Suppression of chatter vibrations during milling process with end-mill by using hybrid spindle system with ball and electromagnetic bearings

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K03878
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18020:Manufacturing and production engineering-related
• Research Institution: Kagoshima University
• Principal Investigator: KONDO Eiji 鹿児島大学, 理工学域工学系, 教授 (10183352)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: びびり振動抑制 / 小径エンドミル / 動的コンプライアンス / ハイブリッド主軸 / 制御磁気軸受

Outline of Final Research Achievements

TThe purpose of this study is to suppress chatter vibrations occurred in the end milling process with a long and small end mill by reducing the peak value of the real part of dynamic compliance at a cutting point, which is controlled by a hybrid spindle system. The spindle of the hybrid spindle system is supported with the rolling bearing at the rear end and the active electromagnetic bearing at the front end. The tool holder with an active electromagnetic bearing attached is used as a prototype hybrid spindle system. It was demonstrated by the impact test that the peak value of the real part of dynamic compliance of the end mill at the natural frequency of the second mode of the prototype hybrid spindle with an end mill was reduced to less than one-third times by the state feedback control. The state feedback coefficients were determined by using analysis for pole assignment of a control system. Furthermore, it was demonstrated in the cutting test that the stability limit increased.

Free Research Field

切削加工学

Academic Significance and Societal Importance of the Research Achievements

本研究の学術的背景はエンドミル加工におけるびびり振動の発生であり、ハイブリッド主軸を用い、制御磁気軸受により細長い小径エンドミル工具のびびり振動を抑制することができないか、というのが研究課題の核心をなす学問的「問い」である。本研究で導入するハイブリッド主軸は、旋盤などの他の工作機械への適用が可能であり、工作機械の主軸の設計方法にイノベーションをもたらすことが期待できる。