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

适用于添加剂制造的高质量金属粉末是生产关键任务应用的无缺陷部件的关键因素。据报道，现有的粉末表征方法在添加剂制造中的应用有限。这是因为它们没有直接解决粉末铺展性问题，这是一个关键但尚未得到很好理解的指标。该工程研究启动(ERI)项目旨在通过设计一种试验台来更好地定义和测量粉末的散布性来填补这一研究空白。将开发新的测量方法来确定粉末扩散层的三维形貌，并将使用先进的数据处理解决方案将这些复杂的测量提取为易于解释的摘要指标，这些指标直接表明粉末质量和是否适合添加剂制造工艺。如果成功，所研究的试验台和指标可以方便地监测原始粉末供应以及重复使用和再循环粉末的粉末铺展性。预期结果将对标准社区和制造业中使用的质量测试方法产生重大影响。可铺展性是粉末的一个鲜为人知的特性，这可能会导致粉末床层中的不均匀，从而导致所制造的组件缺乏熔化。如果没有对可传播性和衡量可传播性属性的支持方法的严格研究，就很难建立这种相关性。与该项目相关的工作目标是询问粉末铺展的物理过程，以确定主要的工艺变量及其对铺展行为的影响。通过改进的表面纹理分析方法，通过根据形成的粉床的物理地形得出的汇总指标来量化可扩散性。将使用一种新型的实验试验台，利用条纹投影轮廓术测量粉末床层形貌。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添加剂制造开发的。将采用筛选试验设计来确定关键工艺变量，并确定最有效的可扩散性措施。研究结果将支持金属粉末原料标准化质量检测程序的未来发展，这将促进整个过程控制和激光粉床融合的更广泛采用。结果将影响其他粉末扩散过程，如粘结剂喷射和选择性激光烧结。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.