JPH0525639A - Polycrystalline diamond cutting tool and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the heat resistance and tool strength of a cutting tool using polycrystalline diamond. [Structure] A polycrystalline diamond cutting tool uses polycrystalline diamond formed by a low pressure vapor phase method as a tool material, and is joined to a shank made of cemented carbide with a brazing layer interposed. The thickness of the polycrystalline diamond layer is 0.1 to 1.0
It is set to mm. The brazing layer has a thickness of 10
It is set to ˜50 μm. The brazing layer has a melting point of 950
˜1300 ° C. material is used, IVa of the periodic table,
One or more materials selected from the group consisting of Va, VIa, and VIIa metals and their carbides; Au, Ag,
It is formed of an alloy layer containing at least one material selected from Cu, Pt, Pd, and Ni.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining structure for a polycrystalline diamond cutting tool having high strength and excellent heat resistance, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Since diamond has high hardness and high thermal conductivity, it exhibits excellent performance as a cutting tool or abrasion resistant tool.
It is used for various purposes. As an example of a cutting tool using diamond, diamond fine particles such as those described in Japanese Patent Publication No. 52-12126 are used as an iron-based material, particularly for the purpose of suppressing defects due to cleavage, which is a drawback of single crystal diamond. It is known to use a diamond sintered body sintered with a metal binder.

However, the one using a diamond sintered body has a problem that the heat resistance is low. That is,
If the diamond sintered body is heated to a temperature of 750 ° C. or higher, the wear resistance and strength are lowered, and if the diamond sintered body is heated to a temperature of 900 ° C. or higher, the sintered body is broken. It is considered that the cause of this is that the graphitization of diamond occurs at the interface between the diamond particles and the binder of iron-based metal, and the thermal stress is generated due to the difference in the coefficient of thermal expansion during the heating of both.

To improve the heat resistance, therefore, a tool using a diamond sintered body has been developed, for example, as disclosed in Japanese Patent Laid-Open No. 53-114589. This uses a method of treating the sintered body with an acid to remove most of the bonded metal layer. However, this technique has a problem that since the removed portion of the joining metal layer becomes a hole, the heat resistance is improved but the strength is remarkably reduced.

Further, in order to improve such a problem, the one using a heat-resistant diamond sintered body having no pores is disclosed in, for example, JP-A-59-161268 and JP-A-61-33865. Is disclosed in. In these heat-resistant diamond sintered bodies, Si, SiC, an alloy of Ni and Si, or the like is used as a binder. The bond between diamond particles of these sintered bodies is weak,
Further, since the content of the binder was large, it was insufficient in terms of wear resistance.

In order to solve the problems of the diamond tool using such a diamond sintered body, for example, a polycrystalline diamond containing no binder as described in Japanese Patent Publication No. 1-212767 is used. Cutting tools are being developed.

[0007]

A cutting tool using polycrystalline diamond as a tool material is one in which a polycrystalline diamond layer is bonded to a tool support and a cutting edge is formed on the polycrystalline diamond layer. is there. However, in a cutting tool in which this polycrystalline diamond is brazed to a tool support as a tool material, not only the performance of the tool material itself, but also the performance of the joint brazing layer with the tool support governs the performance as a tool. The present inventors have found that this is a factor. In particular, it has been found that when the thickness of the polycrystalline diamond is 0.5 mm or less, the heat resistance and the thickness of the brazing material, in addition to the thickness of the polycrystalline diamond, have a great influence on the tool performance.

That is, it is desirable that the thickness of the polycrystalline diamond layer be the minimum necessary from the viewpoint of processing cost, but the thinner the thickness, the lower the strength. Furthermore, even if the thickness of the polycrystalline diamond layer is such that there is no problem in strength, especially when the heat resistance of the brazing material is low or the thickness of the brazing material is too thick, the cutting conditions are such that the cutting edge has a high temperature. Deformation of the brazing material becomes significant below, and the strength of the tool as a whole may be reduced.

Therefore, the present invention has been made to solve the above problems, and an object thereof is to provide a polycrystalline diamond cutting tool having heat resistance and high strength, and a method for manufacturing the same. .

