Analysis Method of Motion Accuracy Using NC System with Synchronized Measurement of Tool-Tip Position
Kotaro Nagaoka*, Atsushi Matsubara**, Tomoya Fujita**,
and Tomonori Sato*
*Advanced Technology R&D Center, Mitsubishi Electric Corporation, 8-1-1 Tsukaguchi-honmachi, Amagasaki, Hyogo 661-8661, Japan
**Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
This paper describes a method of measuring and analyzing the motion accuracy of NC machine tools. A practical method of measuring the motion accuracy is required for the achievement of high precision machining. The motion accuracy of NC machine tools becomes an issue, as motion error emerges while a continuous path control is applied. Error is caused by several factors. In order to determine the effects of each cause, it is necessary to measure the differences among reference positions, feedback positions, and tool tip positions. Thus, a system of measurement that achieves synchronized acquisition of each of the aforementioned positions has been developed. The system is composed of the NC system, which can manage the reference position and the feedback position, and an additional sensor data acquisition system, which receives the tool tip position. A method of analyzing the acquired data to determine the motion accuracy is also proposed. Experimental results show the effectiveness of the proposed method.
-  T. Treib, “Error Budgeting - Applied to the Calculation and Optimization of the Volumetric Error Field of Multiaxis Systems,” Annals. of the CIRP, 36-1, pp. 365-368, 1987.
-  Y. L. Shen and N. A. Duffie, “Comparison of Combinatorial Rules for Machine Error Budgets,” Annals. of the CIRP, 42-1, pp. 619-622, 1993.
-  D. Kono, A. Matsubara, I. Yamaji, and T. Fujita, “High-precision machining by measurement and compensation of motion error,” Int. J. of Machine Tools and Manufacture, 48, pp. 1103-1110, 2008.
-  C-H Liu, W-Y Juwe, and T-H Hsu, “The application of the double-readheads planar encoder system for error calibration of computer numerical control machine tools,” Proc. of Institution of Mechanical Engineers, 218 Part A: Journal of Engineering Manufacture, pp. 1077-1089, 2004.
-  J. B. Bryan, “A Simple method for testing measuring machines and machine tools Part 1: Principles and applications,” Precision Engineering, 4 -2, pp. 61-69, 1982.
-  H. D. Kwon and M. Burdekin, “Measurement and diagnostics of machine tool errors during circular contouring motions,” Proc. on Instrumentation Mechanical Engineers, 212-B, pp. 343-356, 1998.
-  L. N. Lopez de Lacalle, A. Lamikiz, J. A. Sanchez, and I. Fernandez de Bustos, “Simultaneous Measurement of Forces and Machine Tool Position for Diagnostic of Machining Tests,” IEEE Trans. on Instrumentation and measurement, 54-6, pp. 2329-2335, 2005.
-  Measuring systems for inspecting linear axes: KGM181 and KGM 182 grid encoders, Measuring systems for machine tool inspection and acceptance testing (The brochure of the Heidenhain), pp. 10-11, 2007.