KR20070085686A - Cutting insert with cutting tips anchor portions - Google Patents

Abstract

The present invention provides a cutting insert which includes: a cutting insert body having a plurality of cavities formed therein; a plurality of cutting tips, each of the plurality of cutting tips disposed in a respective cavity, the cutting tips having a geometry that provides a mechanical retention or lock when inserted into the cavities of the cutting insert body, said geometry including an anchor portion and substantially spaced away from the cutting edge of the body, and further comprising a braze j oint, between each of. the... cutting tips and the cutting insert body. The cutting insert body and/or the cutting tips have at least one asymmetric feature.

Description

CUTTING INSERT WITH CUTTING TIPS ANCHOR PORTIONS

The present invention relates to a cutting insert with a cutting edge formed from an ultrahard abrasive.

Indexable cutting inserts are typically polygons with superhard materials placed at the corners. Ultrahard materials, usually cubic boron nitride or polycrystalline diamond materials, aid in the cutting of hard workpieces such as metals. These cutting inserts are typically mounted to the cutting tool in a fixed position such that one of the corners or areas comprising the ultrahard material is present on the surface of the workpiece. Over time, areas of ultrahard material wear out.

There are two excellent ways to make such inserts. According to the first technique, a laminate structure is formed comprising a first layer of hard backing material and a layer of superhard cutting material superimposed on the backing layer. The cutting tip is then cut from this laminated structure and brazed to the cutting insert body, typically at the corner (US Pat. No. 5,183,362).

However, there are various problems associated with such techniques. The braze joints that connect the cutting tip to the body of the cutting insert have inherent weaknesses in the structure. In particular, this is due to the high temperatures present in the use of such cutting inserts (these high temperatures are close to the hard joint). In addition, relatively complex fixtures must be used in brazing treatments.

A second technique of forming a replaceable cutting insert includes providing a blank or plate having a pocket formed in the insert and filled with an ultrahard material, and performing a sintering operation in which the blank is bonded to the plate with the hard material. Include. The blank is then machined substantially, giving a cutting insert of a typically polygonal body having its final shape, a superhard material disposed at the corner of the insert (ie US Pat. No. 5,676,496).

Such techniques also present some difficulties. One disadvantage associated with this second technique is the presence of an upper limit of the useful volume of ultrahard material in the finished insert. Another disadvantage associated with this second technique is that if one pocket of ultrahard material is defective, the entire insert may not be sold and may be discarded.

French Patent Publication No. 2,691,657 discloses a cutting insert made in a special autocentering shape made of polycrystalline diamond, CBN or other cutting material. The insert is not brazed and is fixed to the tip by a spring.

French Patent Publication No. 2,706,339 also discloses an insert of similar material of a shape (including a fixed lug) such that the insert can be fixed in the corresponding hole of the tip by mechanical wedging without brazing. .

WO 2004/105983 discloses a cutting insert, the cutting insert comprising a cutting insert body having a plurality of cavities formed in the insert, a plurality of cutting tips, each of the plurality of cutting tips being disposed in a respective cavity, The cutting tip provides mechanical retention or lock when inserted into the cavity of the cutting insert body, and the cutting tip is brazed to the cutting insert body.

Thus, there is a need to address the problems discussed above in the art.

A cutting insert 60 for application to turning, milling, drilling or other machining according to the invention consisting of one or more cutting tips 20 and insert body 32 is shown in FIG. 1. The cutting tip has a geometry that provides mechanical retention or locking when inserted into the cavity of the insert body. The cutting tip 20 is attached to the cavity of the body 32 by any suitable technique along the interface 40. Suitable techniques include glue, soldering or brazing. Preferably, the cavity is provided with a shape or geometry complementary to the shape or geometry of the cutting tip disposed thereon. As shown in FIG. 1, the cutting tip at the top surface of the cutting insert is symmetrical (20x) and asymmetrically disposed at the insert, or asymmetrical (20y) in at least one direction.

More specifically, the one or more cutting tips are disposed asymmetrically with respect to the bisector through the corners of the cutting insert body, and / or the one or more cutting tips are symmetrical with respect to the bisector through the top surface of the cutting tip and / or one or more cutting tips. The cutting tip is asymmetrical at the cutting edge with respect to the straight line dividing the cutting edge of the cutting tip symmetrically and / or the at least one cutting tip is asymmetrical at the rear anchoring portion with respect to the straight line dividing the cutting edge of the cutting tip symmetrically; Or, the one or more cutting tips are asymmetric in a plane that symmetrically divides the cutting tip between the top and bottom surfaces.

It is clear that the asymmetry is expressed differently from the cutting edge and the rear anchor.