[0010]

A polycrystalline diamond cutting tool according to the present invention uses polycrystalline diamond synthesized by a low pressure vapor phase method as a tool material, and the tool material is used as a tool support with a brazing layer interposed. It is constructed by joining.
The polycrystalline diamond layer of the tool material is formed to have a thickness of 0.1 mm or more and 1.0 mm or less. The brazing layer is formed to have a thickness of 10 to 50 μm, and is characterized by using a brazing material having a melting point of 950 ° C. or higher and 1300 ° C. or lower. (Note that the thickness of the polycrystalline diamond layer is defined by the thickness of the layer formed in the vertical direction from the surface of the substrate.) The method for producing a polycrystalline diamond cutting tool of the present invention includes the following steps. There is. First, a polycrystalline diamond layer is formed on a substrate by the low pressure vapor phase method. Then, the substrate is removed, and the polycrystalline diamond layer is cut into a predetermined material shape to form a tool material. Further, a brazing material is interposed between the joining surface of the tool material and the tool material mounting surface of the tool support to heat and melt it, thereby joining the tool material and the tool support.
Examples of the brazing material include IVa, Va, VIa and V of the periodic table.
An alloy layer containing at least one metal selected from the group IIa and at least one metal selected from Au, Ag, Cu, Pt, Pd, and Ni is used.

Furthermore, a method for manufacturing a polycrystalline diamond cutting tool according to another method of the present invention includes the following steps. First, a polycrystalline diamond layer is formed on a substrate by the low pressure vapor phase method. Next, while removing the substrate,
The polycrystalline diamond layer is cut into a predetermined material shape to form a tool material. Furthermore, on the growth upper surface of the tool material of this polycrystalline diamond, the periodic table IVa, Va, VIa,
A coating layer is formed by coating with at least one material selected from Group VIIa metals and their metal carbides. Then, Au, Ag, C are provided between the joining surface of the tool material on which the coating layer is formed and the material mounting surface of the tool support.
heating by interposing a brazing material containing at least one material selected from the group consisting of u, Pt, Pd, and Ni,
The tool material and the tool support are joined by melting.

[0012]

According to the results of various studies, the inventors have found that the characteristics of the polycrystalline diamond layer itself and the characteristics of the brazing material influence the strength and heat resistance of the polycrystalline diamond cutting tool. It started. As a result, the thickness of the polycrystalline diamond layer, which is the tool material, is 0.1m.
It has been found that the preferred range is from m to 1.0 mm. If the thickness is thicker than this value, it is not preferable from the viewpoint of processing efficiency of the tool material. Further, when the thickness is smaller than this range, the strength of the tool material decreases.

Further, the properties and thickness of the brazing material affect the characteristics of the brazing material. The brazing material according to the present invention has a melting point of 950 to 1300 ° C. and has sufficient heat resistance even under cutting conditions under high temperature. Further, when the thickness of the brazing material is in the range of 10 to 50 μm, it is possible to suppress the reduction in the tool strength due to the deformation of the brazing material.

[0014]

EXAMPLES Examples of the polycrystalline diamond cutting tool according to the present invention will be described below.

The outline of the polycrystalline diamond cutting tool according to the present invention will be described according to the manufacturing process. 1 to 5 and 6 are process diagrams sequentially showing a manufacturing process, FIGS. 1 to 5 show a first method, and FIG. 6 shows a second method.

