Analyzing the Effects of Lubrication Techniques on CNC Spindle Bearing Heat: An Experimental Investigation


  • Duc-Do Le School of Mechanical Engineering, Hanoi University of Science and Technology, Vietnam
  • Tuan-Anh Bui School of Mechanical Engineering, Hanoi University of Science and Technology, Vietnam
Volume: 13 | Issue: 5 | Pages: 11581-11585 | October 2023 |


The machining ability and accuracy of a machine are determined by parameters such as the stiffness and load capacity of its spindle unit. In addition, the effectiveness and technique of lubrication and cooling can significantly affect the operational characteristics of the machine spindle. The current study investigated the effects of two different lubrication methods, grease and air-oil mixture, on the temperature which is generated at the spindle bearings of a Computer Numerical Control (CNC) machine. The temperature distribution and rise rate of the bearings were measured using a thermal imaging camera and thermocouples. The results indicated that the air-oil mixture method was more effective in dissipating heat and reducing the temperature of the bearings than the grease method, due to the direct cooling provided by the air-oil mixture to the bearing balls, resulting in improved lubrication efficiency and heat exchange with the environment. Compared to the grease lubrication method, the temperature of the bearings was lower by 7°C to 9°C depending on the position of the bearing on the CNC spindle. Therefore, it is recommended to use the air-oil mixture lubrication method, especially for high-speed processing on CNC machines. However, the discharge of oil particles from the ventilation system should be carefully controlled. Overall, the findings offer valuable insights into optimizing lubrication methods for CNC machines to enhance processing quality and reduce the impact of temperature on the bearing performance.


spindle bearing, Lubrication method, temperature distribution


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X. J. Xuan, Z. H. Haung, K. D. Wu, and J. P. Hung, "Prediction of the Frequency Response Function of a Tool Holder-Tool Assembly Based on Receptance Coupling Method," Engineering, Technology & Applied Science Research, vol. 8, no. 6, pp. 3556–3560, Dec. 2018.

V.-H. Pham, M.-T. Nguyen, and T.-A. Bui, "Oil pressure and viscosity influence on stiffness of the hydrostatic spindle bearing of a medium-sized circular grinding machine," International Journal of Modern Physics B, vol. 34, no. 22n24, Sep. 2020, Art. no. 2040156.

N. B. Serradj, A. D. K. Ali, and M. E. A. Ghernaout, "A Contribution to the Thermal Field Evaluation at the Tool-Part Interface for the Optimization of Machining Conditions," Engineering, Technology & Applied Science Research, vol. 11, no. 6, pp. 7750–7756, Dec. 2021.

A. Zivkovic, M. Knezev, M. Zeljkovic, S. Navalusic, and L. D. Beju, "A study of thermo-elastic characteristics of the machine tool spindle," in 9th International Conference on Manufacturing Science and Education – MSE 2019 "Trends in New Industrial Revolution," 2019, vol. 290, Art. no. 01009.

L. Yu, Z. Xing, M. Gao, and L. Shang, "Research on the influence of spindle temperature rise of drilling and tapping machine on machining accuracy," Journal of Physics: Conference Series, vol. 1885, no. 2, Dec. 2021, Art. no. 022002.

T. H. Le, V. B. Pham, and T. D. Hoang, "Surface Finish Comparison of Dry and Coolant Fluid High-Speed Milling of JIS SDK61 Mould Steel," Engineering, Technology & Applied Science Research, vol. 12, no. 1, pp. 8023–8028, Feb. 2022.

A. D. K. Ali, N. B. Serradj, and M. E. A. Ghernaout, "Cutting Parameter Optimization based on Online Temperature Measurements," Engineering, Technology & Applied Science Research, vol. 13, no. 1, pp. 9861–9866, Feb. 2023.

T.-A. Bui and Q.-T. Vu, "A Study on an Oil-Air Mixed Lubrication Monitoring System for Spindle Unit of CNC Milling Machine," in Proceedings of the 2nd Annual International Conference on Material, Machines and Methods for Sustainable Development (MMMS2020), 2021, pp. 920–928.

D.-D. Le, Q.-T. Vu, and T.-A. Bui, "Simulation and Experimental Study of Heat in Grease-Lubricated CNC Milling Machine Spindle Bearings," in Proceedings of the International Conference on Advanced Mechanical Engineering, Automation, and Sustainable Development 2021 (AMAS2021), 2022, pp. 462–467.

M. Handawi, A. E. I. Elshwain, M. Y. Noordin, N. Redzuan, and D. Kurniawan, "Comparison between Nitrogen-Oil-Mist and Air-Oil-Mist Condition when Turning of Hardened Tool Stainless Steel," Applied Mechanics and Materials, vol. 660, pp. 18–22, 2014.

O. Maeda, Y. Cao, and Y. Altintas, "Expert spindle design system," International Journal of Machine Tools and Manufacture, vol. 45, no. 4, pp. 537–548, Apr. 2005.

S. Li and Y. Wu, "A Study on Oil/Air Lubrication and Preload of a High Frequency Fully Ceramic Motor Spindle," in 2010 International Conference on E-Product E-Service and E-Entertainment, Henan, China, Aug. 2010.

C. Zhao and X. Guan, "Thermal Analysis and Experimental Study on the Spindle of the High-Speed Machining Center," AASRI Procedia, vol. 1, pp. 207–212, Jan. 2012.

C.-H. Wu and Y.-T. Kung, "A parametric study on oil/air lubrication of a high-speed spindle," Precision Engineering, vol. 29, no. 2, pp. 162–167, Apr. 2005.

H. Liang, D. Guo, L. Ma, and J. Luo, "The film forming behavior at high speeds under oil−air lubrication," Tribology International, vol. 91, pp. 6–13, Nov. 2015.

T.-A. Bui, V.-H. Pham, D.-T. Nguyen, and N.-T. Bui, "Effectiveness of Lubricants and Fly Ash Additive on Surface Damage Resistance under ASTM Standard Operating Conditions," Coatings, vol. 13, no. 5, May 2023, Art. no. 851.

T. A. Stolarski, Ed., Tribology in Machine Design. Elsevier, 1999.


How to Cite

D.-D. Le and T.-A. Bui, “Analyzing the Effects of Lubrication Techniques on CNC Spindle Bearing Heat: An Experimental Investigation”, Eng. Technol. Appl. Sci. Res., vol. 13, no. 5, pp. 11581–11585, Oct. 2023.


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