Highly Efficient EB polishing of metal mold with 3D shape by guiding EB under control of magnetic field

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K13673
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 18020:Manufacturing and production engineering-related
• Research Institution: Okayama University
• Principal Investigator: Shinonaga Togo 岡山大学, 自然科学研究科, 助教 (60748507)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 大面積電子ビーム / 金型 / 表面平滑化 / 磁場 / ビーム誘導 / 電磁場解析 / 高アスペクト比 / 穴底面

Outline of Final Research Achievements

Bottom surface smoothing of high aspect ratio hole by EB polishing was proposed. As a basic study for control of magnetic field, magnet was set under the hole bottom surface, and magnetic field lines near the workpiece in large-area EB irradiation were calculated by electric magnetic field analysis. The magnetic field lines distributions show that the EB can be guided to the hole bottom surface since electrons tend to spirally move along the magnetic field lines. Experimental results clarified that the bottom surface of high aspect ratio hole can be uniformly smoothed by guiding the EB to the surface under control of magnetic field.

Free Research Field

電子ビーム加工，レーザ加工

Academic Significance and Societal Importance of the Research Achievements

大面積電子ビームを用いた表面仕上げ技術（EBポリッシング）は，平坦形状や緩やかな凹凸形状を有する金型や金属部品の表面仕上げに一部実用化されている．しかしながら，高アスペクト比の穴形状などを有する工作物では，穴入口や穴内壁の上部へ電子ビームが集中し穴底面全面の平滑化が困難であった．本研究では，磁場制御による電子ビーム誘導に着目し，はじめに，電磁場解析により電子ビーム照射時の工作物近傍の磁場を算出できることを明らかにした．さらに，磁場制御下でのEBポリッシングにより高アスペクト比穴底面仕上げが可能となった．本研究成果は三次元複雑形状金型の高能率表面仕上げに寄与するものと考えられる．