First, referring to FIG. 1, a polycrystalline diamond layer 2 is formed on the surface of a substrate 1 made of a metal or an alloy by the low pressure vapor phase method. The surface of the substrate 1 is finished to be a mirror surface having a surface roughness Rmax of 0.2 μm or less. As a method for depositing a polycrystalline diamond layer on this surface, the following low pressure vapor phase method is used. For example, a method of decomposing / exciting a raw material gas by utilizing thermionic emission or plasma discharge, or a film forming method using a combustion flame is effective. As the source gas,
Hydrocarbons such as methane, ethane, propane,
A mixed gas containing hydrogen as a main component and an organic carbon compound such as an alcohol such as methanol or ethanol or an ester is generally used. Other than this, an inert gas such as argon, oxygen, carbon dioxide, water, etc. may be contained in the raw material within a range that does not impair the synthetic reaction of diamond and its characteristics. A substrate made of a metal or alloy whose surface is mirror-finished to have a Rmax of 0.2 μm or less by such a low-pressure vapor phase method, and which is essentially composed of only diamond and has an average grain size of diamond in the initial stage of growth. On the side of 0.01 to 1 μm on the growth surface, and on the growth surface side at the growth completion position, a polycrystalline diamond having a cross-sectional structure that is coarsened to 5 to 15% of the thickness of the diode phase has a thickness of 0.1 to 1.0.
Precipitate to be mm. Here, the grain size of the polycrystalline diamond is defined as described above because the larger the grain size, the more likely it is to chip. Also,
This is because when the film thickness is less than 0.1 mm, the strength of the polycrystalline diamond layer itself is reduced. Further, as the material thickness of a diamond tool used for ordinary finishing, it is sufficient if it is not less than the flank wear width (0.1 mm or less) at the time of tool life, for example, about 0.1 to 0.2 mm. Is one of the reasons. Film thickness 1.0mm
If it is thicker than this, the processing cost for cutting the tool increases, which is not preferable. However, if necessary, 1.
Even if it is 0 mm or more, there is no problem in performance.

It is preferable that the substrate has a coefficient of thermal expansion close to that of diamond in order to reduce the internal stress of polycrystalline diamond. Further, the polycrystalline diamond layer synthesized on the substrate is recovered by dissolving and removing the substrate by a chemical treatment with hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid or a mixed solution thereof, and used as a tool material. Therefore, it is preferable to use Mo, W, Si, or the like as the substrate material that satisfies these conditions.
Furthermore, the reason why the surface of the substrate is mirror-finished to have a Rmax of 0.2 μm or less is that it is preferable in terms of both tool manufacturing cost and tool performance, as will be described later.

Next, as shown in FIG.
Polycrystalline diamond layer 2 formed on substrate 1 by 2
A cutting line is formed along the predetermined tool material shape.

Further, as shown in FIG. 3, hydrochloric acid, sulfuric acid,
The substrate 1 is dissolved by a chemical treatment with nitric acid, hydrofluoric acid or a mixed solution thereof, and is removed from the polycrystalline diamond layer 2. The polycrystalline diamond tool blank 3 thus formed has a thickness in the stacking direction of 0.1 to 1.0 mm.
Is formed.

Next, as shown in FIG. 4, the polycrystalline diamond tool material 3 and the tool support 4 are joined together via the brazing material 5. When joining the polycrystalline diamond tool material 3 and the tool support 4, it is important to arrange so that the surface that was in contact with the substrate during the synthesis of the polycrystalline diamond is the rake face of the tool. During the synthesis of polycrystalline diamond, the surface of the substrate had a surface roughness Rmax of 0.2 in advance.
The mirror surface is less than μm. Therefore, the surface of the polycrystalline diamond layer synthesized on the surface of this substrate is a smooth surface similar to the surface of the substrate as the transfer surface. Therefore, by arranging and brazing this surface so as to be the rake surface of the tool, it is possible to obtain a smooth tool rake surface without processing the surface of polycrystalline diamond, which is considered to be difficult to process. Further, as described above, the surface of the polycrystalline diamond on the substrate side is formed so that the crystal grains of diamond are fine and coarsen toward the growth upper surface. For this reason, by making the tool rake surface the fine-grained diamond surface on the substrate side, it is possible to construct a tool with excellent fracture resistance. As the brazing material, Li, one or more kinds of metals of groups IVa, Va, VIa, and VIIa of the periodic table are contained in an amount of 0.2 to 50% by volume of the whole brazing material, and the remaining portion of the brazing material is Au. , Ag, Cu, Pt, P
An alloy containing at least one material selected from d and Ni is used. The brazing material made of such an alloy has a melting point of 800 to 1300 ° C., preferably 95.
It is 0-1300 degreeC. These brazing materials are placed between the tool material 3 and the mounting surface of the tool support 4, and are heated to a high temperature to melt the brazing material and then cooled to separate the tool support 4 and the tool material 3. To join. Here, the composition of the brazing material is specified to contain 0.2 to 50% by volume of one or more of Group IVa, Va, VIa, and VIIa of the periodic table, and these metals or carbides are diamond. This is because it has the property of reacting and joining. Of these, Ti,
W, Ta, Zr or their carbides have excellent bonding strength. Further, the melting point of the brazing material is limited because if the melting point is lower than the lower limit, softening and flow of the brazing material occur depending on cutting conditions, and the upper limit is set higher than the upper limit. This is because the polycrystalline diamond deteriorates.

