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As a viable means to enhance the sustainability and competitiveness of aircraft manufacturing and maintenance, three-dimensional (3D) printing has been extensively used in the aircraft industry. However, due to the growing number of suitable 3D printers and the often-high prices of these 3D printers, aircraft manufacturers still face many obstacles in screening possible 3D printers. In addition, dependencies between criteria make it difficult for decision makers to properly assess their absolute priorities. Existing methods fail to address these issues. To solve this problem, this study proposes a nonlinear fuzzy geometric mean (FGM) and dependency-considered fuzzy vise kriterijumska optimizacija i kompromisno resenje (fuzzy VIKOR) approach. The first novel treatment is to design the nFGM method to ensure that the absolute priorities assigned to criteria are correct. Subsequently, in the dependency-considered fuzzy VIKOR, the dependencies between criteria are considered, and a realistic reference point is defined by measuring the distance from each 3D printer to it for proper evaluation. The nonlinear FGM and dependency-considered fuzzy VIKOR approach has been applied to assess and compare five 3D printers for manufacturing aircraft components. [ABSTRACT FROM AUTHOR]

This study mainly aimed to make 3D printing technologies serve as the guidelines for the development of technology-oriented industries. The most important one was tasked to establish modeling technology applicable to 3D printing in view of technological development. For the substrate material of 3D printers, aside from commonly usable plastic, new carbon fiber composite substrates have been proposed. Substrates were selected for manufacturing dependent on different object characteristics. The components were manufactured mainly by focusing on small-sized aircraft components. Additionally, potential problems encountered during 3D printing were explored with feasible suggested solutions. In the aerospace industry, because of the extreme requirements for the weight reduction of aircraft components, in the past, this was limited by manufacturing difficulties. If specific shapes were required, it was highly difficult to produce a component in a single-cast production or cut from a single metal piece. Component manufacturing often had to be divided into several planning blocks, and then welding, assembly, or rivet connection was conducted. This situation was not only flawed with structural weaknesses but also extra weight. If metal powder was operable with 3D printing for integral molding, the above disadvantages could be avoided. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing has great potential for establishing a ubiquitous service in the medical industry. However, the planning, optimization, and control of a ubiquitous 3D printing network have not been sufficiently discussed. Therefore, this study established a collaborative and ubiquitous system for making dental parts using 3D printing. The collaborative and ubiquitous system split an order for the 3D printing facilities to fulfill the order collaboratively and forms a delivery plan to pick up the 3D objects. To optimize the performance of the two tasks, a mixed-integer linear programming (MILP) model and a mixed-integer quadratic programming (MIQP) model are proposed, respectively. In addition, slack information is derived and provided to each 3D printing facility so that it can determine the feasibility of resuming the same 3D printing process locally from the beginning without violating the optimality of the original printing and delivery plan. Further, more slack is gained by considering the chain effect between two successive 3D printing facilities. The effectiveness of the collaborative and ubiquitous system was validated using a regional experiment in Taichung City, Taiwan. Compared with two existing methods, the collaborative and ubiquitous 3D printing network reduced the manufacturing lead time by 45% on average. Furthermore, with the slack information, a 3D printing facility could make an independent decision about the feasibility of resuming the same 3D printing process locally from the beginning. [ABSTRACT FROM AUTHOR]