IL293464A - A cutting insert with cooling channels - Google Patents

Description

A CUTTING INSERT WITH COOLING CHANNELS TECHNOLOGICAL FIELD This invention relates to cutting inserts, in particular cutting tools and cutting inserts comprising internal cooling mechanisms.

BACKGROUND ART References considered to be relevant as background to the presently disclosed subject matter are listed below: - US9095913B- US9656323BAcknowledgement of the above references herein is not to be inferred as meaning that these are in any way relevant to the patentability of the presently disclosed subject matter.

BACKGROUND It is known in the art to provide a cooling fluid, i.e., coolant, to a cutting interface of a cutting tool during a cutting operation on a workpiece. Provision of the cooling fluid cools the cutting interface during the cutting operation, thereby preventing damage to both the cutting edge and the workpiece. In general, cutting tools have a rake face and at least one relief face, defining, at the intersection thereof, the tool’s cutting edge. Cooling fluid is generally provided to the cutting interface, either from the side of the rake face, or from the side of the relief face, or from both external cooling supply arrangements. Cutting tools may also include cutting inserts, which perform the actual machining. Such cutting inserts are associated with cooling arrangements, separate from the cutting insert, which are configured for external provision of cooling fluid to the cutting insert. Conventional cutting inserts may have a cutting corner region defined between a first side surface, second side surface and one of the upper surface and a lower surface. A cooling cavity, including a cooling surface proximal to the cutting corner region, is configured for receiving therein the cooling fluid for cooling the cooling surface, and thereby withdraw heat from the cutting corner region. Typically, the entire cutting corner region is coated with a coating to increase durability; however, the coating may decrease the thermal conductivity of the cooling surface, reducing the effectiveness thereof.

GENERAL DESCRIPTION Accordingly, an object of the present disclosure is to increase thermal conductivity of the cooling surface by leaving the cooling surface free of the coating material, which covers the remainder of the cutting corner region. In accordance with a first aspect of the presently disclosed subject matter there can be provided a cutting insert comprising: an upper surface, a lower surface and a plurality of side surfaces extending therebetween, the plurality of side surfaces including a first side surface and a second side surface adjacent to the first side surface, a cutting corner region defined between the first side surface, the second side surface and one of the upper surface and the lower surface, a first coating material on the cutting corner region, and a cooling cavity having a cooling surface proximal to the cutting corner region, said cooling cavity being configured for receiving therein a cooling fluid for cooling said cooling surface and thereby withdraw heat from the cutting corner region, said cooling cavity, at least at its cooling surface, being free of said first coating material. In accordance with a second aspect of the presently disclosed subject matter there can be provided a masking arrangement for use in the coating process of the cutting insert, the masking arrangement can comprises a masking element comprising at least one fitting portion having corresponding dimensions to at least a portion of the cooling cavity including said cooling surface, said at least one fitting portion being configured for mounting in said cooling cavity during said coating process such that each fitting portion covers and thereby protects at least said cooling surface from being coated. In accordance with a third aspect of the presently disclosed subject matter there can be provided a method for partially coating at least one cutting insert comprising an upper surface, a lower surface and a number of side surfaces extending therebetween, and comprising a cutting corner region defined between two, first and second, adjacent side surfaces and one of the upper and lower surfaces, and a cooling cavity having a cooling surface proximal to the cutting corner region, said cooling cavity being configured for receiving therein a cooling fluid for cooling said cooling surface and thereby withdraw heat from the cutting corner region, said method comprising: a. providing a masking arrangement comprising a masking element including at least one fitting portion having corresponding dimensions to at least a portion of the cooling cavity including said cooling surface; b. mounting said at least one fitting portion in said cooling cavity of the cutting insert such that said fitting portion covers said cooling surface to form a masked insert assembly; c. coating said masked insert assembly with a coating material having a lower heat conductivity value than that of the cutting insert. Any one or more of the following featured designs and configurations can be applied to any of the aspects of the present disclosure, separately or in combinations thereof: The cooling cavity can comprise a channel having a coolant inlet and a coolant outlet different from the coolant inlet and having the cooling surface disposed therebetween. The cooling cavity can extend inwardly from one of the upper and lower surfaces. The cooling cavity can have at least a surface exposed to the exterior of the cutting insert which is free from being coated with said first coating material. The cooling surface of the cooling cavity can be exposed to the exterior of the cutting insert. The cooling surface can also face in the direction of the exterior of the cutting insert. The entire cooling cavity can free of said coating material. The cooling cavity can extend from a corresponding one of said upper surface and said lower surface. The cooling cavity can be encompassed by the corresponding one of the upper surface and the lower surface; and wherein at least a portion of the corresponding one of the upper surface and the lower surface, including the cutting corner region, can be coated with said first coating material.

