Powders by design for additive manufacture through multi-scale simulations

通过多尺度模拟设计用于增材制造的粉末

• 批准号: EP/T009128/1
• 负责人: Sina Haeri
• 金额: $ 48.88万
• 依托单位: University of Strathclyde
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FT009128%2F1
• 关键词: Powders; design; additive; manufacture; through

The selective laser melting process is a promising large-scale additive manufacturing (or 3D printing) technique that allows for rapid production of prototypes, and lately for weight-sensitive/multi-functional parts at small volumes, with almost arbitrary complexity. The process builds the final parts layer-upon-layer by going through three main stages during each cycle: (1) deposition of a layer of fine powder (with a typical grain size of approximately 0.03 mm) on a fabrication surface to form a thin bed of powder, which is only marginally thicker than the average grain size; (2) a laser beam then melts the powder bed at specific locations, based on a 3D computer model of the final product; (3) the powder grains then fuse at those locations after cooling and solidifying to produce a layer of the final product.In general, the selective laser melting process and additive manufacturing provide several advantages compared to conventional manufacturing techniques, such as greater design freedom, mass customisation and personalisation of products, production of complex geometries to improve performance and reduce labour costs, decreased wastage of precious materials, and new business models and supply chains. However, several challenges also exist. For example, a lack of understanding of the impact of powder grain shape on the underlying physical processes has forced the industry to require the majority of individual powder grains to be spherical. Such a stringent requirement increases the cost of powder (raw material), which consequently increases the production cost and hinders the development of new processes and the introduction of new materials. To address this issue, high-quality research software for process simulation is required to complement experiments and to enable new scientific discoveries and innovations. The present research programme addresses this technological need by providing a novel computational package capable of modelling various complex physical phenomena underlying the selective laser melting process. To achieve this, high-performance computing will be used to track the motion of individual grains in the system, their interaction with a laser beam, and their phase changes. This computational package will then be used to uncover the complex impact of powder grain shapes on the absorption and scattering of a laser beam within the bed and the following rapid melting process. Furthermore, it is hypothesised that elongated or satellite-spherical particles with small inclusions on their surfaces (grain shapes which are commonly present in powders and are generally considered undesirable) can, in fact, improve the process if their number densities are carefully selected. This hypothesis will be tested here for the first time, which can greatly reduce the cost of raw materials for selective laser melting, which results in wider adoption of this enabling technology.

选择性激光熔化工艺是一种很有前途的大规模增材制造（或3D打印）技术，可以快速生产原型，最近还可以小批量生产重量敏感/多功能部件，几乎具有任意的复杂性。该工艺通过在每个周期中经历三个主要阶段来层层构建最终部件：（1）沉积一层细粉末（具有大约0.03mm的典型晶粒尺寸）以形成薄的粉末床，其仅稍微厚于平均晶粒尺寸;（2）然后基于最终产品的3D计算机模型，激光束在特定位置熔化粉末床;（3）粉末颗粒然后在冷却和固化后在那些位置熔合以产生最终产品的层。与传统的制造技术相比，选择性激光熔化工艺和增材制造提供了几个优点，例如更大的设计自由度、产品的大规模定制和个性化、复杂几何形状的生产以提高性能并降低劳动力成本、减少贵重材料的浪费以及新的商业模式和供应链。然而，也存在一些挑战。例如，缺乏对粉末颗粒形状对潜在物理过程的影响的理解，迫使工业要求大多数单个粉末颗粒是球形的。这种严格的要求增加了粉末（原材料）的成本，从而增加了生产成本并阻碍了新工艺的开发和新材料的引入。为了解决这个问题，需要高质量的过程模拟研究软件来补充实验，并实现新的科学发现和创新。目前的研究方案解决了这一技术需求，提供了一种新的计算包，能够模拟各种复杂的物理现象的选择性激光熔化过程。为了实现这一目标，高性能计算将用于跟踪系统中单个颗粒的运动，它们与激光束的相互作用以及它们的相变。该计算包将用于揭示粉末颗粒形状对床内激光束的吸收和散射以及随后的快速熔化过程的复杂影响。此外，假设在其表面上具有小夹杂物的细长或卫星球形颗粒（通常存在于粉末中并且通常被认为是不期望的颗粒形状）实际上可以改善该过程，如果仔细选择它们的数密度的话。这一假设将在这里首次得到验证，它可以大大降低选择性激光熔化的原材料成本，从而使这种使能技术得到更广泛的采用。

项目成果

Analysis of radiation pressure and aerodynamic forces acting on powder grains in powder-based additive manufacturing

• DOI: 10.1016/j.powtec.2020.04.031
• 发表时间: 2020-05
• 期刊: Powder Technology
• 影响因子: 5.2
• 作者: S. Haeri;S. Haeri;Jack Hanson;S. Lotfian