The demand for optical glass lenses is rising owing to the increase in image resolution. Optical glass is a hard and brittle material. Thus, an efficient and precise grinding method is required for optical glass to improve lens quality and productivity. There are a few methods of producing crack-free machined surfaces; however, they provide only limited grinding efficiency. To resolve this issue, the authors’ group has proposed the reaction-induced slurry-assisted (RISA) grinding method, which expands the range of ductile-regime grinding by utilizing the chemical–mechanical action of a cerium oxide slurry. In this study, the grinding performance of RISA grinding is experimentally evaluated for different pH levels. The results are compared using Tukey’s test, where surface roughness is considered as the characteristic value and the pH value as the analyzed factor. The result shows that RISA grinding efficiently produces a high-quality surface when the slurry is alkaline. The adhesion of cerium oxide abrasives to the wheel in RISA grinding follows the same mechanism as slurry aggregation. In addition, adhesion is more likely to occur when the alkalization of the slurry promotes aggregation. The tank in the slurry supply unit is replaced with a rotating tank to ensure stable RISA grinding with a highly aggregable slurry while preventing aggregation. The performance evaluation shows that a high-quality surface with a surface roughness of less than 10 nm in most parts is obtained. Moreover, the critical depth of cut stably increases by a factor of 5.8.

1. [1] D. J. Stephenson, X. Sun, and C. Zervos, “A Study on ELID Ultra Precision Grinding of Optical Glass with Acoustic Emission,” Int. J. Mach. Tools Manuf., Vol.46, pp. 1053-1063, 2006.
2. [2] W. Zhu, Y. Yang, N. H. Li, D. Axinte, and A. Beaucamp, “Theoretical and Experimental Investigation of Material Removal Mechanism in Compliant Shape Adaptive Grinding Process,” Int. J. Mach. Tools Manuf., Vol.142, pp. 76-97, 2019.
3. [3] W. Gu, Z. Yao, and H. Li, “Investigation of Grinding Modes in Horizontal Surface Grinding of Optical Glass BK7,” J. Mater. Process. Technol., Vol.211, pp. 1629-1636, 2011.
4. [4] Y. Kakinuma, Y. Konuma, M. Fukuta, and K. Tanaka, “Ultra-Precision Grinding of Optical Glass Lenses with La-Doped CeO2 Slurry,” CIRP Ann. Manuf. Technol., Vol.68, pp. 345-348, 2019.
5. [5] T. Kawasato, K. Hamazono, M. Fukuta, K. Tanaka, M. Nagano, H. Kato, and Y. Kakinuma, “Basic Study on Reaction Induced Slurry Assisted Grinding for Quartz Glass,” Proc. 23rd ISSAT, pp. 170-174, 2021.
6. [6] T. Kawasato, K. Hamazono, M. Fukuta, K. Tanaka, M. Nagano, H. Kato, and Y. Kakinuma, “Experimental Evaluation of Reaction Induced Slurry Assisted Grinding for BK7 Optical glass,” Proc. 10th LEM21, pp. 287-290, 2021.
7. [7] Z. Zhang, J. Cui, B. Wang, Z. Wang, R. Kang, and D. Guo, “A Novel Approach of Mechanical Chemical Grinding,” J. Alloys Compd., Vol.726, pp. 514-524, 2017.
8. [8] A. Rajendran, Y. Takahashi, M. Koyama, M. Kubo, and A. Miyamoto, “Tight-binding Quantum Chemical Molecular Dynamics Simulation of Mechano-Chemical Reactions During Chemical – Mechanical Polishing Process of SiO₂ Surface by CeO₂ Particle,” Appl. Surf. Sci., Vol.244, pp. 34-38, 2005.
9. [9] J. Guo, J. Gong, P. Shi, C. Xiao, L. Jiang, L. Chen, and L. Qian, “Study on the polishing mechanism of pH-dependent tribochemical removal in CMP of CaF₂ crystal,” Tribol. Int., Vol.150, 106370, 2020.
10. [10] Q. Mu, Z. Jin, X. Han, Y. Yan, Z. Zhang, and P. Zhou, “Effects of slurry pH on chemical and mechanical actions during chemical mechanical polishing of YAG,” Appl. Surf. Sci., Vol.563, 150359, 2021.
11. [11] N. Iinuma, B. Chen, T. Kawasato, and Y. Kakinuma, “Shape error analysis in ultra-precision grinding of optical glass by using motor-current-based grinding force monitoring,” Proc. of the 17th MSEC, 85472, 2022.
12. [12] J. N. Israelachvili (translated by T. Kondo and H. Oshima), “Intermolecular and surface forces: with applications to colloidal and biological systems,” pp. 212, 275-280, Asakura Publishing, 2013 (in Japanese).
13. [13] R. Hogg, T. W. Healy, and D. W. Fuerstenau, “Mutual coagulation of colloidal dispersions,” Trans. Faraday Soc., Vol.62, pp. 1638-1651, 1966.
14. [14] H. Masuda, “Adhesion of Powder Particles,” DENSHI SHASHIN GAKKAISHI (Electrophotography), Vol.36, No.3, pp. 169-174, 1997 (in Japanese).
15. [15] The Society of Powder Technology, Japan, “Terminology of dictionary of powder technology,” p. 267, The Nikkan Kogyo Shimbun, 2000 (in Japanese).
16. [16] X. Sun, D. J. Stephenson, O. Ohnishi, and A. Baldwin, “An Investigation into Parallel and Cross Grinding of BK7 Glass,” Precis. Eng., Vol.30, pp. 145-153, 2006.