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AM and sustainability
From lightweighting and material efficiency to energy consumption: Where are we on AM’s sustainability journey? Additive Manufacturing has been heralded as a game-changing technology of the future. But while many ‘green’ and ecological initiatives have bloomed from the AM movement, the question remains: “Is AM environmentally friendly?” As Olaf Diegel, Ray Huff, and Terry Wohlers explain, the short answer is: it can be, in the hands of good designers and well-informed manufacturers. As with any tool or process, knowledge and experience are key. It is important to explore the many ways AM is applied in sustainable ways and whether it is improving.
Amongst its many benefits, Additive Manufacturing is becoming well-known as a weight saving manufacturing process. Strong, organic structures can be integrated within parts, yielding significant reductions in weight. For example, the bracket shown in Fig. 1 was redesigned for metal Binder Jetting (BJT) by a major car manufacturer. The work resulted in a 47% lighter part compared to a conventional design. The redesign also reduced the necessary welding of the part, saving further assembly costs down the line. The long-term benefit is in fuel savings; every gram removed from a car’s weight translates to fuel that is never burned, coupled with less brake wear required to slow it down. With aircraft, ships, trains, mining vehicles, assembly robots and all other moving machinery and transportation systems, these savings are felt in greater energy efficiency over the service life of a product. The contribution of AM to weight reduction and reduced material usage is therefore crucial when considering its sustainability credentials.
Vol. 6 No. 1 © 2020 Inovar Communications Ltd
AM processes are also attractive with regard to dramatically reducing scrap and waste. With subtractive methods of manufacturing, the material for a part is often sourced using the bounding box of the design. With machining, material is removed until only the part is left. In many designs, this results in 90% or more of the
stock becoming chips. With Additive Manufacturing, objects are ‘grown’ from stock powder, producing little waste by comparison. Support material and partially sintered or melted powder are the exceptions, but these may represent 10% or less of the total material used. When producing parts using high-value materials, such as
Fig. 1 Topology optimised bracket weighing about half of the conventional design (Courtesy The ExOne Company)
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