1 7 A D V A N C E D M A T E R I A L S & P R O C E S S E S | J U L Y / A U G U S T 2 0 2 2 Wire-based processes feature the highest deposition rate, allowing large structures to be built rapidly with superior material usage efficiency. In addition to doing away with size constraints and boosting deposition rates, MAM DED processes offer further advantages. Because the substrate can be either a sacrificial build plate or part of the final component design, complex geometries can be built onto standard wrought shapes as shown in Fig. 8. By adapting the deposition heads to multi-axis robots and CNC systems, features can be locally added to parts— creating near-net shapes and significantly reducing final machining. In addition, use of hybrid DED equipment combines the ability to both add and subtract material in one process during component fabrication. Ancillary systems such as process monitoring and feedback loops can also be incorporated onto machine platforms. CONCLUSION MAM DED offers the ability to rapidly build large structures in near-net shape with minimal machining to final dimensions. Because MAM DED occurs outside of a box to locally deposit the feedstock, it provides more efficient material use. Additional cost savings can be achieved by deposition of complex geometries onto standard wrought product, which can be used as both the build plate and part of the finished component. Localized feature repair is also possible with DED. Use of hybrid additive/subtractive systems allows incorporation of machining tools to achieve design objectives such as dimensional control of internal passages and improved surface finish. ~AM&P For more information: Judy Schneider, professor, The University of Alabama in Huntsville, 320 Sparkman Dr., Olin B. King Technology Hall, Room N272A, Huntsville, AL 35899, judith. schneider@uah.edu. References 1. I. Gibson, D.W. Rosen, and B. Stucker, Additive Manufacturing Technologies: Rapid Prototyping to Direct Digital Manufacturing, Springer New York, 2010. 2. W.E. Frazier, Metal Additive Manu- facturing: A Review, J. Mater. Eng. Perform., Vol 23, p 1917-1928, 2014. 3. D. Herzog, et al., Additive Manufacturing of Metals, Acta Mater., Vol 117, p 371-392, 2016. 4. D. Bourell, Introduction to Additive Manufacturing, Additive Manufacturing Processes, Vol 24, ASM Handbook, eds. D. Bourell, et al., ASM International, p 3-10, 2020, https://doi.org/10.31399/ asm.hb.v24.a0006555. 5. P. Gradl, et al., Metal Additive Manufacturing Techniques and Selection, Metal Additive Manufacturing for Propulsion Applications, eds. P. Gradl, et al., in Progress in Astronautics and Aeronautics, AIAA, ISBN: 978-1-62410626-2, 2022. 6. ASTM Standard F2792-12a, Stand- ard Terminology for Additive Manufacturing Technologies, ASTM Intl., West Conshohocken, Pa. 7. V. Bhavar, et al., A Review on Powder Bed Fusion Technology of Metal Additive Manufacturing, Additive Manufacturing Handbook: Product (a) Fig. 7 — Comparison of various arc-based processes that use wire: (a) metal inert gas (MIG); and (b) gas tungsten arc (TIG)[16]. Fig. 8 — Deposition of features onto standard bar stock. Use of additive/subtractive hybrid systems enables improvement of surface finishes after deposition. Courtesy of DMG Mori. (b)
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