.

The print head is integrated into a robotic arm, installed on a gantry crane system that moves along two parallel bars, on site. The building is printed between these two bars.

Research and experimental tests have been carried out with funding from the US Department of Defense, and for this reason there is little information about, for example, what materials can be printed. It is known, however, that the contour materials most used in the tests are a cementitious mortar and that the filling material is similar to concrete.

:: Most adopted methodologies in civil construction :: Opportunities in the application of 3DP in the AEC complex :: Disadvantages and challenges to be overcome in the use of 3DP in AEC :: Experiences and case studies :: Possibilities of the application of 3DP in the AEC complex in Brazil 36

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The robotic arms installed in a gantry crane system can perform other tasks on site in an automated way: :: Reinforcement of the structure with metal or reinforced plastic injected directly through the extrusion mouth :: Tiling of walls and floors :: Installations of hydraulic and electrical networks: :: Painting through a spray mouth or injection Advantage: smoothness of the surface created, in contrast to the layered surface produced by the Concrete Printing method, which is also based on extrusion.

Disadvantage: The printed object is not the final object, that is, the technique only creates a mold that must be filled every 125mm in height with a cementitious material, which causes poor adhesion strength and longer production time (BUSWELL, 2011).

Image 19a- 3D Printer Extrusion Nozzle | Source: University of Southern California-Contour Crafting

Images 19b and 19c: A concrete wall -and lunar structure extruded using Contour Crafting | Source: https://www.architectmagazine.com/technology/products/3d-printed-buildings-are-coming-soon-to-a-planet-near-you_o= | Access in December 2022

Image 18 - 3D CC Printer Scheme | Source: University of Southern California-Contour Crafting

Image 20: Scheme of walls built by CC and placement of passages for the necessary installations | Source: M. Khorramshahi, 2017

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Printing with layers of sand bonded together (D-Shape printer) In this laser stereolithography (SLA) method, powder is deposited in layers that are hardened using a binder. Once the printed object is complete, it needs to be removed from the bed of loose powder (BUSWELL, 2011). The non-solidified material works as a support for the construction of the rest of the structure and can be removed at the end of the process and reused.

The additive process is similar to Binder Jetting (BJ), that is, the material used is a powder that is solidified by an agglomerating agent during the printing process.

The printer is made up of a movable quadrangular frame attached to four columns, whose height varies between 3 and 18 meters. In the square frame, two parallel bars fit, which support the print head with multiple mouths.

Advantages: High strengths provided are the biggest advantage of employing this technique is the fact that the unhardened sand acts as a temporary support for the layers above. For this reason, shapes that cannot be made by extruding a single material layer can be created using this technique.

Disadvantages: the need for unhardened sand often demands a controlled environment, as the use of sand calls for a relatively regulated climate. Rain and wind, for example, can make the printing process impossible. In addition, according to BUSWELL (2011), the technique requires the massive placement of material, continuous compression of the sand and the removal of unused material, which can be laborious tasks in an automated production situation.

The base raw material is in solid form, usually sand or gravel with the addition of a binder. The impression material is also composed by the addition of magnesium oxide (MgO), which contributes to increase the tensile strength of the structure, avoiding the need for iron reinforcement.

The printer has a D-Shape printing area of 6x6m and is intended for buildings with 1 to 2 floors.

The printer is lighter than crane model printers and can therefore be easily transported. It can be assembled and disassembled in just a few hours by two people. It enables the printing of concave and convex surfaces and also the insertion of electrical and hydraulic installations.

The technique has great potential for building more naturalistic and organic architectures. In the field of archeology and restoration, it is possible that the technique is used to build missing elements, such as columns, for example, in addition to reproducing existing buildings in scale (LOPES, 2016).

Image 21 - D-Shape Printer | Source: https://newatlas.com/d-shape-3d-printer/21594/ | Access in December / 2022

From the formal freedom made possible by D-Shape, Enrico Dini proposed the concept of Archinature, engaging in some projects such as the development of replicas of coral reefs and seabed, capable of collaborating in the restoration of part of these marine structures.

Construction steps: 1. Printing takes place over one uninterrupted session of the object. Each layer of powder is deposited, along with magnesium oxide, onto the base.

2. The powder layer is compacted using a set of small rollers.

3. The print head designs the binder according to the computationally defined transverse configuration for each layer.

4. The print head rotates perpendicularly and repeats the procedure, since, due to the spacing between the mouths, there may be gaps to be filled.

5. This process is repeated four times until each layer is printed. Printing occurs as a result of the chemical reaction that occurs through contact between materials, which leads to hardening. The layers become solid after 24h.

6. The process repeats, layer by layer, until the object is completed.

Image 22 - Enrico Dini, creator of D-Shape | Source: https://3dprint. com/27229/d-shape-3d-printed-military/ | Access in December / 2022

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Image 26 - Print Nozzles | Source: D-Shape

Image 23 - Powder Bed Based D-Shape Printer | Source: https://www.sculpteo.com/en/3d-learning-hub/applications-of-3d-printing/construction-and-architecture/| Access in December / 2022

Image 24 -Object production processes by 3DP | Source: TIBAUT, 2014

Image 27 - D-Shape Printer Scheme | Source: https://top3dshop.com/blog/3d-printing-in-construction

Image 25 - Printed bridge in Madrid | Source: https://constructapp.io/pt/impressao-3d-conheca-a-primeira-ponte-do-mundo-proçada-com-a-tecnologia/ | Access in December / 2022

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Concrete Printing (3DCP): Funded by the Engineering and Physical Sciences Research Council (EPSRC) and Innovative Manufacturing CRC (IMCRC), researchers from the Concrete Printing Additive Manufacturing Research Group at Loughborough University have been developing 3D printing technology for the construction industry for nearly a decade.

