KR950000166B1 - Cutting tool assembly - Google Patents

Abstract

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Description

Cutting tool assembly

1 to 5 show a first embodiment of the invention.

1 is a perspective view of a cutting tool assembly.

FIG. 2 is a schematic perspective view showing cutting a workpiece with the cutting tool assembly shown in FIG. 1. FIG.

3 is an enlarged cross sectional view showing a state in which a workpiece is cut using the cutting tool assembly shown in FIG.

4 is a diagram showing a cut portion of the composite sintered body.

FIG. 5 is an exploded view of an arrangement of disassembled parts showing how the cut composite sinter fits into the groove of the stand.

6 to 8 are perspective views of various modifications of the first embodiment of the cutting tool assembly according to the invention.

9 to 13 are diagrams of a second embodiment of this invention.

9 is a perspective view of a composite cutting tool assembly.

10 is a perspective view of the cutting tool assembly of FIG. 9 used.

11 is a partially enlarged cross sectional view of a cutting tool assembly for cutting a workpiece.

12 is a perspective view showing a cut portion of the composite sintered body.

13 is an exploded view of an arrangement of disassembled parts showing how the cut sintered body fits into the groove of the stand.

14 is a perspective view of a variant of a second embodiment of a composite cutting tool assembly according to the present invention.

15 to 18 show a third embodiment of the invention.

15 is a perspective view of a cutting tool assembly having a breaker.

16 is a cross sectional view of the cutting tool assembly taken along the line XVI-VI of FIG.

17 is a perspective view showing how a cutting tool assembly with a breaker is used.

18 is a partially enlarged cross sectional view illustrating cutting a workpiece with a cutting tool assembly with a breaker.

19 and 20 are perspective views of a variant of the third embodiment of a cutting tool assembly according to the invention.

FIG. 21 is a perspective view showing cutting of a workpiece piece using the cutting tool assembly shown in FIG. 20. FIG.

22 and 29 are prior art cutting tools.

22 is a perspective view of a composite cutting tool assembly.

23 is an exploded view of an arrangement of disassembled parts showing how they are fixed relative to the cutting part.

24 is a perspective view of a composite cutting tool assembly.

25 is a cross sectional view showing the arrangement of a cutting part body with a stage having a breaker pin;

26 is a plan view of a cutting tool assembly with a breaker.

FIG. 27 is an enlarged cross sectional view of the cutting tool assembly seen along the line VII-VII of FIG. 26;

28 is a top view of a cutting tool assembly with a breaker.

FIG. 29 is an enlarged cross sectional view of the cutting tool assembly seen along line VII-28 of FIG. 28;

* Explanation of symbols for main parts of the drawings

1: large 2: groove

3: cutting part 3a: cutting edge part

3b: support 4: soldering

5: workpiece 6: chip breaker

11: vs 12: sintered body

13: cemented carbide 14: composite cutting part

15 tip 16 chip breaker

17: chip breaker pin 18: support

The present invention relates to a cutting tool assembly having a composite sintered body as a cutter.

High pressure stages Hard sinters, mainly composed of boron nitride or diamond, are widely used as cutting elements for cutting tools because of their high hardness and high thermal conductivity. Such cutter elements are typically soldered to a track made of a hard alloy such as cemented carbide or cermet. However, because such cutter elements have poor wettability against soldering, they are usually mixed with the coupling body in the form of a composite cutter body that is soldered to the track through the coupling layer.

If the high pressure stage boron nitride or diamond cutting material is subjected to high temperatures (such as during welding), the former is disadvantageously converted to low pressure hexahedral boron nitride and the latter to low pressure stage graphite with reduced hardness. Soldering is typically used because it changes. Therefore, read the fluidity as the cutting mechanism. Soldering, on the other hand, does not have a very high bonding force. It is economical to minimize the size of the cutting part since the price of such cutting tool is proportional to the price of the part being cut. However, because soldering has a relatively low engagement force, it is economical to minimize the size of the cut. However, because soldering has a relatively low engagement force, the cutting tool assembly cannot be used unless the compound cutter has at least a predetermined area.

A typical prior art cutting tool assembly is shown in FIGS. 22 and 23. The cutting assembly includes a base 11 and a composite cutting portion 14. The base is made of cemented carbide or hard alloy and has a notch in one corner. The cutting portion 14 includes the support of the hard sintered body 12 and the cemented carbide 13. The cutting portion 14 is fixed to the notch. This assembly is a so-called tip that is sharpened and not reused. Better to discard when the stools wear out

However, in the cutting tool shown in FIGS. 22 and 23, the stress parallel to the coupling force (herein referred to as the supply force) of the cutting portion 14 and the base 11 during cutting is applied to the cutting portion 14 to the base 11. Lower the binding force. Therefore, the cutting portion 14 comes out of the base 11 or falls out.

