| 摘要 |
PROBLEM TO BE SOLVED: To provide a cemented carbide drill causing low work hardening, which causes relatively small work hardening even in drilling a material liable to be hardened, such as high carbon steel. SOLUTION: The point angleαis set to be in a range from 125°to 135°. The helix angleβof chip discharging flutes 14 is set to be in a range from 20°to 30°. The axial rake angleγof a cutting edge 16 formed by thinning 18 in the neighborhood of the axis is set to be in a range from -5°to +5°. The width L of a negative land at the edge of the cutting edge 16 formed by horning is set to be in a range from 0.05 to 0.15 mm. COPYRIGHT: (C)2006,JPO&NCIPI |