Thereafter, as shown in FIG. 5, the cutting edge portion 8 is processed by grinding or laser processing. By using laser processing for the cutting edge processing, the chipping size of the cutting edge portion can be formed to 0.5 to 5 μm. A polycrystalline diamond cutting tool is manufactured by the above process.

FIG. 6 shows another embodiment of the method of joining the tool material 3 and the tool support 4. In the method, first, a coating layer is formed to a thickness of about 0.1 to 5 μm on the growth upper surface of the polycrystalline diamond of the tool material 3. This coating layer is formed by using, for example, an ion plating method, a sputtering method or a vapor deposition method. And, as the coating layer, Li, IVa, Va, VIa, VIIa of the periodic table
One or more materials selected from the group metals and their carbides are used. The thickness of the coating layer is 0.1-5μ
The range of m is defined because the effect of preventing oxidation is lost if the thickness is less than 0.1 μm. Further, if the thickness is thicker than 5 μm, the cost increases, which is not preferable. After forming the coating layer 6 on the tool material 3, the tool support 4
After arranging at least one kind of material 7 selected from Au, Ag, Cu, Pt, Pd, and Ni on the joint surface of, the tool material 3 and the tool support 4 are arranged at the joint position, Heat to melt the brazing material. By this step, the tool material 3 and the tool support 4 are joined together via the brazing material. In addition, as the metal coating portion 6, Ti, W, Ta, Zr
And, when one or more materials of these carbides are used, the bonding strength is particularly excellent.

After brazing by the above method, a desired tool can be manufactured by forming only the flank and forming the cutting edge. Conventional cutting can be applied as a method of blade attachment, but a sharper edge with less chipping can be formed at low cost by using a laser processing technique. The cutting tool having a cutting edge chipping size of 0.5 to 5 μm by the laser processing has a sharper cutting edge than that of a conventional diamond sintered body tool or a grinding blade tool brazed with vapor-phase synthetic diamond as a tool material. Particularly excellent in sharpness. The cutting edge forming process by laser processing is disclosed in the prior application of the present inventors, Japanese Patent Application No. 2-27101 or Japanese Patent Application No. 2-326277.

Example 1 The surface of the material was Rma by the microwave plasma CVD method.
A diamond polycrystal was synthesized on a Si substrate having a mirror surface state of 0.08 μm at x for 10 hours. The synthesis was performed under the following conditions.

Source gas (flow rate): H ₂ 300 sccm CH ₄ 20 sccm Gas pressure: 120 Torr Microwave oscillation output: 750 W After synthesis, the thickness is obtained by dissolving and removing only the Si substrate by immersing it in hydrofluoric nitric acid. It was possible to recover a diamond polycrystal having a grain size of 0.2 mm. The average grain size of diamond is 0.2μm on the rake side and 20μ on the brazing side.
m had a cross-sectional structure that coarsened. The Rmax of the surface on the substrate side was 0.08 μm. This diamond polycrystal is composed of Ag, Cu, and Ti, each containing 6% by volume and 9%.
A heat resistant brazing material containing 5% and 4% of each was brazed to a cemented carbide shank. Incidentally, brazing as a bonding surface growth surface of the tool material, 5 × 10 ^- during the ⁵ torr vacuum was performed by heating for 10 minutes to 1050 ° C. which is the melting point of the brazing material. The brazing layer thickness of the recovered bonded body is 3
It was 0 μm. Among them, a flank was processed with a # 1500 diamond grindstone and bladed to prepare a cutting tool (A).

For comparison, the same polycrystalline diamond body and cemented carbide shank as described above were joined using a brazing material having a melting point of 700 ° C. and containing Ag and Cu of 30% and 70% by volume, respectively. (B) was produced. Cutting tool (B)
The wax layer had a thickness of 40 μm.

Further, Co having a particle size of 5 μm as a binder is used.
A sintered diamond containing 12% by volume of R was surface-processed to have a Rmax of 0.09 μm to form a tool material, and then a cemented carbide shank was joined with the same brazing material as the cutting tool (B) (C). did. In addition, these were also bladed by cutting using the same diamond grindstone as the cutting tool (A). Performance evaluation of these throwaway tip tools was performed under the following conditions.

