Cutter/Workpiece Engagement Feature Extraction from Solid Models for End Milling
Cutter/Workpiece Engagement Feature Extraction from Solid Models for End Milling
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DOI：
10.1115/1.1948395
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发表时间：
2006-02
影响因子：
4
通讯作者：
Derek Yip-Hoi;Xuemei Huang
中科院分区：
文献类型：
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作者：
Derek Yip-Hoi;Xuemei Huang
准确的工艺建模需要计算刀具/工件啮合 (CWE) 几何形状。当工件的几何形状发生不可预测的变化时（就像大多数中等复杂度的加工部件的情况一样），这是一项挑战。实体建模器越来越多地被视为执行这些计算的计算引擎。这主要是由于该技术不断发展的鲁棒性和计算效率的提高。绝大多数已报道的使用实体建模器的研究都集中在使用平头立铣刀进行 2½ D 加工领域。虽然很重要，但可以用这些方法处理的加工工件几何形状的类型仍然存在限制。特别是，它们假设一组连接的刀具路径具有恒定的轴向接合。当初始工件几何形状为非矩形棱柱毛坯、加工多个装夹以及更换刀具引入不同直径的刀具时，无法做出此假设。在这些情况下，即使没有轴向进给运动，啮合深度也会随着刀具的单次旋转而变化。本文提出了一种基于实体建模的解决方案，用于在考虑多种设置和刀具更换的情况下计算 CWE 几何形状。假设采用正交设置和平端铣刀，以防止刀具在倾斜的工件面上啮合。执行代表切削刀具的半圆柱体与工件之间的相交，以生成 CWE 几何形状。刀具啮合特征 (ceF) 用于表征该几何形状。定义了几类 ceF 来支持这种方法。识别 ceF 的过程被视为特征提取问题。本文提供了 ceF 提取和参数化的算法，并使用测试部件进行了验证。这是传统上用于定义最终零件几何形状或材料去除步骤之间的过程中几何形状的特征的新应用程序。获得的结果验证了所提出的提取算法。这项工作还扩展了计算 CWE 几何形状的实体建模技术的能力。
Accurate process modeling requires the calculation of cutter/workpiece engagement (CWE) geometry. This is challenging when the geometry of the workpiece is changing unpredictably as is the case for most machined components of moderate complexity. Solid modelers are increasingly being considered as a computational engine for performing these calculations. This is largely due to increased robustness and computing efficiency that is evolving within this technology. The vast majority of reported research using solid modelers focuses on the domain of 2½ D machining with flat end mills. While significant there remain restrictions in the types of in-process workpiece geometry that can be processed with these approaches. In particular, they assume a constant axial engagement for a connected set of tool paths. This assumption cannot be made when the initial workpiece geometry is nonrectangular prismatic stock, when multiple setups are machined and when tool changes introduce tools of different diameters. In these cases the depth of engagement can vary over a single rotation of the cutter even though there is no axial feed motion. In this paper a solid modeling based solution is presented for calculating CWE geometry when multiple setups and tool changes are considered. Orthogonal setups and flat end mills are assumed so as to preclude cutter engagement on inclined workpiece faces. Intersections between a semi-cylinder representing the cutting tool and the workpiece are performed so as to generate the CWE geometry. Cutter Engagement Features (ceF) are used to characterize this geometry. Several classes of ceFs are defined to support this approach. The process of identifying ceFs is presented as a feature extraction problem. Algorithms for ceF extraction and parametrization are provided in this paper and validated using a test part. This is a new application for features which have traditionally been used to define final part geometry or in-process geometry between material removal steps. The results obtained validate the extraction algorithms presented. This work also extends the capabilities of solid modeling techniques for calculating CWE geometry.