JP2013111727A - Cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool that prevents cracks to be generated by baking and has high chipping resistance by using a composite fiber body composed of core materials and coating layers for a cutting edge part.SOLUTION: The cutting tool includes a tool body 12 and a cutting edge chip 14 provided on a mounting base of the tool body 12. The cutting edge part 18 of the cutting edge chip 14 comprises fibers of: a plurality of fiber-like core materials arranged side by side; and coating layers surrounding the outer peripheries of the core materials and having different compositions from the core materials. The fiber arrangement direction of the fibers at a flank 12 is bent relative to the ridge direction of a cutting edge 17, so as to form a larger angle than a lower face mounting base 13 side of the tool body 12 immediately below the ridge of the cutting edge 17.

Description

  The present invention particularly relates to a cutting tool having improved fracture resistance and wear resistance.

  Cutting tools widely used for metal cutting are widely used from precision cutting to general-purpose cutting, such as cemented carbide, cermet, ceramic and steel. Tools have insufficient toughness, and it is necessary to further improve the fracture resistance of the cutting edge.

  Therefore, according to Patent Document 1, a composite fiber body having high toughness in which a coating layer made of WC or the like is arranged on the outer periphery of a composite fiber body core material made of diamond or the like is disclosed. It has been proposed to improve the fracture resistance of excavation tools by attaching composite fiber bodies to the periphery. Moreover, in patent document 2, the cutting tool which aligned the direction of the fiber of the fiber body in the direction where force is applied is disclosed.

US Pat. No. 6,063,502 JP 2004-202597 A

  However, Patent Document 1 describes a specific example for an excavating tool, but does not describe a cutting tool such as turning or milling, and applies a composite fiber body to such a cutting tool. A specific structure for sufficiently exhibiting the characteristics of the fibrous body has not been studied at all. Moreover, in the structure which aligns the direction of the fiber with respect to the cutting edge as in Patent Document 2, although high fracture resistance is exhibited for normal cutting, an impact is suddenly applied from different directions. In some cases, large defects sometimes occur during machining. Moreover, when joining with another member by simultaneous baking or brazing, a crack and peeling may generate | occur | produce in the junction part.

  The cutting tool of the present invention comprises a tool body and a cutting blade tip provided on the mounting base of the tool body, and the cutting blade portion of the cutting blade chip includes a fibrous core material in which a plurality of blades are arranged and the core. The cutting edge ridge line is formed of a composite fiber body that surrounds the outer periphery of the material and has a coating layer having a composition different from that of the core material, and the fiber arrangement direction of the composite fiber body on the flank is relative to the ridge line direction of the cutting edge Directly below, it is bent so as to have a larger angle than the lower surface side brazed to the tool body.

  According to the cutting tool of the present invention, the cutting edge tip is brazed to the mounting base of the tool body, or the backing member obtained by simultaneously firing the backing member and the cutting edge tip is brazed to attach the tool body. A cutting edge tip is provided on the pedestal, and the fiber arrangement of the composite fiber body that becomes the cutting edge portion is larger than the lower surface side brazed to the tool body directly below the cutting edge ridge line with respect to the ridge line of the cutting edge By bending so as to form an angle, the impact applied to the cutting edge during cutting can be dispersed, so that the fracture resistance is improved, and the brazing part that exists immediately below the backing member or cutting edge that is simultaneously fired It is possible to suppress the occurrence of peeling and cracks at the interface between the composite fiber body and the backing member or the brazed portion.

It is a schematic perspective view which shows one Embodiment of the cutting tool concerning this invention. FIG. 2A is a schematic diagram of an embodiment of the cutting tool of FIG. 1, in which (a) a structural photograph viewed from the flank, and (b) an enlarged view of part A of (a). It is a perspective view which shows the structure of the fiber which comprises the composite fiber body of FIG. It is a schematic perspective view for demonstrating the structure of the composite fiber body which bundled the fiber of FIG. It is a figure for demonstrating the manufacturing method of a fiber, and is process drawing which shows the manufacturing method of a single type fiber. It is a figure for demonstrating the manufacturing method of a fiber, and is process drawing which shows the method of manufacturing a multitype fiber from the single type fiber of FIG. It is process drawing for demonstrating the method of bending a fiber.

  Hereinafter, an embodiment of the present invention will be described in detail.

  FIG. 1 is a schematic perspective view showing a cutting tool of the present invention, and FIG. 2 is (a) a structural photograph viewed from the flank, (b) A of FIG. It is the schematic diagram which expanded the part.

