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Mitigating sintering distortion
Desktop Metal's Live Sinter : How simulation software is mitigating sintering distortion TM
Sintering distortion is a fact of life in the Metal Injection Moulding industry. However, through the combination of an experienced eye, the ‘trial and error’ iteration of a part’s design, and the use of sintering supports when needed, stable high-volume production is achieved. With the growth of processes such as metal Binder Jetting, however, the need to manufacture a much wider range of parts at lower production volumes and in a shorter time frame means that a more efficient and streamlined approach is required. Andy Roberts, VP Software at Desktop Metal and the inventor of Live PartsTM, presents the simulation software along with a number of case studies illustrating its capabilities
With the ability to eliminate tooling, dramatically reduce manufacturing timelines and create more complex parts than ever before, Binder Jetting (BJT) is quickly revolutionising the way many metal parts are produced. To reach its full potential, though, there is one hurdle that is often overlooked – sintering. As with Metal Injection Moulding (MIM), BJT parts must be debound and then sintered at temperatures close to the melting point of the alloy being used. The sintering process can cause parts to shrink by as much as 20% and, if not properly supported, there is a real risk of parts slumping and sagging. The result is parts that may emerge from the sintering furnace cracked or deformed beyond usability. Even when not cracked, such parts are typically produced to tight tolerances and any requirement to correct the dimensional accuracy of the parts through post-processing creates additional overhead and expense. For MIM suppliers, the low-tech solution has for decades been simply a mix of having an experienced
eye for appropriate part design and basic trial-and-error: testing various combinations of part geometry, ceramic setters and rafts, then locking in the combination that works for mass production. However, what if, instead of fighting against sinteringbased deformation, we joined forces with it?
The need for a sintering simulation tool A first-of-its-kind software application, Live Sinter is capable of simulating, in just minutes, the deformation parts undergo as they sinter, allowing manufacturers to predict how parts will change shape as they densify. Developed over a year in
Fig. 1 A Desktop Metal Production System installed at Indo-MIM’s metal Binder Jetting operation in San Antonio, Texas, USA (Courtesy Indo-MIM Inc)
Vol. 14 No. 3 © 2020 Inovar Communications Ltd
September 2020 Powder Injection Moulding International
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