1987 Fiscal Year Final Research Report Summary
Development of Chisel-less New Point Drills and Study on High Efficiency Drilling System
| Project/Area Number |
61460095
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械工作
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| Research Institution | Fukuoka Insitute of Technology |
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Principal Investigator |
SAKUMA Keizo Fukuoka Institute of Technology, Professor, 工学部, 教授 (10038911)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIYAMA Hiroichi Fukuoka Institute of Technology, Lecturer, 工学部, 講師 (50148912)
SENBA Takuya Fukuoka Institute of Technology, Lecturer, 工学部, 講師 (30154678)
TAGUCHI Koichi Ariake National College of Technology, Professor, 教授 (90037870)
佐久間 敬三 福岡工業大学, 工学部, 教授 (10038911)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Cutting / Design / Chisel-less / New point drill / Twith drill / Measurement / Torque / スラスト |
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| Research Abstract |
In drilling with conventional twist drills, cutting thrust is so large that many roubles occur in workshop. For aims to improve the hole-making process, new type of drill point, called "Chisel-less drill point" is developed. Design, point grinding method and cutting performance on this tool are investigated, using theoretical analysis and cutting experiments.
1. In this drill point, dual apex-point type of cutting lip is constructed by regrinding the conventional drill point. So, "chisel edge" is not formed on center portion of tool. The result of drilling tests by new tool has shown a large decrease o fthrust force. Its magnitude is 1/2 - 1/3 compared with the force of conventional point drill.
2. Optimum value is observed in apex distance. The ratio of 1mm to 12.5 diameter shows good results. Larger the value of apex distance, run-out of the tool increases. It increase the hole oversize as well as instabillity in start of cut. New design of point is further investigated to avoid this phenomenon, which is verified by cutting tests.
3. Point grinding method is introduced by geometrical analysis of tool. This tool shape is easily ground by the periphery and side face of cup-type wheel, using a universal tool grinder. Special tool attachment, which has 3 regulating axis, was produced.
4. The causes of concentration of excessive large thrust force on chisel edge are analyzed on conventional drills. This extra force is perfectly avoidable on "Chisel- less point drill". Theoretical analysis of cutting forces verified that calculated values agreed well with experimental values on thrust force of new tool.
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