  The cutting tool 11 shown in FIG. 1 has a flat plate shape, and the backing member 19 and the composite fiber body 20 that is the cutting edge portion 18 are integrated with the mounting base 13 formed at the corner of the tool body 12. The cutting edge tip 14 is brazed. Further, according to the cutting tool 11, the cutting edge 17 is configured at the intersecting ridge line portion between the rake face 15 and the flank face 16. Further, an attachment hole 25 through which a clamp screw or the like for attaching to a tool such as a cutting tool is inserted is formed at the center of the cutting tool 11. In FIG. 1, the composite fiber body 20 that is the cutting edge portion 18 is directly brazed to the mounting base 13 of the tool body 12 without integrating the composite fiber body 20 that is the cutting edge portion 18 with the backing member 19. It may be a thing.

  According to the present invention, the cutting edge 18 of the cutting edge tip 14 surrounds the outer periphery of the fibrous core 32 and the core 32 as shown in FIG. 2 is composed of a composite fiber body 20 of FIG. 2 in which a coating layer 33 surrounds a core 32 in which a plurality of fibers 31 are arranged. As shown in FIG. An angle α formed by the fiber arrangement direction 20 directly below the ridge line of the cutting edge 17 with respect to the ridge line direction of the cutting edge 17 is the lower attachment in which the composite fiber body 20 brazed to the tool body 2 is directly above the lower surface 22. It is configured to be bent so as to have an angle larger than the angle β formed by the pedestal 13a side. That is, as shown in FIG. 2, the composite fiber body 20 faces in the direction close to the longitudinal direction of the fiber 31 on the lower surface on the mounting base side, and the cross section of the fiber 31 faces the upper surface immediately below the ridge line of the cutting blade 17. bent. According to this configuration, since the impact applied to the cutting edge 17 at the time of cutting is dispersed in the bent portion, it is possible to suppress the occurrence of a large defect, and at the same time, the backing member 19 to be simultaneously fired directly under the composite fiber body 20. Or the adhesiveness with the brazing part 21 to be brazed can be enhanced, and the occurrence of peeling or cracking at the interface between the composite fiber body 20 and the backing member 19 or the brazing part 21 can be suppressed. The brazing portion 21 is formed on the surface of the mounting base 13 of the tool body 12.

Here, the desired angle α formed by the ridge line of the cutting edge 17 of the fiber 31 of the composite fiber body 20 immediately below the ridge line of the cutting edge 17 is 55 to 90 °, and the fiber in the upper surface 22 just above the lower surface to be brazed to the tool body 12. A desirable range of the angle β formed by the ridge lines of the 31 cutting edges 17 is 0 to 45 °. In the present invention, the angle formed by the fiber 31 of the composite fiber body 20 with the ridgeline of the cutting edge 17 is an acute angle of 90 ° or less. Moreover, the measurement of the angle which the fiber 31 of the composite fiber body 20 makes with the ridgeline of the cutting edge 17 is measured for the straight line portion of the ridgeline of the cutting edge 17 capable of measuring the angle, and each fiber 31 and the cutting edge 17 are measured. The angle formed with the ridge line is measured, and the average value is calculated.

  Further, when the backing member 19 made of a cemented carbide is disposed on the lower side of the composite fiber body 20 of the cutting edge tip 14, the adhesion between the composite fiber body 20 and the backing member 19 is high and is difficult to peel off. In addition, since the backing member 19 and the tool body 2 are made of the same cemented carbide, there is an effect that the brazing strength is increased.

  3 (a) and 3 (b) are schematic perspective views of fibers serving as the basis of the composite fiber body 20 used in the present invention. The fiber 31 s of (a) is a single type fiber body that includes a core material 32 and a coating layer 33 that covers the outer periphery of the core material 32 and is made of a material having a composition different from that of the core material 32. The fiber 31m is a multi-type fiber obtained by extending the assembly of the single-type fibers 31s of (a). According to the present invention, the composite fiber body 20 forming the cutting edge 17 is formed by a structure in which the fibers 31s and 31m of (a) or (b) are converged. Desirably, using the multi-type fiber 31m of (b) is excellent in fracture resistance.