Cutting tips 20 included in the present invention are shown in FIGS. 2A (symmetrical) and 2B (asymmetrical). Converging front face pairs 22a and 22b meet at a front nose 24 which is preferably circular. The nose 24 is represented on the workpiece in use of the cutting tip. As shown in FIGS. 2A and 2B, the surfaces 22a and 22b, and at least a portion of the nose 24, comprise a superhard material 16. Moving in a direction away from the front nose 24, next to the opposing surfaces 22a and 22b is a region or a waisted section 25 in which the width is reduced. The waist is formed by the first pair of inclined surfaces 26a and 26b as well as the second pair of surfaces 28a and 28b. Surfaces 26a and 28a as well as surfaces 26b and 28b are trough-like structures that meet in areas of decreasing width and are given in an essentially trapezoidal shape. Surfaces named 'a' and 'b' may be the same length as shown in FIG. 2A or may differ in length and shape as shown in FIG. 2B. The base portion 29 is substantially flat, although other shapes are possible, including ellipses, circles, and polygons.

Ultrahard materials include boron nitride such as cubic boron nitride (CBN), diamond materials such as polycrystalline diamond (PCD), or suitable oxides such as alumina, or ceramic nitrides such as silicon nitride, or compounds thereof. CBN, PCD, or ceramic materials may be added with other materials such as carbides, nitrides, carbides, oxides, and / or borides of the metals of Groups IVa-VIa of the periodic table, and other elements known in the art, such as Al Can be.

Preferably, the CBN composition comprises 40 to 80 vol%, most preferably 55 to 70 vol%, the average particle size of which is 30 µm or less, preferably 5 µm or less, more preferably 0.1 to 4 µm. , In essence, one or more CBN particle sizes, such as in two modes.

Usually, PCBN materials also contain lesser amounts (typically less than 10 wt% each) than other elements, such as Co, Ni, Al, W (eg, often compounds such as WC, AIN and usually Al ₂ O ₃ ). .

In another embodiment, the PCBN material according to the invention comprises at least 2 wt% aluminum compound with at least 60 wt% CBN, preferably at least 80 wt% CBN, and may typically comprise other compositions of Co based. . This material is particularly useful for the machining of cast iron.

3A-3G show three optional cutting tip shapes, with at least the top surface being symmetrical (20a, 20b and 20c). These cutting tip shapes depend on the amount of ultrahard material included. As shown in the figure, the cutting tip 20a may be formed so that the ultrahard material has a relatively few composition, or the cutting tip 20b may be formed so that the whole is made of the ultrahard cutting material.

In one embodiment, the superhard material 16 is continuous from the top surface of the tip (not shown in FIGS. 3A, 3B, and 3C) to the opposite bottom surface of the tip shown by way of example in FIG. 3D.

In an alternative embodiment, the ultrahard material is discontinuous from the top surface of the tip to the opposite bottom surface of the tip (not shown in FIGS. 3A, 3B, 3C) and shown by way of example in FIGS. 3E and 3F. Interposed at least one layer of material different from the top and bottom superhard materials. The shape shown may be symmetrical as in FIG. 3F or asymmetrical as in FIG. 3E, but vice versa.

In another embodiment, the superhard material 16 is shown with only the top surface of the tip (not shown in FIGS. 3A, 3B, and 3C), and the opposite bottom surface of the tip is the top surface shown by way of example in FIG. 3G. It is provided with a layer different from the ultra hard material.

A material different from a superhard material herein means one or more of another super hard material, a hard material such as a predetermined carbide alloy, and a soft material such as a predetermined solder alloy.

The insert body 32 of FIG. 1 is composed of any suitable hard material. Examples of suitable materials include cemented carbide, cermet, and hard metal alloys, and may be high speed steels for application in drilling, and any suitable composition of WC-Co cemented carbide is preferably known in the art. 5 to 20 wt% of Co, as indicated.

Preferably the cutting insert body 32 shown is polygonal or diamond shaped and is configured to receive two cutting tips. However, the shape of the body may be any conventional known art. Body 32 may be formed to receive any suitable number of tips. The tips disposed on the main body 32 need not be identical to each other. An optional central through hole 36 is used for clamping, the actual shape being in accordance with the application of the known art.

4A is an embodiment according to the invention of a thread cutting insert that can be used in rotary operation. In this case, the cutting tip 20d is formed and inserted so as to lie asymmetrically with respect to the bisector A-A of the corner of the insert.

4B is an embodiment according to the invention of a thread milling insert. In this case, the rear part of the cutting tip is arranged symmetrically along the cutting insert body with a plurality of retentions, and the cutting edge which will come into contact with the workpiece is asymmetric.

4A and 4B are illustrated using the shape of FIG. 3C described above.

5 is another embodiment of a thread cutting insert according to the invention. In addition, the cutting tip is asymmetrical with respect to the bisector of the corner of the cutting insert and further has different cutting tip shapes 20a, 20b and 20c. 5 is another embodiment because the cutting tip is asymmetrical with respect to the bisector of the cutting edge with the asymmetric back anchor of the cutting tip of 20c. The remaining reference numerals are determined in FIG. 2A.

