Milling tool as well as a milling insert

Patent metadata

Field	Value
Publication number	US-9233425-B2
Application number	US-201313752595-A
Country	US
Kind code	B2
Filing date	Jan 29, 2013
Priority date	Jan 30, 2012
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

In one aspect, the invention relates to a double-sided, indexable milling insert comprising two rake faces, between which there extends a circumferential clearance face that, in transition to the rake faces, together with the same, forms peripheral cutting edges. Each rake face including lock means for rotationally securing the milling insert in one of several index positions. Along the periphery of the individual rake face, a plurality of tangentially spaced-apart cutting edges are formed, which individually rise at an acute pitch angle from a first end toward a second one. A rake surface is positioned radially inside the individual cutting edge following the cutting edge by rising from a lower boundary line to a crest, via which the same transforms into a declining shoulder surface, which serves as a rotationally securing lock means. In addition, each rake face comprises individual bearing surfaces, which are situated between pairs of adjacent rake surfaces and on a different level from the same. In a further aspect, the invention also relates to a milling tool that is equipped with one or more milling inserts.

First claim

The invention claimed is:

1. A milling tool comprising:
a basic body including front and rear ends between which there extends a first centre axis on which the basic body is rotatable and with which an envelope surface is concentric;
a seat formed with a connecting surface and situated in a transition between the envelope surface and the front end; and
a double-sided, indexable milling insert having two rake faces separated along a second centre axis and perpendicular to the same, wherein the rake faces are equidistantly separated from a neutral plane and between which there extends a clearance face that, in transitions to the rake faces, together with the same, forms peripheral cutting edges, the connecting surface of the seat being located in a tipped-in spatial position in the basic body, in which position an axial tipping-in angle, as well as a radial angle are negative to provide a clearance behind an active cutting edge of the milling insert, and the milling insert being clamped in the seat by a tightening device and rotationally secured in one of several index positions by co-operating lock means in a rake face of the milling insert and the connecting surface in the seat, wherein the milling insert is formed with a plurality of cutting edges tangentially spaced-apart along the periphery of an individual rake face and axially with respect to the second centre axis of the milling insert, which individually rise at an acute pitch angle from a first end toward a second end, wherein a rake surface is positioned radially inside one of the cutting edges and follows the cutting edge by rising from a lower boundary line to a crest, such that when a chip flow is produced along the active cutting edge the chips are transmitted along the successively rising rake surface and leave the same via the crest, via which the rake surface transforms into a declining shoulder surface, which is pressed against a stop surface included in the connecting surface of the seat, wherein, together with the connecting surface forms said lock means, and wherein bearing surfaces, included in the individual rake face of the milling insert, are situated between pairs of adjacent-rake surfaces on a different level and pressed against support surfaces included in the connecting surface of the seat and formed on lugs, each one including a stop surface between which valley surfaces extend, a level difference between the crest of the rake surface and an-individual bearing surface of the milling insert being smaller than a level difference between the support surface of the lug and a neighbouring valley surface in order to keep the rake surfaces of the milling insert spaced apart from the valley surfaces of the connecting surface.

2. The milling tool according to claim 1 , wherein the individual bearing surface of the milling insert is formed adjacent to a shoulder surface and countersunk in relation to the crest.

3. The milling tool according to claim 2 , wherein the individual bearing surface of the milling insert is also countersunk in relation to the lower boundary line of an adjacent rake surface.

4. The milling tool according to claim 1 , wherein the individual bearing surface of the milling insert is wedge-shaped and delimited by boundary lines that converge toward the periphery of the rake face, the support surface on the lug of the connecting surface also being wedge-shaped and delimited by boundary lines that converge in a radially outward direction.

5. The milling tool according to claim 1 , wherein the axial level difference between a crest included in the rake face of the milling insert and a first, lower boundary line to a rake surface is at least 5% and at most 15% of the thickness of the milling insert calculated between two opposite rake faces.

6. The milling tool according to claim 1 , wherein the individual shoulder surface of the milling insert declines at a steep angle that, in arbitrary sections transverse to the crest, is at most 50°.

7. The milling tool according claim 1 , wherein the individual bearing surfaces of the milling inserts between the rake surfaces are planar and situated in a common plane parallel to the neutral plane of the milling insert, and wherein the support surfaces on the lugs of the connecting surface are planar and situated in a common plane.

8. The milling tool according to claim 1 , wherein the number of lugs of the connecting surface and the number of individual bearing surfaces, which are situated between adjacent rake surfaces of the milling insert, are equal to the number of rake surfaces of the milling insert.

9. The milling tool according to claim 1 , wherein the connecting surface of the seat is formed in an upper side of a shim plate, which is semi-permanently connected to the basic body.

10. The milling tool according to claim 9 , wherein the shim plate is fixed to the body by a tubular screw that extends through a hole in the same, the screw including a male thread, which is tightened in a female thread in a hole in a bottom in the seat, and a female thread, in which there is tightened a male thread of a tightening screw extending through a hole in the milling insert.

11. The milling tool according to claim 9 , wherein the shim plate has a round basic shape and includes a conical envelope surface that converges from the upper side of the shim plate toward an underside thereof.

12. The milling tool according to claim 11 , wherein in the envelope surface of the shim plate, there are formed two plane locking surfaces that run at an angle to each other and are pressed against two side support surfaces in the seat running at the same angle in relation to each other.

13. The milling tool according to claim 9 , wherein the milling insert and the shim plate are manufactured from cemented carbide, while the basic body is manufactured from steel.

14. A double-sided, indexable milling insert comprising:
two rake faces separated along a centre axis and perpendicular to the same, the rake faces being equidistantly separated from a neutral plane between which there extends a clearance face that transitions to the rake faces, and together with the same, forms peripheral cutting edges, each of the rake faces including lock means for rotationally securing the milling insert in one of several index positions;
a plurality of tangentially spaced-apart cutting edges formed along the periphery of each of the rake faces, which individually rise axially at an acute pitch angle from a first end toward a second end; and
a rake surface positioned radially inside an individual cutting edge, the rake surface following the cutting edge by rising from a lower boundary line to a crest, such that when a chip flow is produced along an active cutting edge the chips are transmitted along the successively rising rake surface and leave the same via the crest, via which the rake surface transforms into a declining shoulder surface forming the lock means, and that each of the rake faces include an individual bearing surface, which is situated between pairs of adjacent rake surfaces and on a different level from the same.

15. The milling insert according to claim 14 , wherein the individual bearing surface is adjacent to a shoulder surface and is shorter than the same and countersunk in relation to said crest.

16. The milling insert according to claim 15 , wherein the bearing surface is countersunk in relation to a surrounding rake surface.

17. The milling insert according to claim 14 , wherein a periphery angle between the crest and a straight reference line extending between the centre axis and a radially o

Assignees

• Sandvik Intellectual Property

Inventors

• Sunnvius Ulrik
• Norstedt Anders

Classifications

• B23C2200/287

  Positive rake angles · CPC title

• B23C5/2247

  having a special shape · CPC title

• B23C5/2213

  having a special shape · CPC title

• B23C5/202

  Plate-like cutting inserts with special form (special form related to securing of the insert B23C5/22) · CPC title

• B23C2200/085

  discontinuous · CPC title