Freedom of design, mass customisation, waste minimisation and the ability to manufacture complex structures, as well as fast prototyping, are the main benefits of additive manufacturing (AM) or 3D printing. A comprehensive review of the main 3D printing methods, materials and their development in trending applications was carried out. In particular, the revolutionary applications of AM in biomedical, aerospace, buildings and protective structures were discussed. The current state of materials development, including metal alloys, polymer composites, ceramics and concrete, was presented. In addition, this paper discussed the main processing challenges with void formation, anisotropic behaviour, the limitation of computer design and layer-by-layer appearance. Overall, this paper gives an overview of 3D printing, including a survey on its benefits and drawbacks as a benchmark for future research and development.

Additive manufacturing (3D printing): A review of materials, methods, applications and challenges

Additive manufacturing (AM) alias 3D printing translates computer-aided design (CAD) virtual 3D models into physical objects. By digital slicing of CAD, 3D scan, or tomography data, AM builds objects layer by layer without the need for molds or machining. AM enables decentralized fabrication of customized objects on demand by exploiting digital information storage and retrieval via the Internet. The ongoing transition from rapid prototyping to rapid manufacturing prompts new challenges for mechanical engineers and materials scientists alike. Because polymers are by far the most utilized class of materials for AM, this Review focuses on polymer processing and the development of polymers and advanced polymer systems specifically for AM. AM techniques covered include vat photopolymerization (stereolithography), powder bed fusion (SLS), material and binder jetting (inkjet and aerosol 3D printing), sheet lamination (LOM), extrusion (FDM, 3D dispensing, 3D fiber deposition, and 3D plotting), and 3D bioprinting....

Polymers for 3D Printing and Customized Additive Manufacturing

https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=924709

3D printing using concrete extrusion: A roadmap for research

https://hal.archives-ouvertes.fr/hal-01383481/document

Large-scale 3D printing of ultra-high performance concrete – a new processing route for architects and builders

Three-dimensional (3D) printing (also known as additive manufacturing) is an advanced manufacturing process that can produce complex shape geometries automatically from a 3D computer-aided design m...

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3D printing trends in building and construction industry: a review

In the present paper a new additive manufacturing processing route is introduced to produce ultra-high-performance concrete complex architectonic elements, by printing integrated formwork. Interdisciplinary work involving material science, computation, robotics, architecture and design resulted in the development of an innovative way of 3D printing cementitious materials. The 3D printing process involved is based on a FDM-like technique, in the sense that a material is deposited layer by layer through an extrusion printhead mounted on a 6-axis robotic arm. An architectural application is used as a case-study to demonstrate the potentialities of the technology. Along with the detailed description of the design and construction process, a description of the responsibilities and their distribution amongst the stakeholders involved in the project is given. The steps taken to include the 3D printed element in an authorized regulatory context are presented as well. The structural elements produced constitute some of the largest 3D printed concrete parts available until now. Multi-functionality was enabled for structural elements by taking advantage of the complex geometry which can be achieved using our technology for large-scale additive manufacturing. The proposed process succeeds in solving several of the current issues problems that can be found in the production of 3D printed architectural features for an AEC industrial context and therefore suggests an immediately viable route for industry assimilation.

/pdf/large-scale-additive-manufacturing-of-ultra-high-performance-2nrozqkujo.pdf

Large-Scale Additive Manufacturing of Ultra-High-Performance Concrete of Integrated Formwork for Truss-Shaped Pillars

