Simulation and Property Characterization of Nanoparticle Thermal Conductivity for a Microscale Selective Laser Sintering System
Simulation and Property Characterization of Nanoparticle Thermal Conductivity for a Microscale Selective Laser Sintering System
复制标题
微尺度选择性激光烧结系统纳米颗粒热导率的模拟和性能表征
DOI：
10.1115/1.4055820
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Cullinan, Michael
中科院分区：
文献类型：
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作者：
Grose, Joshua;Dibua, Obehi G;Behera, Dipankar;Foong, Chee Seng;Cullinan, Michael
当前的增材制造 (AM) 技术通常受到其可生产零件的最小特征尺寸的限制。微型选择性激光烧结系统（μ-SLS）解决了这个问题，该系统能够构建单微米分辨率的零件。尽管系统分辨率很高，但使用 μ-SLS 工具可生产的最小特征尺寸受到烧结过程中颗粒床不必要的散热的限制。为了解决这种不需要的热流，需要一个颗粒级热模型来表征烧结过程中纳米颗粒床的热导率，并促进热影响区域的预测。这将有助于优化工艺参数并减少最终零件的错误。本文提出了一种使用 inansys 进行的有限元模拟来确定 aμ-SLS 系统中铜纳米粒子床的有效导热率的方法。相场模型 (PFM) 用于跟踪烧结过程中颗粒床内颗粒组的几何演化。从不同时间步长的 PFM 输出数据中提取计算机辅助设计 (CAD) 模型，并对每个颗粒组进行稳态热模拟。这项工作中开发的完整模拟可扩展到具有可变尺寸和几何排列的粒子组。这项工作的颗粒热模型结果用于计算铜纳米颗粒的导热率，作为颗粒组密度的函数。
Current additive manufacturing (AM) technologies are typically limited by the minimum feature sizes of the parts they can produce. This issue is addressed by the microscale selective laser sintering system (μ-SLS), which is capable of building parts with single micrometer resolutions. Despite the resolution of the system, the minimum feature sizes producible using theμ-SLS tool are limited by unwanted heat dissipation through the particle bed during the sintering process. To address this unwanted heat flow, a particle scale thermal model is needed to characterize the thermal conductivity of the nanoparticle bed during sintering and facilitate the prediction of heat affected zones. This would allow for the optimization of process parameters and a reduction in error for the final part. This paper presents a method for the determination of the effective thermal conductivity of copper nanoparticle beds in aμ-SLS system using finite element simulations performed inansys. A phase field model (PFM) is used to track the geometric evolution of the particle groups within the particle bed during sintering. Computer aided design (CAD) models are extracted from the PFM output data at various time-steps, and steady-state thermal simulations are performed on each particle group. The full simulation developed in this work is scalable to particle groups with variable sizes and geometric arrangements. The particle thermal model results from this work are used to calculate the thermal conductivity of the copper nanoparticles as a function of the density of the particle group.