Concrete Printing is also a methodology based on the extrusion of cement mortar and is configured as a technique similar to Contour Crafting, but was developed with a focus on three-dimensional freedom. It is based on using high-performance concrete to form complex structural components – such as curved cladding panels and organic shapes – that cannot be manufactured by conventional processes.

This freedom is provided by the application of two building materials (one of the building materials is deposited and a second is used to create a scaffold-like structure, which will be broken after the construction process is completed).

This technique allows high resolution of material deposition, providing greater control of internal and external geometries. (BUSWELL, 2011).

The biggest difference between Contour Crafting and Concrete Printing is the way the nozzles are configured. The concrete 3DCP print nozzle is designed to have the ability to vary its resolution to allow the deposition of materials with greater freedom and fine detail within the same process (Buswell et al., 2007). The printing machine is designed for manufacturing panels and large building components rather than entire buildings.

Opportunities to redesign complex assemblies into integrated panels is an area the research team focused on; in addition to additional value-added functions that include the optimization of structural, acoustic, thermal and ventilation properties.

Image 29 - 3D Printed Pannel | Source: Loughborough University

Advantages: the printed object is the final object, that is, a mold is not produced that must be filled in as in Contour Crafting.

Disadvantages: the use of Concrete Printing may have limitations on the dimensions of the printed object.

Image 28 - Print Nozzle | Source: http://www.rationaloptimist.com/blog/print-your-own-organs | Access in December / 2022

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Image 30 - 3D Printed Bench | Source: Loughborough University

Image 31 - Internal structure including spaces for installations and structural reinforcement | Source: Loughborough University

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Image 32 - 3D Model, Sliced Model and 3D Printed Object | Adapted from LEE, 2010

Image 33 - Print Structure | Adapted from LEE, 2010

Image 34 - 3D printer in 3DPC | Adapted from LEE, 2010

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CONCRETE PRINTING

CONTOUR CRAFTING

D-SHAPE

Process

Extrusion

Extrusion

3D Printing in powder bed

Use of molds

No

Yes

No

Print Material

Concrete

Mixture of mortar for mold and cementitious material for construction

Granular material, sand and stone fragments

Structural reinforcement

Yes

Yes

No

Advantages

- High resistance - - Minimal printing, deposition and reinforcement process

Smooth surface by trowel

High resistance

Disadvantages

Printing limited by printer dimensions

Extra process (mold) Complexity in linking layers

-

- Slow process - - Rough surfacePrint dimension limited by the print frame - - Placement of massive material - - Removal of unused material

Image 35 - Summary table of information on the most adopted 3DP methodologies in the AEC complex | Adapted from LEE, 2010

CONCRETE PRINTING High resolution

Based on extrusion Print in layers

CONTOUR CRAFTING

Single material

D-SHAPE

Image 36 - Venn Diagram with the most adopted 3DP methodologies in the AEC complex | Adapted from LEE, 2010

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11. OPPORTUNITIES IN THE APPLICATION OF 3DP IN THE AEC COMPLEX As previously exposed, 3DP has been applied in a number of industry sectors showing a range of advantageous attributes. In the AEC complex, the opportunities that this technology offers are also vast, the ones that stand out the most are: Faster and more accurate construction- most cited in the literature as the main advantage (ROMDHANE, 2020). The fact that it is a technology associated with file to factory (FF) allows the printed object to be reproduced exactly as designed through computation, with less dependence on human manual work, which allows for greater precision in production.

Freedom to propose complex designs: 3DP is also related to the ease of building complex shapes that would not be possible with conventional construction. It means, in many cases, the removal of limits that architects normally have to respect, for example, one-size-fits-all related to the mass production of a single standard product. According to Kolarevic (2003) “mass customization technologies and methods allow the creation and production of unique or similar parts of buildings and constructive components, differentiated through digitally controlled variation” (p.53).

Furthermore, with 3D printing, the influence of shape on production price is considerably reduced; even printing a sphere instead of a parallelepiped will not affect the price of the object as long as the amount of material used remains the same (MARIJINISSEN, 2016).

Cost reduction: even though it is difficult to stipulate the exact price of 3D printed works in view of the experimental nature of the technique in AEC, the application of Additive Manufacturing in construction has been pointing to the reduction of production costs in view of the relatively low cost of building construction and structures, surpassing the initial investments in machinery, since it only requires the amount of material of the final object without much loss.

3D printing can also indicate improved productivity, which indirectly results in cost savings.

Michelle Starr (2015) argues that technology allows “a decrease in production time between 50% and 70% and labor costs by 50% to 80%”. Cost and time reduction is also supported

by Busswell (2006) and can be advantageous for both contractors and owners.

Minimization of manual labor in construction: Additive Manufacturing at the construction site can considerably reduce the need for human resources in operations, promoting a reduction in labor costs and conditions of greater comfort and safety at work, in addition to the possibility of reducing accidents at work and waste.

Sustainability - One of the advantages of 3DP is the possibility of using natural construction materials, as well as materials from recycled construction waste; in addition to reducing the need for formwork and, therefore, the amount of wood, two sustainable aspects in the production of architectural objects. WinSun, for example, a Chinese company with Contour Craft printer technology, “uses a printing material created from recycled construction waste, and tailings” (Starr, 2015). Today, concrete is used extensively in conventional construction methods in Brazil. The sustainability of traditional concrete, however, is questionable, since considerable amounts of CO2 are emitted with its production. Concrete, however, is 90% , 50

recyclable.

Another advantage, linked to the sustainability of 3D printed concrete is the possibility of reducing construction waste between 30% and 60% compared to conventional construction methods (MARIJINISSEN, 2016).

Material optimization - 3DP allows you to maximize structural performance, being able to place the material only where necessary, with great freedom of shapes (ELFATAH, 2019).

With traditional subtractive manufacturing of die casting or CNC material extraction, the principle of topology optimization was difficult to apply in manufacturing. However, with 3D printing, it is possible to deposit material where it is needed: optimization removes material from places in the structure where there is no great intensity of applied forces and leaves only material where structurally it is needed. Structural data can also be linked to print speed (MARIJINISSEN, 2016).

