An Extended Lumped-Parameter Model of Melt-Pool Geometry to Predict Part Height for Directed Energy Deposition
An Extended Lumped-Parameter Model of Melt-Pool Geometry to Predict Part Height for Directed Energy Deposition
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DOI：
10.1115/1.4037235
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发表时间：
2017-09-01
影响因子：
4
通讯作者：
Nassar, Abdalla R.
中科院分区：
文献类型：
--
作者：
Li, Jianyi;Wang, Qian;Nassar, Abdalla R.
需要开发集总参数模型，用于基于激光的增材制造（AM）工艺的实时控制设计和优化。我们先前的工作为定向能量沉积工艺的单珠沉积中的熔池几何形状和温度动力学开发了基于物理的多变量模型，然后使用来自Optomec（R）激光工程净成形（透镜（TM））系统上的单珠Ti-6AL-4V（或Inconel（R）718）轨迹沉积的实验数据来验证该模型。在本文中，我们扩展这种模型的熔池几何形状在一个单珠沉积到多珠多层沉积，然后使用扩展模型的熔池高度动态预测的三维构建的部分高度。具体而言，扩展模型在构建过程中包含温度历史，其通过叠加从点热源的Rosenthal解决方案生成的温度场来近似，其中一个热源对应于之前构建的一个珠。然后使用各种形状的构建来验证所提出的部件高度预测模型，包括单珠薄壁结构、补片构建和L形结构，所有构建均使用Optomec（R）透镜（TM）MR-7系统使用Ti-6AL-4V构建。模型预测的平均零件高度与实测的平均零件高度吻合较好，误差率小于15%。
There is a need for the development of lumped-parameter models that can be used for real-time control design and optimization for laser-based additive manufacturing (AM) processes. Our prior work developed a physics-based multivariable model for melt-pool geometry and temperature dynamics in a single-bead deposition for a directed energy deposition process and then validated the model using experimental data from deposition of single-bead Ti-6AL-4V (or Inconel (R) 718) tracks on an Optomec (R) Laser Engineering Net Shaping (LENS (TM)) system. In this paper, we extend such model for melt-pool geometry in a single-bead deposition to a multibead multilayer deposition and then use the extended model on melt-pool height dynamics to predict part height of a three-dimensional build. Specifically, the extended model incorporates temperature history during the build process, which is approximated by super-positioning the temperature fields generated from Rosenthal's solution of point heat sources, with one heat source corresponding to one bead built before. The proposed model for part height prediction is then validated using builds with a variety of shapes, including single-bead thin wall structures, a patch build, and L-shaped structures, all built with Ti-6AL-4V using an Optomec (R) LENS (TM) MR-7 system. The model predictions on average part height show reasonable agreement with the measured average part height, with error rate less than 15%.