Modeling the Material Microstructure Effects on the Surface Generation Process in Microendmilling of Dual-Phase Materials
Modeling the Material Microstructure Effects on the Surface Generation Process in Microendmilling of Dual-Phase Materials
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DOI：
10.1115/1.4006851
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发表时间：
2012-08
影响因子：
4
通讯作者：
A. Elkaseer;S. Dimov;K. Popov;M. Negm;R. Minev
中科院分区：
文献类型：
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作者：
A. Elkaseer;S. Dimov;K. Popov;M. Negm;R. Minev
在微尺度下加工多相材料时，材料微观结构的各向异性行为成为整个加工过程中必须考虑的重要因素。当切屑载荷和加工特征在尺寸上与刀具的切削刃半径相当，并且在尺寸上与材料微观结构中存在的相的晶粒尺寸相似时，情况尤其如此。因此，需要一种可靠的模型来模拟多相材料微铣削过程中的表面生成过程。本文建立了多相材料微铣削过程中表面生成过程的模拟模型。提出的模型考虑了以下因素的影响：刀具的几何形状、进给速度和工件材料微观结构。特别是，通过将材料微观结构图输入到模型中，考虑了相界处最小切屑厚度的变化。因此，该模型考虑了这些变化，这些变化改变了加工机制，从适当的切削到犁耕，反之亦然，这是微毛刺形成的主要原因。通过应用所提出的模型，可以更准确地估计得到的粗糙度，因为在多相材料微铣削过程中，微毛刺的形成主导了表面生成过程。通过加工两种不同的双相钢试样，在一定范围的切屑载荷下对模型进行了验证。测量了所得表面的粗糙度，并与在相同切削条件下提出的模型的预测进行了比较。结果表明，该模型考虑了材料多相组织的影响，能准确地预测加工表面的粗糙度。此外，所建立的模型成功地阐明了微毛刺在相界的形成机制，并定量描述了其对微铣削后表面粗糙度的贡献。
The anisotropic behavior of the material microstructure when processing multiphase materials at microscale becomes an important factor that has to be considered throughout the machining process. This is especially the case when chip-loads and machined features are comparable in size to the cutting edge radius of the tool, and also similar in scale to the grain sizes of the phases present within the material microstructure. Therefore, there is a real need for reliable models, which can be used to simulate the surface generation process during microendmilling of multiphase materials.This paper presents a model to simulate the surface generation process during microendmilling of multiphase materials. The proposed model considers the effects of the following factors: the geometry of the cutting tool, the feed rate, and the workpiece material microstructure. Especially, variations of the minimum chip thickness at phase boundaries are considered by feeding maps of the material microstructure into the model. Thus, the model takes into account these variations that alter the machining mechanism from a proper cutting to ploughing and vice versa, and are the main cause of microburr formation. By applying the proposed model, it is possible to estimate more accurately the resulting roughness because the microburr formation dominates the surface generation process during microendmilling of multiphase materials. The proposed model was experimentally validated by machining two different samples of dual-phase steel under a range of chip-loads. The roughness of the resulting surfaces was measured and compared to the predictions of the proposed model under the same cutting conditions. The results show that the proposed model accurately predicts the roughness of the machined surfaces by taking into account the effects of material multiphase microstructure. Also, the developed model successfully elucidates the mechanism of microburr formation at the phase boundaries, and quantitatively describes its contributions to the resulting surface roughness after microendmilling.