(Cutting Conditions) Work Material: A390-T6 (A1-17% Si) Round Bar Cutting Speed: 800 m / min Cutting Depth: 1.5 mm Feeding Speed: 0.2 mm / rev. Coolant: Water-soluble oil agent (evaluation method) Comparison of cutting edge states after 5 minutes cutting and 60 minutes cutting.

As a result, as shown in Table 1, it was revealed that the tool of the present invention maintained a sharp cutting edge for a long time as compared with the sintered diamond tool. Also,
It has been clarified that a tool that does not use a heat-resistant brazing material causes a serious defect after the brazing material has been washed away, causing fatal damage as a tool.

[0030]

[Table 1]

Example 2 By a thermal CVD method using a linear tungsten filament having a diameter of 0.5 mm and a length of 100 mm as a thermoelectron emitting material, a surface of the Mo substrate having an Rmax of 0.03 μm was used under the following conditions. Synthesized over time. The synthesis conditions are shown below.

Raw material gas (flow rate): H ₂ 500 sccm C ₂ H ₂ 10 sccm Gas pressure: 70 Torr Filament temperature: 2200 ° C. Filament-substrate distance: 6 mm Substrate temperature: 900 ° C. After synthesis, soak in hot aqua regia By melting and removing only the Mo substrate, a diamond polycrystal having a thickness of 0.3 mm could be recovered. The diamond had an average grain size of 0.1 μm on the rake face side and 25 μm on the brazing face side, which had a coarse cross-sectional structure. The surface on the substrate side is R
The maximum value was 0.03 μm. This diamond polycrystal is made of Au, Cu, and Ta, each having a capacity of 35% and 60%.
%, 5% each was used to braze to a cemented carbide shank. Incidentally, brazing as a bonding surface growth surface of the tool material, 4 × 10 ^- heated conducted ⁵ torr of 1100 ° C. for 5 minutes, which is the melting point of the brazing material in a vacuum. The brazing layer thickness of the recovered bonded body is 40 μm.
Met. After that, a cutting tool (D) was prepared by cutting with a YAG laser.

As a comparison, the same tool material as the cutting tool (D) and a brazing material are used for joining, and the brazing layer thickness is 10
A device having a thickness of 0 μm (E) was also produced.

Further, a sintered diamond having a grain size of 10 μm and containing 10% by volume of Co as a binder is Rmax.
After mirror finishing to 0.06 μm to make a tool material, P
A brazing material having a melting point of 800 ° C. containing 10%, 60% and 30% of d, Ag and Cu, respectively, and joined to a cemented carbide shank (F) was also produced. The cutting tools (E) and (F) were bladed by a grinding process using a # 1500 diamond grindstone.

Performance evaluation of these throw-away insert tools was performed under the following conditions.

(Cutting conditions) Work Material: Hard Carbon Cutting speed: 1000m / min Depth of cut: 1.5 mm Feed rate: 0.2 mm / rev. Cutting time: 40 minutes Coolant: Water-soluble oil (Evaluation methods) Comparison of cutting edge conditions after 5 minutes cutting and after 40 minutes cutting.

As a result, as shown in Table 2, it became clear that the tool of the present invention maintained a sharp cutting edge for a long time as compared with the sintered diamond tool. Further, it was revealed that even if a brazing material having the same composition was used, a large displacement occurred due to the thickness of the brazing layer, and the diamond polycrystal was defective.

[0038]

[Table 2]

Example 3 By a thermal CVD method using a linear tantalum filament having a diameter of 0.3 mm and a length of 120 mm as a thermoelectron emitting material, a surface of the Si substrate having a Rmax of 0.12 μm was prepared under the following conditions. Crystal diamond was synthesized for 30 hours. The synthesis conditions are shown below.

