Radius end mill and cutting work method

Patent metadata

Field	Value
Publication number	US-9901995-B2
Application number	US-201415032521-A
Country	US
Kind code	B2
Filing date	Nov 8, 2014
Priority date	Nov 8, 2013
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

Radius mill and cutting work method that includes a plurality of end cutting edges arrayed around a central axis O and a plurality of arc-shaped radius end cutting edges continuous with the end cutting edges on an outer peripheral side in a radial direction. The end cutting edge is divided into an inner peripheral side end cutting edge and an outer peripheral side end cutting edge in a radial direction. Second surfaces of the plurality of inner peripheral side end cutting edges are coupled at a part close to the axis O. A region of coupled second surfaces is continuous from a region including the axis O to outer peripheral sides of respective inner peripheral side end cutting edges in a radial direction in a strip shape. A width of the strip-shaped region gradually enlarges from axis O side to an outer peripheral side in a radial direction.

First claim

The invention claimed is:

1. A radius end mill, comprising
a cutting edge portion disposed on a distal end portion of a tool body, the cutting edge portion including:
a plurality of end cutting edges arrayed around a central axis;
a plurality of arc-shaped radius end cutting edges continuous with the end cutting edges on an outer peripheral side in a radial direction; and
a plurality of peripheral cutting edges continuous with the radius end cutting edges on an outer peripheral side in a radial direction, the peripheral cutting edges being disposed to extend to a rear end portion side of the tool body along cutting edge grooves, wherein:

each of the plurality of end cutting edges is divided into an inner peripheral side end cutting edge and an outer peripheral side end cutting edge in a radial direction,
each of the plurality of radius end cutting edges has a shape such that, for each of the plurality of radius end cutting edges, a lowest point of the radius end cutting edge during cutting with the tool body is positioned in a section from a boundary between the outer peripheral side end cutting edge and the radius end cutting edge to a boundary between the radius end cutting edge and the peripheral cutting edge,
respective second surfaces of the plurality of all the inner peripheral side end cutting edges are coupled to one another at a part close to the central axis, such that the second surfaces of all the inner peripheral side end cutting edges are respective portions of a single continuous surface that includes a central region, which intersects and surrounds the central axis, the single continuous surface extending radially from the central region to an outer peripheral side of each of the inner peripheral side end cutting edges in a strip shape,
a width of the strip-shaped region gradually enlarging from the central axis side to an outer peripheral side in a radial direction, and
end portions of all the inner peripheral side end cutting edges close to the central axis intersect with the boundary lines between the second surfaces of the inner peripheral side end cutting edges positioned on front sides of the inner peripheral side end cutting edges in a rotation direction and gashes formed on rear sides in the rotation direction at positions on an outer peripheral side with respect to the central axis O in a radial direction.

2. The radius end mill according to claim 1 , wherein
the radius end mill has a first point on the radius end cutting edge at a position different from that of a second point on the outer peripheral side end cutting edge,
the first point is an intersection point at which a boundary line, between a second surface of the radius end cutting edge and a second surface of the outer peripheral side end cutting edge, intersects with the outer peripheral side end cutting edge, and
the second point is an intersection point at which a boundary line, between a rake face of the radius end cutting edge and a rake face of the end cutting edge, intersects with the outer peripheral side end cutting edge or the radius end cutting edge.

3. The radius end mill according to claim 2 , wherein
the first point is positioned on an outer peripheral side in a radial direction with respect to the second point.

4. The radius end mill according to claim 1 , wherein
when the distal end portion of the tool body is viewed from an end surface side, the plurality of end cutting edges are equally arrayed in a rotation direction of a tool body around a central axis.

5. The radius end mill according to claim 1 , wherein
a curvature radius of the radius end cutting edge is in a range of 1% to 30% of a cutting diameter.

6. The radius end mill according to claim 1 , wherein
a count of the end cutting edges is two to eight, at least a base constituting a cutting edge being made of a WC-based cemented carbide alloy.

7. A cutting work method, comprising:
using the radius end mill according to claim 1 , in the radius end cutting edges, a section from a boundary between the outer peripheral side end cutting edge and the radius end cutting edge to a boundary between the radius end cutting edge and the peripheral cutting edge having a constant curvature radius;
configuring an axial notch on a work material on which a pocket-shaped groove is formed to meet the following conditional expressions (1) and (2):
ap≦R/ 20  Expression (1):

ap: axial notch
R: curvature radius of a radius end cutting edge
Lw<LR<R   Expression (2):

Lw: (R 2 −Lz 2 ) 1/2
LR: length from a boundary between an outer peripheral side end cutting edge and a radius end cutting edge to a lowest point of a radius end cutting edge
Lz: (R−ap); and

performing contour machining on the groove.

8. The radius end mill according to claim 2 , wherein
when the distal end portion of the tool body is viewed from an end surface side, the plurality of end cutting edges are equally arrayed in a rotation direction of a tool body around a central axis.

9. The radius end mill according to claim 3 , wherein
when the distal end portion of the tool body is viewed from an end surface side, the plurality of end cutting edges are equally arrayed in a rotation direction of a tool body around a central axis.

10. The radius end mill according to claim 2 , wherein
a curvature radius of the radius end cutting edge is in a range of 1% to 30% of a cutting diameter.

11. The radius end mill according to claim 3 , wherein
a curvature radius of the radius end cutting edge is in a range of 1% to 30% of a cutting diameter.

12. The radius end mill according to claim 4 , wherein
a curvature radius of the radius end cutting edge is in a range of 1% to 30% of a cutting diameter.

13. The radius end mill according to claim 2 , wherein
a count of the end cutting edges is two to eight, at least a base constituting a cutting edge being made of a WC-based cemented carbide alloy.

14. The radius end mill according to claim 3 , wherein
a count of the end cutting edges is two to eight, at least a base constituting a cutting edge being made of a WC-based cemented carbide alloy.

15. The radius end mill according to claim 4 , wherein
a count of the end cutting edges is two to eight, at least a base constituting a cutting edge being made of a WC-based cemented carbide alloy.

16. The radius end mill according to claim 5 , wherein
a count of the end cutting edges is two to eight, at least a base constituting a cutting edge being made of a WC-based cemented carbide alloy.

17. A cutting work method, comprising:
using the radius end mill according to claim 2 , in the radius end cutting edges, a section from a boundary between the outer peripheral side end cutting edge and the radius end cutting edge to a boundary between the radius end cutting edge and the peripheral cutting edge having a constant curvature radius;
configuring an axial notch on a work material on which a pocket-shaped groove is formed to meet the following conditional expressions (1) and (2):
ap≦R/ 20  Expression (1):

ap: axial notch
R: curvature radius of a radius end cutting edge
Lw<LR<R   Expression (2):

Lw: (R 2 −Lz 2 ) 1/2
LR: length from a boundary between an outer peripheral side end cutting edge and a radius end cutting edge to a lowest point of a radius end cutting edge
Lz: (R−ap); and

performing contour machining on the groove.

18. A cutting work method, comprising:
using the radius end mill according to claim 3 , in the radius end cutting edges, a section from a boundary between the outer

Assignees

• Mitsubishi Hitachi Tool Eng Ltd

Inventors

• Baba Makoto

Classifications

• B23C5/1018

  with permanently fixed cutting inserts · CPC title

• B23C2210/126

  Rounded cutting edges · CPC title

• B23C2200/36

  Other features of the milling insert not covered by B23C2200/04 - B23C2200/32 · CPC title

• B23C2222/28

  Details of hard metal, i.e. cemented carbide · CPC title

• B23C5/1009

  Ball nose end mills · CPC title