STRUCTURAL DATA

STRUCTURAL OPTIMIZATION

Image 37 - Structural optimization scheme | Source: MARIJINISSEN, 2016

Optimization of the project and construction management process: one of the great difficulties in the construction of buildings is the coordination of all the processes involved. The use of 3DP associated with projects and works makes it possible, within the scope of management, to reduce risks, mitigating critical paths. Technology also offers greater reliability to the project, since several packages of work that depended on people can now be done by computerized machinery. In addition, it assists in cost control, due to its greater predictability, avoiding the extrapolation of the budget foreseen for the execution of the work.

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12. DISADVANTAGES AND CHALLENGES TO BE OVERCOME IN THE USE OF 3DP IN THE AEC COMPLEX Experimental experiences in the application of additive manufacturing in the construction of buildings and construction components have also indicated a series of challenges to be overcome so that this technology is widely disseminated in the AEC complex or used in addition to conventional construction techniques: High cost of machinery: in the case of objects on an architectural scale, the high cost of machinery has been shown to be one of the main challenges to be overcome in relation to this technology. 3D printers for concrete construction can be large and require a high initial investment, in addition to the fact that their transport to the site is also expensive (Kostetskyi, 2021).

Small flexibility with errors - with the rapid hardening of the deposited material layers, reworks may be necessary if there is any error in production. It is impossible to absorb design changes during the construction process. According to Formiga (2021): More studies are needed to optimize the algorithm to calculate the toolpaths to generate the CNC code for printing. Sensor data must be incorporated for process monitoring and real-time adjustments.

Offer of jobs: 3D printing technology can create product designs and prototypes in a matter of hours as it only requires a single step, eliminating steps demanded in subtractive manufacturing. As a result, it does not require a lot of labor, which can indirectly lead to a decrease in jobs in this scenario. For countries that depend on a lot of low-skill jobs, the decline in manufacturing jobs could affect the economy to some extent (ELFATAH, 2019).

Limitations regarding the dimensions of the buildings: it is observed that in 3D printing, there are restrictions on the dimensions of buildings, since built structures are conditioned to the respective dimensions of industrial 3D printers. Furthermore, the fact that three-dimensional printing is based on the successive accumulation of layers of material also limits the size of buildings due to the progressive deformation that the layers undergo sequentially.

Limitations regarding the organization and size of construction sites: the use of this technique has demanded special conditions of organization, topography and size for construction sites, since they often depend on special auxiliary machines in their process. According to Formiga (2019), “Transport, installation, configuration, as well as access levels and the ability to adapt equipment on site are factors that can make it difficult to deploy a 3D printer”.

Absence of regulation and laws: considering that this is still a relatively recent technology, collective efforts by governments related to the creation of codes and legislation that regulate the use of this technology are still scarce. Lack of coordinated policies of proper building standards - electrical codes, plumbing, structural integrity and safety codes. Standardized requirements, benchmarks and testing procedures still need to be developed to validate the safety and sustainable use of concrete printing as a construction method.

Uncertain lifecycle: the lifecycle performance of printed buildings and building components is still unclear, nor is the maintenance required for them. More research needs to be done regarding structures and mechanical stability, as well as material life and toxic effect of materials, etc.

Design compatibility: Traditional plans are not always compatible for use with a 3D printer.

The design process needs to be treated differently.

The reproduction of a CAD file cannot be done independently of the process planning. The physical system can limit the geometry and precision of the printed objects, making it necessary to plan the process according to the type of printer available - gantry, robotic arm, among others (SALET, 2016);

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13. EXPERIENCES, CASE STUDIES AND WORKS UNDERTAKEN Notably in recent years, a series of AM applications have been developed by universities, architecture offices, companies focused on Civil Construction and startups with the intention of testing 3D Printing in the construction of building components and entire buildings, which will be analyzed in the sequence highlighting its most promising attributes in the insertion of this technology in the sector. It is important to point out that most of the projects discussed here are under development and are experimental, with the function of proving ideas and hypotheses.

It is also important to point out that, in the case of “printed” buildings, the so called building printing, buildings are never fully developed using the 3D Printing technique: they are buildings that have walls and structural elements produced in this way, but other elements building materials such as doors, windows and complementary installations produced by other industrial processes. Coatings, slabs, roofs, for example, have to be produced in a complementary way, by conventional means.

In addition, it is important to point out that most of the works were carried out in a laboratory context, that is, non-commercial. There are few experiences regarding the actual use of spaces and maintenance needs or the problems that arise when experiencing the space. Just a few years ago, in 2018, the BBC reported on the first move to a 3D printer-built house in Nantes, France.

14. 1. BUILDING PRINTING 14.1.1. WINSUN 3D Win Sun is a Shanghai-based company originally established as a building materials supplier. Over the last decade, it has been responsible for a series of buildings with 3D Printing and is today the largest company focused on the application of the technique in the AEC complex. It has patented a construction system called the WinSun 3D printed building system, which uses technology developed by Contour Crafting. There is an internal space of the walls structured in the form of a truss, designed with the function of obtaining greater resistance and allowing freedom for the introduction of pipes and can also function as a thermal insulator. These spaces can also contemplate structural reinforcement through iron reinforcements. Openings for doors and windows are considered during manufacturing.

The building construction system by 3D Printing on WinSun 3D is operated entirely within the factory environment, which, as a controlled environment, allows freedom of customization.

The system is based on a printer formed by a robotic arm 6.6 m long, coupled to a gantry 10 m wide, which in turn is installed on two transverse bars through which the robotic arm can move along 40m long.

The method makes it possible to print large parts, which are later transported and assembled in loco, using a crane.

According to WinSun, the material used in the press is composed of cement, sand, glass fibers, and its own additive comes from up to 50% of demolition waste, a sustainable solution.

