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/T009128/2
• 负责人: Sina Haeri
• 金额: $ 47.2万
• 依托单位: University of Edinburgh
• 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: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FT009128%2F2
• 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添加剂制造(或3D打印)技术，它允许快速生产原型，最近还可以生产小体积的重量敏感/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逐层制造最终零件：(1)在制造表面沉积一层细粉(典型的晶粒度约为0.03 mm)，以形成仅比平均晶粒度略厚的细粉床；(2)然后，基于最终产品的3D计算机模型，激光在特定位置熔化粉床；(3)粉末颗粒在冷却和凝固后在这些位置熔化，产生一层最终产品。总的来说，与传统制造技术相比，选择性激光熔化过程和添加剂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、生产复杂的几何形状以提高性能和降低劳动力成本、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，由于缺乏对粉末颗粒形状对潜在物理过程的影响的了解，迫使该行业要求大多数单个粉末颗粒为球形。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，阻碍了新工艺的开发和新材料的引入。为了解决这一问题，需要高质量的过程模拟研究软件来补充实验，并使新的科学发现和创新成为可能。本研究方案通过提供一种能够模拟选择性激光熔化过程背后的各种复杂物理现象的新型计算程序包来满足这一技术需要。为了实现这一点，将使用高性能计算来跟踪系统中单个颗粒的运动、它们与激光的相互作用以及它们的相位变化。然后，这一计算程序包将被用来揭示粉末颗粒形状对床层内激光的吸收和散射以及随后的快速熔化过程的复杂影响。此外，假设细长的或卫星状的颗粒表面有小的夹杂物(颗粒形状通常存在于粉末中，通常被认为是不受欢迎的)，如果仔细选择它们的数密度，实际上可以改善工艺。这一假设将在这里首次得到验证，它可以极大地降低选择性激光熔化的原材料成本，从而使这项使能技术得到更广泛的采用。

项目成果

Lees-Edwards boundary conditions for the multi-sphere discrete element method

• DOI: 10.1016/j.powtec.2021.05.025
• 发表时间: 2021-09
• 期刊: Powder Technology
• 影响因子: 5.2
• 作者: Nathan Berry;Yonghao Zhang;S. Haeri

The effects of interstitial inert gas on the spreading of Inconel 718 in powder bed fusion

• DOI: 10.1016/j.addma.2023.103737
• 发表时间: 2023-08
• 期刊: Additive Manufacturing
• 影响因子: 11
• 作者: S. Khajepor;O. Ejtehadi;S. Haeri

Contact models for the multi-sphere discrete element method

多球离散元法的接触模型

• DOI: 10.1016/j.powtec.2022.118209
• 发表时间: 2023
• 期刊: Powder Technology
• 影响因子: 5.2
• 作者: Berry N

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