  Specifically, as shown in FIG. 4 (a), the composite fiber body 20 includes a cylindrical rod having a predetermined thickness obtained by bundling a plurality of fibers 31 and co-extrusion to a size of 10 mm or more in diameter. As shown in FIG. 4B, the composite sheet 35 cut out or a composite sheet 36 in which the fibers 31 are arranged in the width direction is cut out to a predetermined thickness. The composite fiber body 20 having such a configuration includes a fibrous core material 32 in which a plurality of fibers are arranged, and a coating layer 33 that surrounds the outer periphery of the core material 32 and has a composition different from that of the core material 32. 4 (a) and 4 (b), the cross section of the fiber 31 of the composite sheets 35 and 36 is represented by a circle. This represents a state in which the fibers 31 before firing are arranged, and the composite fibers after firing. In the body 20, the cross section of the fiber 31 is deformed into a hexagon.

  According to the present invention, as shown in FIGS. 1 and 2, the cutting edge portion 14 of the tool main body 12 is cut out and the cutting edge tip 14 having the composite fiber body 20 made of the fiber 31 is fitted into the mounting base 13 and brazed or the like. By fixing, the fiber direction of the fibers 31s and 31m with respect to the cutting edge shape of the tool can be easily controlled. This technique has an advantage that the fibers 31s and 31m can be easily arranged even when cutting edges are provided at a plurality of corners.

  As a material constituting the core material 32 of the fibers 31s and 31m used in the present invention, cubic boron nitride (hereinafter referred to as cBN) 20 to 99% by mass is included in the periodic table 4a, 5a and 6a group metals and silicon and aluminum. A cBN sintered body obtained by bonding a carbide, nitride, carbonitride, boride, and oxide of 1% to 80% by mass of a binder selected from one or more of iron group metals can be suitably used. is there.

  Moreover, as another material which comprises the core material 32, the bond which consists of 60-99 mass% of diamonds at least 1 type chosen from an iron group metal, carbonate, a sulfate, and a hydroxide, especially cobalt and / or nickel. A diamond sintered body formed by bonding at 1 to 40% by mass of metal can be suitably used. Note that the diamond sintered body may appropriately contain hard particles made of one or more of carbides, nitrides, and carbonitrides of the periodic table 4a, 5a, and 6a metals.

Further, as the material constituting the core member 32, first hard particles composed of one or more of carbides, nitrides and carbonitrides of the periodic table 4a, 5a and 6a metals, particularly tungsten carbide, titanium carbide, At least one selected from the group consisting of titanium carbonitride, titanium nitride, tantalum carbide, niobium carbide, zirconium carbide, zirconium nitride, vanadium carbide, chromium carbide and molybdenum carbide, and further from the group of tungsten carbide, titanium carbide or titanium carbonitride First selected by binding at least one selected from 65 to 98% by weight with at least one selected from the group consisting of iron, cobalt and nickel, in particular from 2 to 35% by weight of a binding metal comprising cobalt and / or nickel. A hard sintered body, particularly a cemented carbide or cermet, can be suitably used.

  In addition to the hard sintered body, at least one oxide or carbide selected from the group of periodic table 4a, 5a and 6a metals, aluminum, and silicon can be used as another material constituting the core member 32. , A first ceramic composed of nitride and carbonitride, especially at least one selected from the group consisting of alumina-titanium carbide (titanium carbonitride), silicon carbide, silicon nitride, zirconia, titanium boride, and further alumina-carbonized Titanium (titanium carbonitride) and / or silicon carbide can be suitably used. In addition, it is also possible to appropriately include a sintering aid component in the first ceramic.

  On the other hand, as the material of the covering layer 33 covering the outer periphery of the core material 32, a hard sintered body or ceramics having a composition or material different from that of the core material 32 is used. Also, metals such as iron, cobalt and nickel can be used alone.

  Further, the combination of the core material 32 and the covering layer 33 may be, for example, the same material and a different composition, or a cemented carbide-cermet, cemented carbide-cBN sintered body, cemented carbide-diamond sintered body, Hard alloy-alumina, cemented carbide-silicon nitride, cermet-cemented carbide, cermet-cBN sintered body, cermet-diamond sintered body, cermet-alumina, cermet-silicon nitride, (alumina, titanium carbonitride)-alumina , Silicon carbide-silicon nitride, (silicon carbide, silicon nitride) -silicon nitride, silicon carbide-diamond sintered body, cBN sintered body-cermet, cBN sintered body-superhard alloy, and diamond sintered body-superhard One kind selected from the group of alloys can be used particularly preferably.