Raw material gas (flow rate): H ₂ 400 sccm CH ₄ 10 sccm Gas pressure: 100 Torr Filament temperature: 2100 ° C. Filament-substrate distance: 5 mm Substrate temperature: 950 ° C. After synthesis, immerse in heated nitric acid fluoride By dissolving and removing only the Si substrate, a diamond polycrystal having a thickness of 0.4 mm could be recovered. The average grain size of diamond is 0.4 μm on the rake side and 30 on the brazing side.
It had a cross-sectional structure of coarsening to μm. The Rmax of the surface on the substrate side was 0.12 μm. The growth upper surface of this diamond polycrystal was coated with Ti having a thickness of 2 μm, and then Ni was further coated with 3 μm as an antioxidant film. This metal-coated diamond polycrystal,
A brazing material made of Pt, Pd, and Ni was used to braze the cemented carbide shank. The brazing was carried out by heating for 2 minutes at 980 ° C., which is the melting point of the brazing material, in the air with the growth surface side of the tool material as the joining surface. The brazing layer thickness of the recovered bonded body was 30 μm. After that, a cutting tool (G) was produced by cutting with a YAG laser.

For comparison, a metal-coated tool material similar to the cutting tool (G) is made of Ag and Cu and has a melting point of 70.
A product (H) joined to a cemented carbide shank using a brazing material at 0 ° C. was also produced.

Further, the grain size is 3 μm and Co is used as a binder.
Of the sintered diamond containing 12% by volume of Rmax as a tool material by mirror-finishing to 0.12 μm with Rmax,
A product (I) was also produced, which was joined to a cemented carbide shank using a brazing material having a melting point of 800 ° C. and containing Ag, Cu in the amounts of 10%, 60%, and 30%, respectively. The cutting tools (H) and (I) were bladed by grinding using a # 1500 diamond grindstone.

Performance evaluation of these throw-away insert tools was carried out under the following conditions.

(Cutting Conditions) Work Material: AI-25% Si Round Bar Cutting Speed: 1000 m / min Depth of Cut: 1.2 mm Feed Speed: 0.15 mm / rev. Cutting time: 30 minutes Coolant: None (dry method) (Evaluation method) Comparison of cutting edge states after 10 minutes of cutting and after 30 minutes of cutting.

As a result, as shown in Table 3, it was revealed that the tool of the present invention maintained a sharp cutting edge for a long time as compared with the sintered diamond tool. Further, it has been revealed that a tool produced without using a heat-resistant brazing material causes a large damage after the brazing material has flowed out, causing fatal damage as a tool.

[0046]

[Table 3]

Example 4 Under the conditions shown in Table 4, the surface has an Rmax of 0.05 μm.
A mixed gas of H ₂ , C ₂ H _6, and Ar at a ratio of 7: 2: 1 was supplied at a flow rate of 500 sccm into the reaction tube in which the W substrate, which is a mirror surface state, was placed at a pressure of 120 Torr. Next, the high frequency (13.56 MH)
z, output: 700 W) was applied, the mixed gas was excited to generate plasma, and a diamond polycrystal was synthesized.

After the synthesis, only the substrate was dissolved and removed by acid treatment, so that only the diamond polycrystal having a mirror-surfaced surface on the substrate side of Rmax of 0.05 μm could be recovered. The characteristics are also shown in Table 4.

This diamond polycrystal was used as a tool material, and its growth surface side was used as a joining surface, and brazing was performed with a cemented carbide shank using the brazing material shown in Table 4.
After that, a blade was attached by a diamond grindstone or laser processing.

Performance evaluation of these throw-away insert tools was performed under the following conditions.

(Cutting conditions) Work Material: Al-22% Si Round bar with 8 V-shaped grooves in the axial direction Cutting speed: 900m / min Depth of cut: 0.8 mm Feed rate: 0.12 mm / rev. Coolant: Water-soluble oil (Evaluation method) Comparison of cutting edge conditions up to 60 minutes of cutting.

The results are shown in Table 4.

[0053]

[Table 4]

All of the tools K, L, N and P had defects at the initial stage. However, it was revealed that the tools J, M, and O exhibited excellent wear resistance, fracture resistance, and heat resistance, and that sharp cutting edges were maintained for a long time.

[0055]

As described above, in the polycrystalline diamond cutting tool according to the present invention, a material having heat resistance is used as the brazing layer, and the thicknesses of the polycrystalline diamond layer and the brazing layer are set within a predetermined range. As a result, it is possible to realize a polycrystalline diamond cutting tool having excellent heat resistance and sufficient strength.

