Frontiers of Engineering Reports on Leading-Edge Engineering from the 2011 Symposium (2012) / Chapter Skim
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Additive Manufacturing in Aerospace: Examples and Research Outlook--Brett Lyons
Additive Manufacturing in Aerospace: Examples and Research Outlook--Brett Lyons
Pages 15-24
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From page 15... ...
, aerospace companies have numerous parts that are produced in very low quantities, making these tool-less processes attractive from an economic perspective (Ruffo et al., 2006)
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From page 16... ...
Each A&D manufacturer will have internal specifications or will look to established standards organizations for data that allow accurate design of components from a given material, based on minimum allowable performance. Examples of material performance factors that are considered for even the sim plest of components include specific strengths, fatigue, creep, use temperature, survival temperature, several tests of flammability, smoke release and toxicity, electric conductivity, multiple chemical sensitivities, radiation sensitivity, appearance, processing sustainability, and cost.
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From page 17... ...
EXAMPLES OF AEROSPACE-DRIVEN RESEARCH IN AM To build parts with repeatable mechanical properties and dimensional con trol, the temperature distribution across the part-building platform must be held at as even a temperature as possible. In order to accomplish this and reduce scrap rates, The Boeing Company and its partners at the University of Louisville and at Integra Services International (Belton, Texas)
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From page 18... ...
, and same parts seen via infrared thermography during laser scanning (bottom)
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From page 19... ...
To gain the weight and manufacturing benefits provided by SLS on its commercial aircraft, Boeing collaborated with its suppliers to develop the first material that could be laser processed and that passed the required flammability tests (Booth, 2010)
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From page 20... ...
While injection molding and other methods of polymer processing can make use of both heat and pressure to form a part against the surface of a mold, AM processes have to rely primarily on thermal energy input. Viable materials for additive processes must have very specific viscosity and other properties to be successfully processed.
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From page 21... ...
With a given energy input requirement put on the laser per the above comparison, the layer can be drawn with faster or slower laser scan speeds. The scan speed affects the overall per-layer time which, in addition to the proportion of preheat to laser energy required, results in a variable temperature distribution and cooling rate across a part's cross section, per given layer.
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From page 22... ...
Separate from the specific material development identified earlier, AM equipment must transition from comparable low-reliability laboratorygrade equipment to hardened, cost-effective, high-temperature industrial-grade machines. The AM industry can look to its predecessors in injection molding and computer numerical control machining for examples of how to establish new manufacturing technology and the supporting business case.
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From page 23... ...
2009. Commercial Aircraft Applications for Laser Sintered Poly amides.
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From page 24... ...
2011. High temperature laser sintered components.
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