Development of a desktop NC machine tool with compliant motion capability and its application to LED lens finishing process

Fusaomi Nagata, Shintaro Tani, Takanori Mizobuchi, Tetsuo Hase, Zenku Haga, Masaaki Omoto, Keigo Watanabe

Research output: Contribution to journalArticlepeer-review


In this paper, a novel desktop NC machine tool with compliance controllability is presented for finishing metallic molds with small curved surface. The NC machine tool consists of a robot with three axes. A small ball-end abrasive tool is attached to the tip of 2-axis of the robot. The control system of the NC machine tool is composed of a force feedback loop, a position feedback loop and a position feedforward loop. The force feedback loop controls the polishing force consisting of tool contact force and kinetic friction force. The position feedback loop controls the position in pick feed direction. Also, the position feedforward loop leads the tool tip along cutter location data. It is expected that the NC machine tool delicately removes small surface cusps on a mold, and finishes the surface with high quality. In order to first confirm the application limit of a conventional industrial robot to a finishing task, we evaluate the backlash which causes the position inaccuracy at the tip of the abrasive tool, through a simple position/force measurement. The basic position/force controllability of the proposed NC machine tool is demonstrated by a similar position/force measurement and by a surface-following-control experiment along a lens mold. Finally, the proposed NC machine tool is applied for finishing a LED lens mold to evaluate its performance qualitatively.

Original languageEnglish
Pages (from-to)1056-1064
Number of pages9
JournalNihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C
Issue number752
Publication statusPublished - Apr 2009
Externally publishedYes


  • CL data
  • Compliant motion
  • Desktop NC machine tool
  • LED lens
  • Mold finishing
  • Small curved surface
  • Weak coupling control

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering


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