[Brief description of drawings]

FIG. 1 is a process drawing showing a first process of manufacturing a polycrystalline diamond cutting tool according to the present invention.

FIG. 2 is a process drawing showing a second process of manufacturing a polycrystalline diamond cutting tool according to the present invention.

FIG. 3 is a process drawing showing a third step of manufacturing the polycrystalline diamond cutting tool according to the present invention.

FIG. 4 is a process drawing showing a fourth step of manufacturing the polycrystalline diamond cutting tool according to the present invention.

FIG. 5 is a process drawing showing a fifth step of manufacturing the polycrystalline diamond cutting tool according to the present invention.

FIG. 6 is a process drawing showing a main process of another manufacturing process of the polycrystalline diamond cutting tool according to the present invention.

[Explanation of symbols]

1 substrate 2 Polycrystalline diamond layer 3 Tool material 4 Tool support 5 Brazing layer 6 coating layer 7 Brazing material

Claims (24)

[Claims] 1. A polycrystalline diamond cutting tool comprising a substrate made of polycrystalline diamond synthesized by a low pressure vapor phase method as a tool material, and the tool material being joined to a tool support with a brazing layer interposed therebetween. In the above, the polycrystalline diamond has a film thickness of 0.1 mm or more. 0
1 mm or less, The said brazing layer is comprised by the melting | fusing point of 950 degreeC or more and 1300 degreeC or less, The polycrystalline diamond cutting tool characterized by the above-mentioned. 2. The brazing layer is a periodic table IVa, V
a, VIa, VIIa group metals, IVa, V of the periodic table
a, VIa, VIIa metal carbides selected from one or more kinds, and Au, Ag, Cu, Pt, P
d, one or more kinds selected from Ni are included,
The polycrystalline diamond cutting tool according to claim 1. 3. The first brazing layer is located on the tool support side and contains at least one metal selected from Au, Ag, Cu, Pt, Pd, and Ni. Located on the tool material side, Periodic Table IVa, Va, V
Ia and VIIa metals, IVa, Va and V of the periodic table
1 selected from carbides of metals of group Ia and VIIa
The polycrystalline diamond cutting tool according to claim 1 or 2, which comprises a second layer containing at least one kind. 4. The second layer of the brazing layer comprises Ti, W, T
The polycrystalline diamond cutting tool according to claim 3, comprising at least one selected from a, Zr, and carbides thereof, and having a film thickness of 0.1 μm or more and 5 μm or less. 5. The brazing layer has a thickness of 10 μm or more and 5
The polycrystalline diamond cutting tool according to any one of claims 1 to 4, which has a diameter of 0 µm or less. 6. A growth upper surface of the polycrystalline diamond layer is bonded to the brazing layer, and a tool rake surface of the polycrystalline diamond layer is a surface which is in contact with the substrate at the time of synthesis and has a rough surface. The polycrystalline diamond cutting tool according to any one of claims 1 to 5, wherein the maximum height indication Rmax is 0.2 µm or less. 7. The grain size of the polycrystalline diamond is increased from the rake face side toward the brazing side, and the grain size is 0.01 μm or more on the rake face side.
The polycrystalline diamond cutting tool according to any one of claims 1 to 6, which has a thickness of 5 μm or less and is 5% or more and 15% or less of a thickness of the polycrystalline polycrystalline diamond layer on the brazing surface side. . 8. The polycrystalline diamond layer according to claim 1, wherein the size of chipping of the cutting edge along the line of intersection between the tool rake surface and the tool flank is 0.5 μm or more and 5 μm or less. A polycrystalline diamond cutting tool according to Crab. 9. The polycrystalline diamond cutting tool according to claim 1, wherein the tool support is made of cemented carbide. 10. A step of forming a polycrystalline diamond layer on a substrate by a low pressure vapor phase method; removing the substrate from the polycrystalline diamond layer and cutting the polycrystalline diamond layer into a predetermined chip shape. Between the step of forming the tool material and the growth upper surface of the tool material of polycrystalline diamond and the tool material mounting surface of the tool support, the periodic table IVa, V
a, VIa, or VIIa group metal and at least one metal selected from these carbides;
A brazing material made of an alloy containing at least one kind of metal selected from Ag, Cu, Pt, Pd and Ni is interposed, and the tool material and the tool support are joined by heating and melting. A method for manufacturing a polycrystalline diamond cutting tool, comprising: 11. The brazing material has a melting point of 950 ° C. or higher 13
