ERI: Study of Powder Spreading Behavior for Additive Manufacturing Applications in a Novel Test Bed Environment

适用于增材制造的高质量金属粉末是关键任务应用中生产无缺陷零件的关键因素。据报道，现有的粉末表征方法在增材制造中的应用有限。这是因为它们没有直接解决粉末的涂抹性，这是一个关键但尚未得到很好理解的指标。本工程研究启动（ERI）项目旨在通过设计一个测试平台来更好地定义和测量粉末的涂抹性，从而填补这一研究空白。将开发新的测量方法，确定扩散粉末层的三维形貌，并使用先进的数据处理解决方案，将这些复杂的测量结果提炼成易于解释的总结指标，直接暗示粉末质量和增材制造工艺的适用性。如果成功，所研究的测试平台和指标可以方便地监测原始粉末供应以及再利用和回收粉末的粉末涂敷性。预期的结果将对标准团体和制造业中使用的质量测试方法产生重大影响。铺展性是粉末的一个鲜为人知的特性，它可能导致粉末床的非均匀性，从而在制造的部件中缺乏熔合。如果没有对可扩展性的严格研究和支持测量可扩展性属性的方法，这种相关性很难建立。与此项目相关的工作目标是询问粉末扩散的物理学，以定义主要过程变量及其对扩散行为的影响。铺展性将通过通过适应的表面纹理分析方法从形成的粉末床的物理形貌中得出的汇总指标来量化。采用条纹投影轮廓法测量粉末床地形的实验试验台。这将克服现有粉末表征方法的局限性，这些方法是为粉末冶金而不是增材制造而开发的。筛选实验设计将应用于识别关键的过程变量，并确定最有效的措施的推广。研究结果将支持金属粉末原料标准化质量测试程序的未来发展，这将促进整体过程控制和激光粉末床融合的更广泛采用。其结果将影响其他粉末扩散工艺，如粘合剂喷射和选择性激光烧结。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

High quality metal powder suitable for additive manufacturing is a key factor for producing defect-free parts for mission critical applications. Existing powder characterization methods are reported to have limited applications in additive manufacturing. This is because they do not directly address powder spreadability, a critical but not well understood metric. This Engineering Research Initiation (ERI) project aims to fill this research gap by designing a testbed to better define and measure powder spreadability. Novel measurement methods, which determine the three-dimensional topography of spread powder layers, will be developed and advanced data processing solutions will be used to distill these complex measurements into easily interpreted summary metrics that directly imply powder quality and suitability for the additive manufacturing process. If successful, the researched testbed and metrics can facilitate the monitoring of the powder spreadability for virgin powder supplies as well as re-used and recycled powder. The expected outcomes will have a significant impact on the quality testing methods used in the standard communities and manufacturing industry. Spreadability is a poorly understood characteristic of powder which may lead to heterogeneity in the powder bed and thus lack of fusion in manufactured components. This correlation has been difficult to establish without a rigorous study of spreadability and supporting methodology for measuring the property of spreadability. The objective of work associated with this project is to interrogate the physics of powder spreading to define the main process variables and their influences on spreading behavior. Spreadability will be quantified via summary metrics derived from the physical topography of the formed powder bed via adapted surface texture analysis methods. A novel experimental test bed employing fringe projection profilometry to measure powder bed topography will be utilized. This will overcome existing limitations of powder characterization methods that were developed for powder metallurgy, not additive manufacturing. A screening experimental design will be applied to identify critical process variables and determine the most effective measures of spreadability. Research results will support the future development of standardized quality testing procedures for metal powder feedstocks that will promote overall process control and the wider adoption of laser powder bed fusion. The outcomes will impact other powder spreading processes, such as binder jet and selective laser sintering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.