We present in this paper a work on multi-material additive manufacturing, linking a GA-based multi-objective optimization form-finding algorithm to a robotic fabrication system for prototyping cement based materials. The genetic algorithm is written entirely in Mathematica® and works on multi-material voxel spaces. It produces optimized material distributions, evaluated both in terms of mechanical performances and thermal insulation abilities. The genetic functions are based on 3D-Voronoi diagram representations and the evolution includes an adaptative penalization strategy (Hamda et al. in Appl Intell 16(2):39–155, 2002) for taking constraints into account (maximum deflections, material resistances, geometric or manufacturing needs). Both thermal and mechanical evaluations, to be combined in a Min-Max method based multi-objective fitness, are conducted thanks to Mathematica® 10 Finite-Element Method library for solving partial differential equations. We have implemented a function to compute volumetric stress distribution in a multi-material voxel space together with structure deformation. The same method is used to evaluate thermal performances: under imposed surface temperatures, the thermal distribution is calculated and the global conductive flow is extracted. The form-finding algorithm is scale-independent, and can work with any list of materials, as long as they can be characterized in terms of Young modulus, Poisson coefficient, and thermal conductivity. We address the prototyping problem by working with concrete mixed with polystyrene beads. Therefore the aim is the making of functionally graded material structures, each part (voxel) of them varying from purely structural concrete to almost purely insulating polystyrene. The additive manufacturing system we designed allows us to print different material performance at a large scale (the deposit lace has a diameter of 2 cm). It is composed with an industrial robot, a peristaltic pump and a printing head. The robot controller is given instructions with HAL (Grasshopper plugin) and the printing head controller with Arduino and Firefly® (Grasshopper plugin). We have been able to print prototypes. They were made to calibrate the fabrication process in terms of concrete formulation and deposition reliability. We have also addressed some less straightforward constructive scenarios like printing geometries that include empty spaces to be filled either with flexion-resistant material like UHPFC (as shown in the pictures below), tension cables, or specific architectural parts of the element (pipes, electric wire, etc.). Now that we have a fully operating form finding and manufacturing process for the making of lightweight multi-purpose concrete and polystyrene structures, we are about to link them together. Writing our own algorithm gives a great versatility to our approach, for we can easily simulate any architectural performance or feasibility constraint that our solutions are to respect. Our algorithm also being scale-independent, it is also possible to use it to address multi-scale problems, playing with the search space, the objectives, and the constraints as inputs. Furthermore, because the construction process is completely automated and computer controlled, we can easily adjust each step to ensure our simulation fits with the actual making. Prototyping allows to conduct mechanical and thermal tests, to provide the initial form finding with quantified feedback, and thus to tighten the whole performance oriented (Hensel in Performance oriented architecture rethinking architectural design and the built environment. AD primers. Wiley, New York, 2013) architectural approach.

Additive Manufacturing and Multi-Objective Optimization of Graded Polystyrene Aggregate Concrete Structures

In this chapter a new additive manufacturing (AM) processing route is introduced for ultra-high-performance concrete. Interdisciplinary work involving materials science, computation, robotics, architecture, and design resulted in the development of an innovative way of 3D cementitious material printing. The 3D printing process involved is based on a fused deposition modeling-like technique, in the sense that a material is deposited layer by layer through an extrusion printhead mounted on a six-axis robotic arm. The mechanical properties of 3D-printed materials are then assessed. The proposed technology succeeds in solving many of the problems that can be found in the literature. Most notably, this process allows the production of 3D large-scale complex geometries without the use of temporary supports, as opposed to 2.5D examples found in the literature for 3D concrete printing. Architectural cases of application are used as examples in order to demonstrate the potentialities of this innovative technology. Two structural elements were produced and constitute some of the largest 3D-printed concrete parts available until now. Multifunctionality was enabled for both structural elements by taking advantage of the complex geometry which can be achieved using our technology for large-scale AM.

/pdf/building-applications-using-lost-formworks-obtained-1lk04u6z8e.pdf

Philippe Roux

Papers

Large-scale 3D printing of ultra-high performance concrete – a new processing route for architects and builders

Large-Scale Additive Manufacturing of Ultra-High-Performance Concrete of Integrated Formwork for Truss-Shaped Pillars

Additive Manufacturing and Multi-Objective Optimization of Graded Polystyrene Aggregate Concrete Structures

Building Applications Using Lost Formworks Obtained ThroughLarge-Scale Additive Manufacturing of Ultra-High-Performance Concrete

Industrialising Concrete 3D Printing:: Three Case Studies