The method for manufacturing a polycrystalline diamond cutting tool according to claim 10, wherein an alloy having a temperature of 00 ° C. or lower is used. 12. The brazing material is IVa or V of the periodic table.
a, VIa, VIIa containing at least one metal selected from 0.2 volume% or more and 50 volume% or less,
A method for manufacturing the polycrystalline diamond cutting tool according to claim 10. 13. The brazing material has a thickness of 10 μm or more and 50 or more.
The method for manufacturing a polycrystalline diamond cutting tool according to claim 10, wherein the polycrystalline diamond cutting tool is formed to have a thickness of not more than μm. 14. The step of forming the polycrystalline diamond layer, wherein the average grain size is coarsened along the crystal growth direction on the surface of the substrate having a surface roughness Rmax of 0.2 μm or less, And the average grain size is 0.01 μm or more and 1 μm or less and the growth upper surface side is 5% or more and 15% or less of the thickness of the polycrystalline diamond, and the substrate of the polycrystalline diamond layer is A polycrystalline diamond cutting tool according to any one of claims 10 to 13, wherein the polycrystalline diamond layer and the tool support are brazed so that the surface in contact with the tool rake face becomes a tool rake face. Method. 15. The method for manufacturing a polycrystalline diamond cutting tool according to claim 10, wherein the tool material is formed to have a thickness of 0.1 mm or more and 1.0 mm or less. 16. The substrate is removed from the polycrystalline diamond layer by dissolving in a solution of at least one of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid.
A method for manufacturing a polycrystalline diamond cutting tool according to claim 15. 17. A step of forming a polycrystalline diamond layer on a substrate by a low pressure vapor phase method, the step of removing the substrate from the polycrystalline diamond layer, and cutting the polycrystalline diamond layer into a predetermined material shape. A step of forming a tool material, and at least one selected from the group IVa, Va, VIa, and VIIa metals of the periodic table and metal carbides thereof on the growth upper surface of the tool material of polycrystalline diamond.
A step of coating different types of materials to form a coating layer, and Au, Ag, Cu, Pt, Pd, Ni between the joint surface of the coated tool material and the tool material mounting surface of the tool support.
Of a polycrystalline diamond cutting tool, which comprises a step of joining the tool material and the tool support by heating and melting the brazing material containing at least one material selected from Method. 18. The melting point of the brazing material is 950.degree.
The method for manufacturing a polycrystalline diamond cutting tool according to claim 17, wherein an alloy having a temperature of 300 ° C. or lower is used. 19. The coating layer has a thickness of 0.1 μm or more and 5
The method for manufacturing a polycrystalline diamond cutting tool according to any one of claims 17 to 18, which is formed to have a thickness of not more than μm. 20. The polycrystal according to claim 17, wherein the thickness of the bonding layer interposed between the tool material and the tool support is 10 μm or more and 50 μm or less. Manufacturing method of diamond cutting tool. 21. In the step of forming the polycrystalline diamond layer, the average grain size becomes coarse along the crystal growth direction on the surface of the substrate having a surface roughness Rmax of 0.2 μm or less, and the substrate side And the average grain size is 0.01 μm or more and 1 μm or less and the growth upper surface side is 5% or more and 15% or less of the thickness of the polycrystalline diamond, and the substrate of the polycrystalline diamond layer is 21. The manufacture of a polycrystalline diamond cutting tool according to claim 17, wherein the polycrystalline diamond layer and the tool indicator are brazed so that the surface in contact with the tool becomes a tool rake face. Method. 22. The method for manufacturing a polycrystalline diamond cutting tool according to claim 17, wherein the tool material is formed to have a thickness of 0.1 mm or more and 1.0 mm or less. 23. The substrate is removed from the polycrystalline diamond layer by dissolving in a solution of at least one of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid.
23. A method of manufacturing a polycrystalline diamond cutting tool according to claim 22. 24. The method for manufacturing a polycrystalline diamond cutting tool according to claim 17, wherein the polycrystalline diamond bonded to the tool material has a cutting edge formed by laser processing. .