  On the other hand, the average particle size of the crystal particles of the sintered body forming the core material 32 is that the hardness and strength of the fibers 31s and 31m are improved, and the bonding material (bonding metal, sintering aid) in the core material 32 and the coating layer 33. In view of optimizing the content of the agent, it is preferably 0.05 to 10 μm, particularly 0.1 to 3 μm. On the other hand, the average particle size of the crystal particles forming the coating layer 33 is the toughness of the fibers 31 s and 31 m. In terms of improvement, it is desirable that the thickness is 0.01 to 5 μm, particularly 0.01 to 2 μm.

  Further, the size of the fiber 31 is such that the diameter of the core material 32 is 5 to 300 μm and the diameter of one fiber 31 including the covering layer 33 is 6 to 500 μm in order to improve the fracture resistance as a tool. desirable. The diameter of the core material 32 is calculated as the diameter when the shape of the core material 32 is converted into a circle from the cross-sectional area of the core material 32. Further, the thickness of the covering layer 33 is calculated as a thickness that is half the distance from the core 32 of the adjacent fiber 31.

Here, the cutting blade 17 has a configuration in which the average fiber diameter d ₁ of the composite fiber body 20 on the lower surface side to be brazed is smaller than the average fiber diameter d ₂ of the composite fiber body 20 immediately below the ridge line of the cutting blade 17. In addition, the abrasion resistance of the cutting edge tip 14 can be increased, and the peeling resistance of the backing member 19 and the brazing portion 21 on the lower surface side of the cutting edge tip 14 can be improved.

  Next, the manufacturing method of the cutting tool of this invention is demonstrated. First, the manufacturing method of the composite fiber body 20 used in the present invention will be described. FIG. 5 is a process diagram for explaining a method of manufacturing the fibers 31s and 31m of FIG.

  In producing the composite fiber body, first, a core body molded body is produced. The core material can be basically produced by a known powder metallurgy method, that is, a method in which a raw material powder and a binder (binder) are mixed and molded.

  On the other hand, two half-cylindrical coating layers are formed by kneading a material having a coating layer having a composition different from that of the core material molded body 31a together with the above-described binder by a molding method such as press molding, extrusion molding or casting. A molded body 31b is produced, and a molded body 31c is produced in which the coating body molded body 31b is arranged so as to cover the outer periphery of the core material molded body 31a (see FIGS. 5A to 5C).

  Then, by using the extruder 100, the molded body 31c composed of the core material molded body 31a and the coated layer molded body 31b is coextruded to form a coated layer molded body around the core molded body 31a. The single-type fiber molding 31s shown in FIG. 3A covered with 31b and extended to a thin diameter can be produced (see FIG. 5D).

  Further, in forming the fiber 31, as shown in FIG. 6, a multi-type having a high fiber density is formed by co-extrusion molding of the converging body 34 obtained by converging a plurality of the co-extruded long fiber molded bodies 31s. Fiber 31m can be produced.

  Next, as shown in FIG. 4A, the long fiber molded bodies 31s and 31m are aligned and coextruded to a size of 10 mm or more in diameter, and then cut into a predetermined thickness to form a composite. The composite sheet 36 is obtained by preparing the sheet 35 or converging the fiber molded bodies 31s and 31m and cutting them to a predetermined thickness as desired, as shown in FIG. 4B.

  Then, as shown in FIG. 7, the composite sheets 35 and 36 are accommodated in the concave portion 37 of the backing member 19 having the concave portion 37 at the center of the upper surface formed of a hard sintered body such as cemented carbide. The fiber molded bodies 31s and 31m are bent in a predetermined direction by pressing and deforming the sheets 35 and 36 from the upper surface. At this time, the bending state of the fiber molded bodies 31s and 31m can be changed by adjusting the size of the composite sheet 35 and the size of the concave portion 37 of the concave backing member 19.

  Thereafter, the composite sheet 35 is heated or held at 300 to 700 ° C. for 10 to 200 hours to remove the binder, and the backing member 19 in which the composite sheet 35 is inserted is placed in the ultrahigh pressure apparatus. Baking is performed at 1500-1600 ° C. for 10-20 minutes under a pressure of ˜5.5 GPa. The backing member 19 is integrated with the composite fiber body 20 fired by this firing.

  The composite fiber body 20 is processed into a cutting edge shape by a wire electric discharge machine, cutting, polishing, or the like so that the relationship with the cutting edge 17 of the cutting tool 11 is a predetermined angle α as described above. Then, the cutting edge chip 14 in which the backing member 19 and the composite fiber body 20 are integrated is brazed to the mounting base 13 using silver solder or the like. It is also possible to braze the composite fiber body 20 directly to the tool body 12 without attaching the backing member 19 to the composite fiber body 20.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to a following example.
Example CBN powder having an average particle diameter of 1.5 μm, TiC powder, AlN powder, cellulose, polyethylene glycol as an organic binder, and 100 parts by volume of polyvinyl alcohol as a solvent are added and kneaded to form a cylinder having a diameter of 20 mm. The core was formed by press molding into a shape.