Japanese Unexamined Patent Publication No. 292/1979 discloses a cutting tool assembly in which a rigid polycrystalline material is used as the cutting part. The thickness of the cutting surface (between the top and bottom surfaces) of the cutting portion is larger than the area (between the side surfaces) fixed to the table. In this cutting tool assembly, however, the cutting portion is held fast by only soldering a very limited joining area. Therefore, there is a disadvantage of having a low resistance to the supply force.

The cutting tool assembly disclosed in Japanese Unexamined Patent Publication No. 73391/1979 has a cutting portion in which a pair of opposing sides forms a rigid sintered body such as a strip longer than the remaining pairs. The sintered body is buried in the cutting surface so that one of the short sides becomes the cutting edge. In this cutting tool assembly, however, the bandlike sintered body is often broken due to the effects of thermal stress when soldered to the track. Furthermore, repeated heat treatments to reposition the sintered body to accommodate new cutting edges displace the high pressure stage botonide or diamond into a low pressure stable state with a low path.

Japanese Utility Model Publication No. 10882/1988 also discloses a discarding composite tip assembly cutting tool. As shown in FIG. 24, the cutting portion 14 constitutes an intermediate layer of the upper and lower sintered body layers 12 and the cemented carbide support 13. The cutting part is fixed to one corner of the front two bases 11. However, the cutting portion 14 is fixed to the support of the cemented carbide only by soldering. Therefore, the stress (herein referred to as cutting force) applied perpendicularly to the holding and cutting planes of the rigid sintered compact 12 against the feeding force is sufficient.

In addition, insufficient release of the chip when the treatment of metal or the like is to be cut can result in damage to the cutting tool or bad finish of the workpiece surface. In addition, productivity in the automachining center is dependent on sufficient chip discard.

It is conceivable to have a chip breaker adjacent to the cutting part of the cutting tool in order to change the cutting conditions in order to release the chip effectively or to break the chip in the appropriate piece length. Chip breakers form grooves or protrusions in which the chips are broken into fine pieces. The acceptable range in which cutting conditions vary with the former method will be quite limited under circumstances where high accuracy and high efficiency are desired in cutting. The latter method is therefore generally preferred because it allows for the formation of various types of grooves and protrusions and is widely applied.

When the cutting tool is equipped with a chip breaker, the chip breaker has a high crushing quality, good abrasion resistance and allows relatively easy cutting to effectively show the function. Thus, several embodiments of chip breakers are shown in FIGS. 26 to 29 for a scrapped tip made of cemented carbide.

As shown in FIGS. 26 and 27, a write-down tip 15 with a triangle is notched along each side to form a chip breaker 16. The tip 15 for writing and discarding as shown in FIGS. 28 and 29 is notched along the mains to form the chip breaker 16. In a cutting tool of hard sintered metal, such a chip breaker 16 is formed relatively easily.

However, due to the high hardness, it is difficult to form a chip breaker for chip disposal on the composite sintered body. Soldering the chip breaker to the cutter assembly is also difficult because it is thin (ie usually not larger than 1 mm).

Another prior art cutting tool assembly has a cutting tip that can be discarded as shown in FIG. The chip breaker pin 17 is simply held on the tip assembly 15 which can be discarded by the downward force from the support 18.

It is an object of the present invention to provide a low production cost for a cutting tool assembly having a composite rigid sintered body, such as a cutting part, in which the bonding force between the cutting part and the metabolism is improved.

Another object of the present invention is to provide a cutting tool assembly with a chip breaker that is provided adjacent to the cutting edge to facilitate disposal of the chip with an improved bonding force of the composite rigid sintered body and the metabolism to prevent the cutting part from slipping or slipping. will be.

In order to achieve the above object, the cutting tool assembly is equipped to include a stage having grooves formed therein. The recess includes three inner surfaces, each of which has an area sufficient to be stressed in the other direction from the workpiece during the cutting operation. The cutter assembly includes a support that is connected to the cutting tip and sintering. The support is formed from one group having three support surfaces and comprising cemented carbide and cermet. The cutter assembly is soldered to the stage such that each of the support surfaces is secured to the associated groove surface.

