CUTTING INSERT AND TOOL FOR MACHINING

Abstract

A cutting insert for a tool for machining a workpiece. The cutting insert comprises a clamping section which comprises a coolant channel which is configured as a through-hole. Further, the cutting insert comprises a cutting head having at least one cutting member which comprises a main cutting edge, a rake face which adjoins the main cutting edge, and a chip-breaking geometry which protrudes from the rake face or which is introduced into the rake face and which is configured to break a chip which is machined with the main cutting edge. Furthermore, the cutting insert comprises a cantilever arm which connects the clamping section to the cutting head and which has a smaller diameter than the clamping section. A portion of the cutting head comprising the chip-breaking geometry at least partially covers the coolant channel when viewed in a plan view from a front side along a longitudinal axis of the cutting insert.

Claims

1. A cutting insert for a tool for machining a workpiece, wherein the cutting insert comprises: a clamping section which comprises a coolant channel configured as a through-hole; a cutting head having at least one cutting member which comprises a main cutting edge, a rake face which adjoins the main cutting edge, and a chip-breaking geometry which protrudes from the rake face or which is introduced into the rake face and which is configured to break a chip which is machined with the main cutting edge; and a cantilever arm which extends along a longitudinal axis of the cutting insert and connects the clamping section to the cutting head and which has a smaller diameter than the clamping section; wherein the cutting insert is configured in a monolithic manner so that the clamping section, the cutting head and the cantilever arm are integrally connected to each other; and wherein a portion of the cutting head comprising the chip-breaking geometry, when viewed along the longitudinal axis of the cutting insert, covers at least 10% of a cross section of the coolant channel, but a maximum of 80% of the cross section of the coolant channel.

2. The cutting insert as claimed in claim 1, wherein the cantilever arm does not cover the coolant channel when viewed along the longitudinal axis of the cutting insert.

3. The cutting insert as claimed in claim 1, wherein the chip-breaking geometry is spaced apart from the main cutting edge.

4. The cutting insert as claimed in claim 3, wherein a first portion of the rake face extends along the main cutting edge between the chip-breaking geometry and the main cutting edge.

5. The cutting insert as claimed in claim 4, wherein the cutting member further comprises an auxiliary cutting edge which is orientated transversely relative to the main cutting edge, and wherein a second portion of the rake face extends along the auxiliary cutting edge between the chip-breaking geometry and the auxiliary cutting edge.

6. The cutting insert as claimed in claim 5, wherein the auxiliary cutting edge is rectilinear.

7. The cutting insert as claimed in claim 1, wherein the main cutting edge is rectilinear.

8. The cutting insert as claimed in claim 1, wherein the cantilever arm extends along the longitudinal axis of the cutting insert, and wherein the cutting member protrudes from the cutting head in a direction transverse to the longitudinal axis of the cutting insert.

9. The cutting insert as claimed in claim 1, wherein the coolant channel extends parallel to the longitudinal axis of the cutting insert.

10. The cutting insert as claimed in claim 1, wherein the chip-breaking geometry is configured as a raised geometry which protrudes from the rake face.

11. The cutting insert as claimed in claim 1, wherein a center axis of the coolant channel extends parallel to or is coplanar with a surface portion of the chip-breaking geometry.

12. The cutting insert as claimed in claim 1, wherein a cross section of the coolant channel is non-round.

13. The cutting insert as claimed in claim 1, wherein a first cross section of the coolant channel at a first end of the coolant channel that faces away from the cutting head is larger than a second cross section of the coolant channel at a second end of the coolant channel that faces the cutting head.

14. A tool for machining a workpiece, having a cutting insert and a cutting insert holder for holding the cutting insert, wherein the cutting insert comprises: a clamping section which comprises at least one coolant channel configured as a through-hole; a cutting head having at least one cutting member which comprises a main cutting edge, a rake face which adjoins the main cutting edge, and a chip-breaking geometry which protrudes from the rake face or which is introduced into the rake face and which is configured to break a chip which is machined with the main cutting edge; and a cantilever arm which extends along a longitudinal axis of the cutting insert and connects the clamping section to the cutting head and which has a smaller diameter than the clamping section; wherein the cutting insert is configured in a monolithic manner so that the clamping section, the cutting head and the cantilever arm are integrally connected to each other; and wherein a portion of the cutting head comprising the chip-breaking geometry, when viewed along the longitudinal axis of the cutting insert, covers at least 10% of a cross section of the coolant channel, but a maximum of 80% of the cross section of the coolant channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] FIG. 1 shows a perspective view of an exemplary embodiment of the cutting insert,