The entire corresponding one of the upper surface and the lower surface encompassing the cooling cavity can be coated with said coating material. The cutting insert can comprise a central axis extending normal to the one of the upper surface and the lower surface, wherein the cooling cavity can extend along an axis perpendicular to the central axis towards the cutting corner region. The channel can comprise an upstream section associated with the coolant inlet, extending towards the cutting corner region along and spaced from the first side surface, a downstream section associated with the coolant outlet, extending away from the cutting corner region and extending along and spaced from the second side surface, and a curved section associated with the cooling surface interconnecting the upstream and downstream sections. The cooling cavity can comprise a cavity having a single opening constituting both the coolant inlet and the coolant outlet. The cooling cavity can have a maximal depth which is less than half the distance between the upper and lower surfaces. The cutting insert can comprise a material having a first thermal conductivity, wherein the first coating material can have a second thermal conductivity lower than the first thermal conductivity. The boundaries between coated and uncoated portions of the cutting insert can be distinct from each other. The cooling cavity, at least at its cooling surface, can be coated with a second coating material different from the first coating material of the cutting corner region. The cooling surface can be not coated with any coating material. The cutting insert can be a first cutting insert, and the at least one fitting portion can be further configured, while being mounted on said cooling cavity of said first cutting insert, to be mounted with and support a second cutting insert in a spaced apart manner with respect to the first cutting insert. The second cutting insert can be identical to the first cutting insert, and the at least one fitting portion can include: a first fitting portion positioned at a first end of the masking element, and a second fitting portion positioned on an opposite end thereof, configured to fit within a cooling cavity of said second cutting insert. The cutting insert can comprise two or more cooling cavities, and wherein the at least fitting portion can comprise a plurality of fitting portions, each configured to be mounted in a respective cooling cavity. The plurality of fitting portions can be configured with an identical shape. The plurality of fitting portions can be positioned differently relative to one another. The cutting insert can comprise two or more cooling cavities, and the masking arrangement can comprise a plurality of conjoined fitting portions, each configured to be mounted to a respective cooling cavity. The masking element and the fitting portions can comprise a single body. The masking element can comprise a base having one or more fitting sockets and a corresponding number of the plurality of fitting portions fitted therein. The masking arrangement can comprise a plurality of bases each configured with a single set of the plurality of fitting portions protruding therefrom. The at least one cutting insert can be a plurality of cutting inserts, and said at least one fitting portion can be a plurality of fitting portions, each configured to be mounted with and support one of the plurality of cutting inserts in a spaced apart manner, and the method can further comprise, prior to step (c), stacking the plurality of fitting portions and the plurality of cutting inserts, such that the plurality of cutting inserts are spaced from each other by the plurality of fitting portions.

In accordance with a fourth aspect of the presently disclosed subject matter there can be provided a cutting insert partially coated by the aforementioned method.

BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Fig. 1A is a perspective view of a cutting insert according to an example of the presently disclosed subject matter; Fig. 1B is an enlarged plan view of a cutting corner region of the cutting insert of Fig. 1A; Fig. 1C is a cross sectional view along a plane I-I in Fig. 1A, which a cutting insert of the presently disclosed subject matter may have, the plane I-I passing through two upper and two lower cutting corner regions; Fig. 1D is a perspective view of a coolant dispensing nozzle, according to an example of the presently disclosed subject matter, for use with the cutting insert of Fig. 1A; Fig. 2A is a perspective view of a cutting insert according to another example of the presently disclosed subject matter, when mounted on a base plate with a coolant dispensing nozzle received in a nozzle receiving through-bore of the cutting insert; Fig. 2B is a perspective view of the base plate assembled with the coolant dispensing nozzle of Fig. 2A; Fig. 2C is a cross sectional view of the cutting insert of Fig. 2A along a plane II-II passing through two upper and two lower cutting corner regions, and an axis of the nozzle receiving through-bore; Fig. 2D is an enlarged cross-sectional view of the coolant dispensing nozzle of Fig. 2C; Fig. 3A is a perspective view of a cutting insert with a central nozzle receiving through-bore and a cover, according to another example of the presently disclosed subject matter; Fig. 3B is a perspective view of a base plate and a coolant dispensing nozzle configured for use with the cutting insert of Fig. 3A; Fig. 3Cis a plan view of the cutting insert of Fig. 3A without the cover; Fig. 3D is a cross sectional view of the cutting insert of Fig. 3A when mounted on the base plate with the coolant dispensing nozzle of Fig. 3B received in the nozzle receiving through-bore of the cutting insert along a plane III-III shown in Fig. 3C passing through two upper and two lower cooling channels; Fig. 3E is an enlarged cross-sectional view of the coolant dispensing nozzle of Fig. 3B; Fig. 3F is an exploded view of the cutting insert of Fig. 3A with a coolant dispensing nozzle thereof; Fig. 4A is a perspective view of an assembly including a cutting tool holder, a base plate and a cutting insert, according to an example of the presently disclosed subject matter; Fig. 4B is an exploded view of the assembly of Fig. 4A; Fig. 5A is a perspective view of a cutting insert according to a further example of the presently disclosed subject matter; Fig. 5B is an enlarged plan view of a cutting corner region of the cutting insert of Fig. 5A; Fig. 6A is a perspective view of a cutting tool holder, having the cutting insert of Fig 3A mounted thereon; Fig. 6B is a cross sectional view of the cutting tool of Fig. 7A, taken along a plane IV-IV; Fig. 7is an enlarged plan view of a cutting corner region of the cutting insert, according to further example of the presently disclosed subject matter; Fig. 8A is a cross sectional view, which a cooling channel in any of the cutting inserts of Figs. 1A, 3A, 5A, and any other cutting insert of the presently disclosed subject matter may have, the cross sectional view being taken at the area of merging of an upstream section and a curved section of the cooling channel perpendicular to horizontal surfaces of the cutting insert (such as, e.g., plane V-V in Fig. 7); Fig. 8B is another cross sectional view, which a cooling channel in any of the cutting insert of Figs. 1A, 3A, 5A, and any other cutting insert of the presently disclosed subject matter may have, the cross sectional view being taken at the same area as in Fig. 8A; Fig. 8C is a cross sectional view, which the cooling channel of Fig. 8A may have, the cross sectional view being taken at the area of merging of a curved section and a downstream section of the cooling channel perpendicular to horizontal surfaces of the cutting insert (such as, e.g., plane VI-VI in Fig. 7); and Fig. 8D is another cross sectional view, which a cooling channel of Fig. 8B may have, the cross sectional view being taken at the same area as in Fig. 8C; Fig. 9A is a cross-sectional view of a cutting corner region with coating added, except in the cooling channel; Fig 9B is a cross-sectional view of a cutting corner region with coating added, except in some portions of the cooling channel; Fig. 10A is a perspective view of a masking arrangement for use in a coating process of a cutting insert; Fig. 10B is an exploded view of the masking arrangement of Fig. 10A; Fig. 10C is a top view of the masking arrangement of Fig. 10A; Fig. 10D is a side view of the masking arrangement of Fig. 10A; Fig. 11A is a perspective view of a stacked masking arrangement; Fig. 11B is a side view of an alternative stacked masking arrangement; and Fig. 12 is a flow chart of a method of coating a cutting insert.

Claims (32)

- 30 - CLAIMS:

1. A cutting insert comprising: an upper surface, a lower surface and a plurality of side surfaces extending therebetween, the plurality of side surfaces including a first side surface and a second side surface adjacent to the first side surface, a cutting corner region defined between the first side surface, the second side surface and one of the upper surface and the lower surface, a first coating material on the cutting corner region, and a cooling cavity having a cooling surface proximal to the cutting corner region, said cooling cavity being configured for receiving therein a cooling fluid for cooling said cooling surface and thereby withdraw heat from the cutting corner region, said cooling cavity, at least at its cooling surface, being free of said first coating material.

2. The cutting insert of Claim 1, wherein said cooling cavity comprises a channel having a coolant inlet and a coolant outlet different from the coolant inlet and having the cooling surface disposed therebetween.

3. The cutting insert of Claim 1 or Claim 2, wherein said cooling cavity extends inwardly from one of the upper and lower surfaces.

4. The cutting insert of any one of the preceding claims, wherein the cooling cavity has at least a surface exposed to the exterior of the cutting insert which is free from being coated with said first coating material.

5. The cutting insert of any one of the preceding claims, wherein the cooling surface of the cooling cavity is exposed to the exterior of the cutting insert.

6. The cutting insert of Claim 5, wherein the cooling surface also faces in the direction of the exterior of the cutting insert.

7. The cutting insert of any one of the preceding claims, wherein the entire cooling cavity is free of said coating material. - 31 -

8. The cutting insert of any one of the preceding claims, wherein the cooling cavity extends from a corresponding one of said upper surface and said lower surface.

9. The cutting insert of Claim 8, wherein the cooling cavity is encompassed by the corresponding one of the upper surface and the lower surface; and wherein at least a portion of said corresponding one of the upper surface and the lower surface, including the cutting corner region, is coated with said first coating material.

10. The cutting insert of Claim 9, wherein the entire corresponding one of the upper surface and the lower surface encompassing said cooling cavity are coated with said coating material.

11. The cutting insert of any one of the preceding claims, wherein the cutting insert comprises a central axis extending normal to said one of the upper and lower surfaces, wherein the cooling cavity extends along an axis perpendicular to the central axis towards the cutting corner region.