Features of the invention which are believed to be novel are described in detail in the appended claims. The invention, together with its objects and advantages, may be best understood with reference to the following description of the presently preferred embodiments, in conjunction with the accompanying drawings.

A first embodiment of this invention will be described with reference to FIGS. 1 to 5. As shown in FIGS. 1 and 5, the cemented carbide strip 1 made of cemented carbide has a groove 2 at one side of its entire thickness. For example, mixed sintered materials formed from metals such as nickel and cobalt and carbides such as tungsten carbide are used as a substitute. Instead of cemented carbide, hard alloys such as titanium carbide, titanium nitride, or cermets, which are mostly steel, are used. Contaminants should have good wettability in soldering.

The cutting portion 3 is formed of a composite hard sintered body and includes a rectangular columnar support 3b and a cutting edge 3a. The support 3b is essentially shaped like the recess 2. It is to be noted that the cutting portion 3 does not extend the full thickness of the base 1 adjacent to the support 3b. In one embodiment the support 3b is formed of an alloy of tungsten carbide and cobalt. The cutting edge portion 3a is formed of a material based on hexahedral borotone nitride (CBN). Alternately, the cutting edge 3a is formed of a sintered body based on wurtzite-type borotone nitride or diamond or a mixture thereof.

The process of producing the cutting part 3 and mounting it on the track will be described. First, disc-shaped support material 3b and disc-shaped cutting edge material 3a having the same diameter are sintered and banded as shown in FIG. A combination comprising titanium mixture (such as titanium carbide (TiC), titanium nitride (TiN) or mixtures thereof) and a mixture of aluminum is used to perform sintering at a rate of Ti: Al = 1: 3 (weight ratio). do. With such a combination, the cutting edge molten material 3a and the support material 3b are tightly joined by sintering to form a blank from the cutting portion to be cut.

Next, the portion of the blank (center portion shown in FIG. 4) is cut out and the cutting edge portion 3a is cut out as necessary to have a predetermined shape. As a result, as shown in FIG. 5, the cutting portion 3 has a groove 1 of the base 1 together with a silver lead 3 including a flux so that the side of the support 3b faces the groove 2. Will fit inside.

The assembly is then placed in an oven equipped with a high frequency induction heater and heated at a predetermined temperature, usually 600 to 800 ° C. At such a temperature, both the base 1 and the support 3b have excellent wettability to the silver lead 4, so that a sufficient bonding force is formed between them. The heating temperature for soldering should be such that there is no cracking in the assembly due to the difference in coefficient of thermal expansion between the high pressure stage boton nitride or the diamond and the hard sintered body or the adverse conversion of the high pressure stage boton nitride or diamond to the low pressure stage. After cooling, the desired cutting tool assembly is obtained.

The use of cutting tool assemblies will be described. As shown in FIG. 2, the base 1 is held in a desired position by a generally known holding member (not shown). The workpiece 6 of the cylindrical column can be rotated and supported to move axially in a position adjacent to the cutting tool assembly.

The cutting edge 3a of the cutting tool is pressed against the circumference of the work piece 5 as shown in FIG. In this state, the workpiece 5 is moved axially as it is rotated, and is subjected to a descending force (cutting force F ₁ ) as shown in FIG. 2 as the workpiece 5 rotates. On the other hand, the cutting edge 3a is also subjected to a force (supply force F ₂ ) in the same direction as the axial movement of the workpiece 5 and further from the workpiece 5 cutting surface in a direction perpendicular to the plane mentioned. : F ₁ ).

The cutting tool assembly according to this embodiment is coupled between the groove 2 and the support 3b along three independent surfaces (ie both side and rear surfaces) of the support 3b to have a large engagement area. Therefore, a strong bonding force is obtained between the support 3b and the base 1. Furthermore, since the cutting part 3 is mounted in the groove 2 and sintered together with the cutting edge 3a and the support 3b, the coupling force obtained between the base 1 and the cutting part 3 is not only supplied with the supply force: F ₂ Thrust: withstands F ₃ very well. Thus, no slipping or slipping of the cutting portion 3 occurs.

In the cutting tool assembly formed according to this embodiment, a high coupling force is obtained between the support of the cutting portion 3 and the base 1 so that the cutting tool assembly can be used repeatedly in a stable state with excellent durability.

Furthermore, the size of the cutting portion 3 necessary to maintain the engagement force between the groove 2 and the support 3b at a predetermined level is minimized and thus the production cost is reduced.

This invention is not limited to the first embodiment, and the following configurations are also possible.

