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The advantage of AM over conventional manufacturing methods is its great design freedom in terms of geometry flexibility, hierarchical complexity, material design, and functional complexity [1, 2].
Research shows that these four aspects can combine and compound to form heterogeneous structures by simultaneously considering various cellular structures and densities other than by functional graded materials (FGMs) for instance [3].
At the moment, studies assessing differences between AM and injection moulding indicate that traditional part complexity measurement (based on cost of manufacturing, cost of assembly, and serviceability) needs to be redefined to account for AM characteristics [4-7].
To take advantage of AM, designers need a good understanding of the manufacturing constraints imposed by the various AM fabrication methods. For this purpose, DFM needs to reflect the typical characteristics of AM:
Layer by layer manufacturing
Layer-by-layer material deposition compounded with direct fabrication from CAD model opens up the realm of component design. Unlike more conventional substractive and formative processes, additive methods can build a wide range of geometries.
Components modularity and hybrid manufacturing
Parts could advantageously be designed as 3D customisable puzzles with optional modules. These modules can be built separately and assembled while taking advantages of alternative technology-specific designs to minimise manufacturing difficulties and enhance functionalities. This type of hybrid manufacturing method can be divided into two categories:
[1] An example of lattice structure. a) homogeneous lattice. b) heterogeneous lattice
Materials design
Using AM technologies, materials can be processed selectively. Complex material compositions can be tailored with functional property gradients or heterogeneous lattice structures differentiated by their density.
Hierarchical complexity: manufacturing across several orders of magnitude in length scale
Researchers report three typical features:
[13] 3D model of the sleeve with micro-vane. a Hollow tube and section. b Micro-vanes
Repair flexibility
A few AM processes make it possible to remanufacture and repair components at low cost and relative high speed. For instance, the LENS process is used to repair the worn area of a Ti-6Al-4 V bearing housing from a gas turbine engine. Followed up by conventional CNC machining, the repair costs amount to only 50 % of the price of new component and saves the materials required to manufacture a new bearing housing.
References
1.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 2. Gibson I, Rosen DW, Stucker B (2010) Additive Manufacturing technologies: rapid prototyping to direct digital manufacturing. Springer, US 3. Watts D, Hague R (2006) Exploiting the design freedom of RM. In: Proceeding of the solid freeform fabrication Symp., Austin, TX, August 14-16, Cambridge University Press, pp 656-667 4. Hague R, Mansour S, Saleh N (2003) Design opportunities with rapid manufacturing. Assem Autom 23(4):346–356 5. Hague R,Mansour S, Saleh N (2004)Material and design considerations for rapid manufacturing. Int J Prod Res 42(22):4691–4708 6. Hague R, Campbell I, Dickens P (2003) Implications on design of rapid manufacturing. Proceedings of the Institution of Mechanical Engineers, Part C. J Mech Eng Sci 217(C1):25–30 7. Hague R (2006) Unlocking the design potential of rapid manufacturing. In: Hopkinson N, Hague R, Dickens P (eds) Rapid manufacturing: an industrial revolution for the digital age. Wiley, USA8. Perez KB, Williams CB Combining additive manufacturing and direct write for integrated electronics—a review. In: 24th International Solid Freeform Fabrication Symposium—An Additive Manufacturing Conference, SFF 2013, August 12, 2013 - August 14, 2013, Austin, TX, United states, 2013. 24th International SFF Symposium—An Additive Manufacturing Conference, SFF 2013. University of Texas at Austin (freeform), pp 962–979 9. Lopes AJ, MacDonald E, Wicker RB (2012) Integrating stereolithography and direct print technologies for 3D structural electronics fabrication. Rapid Prototyp J 18(2):129–143 10. Palmer J, Jokiel B, Nordquist C, Kast B, Atwood C, Grant E, Livingston F, Medina F, Wicker R (2006) Mesoscale RF relay enabled by integrated rapid manufacturing. Rapid Prototyp J 12(3):148–155 11. Kerbrat O, Mognol P, Hascoët JY (2011) A new DFM approach to combine machining and additive manufacturing. Comput Ind 62(7):684–692 12. Rosen DW (2007) Computer-aided design for additive manufacturing of cellular structures. Comput-Aided Des Applic 4(5):585–594 13. Choi J-W, Yamashita M, Sakakibara J, Kaji Y, Oshika T, Wicker RB (2010) Combined micro and macro additive manufacturing of a swirling flow coaxial phacoemulsifier sleeve with internal micro- vanes. Biomed Microdevices 12(5):875–886 Comments are closed.
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