Influence of servo characteristics on crack generation in ultra-precision grinding of optical glass lenses

Takumi Suetomi, Yasuhiro Kakinuma, Masahiko Fukuta, Katsutoshi Tanaka

Research output: Contribution to journalConference articlepeer-review

2 Citations (Scopus)


Generally, manufacturing process of optical glass lenses, which are used for single lens reflex cameras, is classified into grinding and polishing for removing cracks generated by grinding. Thus, it is desired not to generate the cracks in grinding as much as possible. Because grinding condition with cracks differs depending on the material properties of the workpiece, suitable grinding condition needs to be selected based on a lot of experimental verifications. In addition, the controller's gain of the tool spindle with grinding wheel may be intentionally set to low value in ultra-precision grinding. Thus, the spindle speed may decrease even under servo control because of grinding load. In this study, the influence of servo characteristics on crack generation is evaluated in ultra-precision grinding of optical glass lenses. Concretely, an optical glass lens was machined using an ultra-precision 5-axis grinding machine and servo information of tool spindle was monitored during the process. Comparison of the obtained servo information and the surface observation of the workpiece revealed that the spindle speed decreased and the number of the cracks increased at the outside of the workpiece. The experimental results suggested the possibility of estimating the grinding load and predicting the surface quality by monitoring the variation in the spindle speed.

Original languageEnglish
Pages (from-to)130-133
Number of pages4
JournalProcedia CIRP
Publication statusPublished - 2018
Event8th CIRP Conference on High Performance Cutting, HPC 2018 - Budapest, Hungary
Duration: 2018 Jun 252018 Jun 27


  • Optical glass lenses
  • Process monitoring
  • Ultra-precision grinding

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering


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