(1) As shown in FIG. 6, a plurality of grooves 2 are formed in the table 1 and grooves are provided in each corner. Each groove receives the cutting portion 3 as previously described. In this modification, all four edges of the blind spot 1 are used as cutting tips. Furthermore, each cutting portion has an upper and a lower cutting edge. Therefore, all eight cutting edges are provided on a common track. This reduces the large size required per cutting edge, which reduces production costs. Other geometric shapes are also used.

(2) The horizontal cross section of the groove 2 of the table 1 may be triangular, trapezoidal, scalloped or rectangular as in the first embodiment. Furthermore, as shown in FIG. 7, when the larger cutting force F ₁ is applied to the cutting edge 3a, the groove is reduced toward the bottom because the cutting force F ₁ is applied toward the thickness of the base 1. It is preferably inclined to have.

A second embodiment of this invention will be described with reference to FIGS. 9 to 13. A table 1 similar to that described in the first embodiment is used. A groove 2 having a right triangle horizontal cross section is formed at one side of the table 1 to extend the full thickness of the table. On the inner wall surface of the groove 2, the support 3b like a rectangular column and the cutting portion 3 constituting the cutting edge 3a formed on one side thereof are fixed. As shown in FIG. 11, the end face 3d and the side face 3c of the support 3b are soldered on the inner wall surface of the recess 2 with silver lead 4. The inner wall surface 2a of one of the two inner wall surfaces of the recess 2, to which the cutting edge 3a and the support 3b are coupled, is pressurized from the workpiece 5 during cutting.

The cutting portion 3 need not extend along the entire thickness of the base 1. The same material used as the support 3b and the cutting edge 3a in the first embodiment is also used in this embodiment.

The process of producing the cutting part 3 and the method of fitting it will be described. First, disc-shaped support material 3b and disc-shaped cutting edge material 3a having the same outer diameter but different thickness are sintered together as shown in FIG. When performing sintering, the same binder as used in the first embodiment is used so that the cutting edge material 3a and the support material 3b are firmly joined by being sintered to form a blank of the cutting part 3. Next, the cutting edge 3a of the blank 3 thus obtained is cut into a predetermined shape. As a result, as shown in FIG. 13, the cutting portion 3 includes the groove 1 of the table 1 together with the silver lead 4 including the flux so that the side surface 3c of the support faces the inner surface 2a of the groove. 2) It is mounted inside.

The assembly is placed in an oven with a high frequency induction heater (not shown) and heated in the same manner as the first embodiment and cooled to obtain the desired cutting tool assembly. As is apparent from FIGS. 2 and 10, this cutting tool assembly is used in the same manner as in the first embodiment.

The workpiece 5 is gradually moved forward in the direction of the arrows (10th and 11th degrees) as it is rotated. Thus, the workpiece 5 is gradually cut from one end to the other because the cutting edge 3a is pressed against the circumference of the workpiece 5. As shown in FIGS. 10 and 11, the cutting edge portion 3a receives the cutting force F ₁ , the supply force F ₂ , and the thrust F ₃ during cutting.

In this embodiment, the engagement between the groove of the base 1 and the support 3b of the cutting portion 3 is formed on two sides, that is, on the end face 3d and the side face 3c of the support 3b. This makes for a large bonding area. Thus a good bonding force is obtained between them. This allows the cutting tool assembly to withstand the cutting force F ₁ . Furthermore, the cutting tool assembly is fixed to the inner surface 2a of the recess 2 under which the pressure from the workpiece 5 is applied during cutting so that the cutting tool assembly has a supply force F ₂ and a thrust F ₃ . Will be able to withstand completely.

As described above, the cutting tool assembly of this embodiment, like the cutting tool assembly of the first embodiment, also has excellent durability without experiencing slipping or slipping of the cutting portion 3. In addition, the size of the cutting portion 3 is also minimized to lower the production cost.

The second embodiment is also modified within the scope of the invention as suggested in the following modifications. As shown in FIG. 14, the recess 2 is formed on the base 1 in each corner as described above with respect to the first embodiment. Similarly, two cutting edges are formed in each cutting portion.

A third embodiment of the invention will be described with reference to FIGS. 15 to 18. 15 is a perspective view of a cutting tool assembly having a chipbreaker according to a third embodiment. FIG. 16 is a cross sectional view taken along the line XVI-VI of FIG. 15. FIG.

As shown in FIGS. 15 and 16, the stage 1 has a recess 2 as formed in the first embodiment. The stage is formed of a sintered material as in the first embodiment.