Construction deadlines presented by WinSun have been reported globally: the construction of a two-story, 1,100 m² building took one day of printing, two days of assembly, with internal structures of bars erected in advance, requiring only three workers. In 2013, the construction of a plot of 10 houses in 2013 by Winsun was reported.

Image 38 - Map with distribution of 3D printed works around the world | Source: ALVARADO, 2021

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Image 39 - Outline - Advantages of Winsun’s 3D Printing Process | Source: Winsun | Access in December/2022

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Image 41 - Gantry 3D Printer | Source: https://siliconangle. com/2015/01/20/china-super-sizes-3d-printing-with-worlds-first-printed-apartment-building/ | Access in December/2022

Image 40 - 3D printing process | Source: Winsun | Access in December/2022

In 2015, they were responsible for the additive manufacturing construction of the first multi-floor 3D printed building, reaching 10m in height in Shanghai and, in 2016, for the first 3D-printed office building in Dubai.

Construction steps: 1- Conception of the project to be printed in 3D; 2. Printing of the elements that will be part of the assembly for the construction; 3- Identification of parts for transport to the construction site; 4- Assembly of the foundation of the construction, in a conventional way (piles, shoes or raft); 5- Transportation of the walls to the work site; 6- Assembling the walls, previously loose parts of a puzzle, will now be fitted using cranes or hoists; 7- Interior decoration with openings and other decorative elements; 8- Finishing and application of coatings and paints;

Image 42 - 3D Printed Lattice Walls | Source: http://infinitedictionary.com/blog/2016/06/08/suburban-mansions-to-life-on-mars-3d-printed-buildings/ | Access in December/2022

Image 43 - Assembly of panels in situ | Source: ArchDaily | Access in December /2022

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14.1.2. APIS COR

Image 44 - Assembly of the building in situ | Source: hhttps://popupcity. net/insights/worlds-first-3d-apartment-complex-printed-in-china/ | Access in December/2022

Apis Cor is a company founded in Russia that currently operates in the United States. Its printer consists of a robotic arm attached to a crane-shaped structure that rests on a rotating base.

Apis Cor’s differential is that the 3D printer is mobile and compact, and can be easily transported and its assembly is also advantageous, since it takes, according to the company, less than 1 hour.

The principle of the printing process is based on rotating the printer around its own axis, printing from the inside out. What is new is that the house is printed all at once, that is, without the need to print parts and components of the building for later assembly.

The impression material is based on concrete reinforced with lattice glass fibers. Apis Cor’s research regarding the production of the material stands out due to the additional needs that an outdoor environment demands in relation to the controlled environment of the factory: as the construction is printed in situ, the material developed by Apis Cor has the necessary attributes for construction both in very low winter temperatures, and can also be built in the hottest summer periods.

Image 48 - 3D printer with fixed robotic arm | Source: APISCOR Image 45 and Image 46 - Buildings printed in 3D by Winsun | Source: http://infinitedictionary.com/blog/2016/06/08/suburban-mansions-to-life-on-mars-3d-printed-buildings/ | Access in December/2022

Image 47 - Offices in Dubai printed in 3D in China by Winsun | Source: https:// www.winsun3dbuilders.com/project/3d-printed-office-in-dubai/ | Access in December/2022

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Image 49 - Conventional Construction Process Diagram Versus 3D Printing | Source: APISCOR

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3D PRINTING INTRODUCED TO THE BRAZILIAN COMPLEX OF ENGINEERING, ARCHITECTURE, CONSTRUCTION (AEC)

14.1.3. 3D CANAL HOUSE, NETHERLANDS The 3D Print Canal House is a research project developed in Amsterdam and carried out by the architecture office DUS Architects, with the support of the company Ultimaker, which originally produced objects with 3D printers for other industrial sectors. It is a house with 13 rooms created using a special 3D printer called “KamerMaker”, installed inside a shipping container near the Amsterdam Canal. The house was produced from the assembly of a series of elements printed by 3D Printing technology. Each element that makes up the house presents a research update in form, structure and material and represents a construction in the modular logic. Production in modules facilitates transport, assembly and subsequent dismantling.

The printer creates wall components from a bioplastic blend of plastic fibers and 80% vegetable oil. The wall components are then interconnected and filled with bioconcrete to provide structural strength. It is important to note that all materials used in the project are recyclable.

Image 50 - 3D printed building by APISCOR | Source: APISCOR

The Kamermaker printer can print parts of the building that do not exceed 1.8 x 1.8 x 3m and uses an extrusive printing process (similar to FDM), with the particularity of only printing thermoplastic materials or mixtures based on them. This can be seen as a difficulty, since these are materials that are rarely used by the construction industry, mainly at a structural level, which implies the continuous carrying out of various tests and trials to assess their characteristics. In addition, the thermal properties of materials gain special focus in this process, since a low melting temperature has a strong influence at a mechanical level and can cause problems if there is a strong incidence of solar radiation and fires.

Image 51 - Printer data and operation | Source: APISCOR Image 52 - Diagram of modular components | Source: https://www.dezeen.com/2013/03/09/ amsterdam-architects-plan-3d-printed-house/ Accessed in December /2022

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14.1. 4. WASP World’s Advanced Saving Project (WASP) is an Italian company dedicated to the construction of buildings focused on the principles of ecology and sustainability. In many of its projects, the objective is the construction of buildings based on the local extraction of the materials used.

WASP developed the Big Delta, one of the largest 3D printers developed to date at the AEC complex. On an extended scale, the operation is similar to the filament extrusion process (FDM).

IG Delta can print cement-based composites, like most companies dedicated to 3D printing, but it is particularly interesting due to the fact that it can use clay and other natural materials in association with lime-based mixtures, wood waste and polystyrene for printing, a great advantage from a sustainability point of view. Using local materials for the print can, however, also be a challenge, as the hardening period of each layer needed to ensure the strength to support the next one can be longer.

