End mill
An end mill includes a plurality of peripheral cutting edges have respective helix angles which are equal to each other and which range from 0° to 5°. Each of the plurality of peripheral cutting edges is defined by one of four types of teeth A-D consisting of (a) teeth A-C each defining a partially-uneven cutting edge that includes an uneven edge portion consisting of a nicked portion or a roughing portion and (b) a tooth D that does not define the uneven edge portion. The peripheral cutting edges are defined by at least two of the four types of teeth A-D, such that each adjacent pair of the peripheral cutting edges adjacent to each other are defined by the teeth that are different in type from each other.
1 . An end mill comprising peripheral cutting edges, wherein
the peripheral cutting edges have respective helix angles that are equal to each other,
at least one of the peripheral cutting edges is constituted by a partially-uneven cutting edge that includes an uneven edge portion including a nicked portion or a roughing portion,
the uneven edge portion is provided in only a part of a tooth length of the partially-uneven cutting edge,
the partially-uneven cutting edge is defined by a tooth A in which the uneven edge portion has a length ranging from 5% of the tooth length to 65% of the tooth length and is provided in a region extending from a shank-portion side end toward a bottom-cutting-edge side in an axial direction of the end mill by a distance corresponding to 70% of the tooth length, a tooth B in which the uneven edge portion has a length ranging from 5% of the tooth length to 65% of the tooth length and is provided in a region extending from a bottom-cutting edge side end toward a shank-portion side in the axial direction of the end mill by a distance corresponding to 70% of the tooth length, or a tooth C in which the uneven edge portion has a length ranging from 5% of the tooth length to 65% of the tooth length, and is provided in a region extending from a center of the tooth length in directions opposite to each other in the axial direction of the end mill by a distance corresponding to 35% of the tooth length,
each of the peripheral cutting edges is defined by one of four types of teeth A-D, such that the four types of teeth A-D include the teeth A-C each of which defines the partially-uneven cutting edge and a tooth D which does not define the uneven edge portion,
each of the peripheral cutting edges is of a type, among the four types of teeth A-D, that is different from a type of an adjacent one of the peripheral cutting edges, and
the helix angles of the peripheral cutting edges range from 0° to 5°.
2 . The end mill according to claim 1 , wherein a surface of a tooth portion, which is provided with the peripheral cutting edges, is covered with a hard coating.
3 . The end mill according to claim 1 , wherein the peripheral cutting edges are defined by at least three of the four types of teeth A-D.
4 . The end mill according to claim 3 , wherein the at least three of the four types of teeth A-D, which define the peripheral cutting edges, include at least the teeth A-C.
5 . The end mill according to claim 1 , wherein the peripheral cutting edges include two adjacent cutting edges that are adjacent to each other in a circumferential direction of the end mill, each of the two adjacent cutting edges is constituted by the partially-uneven cutting edge, and at least a part of the uneven edge portion included in one of the two adjacent cutting edges overlaps with at least a part of the uneven edge portion included in another one of the two adjacent cutting edges in a circumferential direction of the end mill.
6 . An end mill comprising peripheral cutting edges, wherein
the peripheral cutting edges have respective helix angles that are equal to each other,
at least one of the peripheral cutting edges is constituted by a partially-uneven cutting edge that includes an uneven edge portion including a nicked portion or a roughing portion,
the uneven edge portion is provided in only a part of a tooth length of the partially uneven cutting edge,
the partially-uneven cutting edge is defined by a tooth B in which the uneven edge portion has a length ranging from 5% of the tooth length to 65% of the tooth length and is provided in a region extending from a bottom-cutting edge side end toward a shank-portion side in the axial direction of the end mill by a distance corresponding to 70% of the tooth length, or a tooth C in which the uneven edge portion has a length ranging from 5% of the tooth length to 65% of the tooth length, and is provided in a region extending from a center of the tooth length in directions opposite to each other in the axial direction of the end mill by a distance corresponding to 35% of the tooth length,
each of the peripheral cutting edges is defined by one of at least three types of teeth B-D, such that the three types of teeth B-D include the teeth B and C each of which defines the partially-uneven cutting edge and a tooth D which does not define the uneven edge portion,
each of the peripheral cutting edges is of a type, among the at least three types of teeth B-D, that is different from a type of an adjacent one of the peripheral cutting edges, and
the helix angles of the peripheral cutting edges range from 0° to 30°.
7 . The end mill according to claim 6 , wherein at least one of the peripheral cutting edges is constituted by another partially uneven cutting edge that includes the uneven edge portion including the nicked portion or the roughing portion,
the another partially-uneven cutting edge is defined by a tooth A in which the uneven edge portion has a length ranging from 5% of the tooth length to 65% of the tooth length and is provided in a region extending from a shank-portion side end toward a bottom-cutting edge side in an axial direction of the end mill by a distance corresponding to 70% of the tooth length, and
each of the peripheral cutting edges is defined by one of four types of teeth A-D, such that the four types of teeth A-D include the teeth B-D and the tooth A that defines the partially-uneven cutting edge.
8 . The end mill according to claim 7 , wherein the peripheral cutting edges are defined by at least three of the four types of teeth A-D.
9 . The end mill according to claim 8 , wherein the at least three of the four types of teeth A-D, which define the peripheral cutting edges, include at least the teeth A-C.
10 . The end mill according to claim 6 , wherein the peripheral cutting edges include two adjacent cutting edges that are adjacent to each other in a circumferential direction of the end mill, each of the two adjacent cutting edges being constituted by the partially-uneven cutting edge, and
at least a part of the uneven edge portion included in one of the two adjacent cutting edges overlaps with at least a part of the uneven edge portion included in another one of the two adjacent cutting edges in a circumferential direction of the end mill.
11 . The end mill according to claim 6 , wherein the helix angles of the peripheral cutting edges range from 0° to 5°.