The cutting portion 3 of the same material as in the first embodiment is fitted in the groove 2 and fixed therein with a silver lead 4. The chipbreaker 6 is formed on the upper surface of the support 3b of the cutting portion 3. The chipbreaker 6 is formed of an inclined groove that deepens toward the base 1. The chipbreaker 6 is formed by machining the upper surface of the support 3b with a diamond grindstone. The shape, dimensions, position, etc. of the chipbreaker 6 are determined depending on the type of workpiece material and the cutting conditions. In the embodiment shown in FIG. 15, the chipbreaker 6 is formed on the upper surface of the support 3b. It should be understood that the chipbreaker may be formed on its lower surface or on both surfaces.

Tilting and fixing the cutting part 3 in the groove of the base 1 is performed in the same manner as in the first embodiment.

When the cutting tool assembly of this embodiment is used in the same way as the previous embodiment, the chip from the work piece 5 continuously flows along the cutting surface and breaks into pins when it hits the chipbreaker 6.

In this cutting process, the cutting edge portion 3a receives the cutting force F ₁ by the rotation of the work piece 5. The cutting edge 3a is also subjected to the supply force F ₂ and the thrust F ₃ by the axial feed of the workpiece 5 as the first shown in FIG. 18.

In this embodiment, a wide coupling area is fixed between the support 3b of the cutting part 3 and the groove 2 of the base 1 as in the first embodiment. This makes a great bond between them. The cutting tool assembly therefore withstands any of the cutting forces F ₁ , feed force F ₂ and thrust F ₃ . Furthermore, the chip continuously ejected from the workpiece is broken and chipped smoothly when it hits the chipbreaker when it reaches the cutting surface.

The present invention is not limited to the third embodiment and, for example, the following modifications are possible. As shown in FIG. 20, the groove 2 is formed at one side of the base 1 having another triangular plane and the support 3b of the cutting portion 3 is fixed to the surface of one inner wall of the groove 2; Chipbreakers 6, such as ridges, are formed on the outer surface of the support 3b on opposite sides of the mated surfaces.

As shown in FIG. 21, the work piece 5 is cut by moving the cutting tool assembly to the cutting edge 3a and the support 3b is adjacent to the work piece 5 and the chip is effectively released.

Although only a few embodiments of the invention have been described herein, it will be apparent to those skilled in the art that the invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Therefore, the present examples and embodiments are to be considered in all respects only as schematic, and the invention is not limited to the details given herein but may be modified within the scope of the appended claims.

Claims (7)

As the base 1 having a constant thickness and one edge, the groove 2 is formed at the edge in the base 1 so as to extend the entire thickness of the base 1, and the grooves 2 are perpendicular to each other. The entire thickness of the table 1 is extended so that the table 1 has one inner surface (first inner surface) and another inner surface (second inner surface), and a pair of cutting edges 3a on opposite sides. A cutting edge assembly comprising a cutting tip and a support 3b, wherein the cutting tips have a triangular shape and are perpendicular to each other and one contact surface (first contact surface) and the other contact surface (second contact). Surface), the support 3b having a rectangular shape, the first and second opposing side faces 3c and the first and second end faces 3d having a smaller area than and perpendicular to these first and second side faces. ), The first end of the support (3d) Attached to the surface (upper end surface), the second end surface (lower end surface) 3d of the support 3b is attached to the second inner surface of the groove 2, and the second contact surface of the cutting tip (large Cutting tool assembly facing the (1) and the second side surface of the support (3b) to be attached to the second inner surface (2a) of the groove (3) so that it can be mounted in the groove of the stand (1). 2. A cutting edge assembly according to claim 1, characterized in that the stage 1 has four corners each having one groove 2 formed therein, and a plurality of cutting edge assemblies are provided which are mounted in the associated grooves 2, respectively. Cutting tool assembly. The cutting tool assembly according to claim 1, characterized in that the width of the groove (2) is inclined so that it becomes gradually wider away from the cutting tip. 2. The cutting tool assembly of claim 1, wherein a pair of cutting tips are provided, with a second support interposed between these cutting tips, and both the cutting tip and the second support being sintered to the first support. The cutting tool assembly according to claim 1, wherein an inclined surface is provided on the support (3b) and a chip breaker (6) is provided on the inclined surface. 6. The cutting tool assembly according to claim 5, wherein the chipbreaker has an inclined groove so that it becomes deeper toward the table (1). A cutting tool assembly according to claim 1, wherein a plurality of grooves (2) are formed in the table (1), a plurality of said cutting edge assemblies are provided, and each cutting edge assembly is mounted for each said groove. .

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