| Project/Area Number |
08650138
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
機械工作・生産工学
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| Research Institution | Osaka University |
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Principal Investigator |
HANASAKI Shinsaku Osaka University, Mechanical Engineering, Professor, 工学部, 教授 (50029097)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Junsuke Osaka University, Mechanical Engineering, Associate Professor, 工学部, 助教授 (60116093)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1997: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1996: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Twist drill / Cutting edge geometry / Flute geometry / Point geometry / Chip exhaust / Cutting temperature / Cutting resistance / Chip shape / 加熱穴あけ / 切りくず |
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| Research Abstract |
In order to exhaust chip in deep hole drilling with a twist drill under continuous feed, it is necessary that the drill flute and the driffed hole deform it to the smaller diameter conical helix type or to the long pitch helix type chip whose pitch is equal to the flute pitch.
A new type twist drill has two cutting edges on each side. Each cutting edge cuts work material independently. The chip generated by each cutting edge are not perfectly unified. The chip by the 2nd main cutting edge is attached to the chip generated by the 1st main cutting, edge which is main chip. This is the basis to the deform and exhaust controll of chip. As the 1st main cutting edge has large oblique angle, so the conical helix type chip has longer pitch, and the flute and the drilled hole controll it to the long pitch type in deep hole drilling. The cutting ratio of the long pitch helix type chip is smaller than that of the conical helix type chip. Especially, at the outside edge it is very small. Under the
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action of the bending moment and the frictional force agaist chip by the flute and the drilled hole, the compressed stress occurs at the cutting region. Especially it is large at the outside edge. This makes the shearing angle small under good plasticity of work material and then the long pitch helix type chip occurs. The effect of 2nd main cutting edge is also large. The drill with the 2nd main cutting edge of 4 degree rake angle produces the long pitch helix type chip at earlier stage in drilling than in case of the 0 degree rake angle drill.
The cutting temperature is about 400ﾟC at rake face when the chip form chages to the long pitch type under various cutting conditions in drilling S50C.Its plasticity becomes large at this temperature. So, the chip does not fracture and changes to the long pitch type.
Unstable generation of the long pitch type chip makes the radial cutting force vibratory. The relation between change of chip form and the characteristics of cutting force is not clear. Less
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