Image 53 - Maritime Container that houses the 3D Printer || Source: https://www.dezeen.com/2013/03/09/amsterdam-architects-plan-3d-printed-house// Accessed in December /2022 Image 54 -External View of the Project | Source: https://www.ignant. com/2016/09/16/the-worlds-first-3d-printed-canal-house/ Accessed in December /2022

Image 55 - KameMaker - portable project printer | Source:https://www.dezeen.com/2013/03/09/amsterdam-architects-plan-3d-printed-house// Accessed in December /2022

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Another disadvantage is that, due to the large size of the print, transport and assembly can be complex and increase initial construction costs.

In association with Mario Cucinella Architects, WASP built TECLA, an innovative eco-habitat, in the Massa Lombarda region. The project represents an unprecedented perspective for buildings and new settlements, where the value of local raw materials is amplified through digital design and manufacturing technologies. TECLA is the company’s second housing project. In 2018, in the first experience in the area, WASP had teamed up with the Italian startup RiceHouse to build GAIA, a fully 3D printed house made from organic waste from rice production.

Image 56 - Aerial view of GAIA, with the gantry cranes of the 3D printers attached| | Source: https://www.designboom.com/architecture/tecla-3d-printed-habitat-sustainable-living-mario-cucinella-wasp-10-22-2019/ Accessed in December /2022

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14.1.5. IAAC - MINIBUILDERS The IAAC - Institute for Advanced Architecture of Catalonia, based in Barcelona, is an international research center for innovative architectural solutions, with ventures in the field of 3D Printing.

The IAAC addressed, based on the Minibuilders project, the problem related to the increase in the scale of construction of buildings with 3DP, naturally limited by the size of the printing machine: printers based on a circular robotic arm have a limitation on the size of the printing.

The IAAC has developed an alternative approach to 3D Printing in particular, using a system of small mobile robots, which operate together in a complementary way, but perform specific functions. Printing is done in situ.

This idea applies the concept of Industrial Assembly Line in the field of Additive Manufacturing: in this case, the product is produced through a sequence of tasks, performed by different workers, but in a complementary way. In this way, Minibuilders manages to increase the scale of the construction, without the need for a large printer.

When the robotic arm is mounted on a mobile structure, the scale of the print can be increased considerably, without the need for a large 3D printer. When using a group of mobile robots, the scale and speed of printing can be further increased. [...] The first prints the base, following a marked path. The second prints additional layers of concrete and the third uses suction cups and pressurized air to print vertically, reinforcing the previously printed structure. (FORMIGA, 2021)

Image 58 - Division of Minibuilders by tasks | Source: https://iaac.net/project/minibuilders/ Accessed in December /2022

Image 57 - GAIA printing steps | Source: https://www.designboom.com/architecture/tecla-3d-printed-habitat-sustainable-living-mario-cucinella-wasp-10-22-2019/ Accessed in December /2022

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14.2. USE OF 3DP IN THE PRODUCTION OF CONSTRUCTIVE ELEMENTS Another approach in experiments with 3D printing in the context of universities, architecture offices, companies focused on construction and startups, is related to the construction of constructive elements that will later be part of the buildings. These can be prefabricated structural elements, stacked together on site, or single printed components in a more traditional building, such as façade systems. The lowest level of technology incorporation, which can be a solution for the gradual insertion of the practice in the construction site, is to use the printer in combination with traditional prefabrication and just adjust the prefabricated elements to increase, in a certain way, way, its customization (SALET, 2016).

Image 59 - Printing nozzle of one of the Minibuilders robots | Source: https://iaac.net/project/minibuilders/ Accessed in December /2022

Image 60 - Division of Tasks of Minibuilders | Source: https://iaac.net/project/minibuilders/ Accessed in December /2022

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14.2.1. EMERGING OBJECTS – Bricks and Columns: “Cool Bricks” and “Quake Column” Emerging Objects is an Oakland-based firm engaged in applied architectural research, developing unconventional materials and designing experimental structures. The company takes a modular approach to 3D printing and its application in construction, and advocates creating small parts for later assembly and building a larger object, dispensing with the need for sizable printers. The 3D printer used by Emerging Objects applies the Binder Jetting (BJ) printing principle, and for that reason, all materials that are used are previously reduced to powder.

Two of Emerging Objects’ initiatives show how 3DP can be applied to AEC as well in the construction of building elements: Cool Brick and Quake Column.

The Cool Brick is a brick adapted for a desert climate, therefore hot and dry, and is produced with porous ceramic material, which allows passive ventilation and humidification of the building. The shape of the bricks allows them to fit together perfectly using mortar.

Image 61 - Cool Brick | Source: LOPES, 2017

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The Quake Column is a column, also made up of stackable blocks, with reinforced resistance for use in areas of seismic activity.

The design of ARUP’s metallic nodes shows how it is possible, with the use of additive manufacturing, to produce components with complex and organic shapes, which are lighter, with less need for material and greater resistance. It also illustrates how typological optimization can streamline design, creating aesthetically interesting shapes while facilitating traditional manufacturing processes.

ARUP engineers estimate that the use of metallic nodes can represent a decrease of up to 40% in the total weight of the metallic structure in relation to conventional structures, also indicating a reduction in costs and waste associated with the construction process.

14.2.3. SMARTSLAB: slab systems

Image 62 - Quake Column | Source: LOPES, 2017

14.2.2. ARUP - METALLIC KNOTS ARUP is a London-based multinational company involved in projects worldwide. Much of the structure of the projects in its portfolio involves the use of steel. Motivated by this question, ARUP started a research focused on the development of optimized components for metallic structures, mainly for complex projects, with the use of maraging steel, a material of high hardness, malleability and that can have resistance up to 4 times greater than steel. traditionally used in construction (LOPES, 2017)

Image63 - ARUP metallic knots - the first knot was built with traditional methods, while the others were produced by additive manufacturing | Source: LOPES, 2017

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Smart Slab, an Australian company, has developed a set of prefabricated elements that, when assembled, manage to reduce by 70% the weight that would be needed for a conventional concrete slab.