[0051] FIG. 2 shows a side view of an exemplary embodiment of the tool with the cutting insert and a cutting insert holder which is illustrated schematically and in section,

[0052] FIG. 3 shows a partial view of a cutting head of the cutting insert from FIG. 1;

[0053] FIG. 4 shows a detailed view of a cutting member of the cutting head illustrated in FIG. 3;

[0054] FIG. 5 shows a plan view from the front of the cutting insert illustrated in FIG. 1; and

[0055] FIG. 6 shows a detail from FIG. 5.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0056] FIG. 1 and FIGS. 3 to 6 show an exemplary embodiment of the cutting insert in various views. The cutting insert is designated 10 in its entirety. FIG. 2 shows an exemplary embodiment of the tool which comprises the cutting insert and an associated cutting insert holder. The tool is designated 100 in its entirety.

[0057] The cutting insert 10 shown in FIG. 1 is a cutting insert for a reaming tool. The cutting insert 10 has a clamping section 12, a cutting head 14 and a cantilever arm 16. The cutting insert 10 is configured in a monolithic manner. It thus comprises one piece, wherein the clamping section 12, the cutting head 14 and the cantilever arm 16 are connected to each other in an integral manner. The cutting head 10 is preferably produced completely from hard metal.

[0058] The clamping section 12 serves to clamp the cutting insert 10 in a cutting insert holder 18 (see FIG. 2). In the exemplary embodiment shown in this instance, the clamping section is configured in a cylindrical manner. Accordingly, the cutting insert receiving member 20 provided in the cutting insert holder 18 also has a cylindrical cross section. However, it is self-evident that the clamping section 12 and the cutting insert receiving member 20 may have any other cross sectional shapes (for example, shaped in a rectangular, square, oval or complex manner).

[0059] The cutting insert receiving member 20 which is provided in the cutting insert holder 18 is preferably in the form of a pot-like receiving member in which the cutting insert 10 can be introduced from the front side. Screws or other securing means may be provided in order to fix the cutting insert 10 in the cutting insert receiving member 20. In the assembled state, the clamping section 12 of the cutting insert 10 preferably abuts along the circumference thereof and with the end rear side 22 thereof against corresponding counter-abutment faces in the cutting insert receiving member 20. Instead of a complete abutment, a partial abutment against the circumference of the clamping section 12 may also be provided.

[0060] The cutting insert holder 18 is illustrated schematically in FIG. 2. The cutting insert holder 18 may be a conventional tool holder. Similarly, the cutting insert holder 18 may also be a part of a machine tool in which the cutting insert 10 is used. For example, in the latter case, the cutting insert holder 18 is a clamping chuck which is integrated directly in the machine tool.

[0061] The cutting head 14 has in the exemplary embodiment shown in this instance five cutting members 24 which protrude laterally from the cutting head 14. Each of these cutting members 24 has a main cutting edge 26 and an auxiliary cutting edge 28 which adjoins the main cutting edge 26 and which extends transversely relative thereto (see FIGS. 3-4). The main cutting edge 26 and the auxiliary cutting edge 28 are in the exemplary embodiment shown in this instance in the form of linear cutting edges. The main and auxiliary edges 26, 28 are adjoined inwardly by a clamping face 30 which can be seen in particular in the detail illustrated in FIG. 4.

[0062] A chip-breaking geometry 32 which in practice is also often referred to as a chip guiding step is arranged on the rake face 30.

[0063] The chip-breaking geometry 32 is configured to break a chip (not illustrated) which is machined with the main cutting edge 26. This is carried out substantially by means of chip deformation. The chip which is machined at the main cutting edge 26 is redirected by means of the chip-breaking geometry 32, whereby it is even more powerfully curved and is thereby forced to break.

[0064] The chip-breaking geometry 32 is in the embodiment shown in this instance in the form of a raised geometry which protrudes upward from the rake face 30. In principle, however, it is also possible to configure the chip-breaking geometry as a recessed structure which is introduced into the rake face 30.

[0065] Depending on the type of use and configuration of the cutting insert 10, the cutting head 14 may also comprise more or less than five of these cutting members 24. For example, the cutting head 14 of the cutting insert 10 may also comprise only one cutting member 24. This is mostly the case particularly when the cutting insert 10 is used in a turning tool. Of course, the cutting head 14 when used as a turning tool cutting insert is shaped very differently from the one in the exemplary embodiment shown in this instance.

