ISO 10791-7, which specifies the machining accuracy test standard for machining centers, and ISO 10791-6, which specifies the interpolation motion test standard, were revised in 2014 to include five-axis machining centers (5-axis MCs). In addition, cone frustum test, which has been used as the National Aerospace Standard (NAS), was revised and introduced in these ISO standards. However, prior to the establishment of these standards, an aircraft manufacturing company in China proposed S-shaped machining test to measure the accuracy of the test piece of an aircraft. This was adopted as an informative annex of ISO 10791-7 in 2020. Furthermore, in 2019, China proposed a method related to S-shaped machining test and a method of 8-shaped interpolation motion test. Since the S-shaped test requires high acceleration and deceleration in some sections, the test results depend on the performance of the computer-aided manufacturing (CAM) software; therefore, it is not efficient in determining the accuracy of the machine tools. In contrast, in the 8-shaped motion test, the tip of the spindle moves based on a sine curve; consequently, high acceleration/deceleration does not occur. Since the tip of the cutting tool is fixed, a device called R-test is used to measure the position of the center of reference ball using three displacement sensors. In this study, we have discussed the feasibility and problems of the 8-shaped motion test. First, the motion of the machine in the figure “8” motion test is clarified. Next, the definition of the parameters necessary to create the NC programs is outlined. In addition, we have proposed a method in which suitable conditions are set for simultaneous 5-axis feed on a 5-axis MC. Finally, the results of an actual test are applied to the 5-axis MC to confirm that no major problems exist.

1. [1] S. Bossoni, “Geometric and Dynamic Evaluation and Optimization of Machining Centers,” Fortschritt-Berichte VDI, 672, 2, 2009.
2. [2] Y. Ihara and S. Matsushita, “A Study on Tool Position and Posture Measurement Device by Using Parallel Mechanism,” Int. J. Automation Technol., Vol.3, No.3, pp. 271-276, 2009. https://doi.org/10.20965/ijat.2009.p0271
3. [3] Y. Mizugaki, “Effect of Workpiece Location on Manipulability Measure in 5-Axis-Controlled Machine Tools,” Int. J. Automation Technol., Vol.4, No.3, pp. 268-272, 2010. https://doi.org/10.20965/ijat.2010.p0268
4. [4] S. Ibaraki and W. Knapp, “Indirect Measurement of Volumetric Accuracy for Three-Axis and Five-Axis Machine Tools: A Review,” Int. J. Automation Technol., Vol.6, No.2, pp. 110-124, 2012. https://doi.org/10.20965/ijat.2012.p0110
5. [5] S. Ibaraki and Y. Ota, “Error Calibration for Five-Axis Machine Tools by On-the-Machine Measurement Using a Touch-Trigger Probe,” Int. J. Automation Technol., Vol.8, No.1, pp. 20-27, 2014. https://doi.org/10.20965/ijat.2014.p0020
6. [6] F. Sellmann, T. Haas, H. Nguyen, S. Weikert, and K. Wegener, “Orientation Smoothing for 5-Axis Machining Using Quasi-Redundant Degrees of Freedom,” Int. J. Automation Technol., Vol.10, No.2, pp. 262-271, 2016. https://doi.org/10.20965/ijat.2016.p0262
7. [7] T. Nishiguchi, S. Hasegawa, R. Sato, and K. Shirase, “Evaluation Method for Behavior of Rotary Axis Around Motion Direction Changing,” Int. J. Automation Technol., Vol.11, No.2, pp. 171-178, 2017. https://doi.org/10.20965/ijat.2017.p0171
8. [8] S. Ibaraki and I. Yoshida, “A Five-Axis Machining Error Simulator for Rotary-Axis Geometric Errors Using Commercial Machining Simulation Software,” Int. J. Automation Technol., Vol.11, No.2, pp. 179-187, 2017. https://doi.org/10.20965/ijat.2017.p0179
9. [9] Y. Ihara, K. Tsuji, and T. Tajima, “Ball Bar Measurement of Motion Accuracy in Simulating Cone Frustum Cutting on Multi-Axis Machine Tools,” Int. J. Automation Technol., Vol.11, No.2, pp. 197-205, 2017. https://doi.org/10.20965/ijat.2017.p0197
10. [10] R. Sato and K. Shirase, “Geometric Error Compensation of Five-Axis Machining Centers Based on On-Machine Workpiece Measurement,” Int. J. Automation Technol., Vol.12, No.2, pp. 230-237, 2018. https://doi.org/10.20965/ijat.2018.p0230
11. [11] N. Lanz, D. Spescha, S. Weikert, and K. Wegener, “Efficient Static and Dynamic Modelling of Machine Structures with Large Linear Motions,” Int. J. Automation Technol., Vol.12, No.5, pp. 622-630, 2018. https://doi.org/10.20965/ijat.2018.p0622
12. [12] R. Sato, S. Hasegawa, K. Shirase, M. Hasegawa, A. Saito, and T. Iwasaki, “Motion Accuracy Enhancement of Five-Axis Machine Tools by Modified CL-Data,” Int. J. Automation Technol., Vol.12, No.5, pp. 699-706, 2018. https://doi.org/10.20965/ijat.2018.p0699
13. [13] M. Tsutsumi and A. Saito, “Identification and compensation of systematic deviations particular to 5-axis machining centers,” Int. J. of Machine Tools & Manufacture, Vol.43, Issue 8, pp. 771-780, 2003. https://doi.org/10.1016/S0890-6955(03)00053-1
14. [14] M. Tsutsumi and A. Saito, “Identification of angular and positional deviations inherent to 5-axis machining centers with a tilting-rotary table by simultaneous four-axis control movements,” Int. J. of Machine Tools & Manufacture, Vol.44, Issues 12-13, pp. 1333-1342, 2004. https://doi.org/10.1016/j.ijmachtools.2004.04.013
15. [15] Y. Kakino, S. Ibaraki, I. Yamaji, K. Ogawa, and H. Ota, “Measurement of Motion Accuracies of Five-axis Machine Tools by Using the Double Ball Bar Method DBB5,” Proc. of 2008 Int. Symp. on Flexible Automation, 2008.
