Ultraprecision machining characteristics of poly-crystalline germanium

Jiwang Yan, Yasunori Takahashi, Jun'ichi Tamaki, Akihiko Kubo, Tsimemoto Kuriyagawa, Yutaka Sato

Research output: Contribution to conferencePaperpeer-review

1 Citation (Scopus)


Germanium is an excellent infrared optical material. On most occasions, single-crystalline germanium is used as optical lens substrate because its homogeneous structure is beneficial for fabricating uniform optical surfaces. In this work, we attempt to use poly crystals as lens substrates instead of single crystals, which may lead to a significant reduction in production cost. We conducted ultraprecision cutting experiments on poly-crystalline germanium to examine the microscopic machinability. The crystal orientations of specific crystal grains were characterized, and the machining characteristics of these crystal grains including surface textures, cutting forces, and grain boundary steps were investigated under various machining conditions. It was possible to produce uniformly ductile-cut surfaces cross all crystal grains by using an extremely small undefonned chip thickness (∼80 nm) under high negative tool rake angles (∼-45°). This work indicates the possibility of fabricating high-quality infrared optical components from poly-crystalline germanium.

Original languageEnglish
Number of pages6
Publication statusPublished - 2005 Dec 1
Externally publishedYes
Event3rd International Conference on Leading Edge Manufacturing in 21st Century, LEM 2005 - Nagoya, Japan
Duration: 2005 Oct 192005 Oct 22


Other3rd International Conference on Leading Edge Manufacturing in 21st Century, LEM 2005


  • Diamond turning
  • Ductile regime machining
  • Germanium
  • Optical surface
  • Poly crystalline
  • Ultraprecision machining

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering


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