12. The cutting insert of any one of Claims 2 to 11, wherein the channel comprises an upstream section associated with the coolant inlet, extending towards the cutting corner region along and spaced from the first side surface, a downstream section associated with the coolant outlet, extending away from the cutting corner region and extending along and spaced from the second side surface, and a curved section associated with the cooling surface interconnecting the upstream and downstream sections.

13. The cutting insert of any one of Claims 2 to 11, wherein the cooling cavity comprises a cavity having a single opening comprising both the coolant inlet and the coolant outlet.

14. The cutting insert of any one of the preceding claims, wherein the cooling cavity has a maximal depth which is less than half the distance between the upper and lower surfaces. - 32 -

15. The cutting insert of any one of the preceding claims, wherein the cutting insert comprises a material having a first thermal conductivity, wherein the first coating material has a second thermal conductivity lower than the first thermal conductivity.

16. The cutting insert of any one of the preceding claims, wherein the boundaries between coated and uncoated portions of the cutting insert are distinct from each other.

17. The cutting insert of any one of Claims 1 to 3, wherein the cooling cavity, at least at its cooling surface, is coated with a second coating material different from the first coating material of the cutting corner region.

18. The cutting insert of any one of Claims 1 to 3, wherein said cooling surface is not coated with any coating material.

19. A masking arrangement for use in a coating process of the cutting insert of any one of claims 1 to 18, said masking arrangement comprising a masking element comprising at least one fitting portion having corresponding dimensions to at least a portion of the cooling cavity including said cooling surface, said at least one fitting portion being configured for mounting in said cooling cavity during said coating process such that each fitting portion covers and thereby protects at least said cooling surface from being coated.

20. The masking arrangement according to Claim 19, wherein said cutting insert is a first cutting insert, and said masking element is further configured, while being mounted on said cooling cavity of said first cutting insert, to be mounted with and support a second cutting insert in a spaced apart manner with respect to the first cutting insert, optionally, said masking element is rigid and has a length greater than a depth of the cooling cavity of the first cutting insert, and particularly greater than the depth of a the cooling cavities of the first and second cutting inserts, combined.

21. The masking arrangement of Claim 20, wherein the second cutting insert is similar to said first cutting insert, and - 33 - wherein said at least one fitting portion includes: a first fitting portion positioned at a first end of the masking element configured to fit within a cooling cavity of said first cutting insert, and a second fitting portion positioned on an opposite end thereof, configured to fit within a cooling cavity of said second cutting insert.

22. The masking arrangement of any one of Claims 19 to 21, wherein said cutting insert comprises two or more cooling cavities, and wherein said at least one masking element comprises a plurality of masking elements, each configured to be mounted in a respective cooling cavity.

23. The masking arrangement of Claim 22, wherein the plurality of masking elements are configured with an identical shape.

24. The masking arrangement of Claim 23, wherein the plurality of masking elements are configured to be positioned in different orientations relative to one another.

25. The masking arrangement according to any one of Claims 19 to 24, wherein said cutting insert comprises two or more cooling cavities, and wherein said masking element comprises a plurality of conjoined fitting portions, each configured to be mounted to a respective cooling cavity.

26. The masking arrangement of Claim 25, wherein the masking element and the fitting portions comprises a single body.

27. The masking arrangement of Claim 25, wherein the masking arrangement comprises a base having one or more fitting sockets and a corresponding number of the plurality of masking elements configured to be fitted therein, in a manner in which they extend thereabove.

28. The masking arrangement of any one of Claims 19 to 27, wherein said masking element is rigid so as to support a cutting insert from below. - 34 -

29. The masking arrangement of any one of Claims 19 to 28, wherein said masking element is made of metallic material.

30. A method for partially coating at least one cutting insert comprising an upper surface, a lower surface and a number of side surfaces extending therebetween, and comprising a cutting corner region defined between two, first and second, adjacent side surfaces and one of the upper and lower surfaces, and a cooling cavity having a cooling surface proximal to the cutting corner region, said cooling cavity being configured for receiving therein a cooling fluid for cooling said cooling surface and thereby withdraw heat from the cutting corner region, said method comprising: a) providing a masking arrangement comprising a masking element including at least one fitting portion having corresponding dimensions to at least a portion of the cooling cavity including said cooling surface; b) covering, with said masking arrangement, said cooling cavity of the cutting insert such that said at least one fitting portion covers said cooling surface to form a masked insert assembly; c) coating said masked insert assembly with a coating material having a lower heat conductivity value than that of the cutting insert.

31. The method of Claim 30, wherein said at least one cutting insert is a plurality of cutting inserts, and said at least one masking element is a plurality of masking elements, each configured to be mounted with and support at least one of the plurality of cutting inserts in a spaced apart manner and said method further comprises, prior to step (c), stacking said plurality of masking elements and said plurality of cutting inserts, such that said plurality of cutting inserts are spaced from each other by said plurality of fitting portions.

32. A cutting insert partially coated by the method of Claims 30 or 31.