On the other hand, cBN powder having an average particle size of 1.5 μm, TiN powder, AlN powder, cellulose as an organic binder, polyethylene glycol, and 100 parts by volume of polyvinyl alcohol as a solvent are added and kneaded to form a halved cylindrical shape. Two coating layers for the coating layer having a thickness of 1 mm were produced by press molding, and these were arranged so as to cover the outer periphery of the core material molding to produce a composite fiber body.

  Then, the composite fiber body is coextruded to produce a stretched composite molded body having a diameter of about 2 mm, and then the 100 stretched composite molded bodies are converged and coextruded again to obtain a multi-stretch having a diameter of 1 mm. A composite fiber body having a filament structure was produced.

  Next, the composite fiber molded body having the multifilament structure was cut to a length of 100 mm, and a molded body aligned in the direction of FIG.

Thereafter, this laminate was placed in a concave portion of a backing member made of a cemented carbide having a concave portion with a diameter of 20 mm and a depth of 5 mm. In this state, a pressure of 15 MPa was applied to the composite fiber molded body, The fiber array was deformed so as to be in the state shown in Table 1. And after performing a binder removal process by heating up to 300-700 degreeC in 100 hours, it arrange | positions to an ultrahigh pressure apparatus and baked on 5GPa and 1450 degreeC * 15 minute conditions, and a composite structure and a backing member are An integrated cutting edge tip was produced. Thereafter, this cutting edge tip is processed and cut so that the fiber direction on the flank face is as shown in Table 1, and the backing member is brazed at 700 ° C. using silver brazing on a mounting base of a tool body made of cemented carbide. I attached.

Cutting performance was evaluated using each cutting tool produced as described above.
Work material: SCM415 Maru H carburized and hardened steel cutting depth ap: 0.2 mm
Cutting speed Vc: 150 m / min Feed f: 0.15 mm / rev
Cutting environment: Wet evaluation items: The number of interrupted machining impacts (number of hits) until chipping or chipping occurs in end turning of a workpiece with 8 holes, and the state of the bottom surface of the composite fiber body at that time

As can be seen from Table 1, the sample No. 2 bent so that the angle of the fiber on the flank face is larger than the lower surface side brazed to the tool body immediately below the cutting edge ridge line. Nos. 1 to 5 have a large number of impacts that can be processed. In 1-4, the favorable brazing state was shown. On the other hand, the angle of the fiber on the flank is the same between the ridge line directly below the cutting edge ridge line and the lower surface side brazed to the tool body, and the sample No. 6 and the flank face in which the fibers are arranged in a direction parallel to the cutting edge ridge line, and the sample number of 0 ° between the part directly below the cutting edge ridge line and the lower surface side brazed to the tool body. No. 7 was lost in a state where the number of impacts was small.

DESCRIPTION OF SYMBOLS 11 Cutting tool 12 Tool main body 13 Mounting base 13a Lower side mounting base 14 Cutting edge tip 15 Rake face 16 Flank face 17 Cutting edge 18 Cutting edge part 19 Backing member 20 Composite fiber body 21 Brazing member 22 Right above the lower surface of the composite fiber body 25 Mounting hole 31 Fiber 32 Core material 33 Coating layer 35, 36 Composite sheet 37 Recess

Claims (3)

It consists of a tool body and a cutting edge tip provided on the mounting base of the tool body,
The cutting edge portion of the cutting edge chip is composed of a composite fibrous body of a fibrous core material in which a plurality of the fibers are arranged and a coating layer that surrounds the outer periphery of the core material and has a composition different from that of the core material,
A cutting tool that is bent so that the fiber arrangement direction of the composite fiber body on the flank face is greater than the cutting edge ridge line at an angle directly below the cutting edge ridge line than the lower surface mounting base side of the tool body.   The cutting tool according to claim 1, wherein an average fiber diameter of the composite fiber body on the mounting base side of the tool body is smaller than an average fiber diameter of the composite fiber body immediately below the cutting edge ridge line.   The cutting tool according to claim 1 or 2, wherein a backing member is disposed below the composite fiber body of the cutting edge tip.