[0066] There are arranged in the clamping section 12in accordance with the number of cutting members 24in the present exemplary embodiment five coolant channels 34 which serve to supply coolant to the cutting head 14. From these coolant channels 34 one coolant jet is discharged in each case and is orientated in each case with respect to one of the cutting members 24. These coolant jets preferably strike the cutting head 14 as free jets without being diverted or redirected by the cantilever arm 16. The cantilever arm 16 which connects the clamping section 12 to the cutting head 14 therefore preferably has a smaller diameter than the clamping section 12 and the cutting head 14. The cantilever arm 16 extends substantially along the longitudinal axis 38 of the cutting insert 10.

[0067] The coolant supply to the individual coolant channels 34 is carried out via the cutting insert holder 18. To this end, for example, a coolant channel 36 which feeds all the coolant channels 34 provided in the cutting insert 10 together is provided in the cutting insert holder 18. Alternatively, however, a plurality of coolant channels 36 which supply the coolant channels 34 provided in the cutting insert 10 individually may also be provided in the cutting insert holder 18. At this point, it should also be noted again that, in the event of a configuration of the cutting head with only a single cutting member 24, preferably only one coolant channel is also provided inside the clamping section 12.

[0068] Each of the coolant channels 34 extends preferably parallel with the longitudinal axis 38 of the cutting insert 10. Each of the coolant channels 34 is in the form of a through-hole which extends through the clamping section 12. The respective through-hole has a contour which is completely closed at the circumference. The coolant channels 34 are thus in each case closed at the circumference so that laterally no coolant can be discharged from the clamping section 12 of the cutting insert 10.

[0069] The arrangement of the coolant channels 34 relative to the cutting members 24 will be discussed in greater detail below. This is carried out using the example of a coolant channel 34 or a cutting head 24.

[0070] The coolant channel 34 is arranged in such a manner that, in the plan view from the front of the cutting insert, as illustrated in FIGS. 5 and 6, it is at least partially concealed by the cutting member 24 which is associated therewith. The coolant channel 34 is in this instance in particular concealed by the portion of the cutting member 24 on which the chip-breaking geometry 32 is arranged. Preferably, the portion of the cutting member 24 comprising the chip-breaking geometry 32, when viewed as a plan view from the front along the longitudinal axis 38 of the cutting insert 10, covers at least 10% of the cross section of the coolant channel 24, but a maximum of 80% of the cross section of the coolant channel 34. An optimum cooling and lubrication of the components of the cutting head 14 used in the machining processing operation is thereby ensured.

[0071] The cutting member 24 and the chip-breaking geometry 32 which is arranged thereon are preferably arranged to be offset radially outward relative to the coolant channel 34. It is particularly preferable for a center axis 40 of the coolant channel 34 to be orientated parallel with a surface portion 42 of the chip-breaking geometry. The mentioned surface portion 42 which is located at the upper side of the chip-breaking geometry 32 may also be arranged in a plane with the center axis 40 of the coolant channel 34.

[0072] Although a portion of the coolant jet which is discharged from the coolant channel 34 as a result of the mentioned coverage of the coolant channel 34 strikes the rear side of the cutting head 14, it has nonetheless been found that such an arrangement of the coolant channel 34 relative to the cutting head 14 ensures an optimum cooling and lubrication and also an optimum chip removal since the coolant can thus flow around the cutting head 14 or the cutting member 24 thereof in an optimum manner.

[0073] Various other optimizations of the cutting insert 10 are possible. The coolant channel 34 does not necessarily have to be configured with a circular cross section. Oval or elliptical cross sections are, for example, also conceivable in order to construct the coolant jet in a flat manner as far as possible. There may further be provision for the cross section of the coolant channel 34 to taper from the first end thereof facing away from the cutting head 14 toward the second end thereof facing the cutting head 14. A type of nozzle effect is thereby achieved, by means of which the coolant is accelerated within the coolant channel 34. Alternatively, the coolant channel 34 may also be recessed or stepped in the interior thereof so that, for example, a first portion which adjoins the first end has a larger diameter and a second portion which adjoins the second end has a smaller diameter. Various other adaptations, in particular to the shape of the cutting head 14, are, as already mentioned, also possible depending on the application of the cutting insert 10.