| 摘要 |
[Problem] To provide an end mill with good chip-discharging performance even under a machining condition wherein chips are discharged in a large amount. [Solution] An end mill (10) has: an end mill body (1) that has a central axis of rotation (O); three or more end cutting edges (2) that are formed on the tip side of the end mill body (1); outer peripheral cutting edges (5) that are formed posterior to the end cutting edges (2); chip-discharging grooves (7) that are formed between the outer peripheral cutting edges (5); and heels (3), each being positioned on the opposite side of a chip-discharging groove (7) from an outer peripheral cutting edge (5). Each chip-discharging groove (7) between outer peripheral cutting edges (5) has a cross-section perpendicular to the central axis of rotation (O) with a shape that comprises a first concave curved line (12) formed on the outer peripheral cutting edge (5) side, a second concave curved line (13) formed on the heel (3) side, and a protrusion (14) formed between the two concave curved lines (12, 13), the lines on both sides of the protrusion (14) comprising concave curved lines. The ratio h/H is 0.1-0.4, where H is the distance from the circle (c) with the maximum diameter that can be drawn in the end mill body (1) around the center axis of rotation (O) to an outer peripheral cutting edge (5), and h is the distance (H) from the circle (c) to the peak (P) of a protrusion (14). |
