Cutting insert and cutting tool

Abstract

The invention relates to a cutting insert having a polygonal upper side. Cutting edges, which are alternately configured as roughing cutting edges and finishing cutting edges, are provided at the edges of the upper side. The finishing cutting edges define an incircle (K1) having a diameter that is enlarged in comparison to a nominal size of the cutting insert, and the roughing cutting edges define an incircle (K2) having a diameter that is reduced in comparison to the nominal size of the cutting insert. The invention further relates to a cutting tool having a tool body on which at least one such cutting insert is disposed.

Claims

1. A cutting insert comprising: a polygonal upper side and a polygonal lower side, wherein the upper side and the lower side are congruent when viewed along a center axis of the cutting insert, with a number of lateral surfaces which corresponds to the number of corners of the upper side, wherein each of the lateral surfaces connects an edge of the upper side to an edge of the lower side that is adjacent along the center axis of the cutting insert, with a number of cutting edges which corresponds to the number of corners of the upper side, wherein the cutting edges are provided on the edges of the upper side and are alternately configured as roughing cutting edges and finishing cutting edges, and wherein the lateral surfaces are continuous along the center axis of the cutting insert, and the finishing cutting edges define an incircle (K1) having a diameter that is enlarged in comparison to a nominal size of the cutting insert, and the roughing cutting edges define an incircle (K2) having a diameter that is reduced in comparison to the nominal size of the cutting insert.

2. The cutting insert according to claim 1, wherein cutting edges are provided on the edges of the lower side, wherein the cutting edges are alternately configured as roughing cutting edges and finishing cutting edges and similar cutting edges are disposed adjacent to one another along the center axis of the cutting insert.

3. The cutting insert according to claim 1, wherein the cutting edges configured as roughing cutting edges are inclined, convex or concave with respect to the upper side or the lower side.

4. The cutting insert according to claim 1, wherein the cutting edges configured as finishing cutting edges are inclined, convex or concave with respect to the upper side or the lower side.

5. The cutting insert according to claim 3, wherein, at least in sections, the cutting edges configured as roughing cutting edges and/or the cutting edges configured as finishing cutting edges are inclined at an angle of 3° to 20° relative to the upper side or the lower side.

6. The cutting insert according to claim 3, wherein a connecting edge is provided on the upper side and the lower side in each corner region of the cutting insert which continuously connects adjacent cutting edges.

7. The cutting insert according to claim 3, wherein the cutting edges configured as finishing cutting edges are more inclined than the cutting edges configured as roughing cutting edges.

8. The cutting insert according to claim 1, wherein the lateral surfaces which are associated with the finishing cutting edges are abutment surfaces for abutment of the cutting insert against a tool body.

9. The cutting insert according to claim 1, wherein the lateral surfaces are free surfaces of the adjacent cutting edges.

10. The cutting insert according to claim 1, having an even number of corners.

11. The cutting insert according to claim 10, having four, six, or eight corners.

12. The cutting tool of claim 5, wherein the angle is 5° to 15°.

13. The cutting tool of claim 1, wherein the cutting tool is a milling tool.

14. A cutting tool comprising a tool body on which at least one cutting insert according to claim 1 is disposed.

15. The cutting tool according to claim 14, characterized in that at least one lateral surface of the cutting insert which is associated with one of the finishing cutting edges abuts a counter-abutment surface of the tool body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained below with the aid of a design example, which is shown in the accompanying drawings. The figures show:

(2) FIG. 1 a cutting tool according to the invention with a cutting insert according to the invention, wherein the cutting tool is shown only in sections,

(3) FIG. 2 the cutting insert according to the invention of FIG. 1 in a plan view,

(4) FIG. 3 an enlarged section III of the cutting insert of FIG. 2, and

(5) FIG. 4 the cutting insert of FIGS. 1 to 3 in a lateral view.

