DEFORM- AND EXHAUST-CONTROLL OF CHIP IN DRILLING WITH A NEW TYPE TWIST DRILL

Research Project

Project/Area Number	06650142
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	機械工作・生産工学
Research Institution	Osaka University
Principal Investigator	HANASAKI Shinsaku Osaka University, Mechanical Engineering, Professor, 工学部, 教授 (50029097)
Co-Investigator(Kenkyū-buntansha)	FUJIWARA Junsuke Osaka University, Mechanical Engineering, Associate Professor, 工学部, 助教授 (60116093)
Project Period (FY)	1994 – 1995
Project Status	Completed (Fiscal Year 1995)
Budget Amount *help	¥1,800,000 (Direct Cost: ¥1,800,000) Fiscal Year 1995: ¥300,000 (Direct Cost: ¥300,000) Fiscal Year 1994: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	Twist drill / Cutting edge geometry / Flute geometry / Point geometry / Chip / Chip exhaust / Cutting resistance / Chip shape
Research Abstract	In order to exhaust chip in deep hole drilling with a twist drill under continuous feed, it is necessary that the chip is a continuous type and can move through the drill flute, because the segment type chip tends to clog the drill flutes. The freely generated chip is the conical helix type. Therefore, it is necessary that the drill flute and the drilled hole deform it to the smaller diameter or to the long pitch helix type chip, whose pitch is equal to the flute pitch. As the main cutting edge of a conventional drill is wide and almost corresponds to the radius vector, the semi-orthogonal cutting is carried out, and the freely generated chip is a conical helix type one with small pitch. It is difficult to deform it to the above mentioned chips. A new type twist drill has two cutting edges on each side. Each cutting edge cuts work material independently. The chips generated by each cutting edge are not perfectly unified. The chip by the inside cutting edge is attached to the chip generated by the outside cutting edge which is main chip. This is the basis to the deform- and exhaust-controll of chip. As the outside cutting edge has a large oblique angle, this 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.