Determination of Geometry-Based Errors for Interpolated Tool Paths in Five-Axis Surface Machining
Determination of Geometry-Based Errors for Interpolated Tool Paths in Five-Axis Surface Machining
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DOI：
10.1115/1.1831285
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发表时间：
2005-02
影响因子：
4
通讯作者：
O. Tutunea-Fatan;Hsi-Yung Feng
中科院分区：
文献类型：
--
作者：
O. Tutunea-Fatan;Hsi-Yung Feng
五轴联动数控加工的特点是误差较大。其中一个重要组成部分来自于计算机辅助制造软件，称为基于几何的误差。本文提出了一种新的准确确定这些误差的方法，而不是传统的弦线偏差法。本方法允许基于机床的逆运动学分析，在给定刀具路径上的两个刀具接触点之间建立精确的线性插补刀具位置。已经制定了一个通用程序，以确保所提议的方法的广泛适用性。基于几何的误差的解析推导提供了关于这些误差的来源及其影响参数的见解。由于问题的高度非线性特性，只能得到简单曲面几何的解析解。数值计算能够确定一般曲面形状的误差，但很难从计算的误差值中发现更有洞察力的信息。除了局部曲面几何形状外，数控机床运动链的结构被发现是控制基于几何误差的结果的大小和类型的主要因素。对一个典型的复杂自由曲面的实现表明，传统的弦线偏差方法是不可靠的，并且可能会严重低估基于几何的误差。
Five-axis computer numerical control (CNC) machining is characterized with a multitude of errors. Among them an important component comes from the computer-aided manufacturing software known as the geometry-based errors. A new and accurate method to determine these errors is presented in this paper as opposed to the conventional chordal deviation method. The present method allows establishing the exact linearly interpolated tool positions between two cutter contact points on a given tool path, based on the inverse kinematics analysis of the machine tool. A generic procedure has been developed to ensure wide applicability of the proposed method. Analytical derivation of the geometry-based errors provides insights regarding the origin of these errors and their affecting parameters. Due to the highly non-linear characteristics of the problem, analytical solutions can only be obtained for simple surface geometry. Numerical computation is able to determine the errors for general surface shapes but it would be difficult to uncover further insightful information from the calculated error values. Besides the local surface geometry, the configuration of the kinematic chain of the CNC machine has been found to be the primary factor controlling the resulting value and type of the geometry-based errors. Implementations with a typical complex free-form surface demonstrated that the conventional chordal deviation method was not reliable and could significantly underestimate the geometry-based errors.