Challenge to develop high-precision boring tools based on self-excited vibration theory

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03949
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 20010:Mechanics and mechatronics-related
• Research Institution: Oita University
• Principal Investigator: Ryu Takahiro 大分大学, 理工学部, 教授 (60230877)
• Co-Investigator(Kenkyū-buntansha): 松崎 健一郎 鹿児島大学, 理工学域工学系, 教授 (80264068) ; 中江 貴志 大分大学, 理工学部, 准教授 (80579730)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 自励振動 / 回転体の振動 / 多角形化現象 / リーマ加工 / 不等分割刃

Outline of Final Research Achievements

Theoretical analysis was performed using genetic algorithm to determine the angular arrangement of irregular-pitch reamer that can suppress the polygonal formation phenomenon of borehole with 4, 6, 7, and 8-flute reamers. As a result, it was found that the effect of optimized angular arrangement of cutting edges can reduce instability, and that there exists an angular arrangement that can stabilize polygonal deformation with 6, 7, and 8-flute reamers. Experiments were conducted using the irregular-pitch reamers with the optimized angular arrangements and regular-pitch reamers with even-pitch cutting edges. It was found that the roundness of the irregular-pitch reamer was significantly improved compared to that of the regular-pitch reamer. An evaluation criterion that is not dependent on the number of cutting edges was also proposed.

Free Research Field

機械力学

Academic Significance and Societal Importance of the Research Achievements

本研究は，リーマを主たるターゲットとしたボーリング加工における多角形化現象を完全に抑制可能な，切れ刃角度配置を求めること，および多角形化現象を完全抑制可能な角度配置を，統一的に評価できる理論的基準値（QCR値）を決定し，実験的に有効性を検証することが目的である。不等分割刃リーマに対する多角形化現象を完全に抑制できる手法を提案することは極めて有用性が高い。また，対策を定量化できるQCR値は，リーマ形状や刃数によらず，不安定性を評価できる基準値であるため，不等分割刃リーマの開発における設計指針となる。