16. [16] S. Ibaraki, Y. Nakino, T. Akai, N. Takayama, I. Yamaji, and K. Ogawa, “Identification of Motion Error Sources on Five-axis Machine Tools by Ball-bar Measurements,” Precision Engineering, Vol.76, No.3, pp. 333-337, 2010. https://doi.org/10.2493/jjspe.76.333
17. [17] Y. Ihara, “Ball Bar Measurement on Machine Tools with Rotary Axes,” Int. J. Automation Technol., Vol.6, No.2, pp. 180-187, 2012. https://doi.org/10.20965/ijat.2012.p0180
18. [18] S. Weikert, “R-test, a New Device for Accuracy Measurement on Five Axis Machine Tools,” CIRP Annals, Vol.53, No.1, pp. 429-432, 2004. https://doi.org/10.1016/S0007-8506(07)60732-X
19. [19] B. Bringmann and A. Kung, “A new Measuring Artefact for true 3D Machine Tool Testing and Calibration,” Annals of CIRP, Vol.54, No.1, pp. 471-474, 2005. https://doi.org/10.1016/S0007-8506(07)60732-X
20. [20] B. Bringmann and W. Knapp, “Model-based Chase-the-Ball Calibration of a 5-Axes Machining Center,” CIRP Annals, Vol.55, No.1, pp. 531-534, 2006. https://doi.org/10.1016/S0007-8506(07)60475-2
21. [21] G. H. J. Florussen and H. A. M. Spaan, “Static R-test: allocating the centerline of rotary axes of machine tools,” Laser Metrology and Machine Performance VIII, pp. 196-202, 2007.
22. [22] S. Ibaraki, C. Oyama, and H. Otsubo, “Construction of an Error Map of Rotary Axes on a Five-axis Machining Center by Static Rtest,” Int. J. of Machine Tools and Manufacture, Vol.51, Issue 3, pp. 190-200, 2011. https://doi.org/10.1016/j.ijmachtools.2010.11.011
23. [23] Y. Ihara and Y. Hiramatsu, “Design of Motion Accuracy Measurement Device for NC Machine Tools with Three Displacement Sensors,” Int. J. Automation Technol., Vol.5, No.6, pp. 847-854, 2011. https://doi.org/10.20965/ijat.2011.p0847
24. [24] C. Hong and S. Ibaraki, “Observation of Thermal Influence on Error Motions of Rotary Axes on a Five-Axis Machine Tool by Static R-Test,” Int. J. Automation Technol., Vol.6, No.2, pp. 196-204, 2012. https://doi.org/10.20965/ijat.2012.p0196
25. [25] S. Ibaraki, Y. Nagai, H. Otsubo, Y. Sakai, S. Morimoto, and Y. Miyazaki, “R-Test Analysis Software for Error Calibration of Five-Axis Machine Tools Application to a Five-Axis Machine Tool with Two Rotary Axes on the Tool Side,” Int. J. Automation Technol., Vol.9, No.4, pp. 387-395, 2015. https://doi.org/10.20965/ijat.2015.p0387
26. [26] C. Hong, S. Ibaraki, and A. Matsubara, “Influence of Position dependent Geometric Errors of Rotary Axes on a Machining Test of Cone Frustum by Five-axis Machine Tools,” Precision Engineering, Vol.35, No.1, 2011. https://doi.org/10.1016/j.precisioneng.2010.09.004
27. [27] Y. Ihara, “Possibility of Ball Bar Test on Multi-axis Machining Center,” Laser Metrology and Machine Performance VII, pp. 107-115, 2005.
28. [28] M. Matano and Y. Ihara, “Ball bar measurement of five-axis conical movement,” Laser Metrology and Machine Performance VIII, pp. 34-43, 2007.
29. [29] ISO10791-6, “Machine Tools — Test conditions for machining centres — Part 6: Accuracy of speeds and interpolations,” 2014.
30. [30] ISO10791-7, “Machine Tools — Test conditions for machining centres — Part 7: Accuracy of finished test piece,” 2020.
31. [31] NAS 979, “Uniform cutting tests — metal cutting equipment specifications,” Aerospace Industries Association of America, pp. 34-37, 1969.
32. [32] Y. Ihara, K. Takubo, T. Nakai, and R. Sato, “Effect of CAD/CAM Post Process on S-Shaped Machining Test for Five-Axis Machining Center,” Int. J. Automation Technol., Vol.13, No.5, pp. 593-601, 2019. https://doi.org/10.20965/ijat.2019.p0593
33. [33] Z. Jiang, J. Ding, J. Zhang, Q. Ding, Q. Li, L. Du, and W. Wang, “Research on detection of the linkage performance for five-axis CNC machine tools based on RTCP trajectories combination,” The Int. J. of Advanced Manufacturing Technology, Vol.100, pp. 941-962, 2019. https://doi.org/10.1007/s00170-018-2715-1
34. [34] Q. Ding, W. Wang, F. Lei, C. Hu, J. Ding, L. Du, and L. Wang, “Extension of a multi-trigonometric-function-based axis motion plan for RTCP tests aimed at five-axis machine tool dynamic control accuracy,” The Int. J. of Advanced Manufacturing Technology, Vol.120, pp. 6921-6957, 2022. https://doi.org/10.1007/s00170-022-09151-x