2022 Fiscal Year Final Research Report
Elucidation of effects of pipe-electrode shape in small-hole EDM and instability factors during deep-hole EDM
| Project/Area Number |
20K04213
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 18020:Manufacturing and production engineering-related
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| Research Institution | Kogakuin University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 細穴放電加工 / パイプ電極 / 放電不安定状態 / 加工粉 / 加工液噴出圧 / 高アスペクト比 |
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| Outline of Final Research Achievements |
Electrical discharge machining is good at shape machining of high hardness materials. Among them, there is small-hole electrical discharge machining for machining small holes. This is done by spraying a water-based machining fluid from a pipe-shaped brass or copper electrode. In deep hole drilling, where the depth is more than 100 times the electrode diameter, the drilling becomes unstable and the machining speed decreases, probably because the discharge of debris is delayed. In order to eliminate such a phenomenon, we added a straight groove to the outer circumference of the electrode and performed a machining experiment by changing the cross-sectional shape of the electrode. In addition, it was found that the unstable discharge phenomenon did not occur even if the injection pressure of the machining fluid was changed.
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| Free Research Field |
生産工学・加工学
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| Academic Significance and Societal Importance of the Research Achievements |
深い細穴は，各種金型の冷却用細穴や発電用タービンブレードの冷却穴など，多岐にわたり必要とされている．特にアスペクト比１００を超える深穴になると，放電加工あるいは電解加工が多く用いられる．ただし，どちらも加工深さが深くなると加工液および加工粉の排出が滞るため，加工速度の低下が生じてしまい，結果として加工時間を長くしている．
そのような状況において，本研究で提案する電極形状の工夫や加工液噴出圧を制御することで加工速度の低下を防ぐ効果があることが分かった．特に，加工液噴射圧制御は既存の設備ですぐに対応することが可能であり，すぐに活用可能な技術という意味では工業的意義は高い．
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