Smart Slab is not a fully printed concrete structure, however, in this project, the intensive use of digital fabrication with 3D printing and laser cutting enabled the construction of a unique slab, with high precision and formal complexity.

This technique combined with conventional prestressed concrete has shown that the integration of different techniques, digital and conventional, can be one of the shortest ways to introduce 3D printed concrete in works safely and in compliance with established standards. (FLORÊNCIO, 2019)

Image 64 - Diagram of the parts that make up the Smart Slab | Source: https://dbt.arch.ethz.ch/ media-feature/the-smart-slab/ https://dbt.arch.ethz.ch/media-feature/the-smart-slab/ Accessed December / 2022

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14.2.4. BRANCH TECHNOLOGY - modular wall C-FAB Branch Technology is an American startup that developed a modular wall combining conventional construction materials with a 3D printed frame based on ABS plastic reinforced with carbon fibers, proposing a light frame, with dense materials added for closing, increasing resistance and the integrity of the wall.

With the frame being produced using 3DP, it is possible to obtain formal freedom and geometry optimization. The frame is printed using a Freeform robotic arm printer. The particularity of the process is that the company has developed its own method of additive manufacturing, called Cellular Fabrication (C-fab), which does not presuppose construction through superimposed layers.

The plastic frame is printed in the factory environment, in smaller pieces that are transported and assembled later. The structure is easily transportable as one of the pieces can be carried by two men. On site, the pieces are welded together to compose the final structure of the modular wall.

Images 65, 66 and 67 - Assembly and final appearance of the Smart Slab | Source: https://dbt.arch.ethz.ch/media-feature/the-smart-slab/ | Access in December / 2022

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Image 68 - Modular wall | Source: https://www.arch2o.com/c-fab-branch-technology/ Accessed in December / 2023

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Image 69 - Diagram of the layers that make up the modular wall | Source: https://3dprint.com/85215/ branch-3d-printed-walls/ December / 2022.

Image 70 - 3D printing of the structure | Source: https://hypepotamus.com/companies/branch-technology/ | Access in December / 2022

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The table below summarizes information on the main companies and organizations that are dedicated to the application of 3D Printing in the AEC complex, considering the country of application, type of printer used and materials used:

COMPANY / ORGANIZATION

COUNTRY

PRINTER TYPE

MATERIALS

Ap is Co r

USA

Robotic arm

Concrete, cement and plaster

Batiprint 3D

France

Robotic arm

Urethane foam filled with concrete/cement

B e t A b r am

Eslovênia

Gantry

Torcrete with sand gravel filling

Branch Technology

USA

Robotic arm

ABS plastic (95%) reinforced with carbon fibers (5%)

Co b o d

Denmark

Gantry

High performance concrete mix

Contour Crafting Corporation

USA

Gantry

High-strength cement / fiberglass-reinforced concrete

Cyb Be Construction

Netherlands

Robotic arm

Concrete / Cement Mixture

Dus Architects

Netherlands

Gantry Portable

Recycled plastic filled with lightweight concrete mix

Emerging Objects

USA

Robotic arm

Clay, ceramics, sand, cement and salt

IAAC - Minibuilders

Spain

3 Mobile Robots

Concrete / Cement Mixture

I c on

USA

Gantry

Concrete / Cement Mixture

Lounghborouh University

United Kingdom

Gantry

Concrete / Cement Mixture

MIT Media Lab

USA

Robotic arm

Urethane foam filled with concrete/cement

MudBots

USA

Robotic arm

Cement, clay, polyethylene, polyurethane, geopolymer and geopolycrete

MX3D

Netherlands

Robotic arm

Mixtures of metals

SQ4D

USA

Gantry

Concrete / Cement Mixture

T o t a l K u st o m L L C

USA

Gantry

Concrete / Cement Mixture

W AS P

Italy

Gantry

Concrete / Mixtures of water, clay and natural fibers

WinSun

China

Gantry

Mixture of cement and sand, recycled construction waste

Xtree

France

Robotic arm

Concrete / Cement Mixture

Image 71 - Table with summary of data on companies that develop 3D printing applied to AEC | Elaborated by the author

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15. POSSIBILITIES IN THE APPLICATION OF 3DP IN THE AEC COMPLEX IN BRAZIL Despite the accelerated pace of experimentation with 3DP associated with the construction site in other countries, Brazil has not yet adhered to the use of 3DP, not even as a support tool for the prefabrication industry in the AEC complex. Factors such as the conservatism of the construction sector, bureaucracy, as well as the difficulty of funding research and development projects within universities and the challenges faced by automated construction systems are part of the causes of this delay. The theme is still timidly explored within the Brazilian academic context – particularly within the curricular structure of the schools of Architecture and Urbanism and Civil Engineering.

It is noted in Brazil, a slow pace of research on the themes of Digital Fabrication and 3D Printing, when compared to other countries. This perception is accentuated when verifying the absence of results in the search for patents deposited in the National Institute of Industrial Property (INPI) database and the lack of Brazilian patents in the international databases in the World Intellectual Property Organization (WIPO –PATENTSCOPE) and ORBIT Intelligence, the which indicates the embryonic stage in investment in R&D of this technology nationally in contrast to the global trend (FLORÊNCIO, 2017).

that is, for creating models, its use is linked to the use of the BIM (Building Information Modeling) concept that uses 3D models. In Brazil, the Civil Construction industry is one of the most backward from a technological point of view. Evolutions in construction techniques do not keep up with the pace of industry automation or advances achieved in informatics or nanotechnology. The execution of the building still depends heavily on manual labor, as well as on the use of conventional materials. Despite the adoption of the production of prefabricated concrete elements, works in Brazil still, to a large extent, use masonry and reinforced concrete and continue to be produced mostly by hand.