DETAILED DESCRIPTION

(6) FIG. 1 shows a cutting tool 10, which here is configured as a milling tool. It comprises a tool body 12 to which a cutting insert 14 is attached. The cutting tool 10 can, of course, also include other cutting inserts. However, these are not shown.

(7) For precise positioning of the cutting insert 14, said cutting insert abuts respective associated counter-abutment surfaces 18a, 18b of the tool body 12 with two of its lateral surfaces 16, which are identified as 16a and 16b.

(8) The lateral surfaces 16 identified as 16a and 16b are therefore abutment surfaces for the abutment of the cutting insert 14 against the tool body 12.

(9) The cutting insert can furthermore be attached to the tool body via the opening 19 using a not more closely depicted screw.

(10) The shown cutting insert 14 is octagonal.

(11) It therefore has a polygonal upper side 20 having eight corners. A lower side 22 is octagonal as well.

(12) The upper side 20 and the lower side 22 are congruent when viewed along a center axis of the cutting insert 24.

(13) The cutting insert accordingly has a total of eight lateral surfaces 16, but only two of them are used as abutment surfaces (see above).

(14) Each lateral surface 16 connects an edge of the upper side 20 to an edge of the lower side 22 that is adjacent along the center axis of the cutting insert 24.

(15) The lateral surfaces 16 are continuous along the center axis of the cutting insert 24; i.e. configured without steps, shoulders or the like.

(16) Cutting edges are also configured on the edges of the upper side 20, i.e. at the transition between the upper side 20 and the associated lateral surfaces 16, whereby said cutting edges are alternating roughing cutting edges 26 and finishing cutting edges 28.

(17) The same applies to the lower side 22. Here, too, alternating roughing cutting edges 26 and finishing cutting edges 28 are provided.

(18) On both the upper side 20 and the lower side 22, the finishing cutting edges 28 define an incircle K1 and the roughing cutting edges 26 define an incircle K2. A diameter of the incircle K1 is enlarged in comparison to a nominal size of the cutting insert 14 and a diameter of the incircle K2 is reduced in comparison to the nominal size of the cutting insert 14.

(19) The roughing cutting edges 26 and the finishing cutting edges 28 are thus disposed on different incircles.

(20) With respect to the roughing cutting edges 26 and the finishing cutting edges 28, the lateral surfaces 16 all form free surfaces.

(21) Associated rake faces are provided on the upper side 20 and the lower side 22 respectively.

(22) The roughing cutting edges 26 provided on the upper side 20 are furthermore concave and the finishing cutting edges 28 provided on the upper side 20 are inclined at a constant angle of approx. 10° relative to the upper side 20. The roughing cutting edges 26 therefore initially fall from a first corner of the cutting insert delimiting them in the direction of the center of the cutting insert and then rise again in the direction of the second corner delimiting them.

(23) The same applies to the roughing cutting edges 26 and finishing cutting edges 28 provided on the lower side 22.

(24) As an example in FIG. 4, the angle at which the frontally depicted finishing cutting edge 28 provided on the upper side 20 is inclined is α and the angle at which the likewise frontally depicted finishing cutting edge 28 provided on the lower side 22 is inclined is β.

(25) The angles at which the remaining finishing cutting edges 28 and roughing cutting edges 26 are inclined with respect to the upper side 20 and the lower side 22 are measured in a similar manner.

(26) It goes without saying that this angle is variable over the extent of convex or concave finishing cutting edges 28 or roughing cutting edges 26.

(27) In order to be able to ensure a continuous peripheral edge of the upper side 20 and the lower side 22 despite the inclination of the finishing cutting edges 28 and the concavity of the roughing cutting edges 26, a connecting edge 32 for the cutting edges of the upper side 20 and a connecting edge 32 for the cutting edges of the lower side 22 is provided in each corner region 30 of the cutting insert 14.

(28) The connecting edge 32 continuously connects respective adjacent roughing cutting edges 26 and finishing cutting edges 28.