From Architectured Materials to Large-Scale Additive Manufacturing

The classical material-by-design approach has been extensively perfected by materials scientists, while engineers have been optimising structures geometrically for centuries. The purpose of architectured materials is to build bridges across themicroscale ofmaterials and themacroscale of engineering structures, to put some geometry in the microstructure. This is a paradigm shift. Materials cannot be considered monolithic anymore. Any set of materials functions, even antagonistic ones, can be envisaged in the future. In this paper, we intend to demonstrate the pertinence of computation for developing architectured materials, and the not-so-incidental outcome which led us to developing large-scale additive manufacturing for architectural applications

A Comparative Investigation of Sintering Methods for Polymer 3D Printing Using Selective Separation Shaping (SSS)

Selective Separating Shaping (SSS) is a novel additive manufacturing process which is capable of processing polymeric, metallic, ceramic and cementitious materials. In earlier experiments, the capabilities of SSS in fabrication of metallic, ceramic, cement-based and polymeric parts have been demonstrated. The focus of this research has been on exploration of sintering methods in SSS for successful fabrication of polymeric parts. The SSS machine has been used to build specimens made of polyamide (PA6) material. Bonds between layers under two different thermal sintering methods are investigated to achieve better control over shrinkage and maintain effective binding between layers. ImageJ platform and binary surface plots have been used for image processing and evaluating final porosity under each heating mechanism. Further investigations are carried out on properties of the base materials and the choice of sintering mechanism to further improve resolution of final parts.Mechanical Engineerin

Selective Separation Shaping of Polymeric Parts

Additive manufacturing (AM), or 3D printing has enjoyed a recent surge of attention over the past decade. AM is a process in which digital 3D design data is used as input to build physical objects by combining sequence layers of material. By increasing demand in use of additive manufacturing for fabrication of end-user parts, there is considerable interest in developing new techniques which can offer high quality customized parts at low cost. Selective Separation Shaping (SSS) is a new AM technology developed with the goal of fabricating low cost, high resolution 3D parts. The main advantage of SSS is that this process enables building fully functional pieces without the need of any intermediate binder or high cost laser operation. This process has been primarily applied to metallic, and ceramic materials and test cases were successfully built. There has been no study on fabrication of parts using polymeric material and the goal of this research is to examine successful fabrication of polymer parts. Nylon 6,6 has been used as starting base material and several test cases were fabricated to identify key factors in success of this process. Different classes of nylon are studied to achieve better understanding of material properties on success of fabrication and achieve an effective binding between layers. Finally, 3D printed parts built by SSS are presented.Mechanical Engineerin

A Compound Arm Approach to Digital Construction

We introduce a novel large-scale Digital Construction Platform (DCP) for on-site sensing, analysis, and fabrication. The DCP is an in-progress research project consisting of a compound robotic arm system comprised of a 5-axis Altec hydraulic mobile boom arm attached to a 6-axis KUKA robotic arm. Akin to the biological model of human shoulder and hand this compound system utilizes the large boom arm for gross positioning and the small robotic arm for fine positioning and oscillation correction respectively. The platform is based on a fully mobile truck vehicle with a working reach diameter of over 80 feet. It can handle a 1,500 lb lift capacity and a 20 lb manipulation capacity. We report on the progress of the DCP and speculate on potential applications including fabrication of non-standard architectural forms, integration of real-time on-site sensing data, improvements in construction efficiency, enhanced resolution, lower error rates, and increased safety. We report on a case study for platform demonstration through large-scale 3D printing of insulative formwork for castable structures. We discuss benefits and potential future applications.National Science Foundation (U.S.) (Early Concept Grants for Exploratory Research (EAGER) Grant Award 1152550

Robotic Construction by Contour Crafting: The Case of Lunar Construction

Contour Crafting is a digitally controlled construction process invented by Professor Behrokh Khoshnevis that fabricates components directly from computer models, using layered fabrication technology. By obviating the need for formwork used in traditional concrete construction, CC can reduce costs and construction times significantly. The technique has great potential as a robotic form of construction reliant on relatively minimal human labor as a form of construction in relatively hazardous environments, such as the Moon with its radiation levels that can prove highly damaging. Current research funded by NASA has been exploring the potential for using CC on the Moon to build structures making use of readily available regolith that is found in great abundance on the surface of the Moon. This article offers an overview of this research and evaluates the merits of using CC on the Moon