In this context of crisis, the search for new technologies that make it possible to reduce costs, increase profitability, as well as reduce waste must be increased, exploring alternatives to the conventional structure of building construction.

There are no records so far on the commercial use of 3D printing in concrete at construction sites in Brazil, however, some initiatives headed by the academic field promise to introduce the technology soon.

Image 72 - Result of research on patents at INPI (National Institute of Industrial Property)

The Civil Construction sector is, in a way, a sector with low productivity and atrophied technologies, when compared to other sectors, which have automated and digitized their manufacturing processes.

The civil construction industry [in Brazil], however, remained tied to a largely artisanal process, even though pre-fabrication elements were integrated into its composition and techniques for rationalizing management processes (QUINTELLA, 2016).

According to FARIAS (2013), Civil Construction in Brazil is still characterized by the use of traditional and craft techniques related to great waste. The use of additive manufacturing on the scale of civil construction in the country is even more limited and it is used for prototyping, 76

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15.1. INITIATIVES IN BRAZIL INVOLVING ADDITIVE MANUFACTURING In Brazil, initiatives in the area of 3D printing in large-scale concrete are still few and recent. Current research involving construction automation and digital fabrication focuses mostly on subtractive and formative manufacturing techniques (FLORÊNCIO, 2019).

Relevant research using concrete for assisted construction through digital fabrication has been developed by research groups at the University of São Paulo (USP). USP has focused on how to build open laboratories with innovation where the consumer customizes the production line, as reflected in the case of the construction of CICS Living LAB, Center for Innovation in Sustainable Construction. Still in this direction, one can highlight the DIGI-FAB/ FAU-USP laboratory, Research Group on Digital Fabrication, led by Professor Paulo Fonseca de Campos, which promoted experiments and research with the support of the tools and machinery available in the first laboratory of digital fabrication in Brazil, the FAB-LAB of the Faculty of Architecture and Urbanism FAU-USP, founded in 2012 linked to the worldwide FAB LAB network, led by the Center for Bits and Atoms, of the Massachusetts Institute of Technology (MIT).

Image 75 - Pavilion developed by DIGI-FAUUSP | Source: http://digifab.fau.usp.br/ Accessed in December 2022

Recently, HubIC stands out, the Innovation Hub for Digital Construction, a space that has dedicated efforts to construction by digital means. HubIC is the first Hub in the country focused on Hard Tech innovation and digital construction, founded from the partnership between the University of São Paulo, the Brazilian Association of Portland Cement (ABCP) and the National Union of the Cement Industry (SNIC).

Hubic represents the availability of laboratory resources from USP and ABCP for research and innovation in favor of disruptive projects and is equipped with a 1:1 scale 3D printer. HubIC involves professors from the Architecture and Urbanism School of USP (FAU-USP) and from the Polytechnic University of USP (POLI-USP), and headed by professors Rafael Pileggi (POLI-USP) and Arthur Hunold Lara and Fernando Simões (FAU-USP), it has experiments regarding workshops involving software, hands-on training and testing with construction and 3D printing in concrete and polymers. HuBIC’s proposal goes against the ideals, initiatives and questions that permeate the entrepreneurial ecosystem and the creative economy linked to the construction industry.

Images 73 e 74 - Activities developed by DIGI-FAUUSP | Source: http://digifab.fau.usp.br/ Accessed in December 2022

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Image 76 - Workshops on software developed at HubIC | Courtesy HubIC

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It is also interesting to mention the Laboratory of 3D Models and Digital Fabrication - LAMO, from the Faculty of Architecture and Urbanism of the UFRJ, another space that made efforts in the construction of structures by digital means and developed research on the construction of temporary pavilions and formal studies through of algorithms.

Image 83 - Experiences carried out at LAMO involving Digital Fabrication | Source; http://www.lamo.fau.ufrj.br/ | Access in December/2023

15.1.1 UFRN and UNP - First house built with Brazilian technology

Images 77, 78, 79, 80, 81 e 82 - Tests and prototypes developed in practical activities at HubIC | Courtesy HubIC

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The first house built using additive manufacturing technology in Brazil is in Macaíba, in the metropolitan region of Natal, in Rio Grande do Norte. In 2017, a group of engineering students from the Potiguar University and the Federal University of Rio Grande do Norte started the process of idealizing and building a house using a gantry printer and concrete as the basis of the construction material.

After 3 years, the group was able to build a 3D printer and also developed the material a cementitious composite – based on the use of machine software inspired by technology from Win Sun and Apis companies.

The stage of printing the structural walls of the 66.32 m2 house, including tests, modifications and refurbishments, lasted about 7 months. The printing took place in an open place, which 81

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made with climate changes interfering in the performance of the machine. The developed structure has a printing area of 3m in height, 7.6m in width and 12m in length.

Having an experimental character, a series of adjustments and adaptations were carried out throughout the construction. The foundations were developed in a conventional way. Students from the group later founded the startup 3D Home Construction.

According to Professor André Felipe Oliveira de Azevedo Dantas, from the civil engineering department of the Potiguar University, who guided the group of students involved in this project: We believe that the future of construction lies in hybrid projects, where 3D printing comes in as a tool to increase the productivity of construction at scale, in the case of popular housing projects, and also with precision for projects of high geometric complexity, in the case of high-end buildings.

Image 84 - Walls printed by 3DHomeConstruction. Source: InovaHouse 3D

Image 85 - Structures printed by 3DHome Construction (FLORÊNCIO, 2019)

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In addition to undertakings in the academic field, it is important to highlight two startups that challenge the limits of the construction sector and seek to develop technology in Brazil: 15.1.2. INOVAHOUSE3D Initially motivated by the news released by the constructions headed by WinSun and challenged by startup competitions, InovaHouse3D was founded in 2015 by students from different UniCEUB courses (Centro de Ensino Unificado de Brasília), merging knowledge of electrical, civil, mechanics and chemistry.

