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Traditionally, Design for Assembly (DFA) aims to facilitate the assembly operations and to minimise the time and costs [1] involved in joining sub-systems to form a complex product [2, 3]. This means minimising the number of sub-parts and eliminating fasteners fabricated.
Additive Manufacturing technologies offer more processing flexibility than other more conventional manufacturing methods. For instance, it promotes the combined fabrication of parts traditionally built separately due to geometry limitations, material differentiation, or costs.
Integrated operational assembly
The use of layer-by-layer deposition and selective processing promotes geometrical flexibility so a certain extent. In operational mechanisms, two or more components must move with respect to one another: AM can build these components fully assembled. For instance, a five-fingered robotic hand prototype featuring fingers with four degree of freedom was fabricated by Selective Laser Sintering [4]. One of the key parameters for performance is the joint clearance [5]. 
robotic hand with fingers exhibiting four degree of freedom [2]
Embedding components
Some AM methods also facilitate the ability to embed functional parts such as electric motors, gears, silicon wafers, printed circuit boards, and strip sensors.
Multi-materials components
Multiple materials can be used concurrently in AM to increase components functionality such as with ultrasonic additive manufacturing or with functionally graded materials (FGM) [6–9] made by direct laser deposition. Functionally graded rapid prototyping (FGRP) is a novel design approach and technological framework enabling the controlled spatial variation of material properties through continuous gradients in functional components [10-14]. For instance, design can combine structural, environmental, and corporeal performance by adapting elements such as thickness, cell density, stiffness, flexibility, and translucency to load, curvature,…
References
[1] Boothroyd G, Dewhurst P, Knight WA, Press C (2002) Product design for manufacture and assembly. M. Dekker, New York [2] Sheng Yang & Yaoyao Fiona Zhao, Additive manufacturing-enabled design theory and methodology: a critical review, Int J Adv Manuf Technol. DOI 10.1007/s00170-015-6994-5 [3] AndreasenMM,Kähler S, Lund T (1983)Design for assembly. Ifs Publications, London [4] Mavroidis C, DeLaurentis KJ,Won J, AlamM(2001) Fabrication of non-assembly mechanisms and robotic systems using rapid prototyping. J Mech Des 123(4):516–524 [5]. Chen YH, Chen ZZ (2011) Joint analysis in rapid fabrication of non-assembly mechanisms. Rapid Prototyp J 17(6):408–417. doi: 10.1108/13552541111184134 [6] Agarwala M, Bourell D, Beaman J, Marcus H, Barlow J (1995) Direct selective laser sintering of metals. Rapid Prototyp J 1(1): 26–36 [7] Siu YK, Tan ST (2002) Modeling the material grading and structures of heterogeneous objects for layered manufacturing. Comp-Aided Des 34(10):705–716 [8] Tolochko N, Mozzharov S, Laoui T, Froyen L (2003) Selective laser sintering of single- and two-component metal powders. Rapid Prototyp J 9(2):68–78 [9] Chiu W, Yu K (2008) Direct digital manufacturing of threedimensional functionally graded material objects. Comp-Aided Des 40(12):1080–1093 [10] Oxman N, Keating S, Tsai E Functionally graded rapid prototyping. In: 5th International conference on advanced research in virtual and physical prototyping, VR@P 2011, September 28, 2011 - October 1, 2011, Leiria, Portugal, 2012. Innovative developments in virtual and physical prototyping - Proceedings of the 5th International Conference on Advanced Research and Rapid Prototyping. Taylor and Francis Inc., pp 483-489 [11] Oxman N (2007) Get real towards performance-driven computational geometry. Int J Archit Comput 5(4):663–684 [12] Oxman N (2010) Material-based design computation. Massachusetts Institute of Technology [13] Oxman N (2010) Structuring materiality: design fabrication of heterogeneous materials. Archit Des 80(4):78–85 [14] Oxman N (2011) Variable property rapid prototyping: inspired by nature, where form is characterized by heterogeneous compositions, the paper presents a novel approach to layered manufacturing entitled variable property rapid prototyping. Virtual Phys Prototyp 6(1):3–31 Comments are closed.
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