Insert-exchangeable, rotary tool and throwaway insert

• US 6,884,006 B2
• Filed: 05/22/2002
• Issued: 04/26/2005
• Est. Priority Date: 05/25/2001
• Status: Expired due to Term

• Current Assignee: Hitachi Tool Engineering, Ltd. (Mitsubishi Materials Corporation)
• Original Assignee: Hitachi Tool Engineering, Ltd. (Mitsubishi Materials Corporation)
• Inventors: Nagashima, Yoshimitsu
• Primary Examiner(s): Fridie, Jr., Willmon
• Application Number:
  US10/151,936
• Publication Number:
  US 20030002929A1
• Time in Patent Office: 1,070 Days
• Field of Search: 407/34, 407/35, 407/42, 407/113, 407/114, 407/115
• US Class Current: 407/34
• CPC Class Codes: B23C 2200/125 discontinuous
• CPC Class Codes: B23C 2200/203 Curved cutting edges
• CPC Class Codes: B23C 2210/0435 radial rake angle
• CPC Class Codes: B23C 2210/045 axial rake angle
• CPC Class Codes: B23C 5/06 Face-milling cutters, i.e. having only or primarily a substantially flat cutting surface
• CPC Class Codes: B23C 5/202 Plate-like cutting inserts with special form special form related to securing of the insert B23C5/22
• CPC Class Codes: Y10T 407/1908 Face or end mill
• CPC Class Codes: Y10T 407/192 with separate means to fasten tool to holder
• CPC Class Codes: Y10T 407/23 including tool having plural alternatively usable cutting edges

Abstract

An insert-exchangeable, rotary tool to which throwaway inserts are detachably attached, the insert comprising substantially square-shaped face and bottom surface and an outward curved flank on each side surface, and having a positive-type shape in which an outward curved edge line formed by the face and the flank serves as a cutting edge; each flank having in a substantially center portion a flat surface portion extending to the bottom surface without contacting with the cutting edge; a major cutting edge formed by the outward curved edge line circularly extending from its lowermost point toward a periphery of the tool when the insert is attached to the insert-exchangeable, rotary tool, such that it has a negative radial rake; and the lowermost point being positioned inward a center of the outward curved major cutting edge.

Claims

1. A throwaway insert detachably attached to an insert-exchangeable, rotary tool, comprising substantially square-shaped face and bottom surface and an outward curved flank on each side surface, said throwaway insert having a positive-type shape in which an outward curved edge line formed by said face and said flank serves as a cutting edge, each flank having in a substantially center portion a flat surface portion extending to said bottom surface without contacting with said cutting edge, and a major cutting edge formed by said outward curved edge line circularly extending from its lowermost point toward a periphery of said tool when said insert is attached to said insert-exchangeable, rotary tool, such that it has a negative radial rake.

2. The throwaway insert according to claim 1, wherein an angle between said flat surface portion and said face is 3°

-10°

smaller than an angle between said face and said flank.

3. The throwaway insert according to claim 1, wherein part of said outward curved cutting edge is straight.

4. The throwaway insert according to claim 2, wherein part of said outward curved cutting edge is straight.

5. The throwaway insert according to claim 1, wherein said major cutting edge is constituted by a plurality of lines and/or curved lines.

6. The throwaway insert according to claim 1, wherein it has a breaker-shaped face groove along said major cutting edge.

7. The throwaway insert according to claim 1, wherein the radius of curvature of said outward curved edge line is 0.6-1.6 times the diameter of an inscribed circle in said insert.

8. An insert-exchangeable, rotary tool to which throwaway inserts are detachably attached, said insert comprising substantially square-shaped face and bottom surface and an outward curved flank on each side surface, and having a positive-type shape in which an outward curved edge line formed by said face and said flank serves as a cutting edge;

each flank having in a substantially center portion a flat surface portion extending to said bottom surface without contacting with said cutting edge;

a major cutting edge formed by said outward curved edge line circularly extending from its lowermost point toward a periphery of said tool when said insert is attached to said insert-exchangeable, rotary tool, such that it has a negative radial rake; and

said lowermost point being positioned inward a center of said outward curved major cutting edge.

9. The insert-exchangeable, rotary tool according to claim 8, wherein said major cutting edge has a cutting edge angle of 35°

or less.

10. The insert-exchangeable, rotary tool according to claim 8, wherein said radial rake is from −

5°

to −

45°

.

11. The insert-exchangeable, rotary tool according to claim 8, wherein the radial rake of said major cutting edge continuously or intermittently changes toward the periphery of said tool.

12. The insert-exchangeable, rotary tool according to claim 8, wherein said major cutting edge has a true rake from +3°

to +15°

.