SusChEM: Sustainable material use in laser deposition: integrating experimental design, environmental impact assessment and economic evaluation

1605392用于制造金属部件的传统方法通常需要铸造或锻造制造过程，例如挤压或锻造。为了达到指定的表面光洁度、尺寸精度和几何复杂性，二次加工步骤通常是必要的。但机械加工既浪费材料，也浪费能源，从可持续发展的角度来看，传统方法效率极低。作为另一种选择，人们正在探索直接金属沉积技术，该技术通过熔化金属粉末并仅在需要的地方沉积材料来制造固体金属部件，从而通过添加而不是减少材料来制造部件。这种制造策略的改变旨在通过避免(或减少)所需的二次加工程度，从本质上减少能源需求和材料浪费。然而，实际沉积效率，即实际成为固结成分一部分的原料的一部分，已被证明低至~5%。在实践中，剩余的粉末通常不会被重复利用，而成为废物(废粉)，就像机械加工的切屑一样。因此，这些直接金属沉积工艺也带来了可持续性方面的关键问题。本研究计划有三个主要研究目标：制定直接金属沉积技术环境影响评价和经济评价的定量评估框架，利用该框架指导利用废粉和加工芯片作为直接金属沉积替代原料的实验设计空间，以及实施实验设计，包括严格控制元件制造，并进行深入的表征和测试。这项研究将各种评估和评估工具纳入了一个量化评估框架，该框架捕捉了与直接金属沉积有关的实验变量，特别是在使用替代原料时。这一框架的制定将使其与实验设计空间相结合，并因此指导实验设计空间，而不是像目前评估研究的标准那样，在所有实验参数确定后才进行。总体而言，这项研究将促进对直接金属沉积的性能-可持续性-经济性权衡空间的理解。直接金属沉积是一种相对较新的技术，由于其能够通过增加而不是减少材料来制造零件，因此被推广为具有成本效益和可持续发展的技术。然而，这一过程目前在材料利用方面存在局限性，而且似乎足够强大，可以通过使用替代原料材料来克服这些限制。从广泛的角度来看，这些主题提供了一个基本的机会，以突出性能、可持续性和经济性之间的权衡，并进一步促进在设计过程的早期将可持续性和经济性评估纳入其中。

1605392 Schoebubg, Julie M.Conventional methods used to fabricate metallic components generally require casting or wrought fabrication processes such as extrusion or forging. Secondary machining steps are generally necessary in order to achieve specified surface finish, dimensional accuracy and geometrical complexity. But machining wastes both material, i.e., the scrap material removed from the bulk part (machining chips), and energy, rendering conventional methods highly inefficient from a sustainability perspective. As an alternative, direct metal deposition techniques are being explored, which create solid metal parts by melting metal powder and depositing material only where it is wanted, thus fabricating the component by adding, rather than subtracting material. This change in fabrication strategy is intended to inherently reduce both energy requirements and material waste by avoiding (or reducing) the extent of secondary machining required. However, the actual deposition efficiency, i.e., fraction of feedstock material that actually becomes part of the consolidated component, has been demonstrated to be as low as ~5%. In practice, the remainder of the powder is generally not reused, and becomes waste (waste powder), just like the machining chips. Consequently, these direct metal deposition processes also present critical issues in terms of sustainability. This research program has three primary research objectives: to formulate a quantitative assessment framework for environmental impact assessment and economic evaluation of direct metal deposition technologies, to utilize this framework to guide the experimental design space for utilizing waste powder and machining chips as alternative feedstock materials in direct metal deposition, and to implement the experimental design, including carefully controlled component fabrication, coupled with in-depth characterization and testing. This research incorporates various assessment and evaluation tools into a quantitative assessment framework that captures the experimental variables associated with direct metal deposition, especially when utilizing alternative feedstock materials. This framework will be formulated so that it is integrated with and therefore guides the experimental design space, rather than being carried out after all the experimental parameters have been rigidly defined, as is the current norm for assessment studies. Overall, the research will advance the understanding of the performance-sustainability-economics trade-off space for direct metal deposition. Direct metal deposition is a relatively new technology that is promoted to be cost effective and sustainable, due to its ability to create parts through addition, rather than subtraction, of material. Yet the process currently has limitations in materials utilization, but moreover appears to be sufficiently robust to potentially overcome these limitations through the utilization of alternative feedstock materials. From a broad perspective, these topics present a foundational opportunity to highlight trade-offs between performance, sustainability and economics, and furthermore to promote the incorporation of sustainability and economic assessment early in the design process.