6A-6E show another embodiment of a cutting insert according to the invention of an oversized size of a cutting tip having the shape of FIG. 3C as an example. 6A is a square (possibly rectangular) cutting insert with cutting tips typically disposed asymmetrically with respect to the bisector of the insert corner. 6B and 6D are similar triangular inserts with the cutting tip disposed symmetrically (FIG. 6B) and asymmetrically (FIG. 6D) with respect to the bisector of the corner of the insert. In Fig. 6B, when attached to the cutting insert body, the cutting tip is asymmetric in two directions at the cutting edge. 6C and 6E are also similar parting-off tools, with cutting tips disposed symmetrically (FIG. 6C) and asymmetrically (FIG. 6E) with respect to bisectors through the cutting edge. In FIG. 6C, the cutting tip is also asymmetrical, for example by an inclined top surface with tip breaking characteristics.

7A and 7B are yet another embodiment of the present invention. In this case, the cutting tip 52 is typically located in the drill, indicated by 50. As shown in Fig. 7A, the drill has a single cutting tip, and the drill shown in Fig. 7B has two cutting tips 52 disposed on both sides of the central axis of the drill. Although not shown, the drill may be equipped with a flute, otherwise it is a conventional product. In FIG. 7A the cutting tip is arranged essentially parallel to the central axis of the drill, and in FIG. 7B the cutting tip is arranged essentially perpendicular to the axis.

8A-8C show side cross-sectional views of the drill of the present invention. For example, FIG. 7A is a cross section taken along the line (A-A) of FIGS. 8A, 8B and 8C. 8B and 8C are also cross sections (B-B) of the embodiment of FIG. 7B.

9 shows another embodiment of the invention in which the surfaces 28a 'and 28b' are asymmetric with different lengths. The cutting tip is still attached to the body belonging to the cutting insert body 32. In this particular embodiment, for simplicity a tool named cutting insert can be used as a boring bar, or can be used for internal turning of the workpiece, and the cutting tip can be used for a locking feature as compared to FIG. Cut in the other direction.

10 is a side view of an insert of the invention similar to FIG. 11C, for example with a cutting tip used as a peel tool.

The insert is fixed in the cavity, typically indicated at 60, and corresponds to the shape of the anchor portion of the insert. The cutting tip operates in a different direction with respect to the locking arrangement as compared to FIG. 1.

FIG. 11 is a top view of a small portion of the inner boring bar, which is named cutting tip having an internal locking configuration at least partially in the mutual interface of the divided rod and the cutting tip. FIG. The cutting tip cuts in a different direction with respect to the locking arrangement as compared to FIG. 1.

In addition, the insert 60 of FIG. 1 may be provided with a chip breaker configuration as disclosed in US Pat. No. 5,569,000.

Cutting tip 60 may be provided with a coating comprising at least one layer known in the art at least on its working surface.

In the detailed description the cutting tip has a plane which occupies the same space as the plane of the insert body. It is clear that the plane of the cutting tip can be positioned and / or inclined below or above the insert body plane using the adjusted anchor and / or the cutting tip shown in FIGS. 6B and 6C.

Inserts according to the invention can be produced, for example, according to the method disclosed in WO 2004/105983. A symmetrical 'a' or asymmetrical 'b' cutting tip is prepared from the blank of FIG. 2 of WO 2004/105983, as shown by blank 10 in FIG. 12. The blank comprises a plurality of pockets 14 filled with superhard material 16. The cutting tip 20 is formed after cutting along the contour 18 forming the rear anchor portion 21. The cutting tip is then placed and attached symmetrically or asymmetrically to the cutting insert body.

Also possible are the methods disclosed in US 4,714,385 or US 5,813,105.

1 is a plan view of a cutting insert formed in accordance with the present invention, where the black areas represent superhard materials.

2A and 2B are plan views showing detailed geometrical shapes of cutting tips formed in accordance with the present invention.

3A-3G are top and side views of various cutting tips formed in accordance with the present invention.

4A and 4B are plan views of thread cutting inserts and thread milling inserts, respectively, formed according to the invention.

5 is a plan view of another type of thread cutting insert formed in accordance with the invention.

6A-6E are top and three side views of another insert formed in accordance with the present invention.

7A and 7B are side cross-sectional and plan views, respectively, of a drill formed in accordance with the present invention.

8A, 8B and 8C are side cross-sectional views of a drill shape formed in accordance with the present invention.

9 is a side view of a tool that can be used for internal turning, boring, slotting, or parting, formed in accordance with the present invention.

10 is a side view of a peeling and grooving tool formed in accordance with the present invention.

11 is a plan view of a tool formed in accordance with the present invention.

