Influence of position-dependent geometric errors of rotary axes on a machining test of cone frustum by five-axis machine tools

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• 作者：Cefu Hong ; Soichi Ibaraki ; Atsushi Matsubara
• 关键词：Five-axis machine tool ; Cone frustum machining test ; Position-independent geometric error ; Position-dependent geometric error ; R-test
• 刊名：Precision Engineering
• 出版年：2011
• 出版时间：January 2011
• 年：2011
• 卷：35
• 期：1
• 页码：1-11
• 全文大小：1332 K

文摘

A machining test of cone frustum, described in NAS (National Aerospace Standard) 979, is widely accepted by machine tool builders to evaluate the machining performance of five-axis machine tools. This paper discusses the influence of various error motions of rotary axes on a five-axis machine tool on the machining geometric accuracy of cone frustum machined by this test. Position-independent geometric errors, or location errors, associated with rotary axes, such as the squareness error of a rotary axis and a linear axis, can be seen as the most fundamental errors in five-axis kinematics. More complex errors, such as the deformation caused by the gravity, the pure radial error motion of a rotary axis, the angular positioning error of a rotary axis, can be modeled as position-dependent geometric errors of a rotary axis. This paper first describes a kinematic model of a five-axis machine tool under position-independent and position-dependent geometric errors associated with rotary axes. The influence of each error on machining geometric accuracy of a cone frustum is simulated by using this model. From these simulations, we show that some critical errors associated with a rotary axis impose no or negligibly small effect on the machining error. An experimental case study is presented to demonstrate the application of R-test to measure the enlargement of a periodic radial error motion of C-axis with B-axis rotation, which is shown by present numerical simulations to be among potentially critical error factors for cone frustum machining test.