In the year following its founding, InovaHouse3D developed the first prototype of a 3D printer for concrete in Latin America and thus received investments for the development of the project through Innovation Notices from SENAI12 and FAPDF13.

Today, InovaHouse 3D presents itself as a service and consulting company, serving designers, architects, landscapers and individuals who want to explore the printing of design and decoration pieces. The startup also intends to have printing capacity for a low-cost 32m² residence.

Image 86 -Printer prototype used by InovaHouse3D | Source: Portal da Indústria

Image 87 -Prototype of printer used by InovaHouse3D | Source: Portal da Indústria

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15.1.3 URBAN 3D

16. POSSIBILITIES IN BRAZILIAN CONSTRUCTION

Urban3D is another Brazilian startup that has focused, in an approach similar to that of the French company XTreE, to develop a printing method for formwork to be subsequently filled with concrete by robots.

The company sells its technology to interested construction companies and promotes the construction of a 3D printing module. Urban 3D proposes the use of a robot that is capable of reading a 3D project. In this reading, the robot identifies the concrete walls and the spaces intended for installations. The robot then 3D prints a mold and then inserts the concrete. The walls later receive sensors that will be used for tracking in stock, transport and monitoring within the construction site.

For technology to be increasingly used in Brazil, it is important to point out the relevance of relationships within the creative ecosystem: the union between universities, startups and the private sector is essential for more research to be carried out.

Because it is a system with great feasibility of development, in terms of software and hardware, with known, simple, low-cost, and patent-free technology - as seen through the surveys presented by companies such as WinSun, ApisCor and Total Kustom, it is believed that this type of machinery could be inserted with great potential in construction sites in Brazil.

Below, there is a SWOT table that summarizes the strengths and weaknesses (internal factors) and opportunities and threats (external factors) of the application of this technology in the complex of Architecture, Engineering and Construction Management in Brazil:

SWOT TABLE Application of 3DP in the Engineering, Architecture, Construction and Works Management (AEC) INTERNAL FACTORS STRENGTHS

WEAKNESSES

- Reduction of construction time - Increased accuracy of construction - Freedom of Design and Complexity - Increased safety at work

- Lack of investment in R&D - Need for skilled labor - High initial cost - Limitations on the size of printed buildings

EXTERNAL FACTORS OPPORTUNITIES

Images 88 and 89 - Schemes of the Printer used by Urban 3D and the Production Line | Source: https://exame.com/pme/a-startup-brasileira-que-vai-fazer-predios-com-impressao-3d/ Accessed in December / 2022

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- Application of BIM and integration of construction processes - Greater insertion of Brazil in Industry 4.0 processes - Application of more sustaintable processes

THREATS - Economic crises in the sector and the possibility of reducing jobs - Reluctance of companies to adopt new technologies - Conservatism towards automated building systems

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It is unquestionable that innovations in the field of Engineering, Architecture, Construction and Construction Management demand increasingly advanced constructions and new processes, different from traditional construction techniques. This research focused on this challenge, aiming to investigate 3DP in the scenario of new manufacturing methods, now necessary to face the new demands of modern construction. This study sought to demonstrate how the advent of 3D printing in concrete can reduce the distance between the AEC complex industry and manufacturing.

Chronologically situating the technology and studying the advances in its application in other industry sectors and, more recently, in the construction of buildings, it is seen that 3DP technology is of great importance in the current scenario of Industry 4.0, with predictions that its market will experience rapid growth in the coming years. If the use of technology in the AEC complex in Brazil expands according to forecasts, it could bring substantial benefits in the construction of buildings, new spaces and infrastructure in cities.

Among the potentialities of using 3DP in this sphere, it is possible to mention faster and more accurate construction, freedom to propose complex designs, cost reduction, minimization of manual work in construction, optimization of material and the project management process and works, as well as the opportunity to include more sustainable processes in the AEC production chain.

It was sought to analyze how, in recent years, a series of 3DP applications were developed by universities, architecture offices, companies and startups with the intention of testing 3D Printing for the construction of building components and entire buildings, pointing out the attributes promising in the insertion of this technology in the sector. Despite being projects under development and of experimental content, with these case studies it was found that 3D printing can reach great potential in construction in the near future, however, it is necessary that new research be carried out to clarify some of its negative points. and the challenges posed by the technique.The high cost of the machinery, limitations on the dimensions of the printed constructive elements, lack of regulatory laws, little margin for error, as well as the uncertain life cycle in relation to the required maintenance, mechanical stability, useful life of the materials are some of the challenges to be overcome.

CONCLUSIONS 86

In Brazil, it appears that the implementation of this technology in the construction industry offers a wide range of opportunities for development in both software and hardware, due to its well-known, low-cost, and patent-free technology, as shown in the analyzed cases of companies such as WinSun, ApisCor and Total Kustom. Attachment to artisanal processes, skepticism associated with the Civil Construction sectors and the lack of investment in R&D are some of the obstacles to be overcome so that the technique can be effectively applied on the Civil Construction sector.

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For technology to be increasingly used in Brazil, it is important to place it within the relationships of the creative ecosystem: the union between universities, startups and the private sector is essential for more research to be carried out. There needs to be cooperation between conventional suppliers, in addition to the participation of governments in the process, to support the development of 3D printing in concrete.

Finally, as a Digital Fabrication theme that is part of the constellation of subjects related to the EAC innovation ecosystem, the 3DP brings to light the need to review the figure of the architect – as well as other professionals in this industry – as parts of collaborative networks of smart cities that take advantage of the technologies available in Industry 4.0.

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3D Printing: additive manufacturing introduced to the complex of Engineering, Architecture, Construction (AEC) in Brazil

Caroline Afonso Manolio

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International Exchange Scholarship Program - Entrepreneurship and Innovation AUSPIN-USP

2023