12 is a plan view of a blank comprising a plurality of pockets filled with ultrahard material and a cutting line for removal of a plurality of cutting tips therefrom.

Claims (34)

A cutting insert, comprising: a cutting insert body having a plurality of cavities formed in the insert, and a plurality of cutting tips, each of the plurality of cutting tips being disposed in a respective cavity and cutting upon insertion into a cavity of the cutting insert body The tip has a geometry that provides mechanical retention or locking, the geometry comprising an anchor portion having a base substantially disposed in a direction away from the cutting edge of the body, each having one or more asymmetrical configurations in the cutting insert. The cutting insert further comprising a joint between the cutting tip and the cutting insert body. The cutting insert of claim 1, wherein the one or more cutting tips are disposed asymmetrically with respect to bisectors through the corners of the cutting insert body. The cutting insert of claim 1, wherein the at least one cutting tip is asymmetrical with respect to bisector through the top surface of the cutting tip. The cutting insert of claim 1, wherein the at least one cutting tip is asymmetrical with respect to a straight line that symmetrically divides the anchor portion of the cutting tip at the cutting edge. The cutting insert of claim 1, wherein the at least one cutting tip is asymmetrical with respect to a straight line that symmetrically divides the cutting edge of the cutting tip at the rear anchor portion. The cutting insert of claim 1 wherein each cutting tip comprises at least partially an ultrahard cutting material. The cutting insert of claim 1 wherein each of the cutting tips is entirely made of a hard cutting material. 8. The cutting insert according to claim 6 or 7, wherein the ultrahard material comprises cubic boron nitride or polycrystalline diamond. 9. The cutting insert according to claim 8, wherein the ultrahard material comprises at least one of nitrides, carbide nitrides, oxides or borides of Group IVa-VIa metals of the periodic table. 8. The composition of claim 6 or 7, wherein the ultrahard material comprises a composition having a first phase comprising cubic boron nitride or polycrystalline diamond particles and a second phase comprising metal, metalloid, or alloys thereof. Cutting inserts. The cutting insert of claim 1, wherein the cutting edge portion comprises a top surface and an opposite bottom surface, and the hard material runs from top to bottom to form two cutting edges. The method of claim 1, wherein at least the cutting edge portion comprises a top surface and an opposing bottom surface, wherein the ultrahard material extends from the top cutting edge surface and the bottom cutting edge surface to one or more insert materials different from the material of the cutting edge, Cutting inserts. The cutting insert of claim 1, wherein at least the cutting edge portion comprises a top surface and an opposite bottom surface, and the ultrahard material extends from the top cutting edge surface and the bottom surface to a material different from the material of the cutting edge. 13. The cutting insert of claim 12, wherein the insert material is part of a cutting tip. 13. The cutting insert of claim 12, wherein the insert material is part of a cutting insert body. The cutting insert according to claim 1, wherein the anchor portion of the cutting tip has a conventional trapezoidal shape. The cutting insert of claim 16, wherein the anchor portion of the cutting tip is substantially flat. The cutting insert of claim 1, wherein the anchor portion of the cutting tip has a polygon. The cutting insert of claim 1, wherein the anchor portion of the cutting tip has an elliptical or circular shape. 20. The cutting insert according to any one of claims 16 to 19, wherein the cutting tip comprises a rounded front nose and opposing front face pairs at the noses. 21. The cutting insert according to any one of the preceding claims, wherein the cutting tip is provided with a waist portion having a reduced width compared to the anchor portion. 22. The cutting insert of claim 21 wherein the waist comprises a first angled pair of surface substantially and a second pair of surface meeting in a region of reduced width relative to the anchor portion. The cutting insert of claim 1, wherein the cutting insert body is formed of a cemented carbide, cermet, or hard metal alloy. The cutting insert of claim 23, wherein the cutting insert body comprises a cemented carbide alloy comprising WC and Co, wherein the cemented carbide alloy comprises 5-20 wt% Co. The cutting insert of claim 24, wherein the cutting insert body is polygonal. 26. The cutting insert according to any one of claims 1 to 25, wherein the cavity has a shape that is sufficiently complementary to the shape of the cutting tip. The cutting insert of claim 1, wherein at least one of the cutting tips comprises a coating disposed on at least a portion thereof. The cutting insert of claim 1, wherein the cutting insert body comprises a chip breaking configuration. The cutting insert of claim 1, wherein the cutting insert body is a peeling and grooving tool. The cutting insert of claim 1, wherein the cutting insert body is a boring tool. The cutting insert of claim 1, wherein the cutting insert body is a drill. The cutting insert of claim 31, wherein the one or more cutting tips are disposed substantially parallel to the axial direction of the drill. 32. The cutting insert of claim 31 wherein the cutting tip is disposed substantially perpendicular to at least the axial direction of the drill. The cutting insert of claim 1 wherein the joint is a brazed joint.

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