Geometric consideration of support structures in part overhang fabrications by electron beam additive manufacturing
Geometric consideration of support structures in part overhang fabrications by electron beam additive manufacturing
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DOI：
10.1016/j.cad.2015.06.007
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发表时间：
2015-12-01
影响因子：
4.3
通讯作者：
Chou, Kevin
中科院分区：
文献类型：
--
作者：
Cheng, Bo;Chou, Kevin
粉末床电子束增材制造（EBAM）已成为生物医学和航空航天应用的高价值，小批量生产的潜在成本效益的过程。在EBAM中，该过程将不需要用于悬突几何形状的支撑结构，因为构建部件浸没在粉末床中。然而，实际上对于悬突确实需要支撑结构;没有支撑结构，悬突区域将具有诸如翘曲的缺陷，这是由于EBAM中复杂的热机械过程。在这项研究中，数值方法被引入到模拟的热机械响应的EBAM过程中的悬垂结构。本研究的目的是开发一个二维热机械模型，使用有限元法（FEM），以评估在EBAM过程中不同的悬垂支撑模式的温度引起的变形。主要结果总结如下。(1)该热力学模型能够模拟电子束拉伸成形过程中的外伸件变形。悬挑长度会显著影响悬挑变形。(2)作为传统的支撑结构，实心柱可以减小悬挑翘曲;此外，可以最小化柱的尺寸以满足变形约束，同时减少支撑材料的量。(3)在悬突下方包括用作散热器的实心件也可以减少悬突变形;然而，必须结合适当的间隙，以便不熔合到悬突区域，同时仍然有效地减少变形。(C)2015爱思唯尔有限公司版权所有。
Powder bed electron beam additive manufacturing (EBAM) has emerged as a potentially cost-effective process for high-value, small-batch productions for biomedical and aerospace applications. In EBAM, the process would not require support structures for overhang geometry because a build part is immersed in the powder bed, However, support structures are indeed needed in practice for an overhang; without it, the overhang area will have defects such as warping, which are due to the complex thermomechanical process in EBAM. In this study, a numerical approach is introduced to simulate the thermomechanical responses in the EBAM process of overhang structures. The objective of this study was to develop a 2D thermomechanical model, using a finite element method (FEM), to evaluate temperature induced deformation on different overhang support patterns in the EBAM process. The major results are summarized as follows. (1) The thermomechanical model is able to simulate the deformation of overhang parts in EBAM. The overhang length noticeably affects the overhang deformation. (2) As a traditional support structure, solid columns can reduce the overhang warping; further, the size of the column may be minimized to satisfy a deformation constraint, and meanwhile, reduce the amount of support materials. (3) Including a solid piece beneath the overhang, acting as a heat sink, may also-reduce the overhang deformation; however, an appropriate gap must be incorporated so as not to fuse to the overhang area, while still effectively reducing the deformation. (C) 2015 Elsevier Ltd. All rights reserved.