Heat transfer characteristics of cutting tool and workpiece surfaces under cryogenic cooling conditions and optimum supply conditions of coolant

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04125
• 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: Tottori University
• Principal Investigator: SATO Masahiko 鳥取大学, 工学研究科, 教授 (50244512)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 切削加工 / 温度 / クーラント / 極低温

Outline of Final Research Achievements

In this study, the heat transfer characteristics of the surface layer of workpiece material and the rake face temperature during cutting were investigated under a cooling condition using cryogenic coolant of liquefied carbon dioxide and liquid nitrogen. The cooling effect of the surface layer of workpiece material is higher for materials with low thermal conductivity. The rake face temperature of cutting tool in the turning of titanium alloy was measured by tool-workpiece thermocouple circuit. The lower the cutting speed and feed rate, the greater the effect on decreasing the average rake face temperature under coolant conditions. The cooling effect was larger at lower cutting speeds than at lower feed rates.

Free Research Field

生産工学・加工学

Academic Significance and Societal Importance of the Research Achievements

航空機等に使用される耐熱金属は高融点で低熱伝導率なため切削温度が高く工具摩耗が大きい．このためクーラント技術が重要であるが，切削液は環境汚染や作業者の健康被害など悪影響も多い．液体窒素や液化二酸化炭素による極低温切削では，切削液の廃棄がなく，製品の洗浄工程が省略できるなど利点が大きい．本研究は，極低温切削における工具および被削材表層での熱伝達状態を明らかにし，環境負荷の小さな機械加工技術の実現を目指す点で社会的意義は大きい．