JPH0592307A - Cutting tool of diamond polycrystalline substance and its manufacture - Google Patents

Abstract

PURPOSE:To prevent the strength lowering of a soldering portion due to heat generated upon cutting in the case of a diamond polycrystalline substance layer being provided at a cutting face, by forming a tool material by providing a heat diassipation layer at the diamond polycrystalline substance layer through the soldering portion. CONSTITUTION:A diamond polycrystalline substance layer 3 is synthesized on an Si substance 1 by means of a micro wave plasma CVD process, and then, the diamond polycrystalline substance layer 3 whose average crystal granule diameter is about 3mum and whose thickness is 0.15mm, is recovered by immersing it in nitric/hydrofluoric acid and removing in dissolution the Si substrate 1 alone. Next, a TiC film 11 is formed on the growth upper surface of the diamond polycrystalline substance layer 3 by means regarded of a process, which is as a tool material 19. And the tool material 19 is joined to a shank 13 made of a super hard alloy by using a solder material 15 whose melting point is about 680 deg.C, so that the TiC film 11 may be positioned between the diamond polycrystalline substance layer 3 and a soldering portion 17. Afterwards, a desired cutting tool is completed by conducting edging by means of grinding processing using a diamond grinding wheel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond polycrystal cutting tool in which a tool material containing a polycrystal diamond is brazed to a tool support, and a method for producing the same.

[0002]

2. Description of the Related Art Since diamond has high hardness and high thermal conductivity, it exhibits excellent performance as a material for cutting tools and abrasion resistant tools. For this reason, it has recently been widely used in the field of cutting tools and wear resistant tools. In particular, a diamond sintered body obtained by sintering diamond fine particles with an iron-based metal binder as described in Japanese Patent Publication No. 52-12126 is less likely to cause defects due to cleavage, which is a defect of single crystal diamond. Widely used for finishing Al alloys.

However, it is known that this diamond sintered body has a problem in heat resistance due to the metal binder. That is, this diamond polycrystal has a temperature of 750 ° C.
At the above temperatures, there is a problem that abrasion resistance and strength decrease, and at temperatures of 900 ° C. or higher, the sintered body is broken. It is considered that these phenomena are caused by the graphitization of diamond at the interface between the diamond particles and the metal binder at high temperature, and the thermal stress based on the difference in thermal expansion coefficient between the two.

For the purpose of improving the heat resistance of the diamond sintered body, it has been proposed to treat the diamond sintered body with an acid to remove most of the metal binder. JP-A-53-
Japanese Patent No. 114589 discloses a method for producing a diamond sintered body having improved heat resistance by this method.
However, in this prior art, although the heat resistance is improved, the removed portion of the metal binder becomes voids,
There was a new problem of reduced strength.

A heat-resistant diamond sintered body having no pores is disclosed in JP-A-59-161268 and JP-A-61-33865. Si, SiC, an alloy of Ni and Si, or the like is used as the binder of the diamond sintered body disclosed in these prior arts. However, although these heat-resistant diamond sintered bodies are improved in heat resistance, there are problems in that the content of the binder is large and the bond between diamond particles is weak.

In order to solve these problems, Japanese Patent Laid-Open No.
A tool using a diamond polycrystal body containing no binder, that is, a diamond polycrystal body synthesized by a low-pressure vapor phase method, has been developed as disclosed in Japanese Patent Laid-Open No. 221767/1990.

Since the diamond polycrystal body containing no binder is substantially composed of only diamond, it is superior to the diamond sintered body in any of the strength, wear resistance and heat resistance. Shows the nature.

[0008]

By the way, in order to enhance the processing efficiency in the tool production, it is preferable to make the thickness of the diamond polycrystal body to the minimum necessary. As the material thickness of the diamond tool used for normal finishing,
A flank wear width (0.1 mm or less) at the time of tool life, for example, about 0.1 to 0.2 mm is sufficient. However, when this diamond polycrystal is used as a material, it has a high thermal conductivity because it consists essentially of diamond, and when it is used as a tool, especially when the thickness is thinned to 0.1 to 0.2 mm. Since the heat of the cutting edge generated in 1) is easily conducted to the brazing portion, the brazing portion is deformed and the strength of the tool cutting edge is significantly reduced.

In order to solve such a problem, the present inventors have proposed a polycrystalline diamond cutting tool in which the thickness of the polycrystalline diamond body, the type of brazing material, etc. are specified (Japanese Patent Application No. 03-104411). issue).

The present invention has been made to solve the above conventional problems. An object of the present invention is to provide a diamond polycrystalline tool having excellent heat resistance and a method for manufacturing the same.

[0011]

According to a first aspect of the present invention, there is provided a diamond polycrystal cutting tool having a diamond polycrystal layer serving as a rake face, which has a thermal conductivity of 3 at room temperature.
˜20 W / cm · K diamond polycrystalline layer, brazing part, and thermal conductivity at room temperature located between the diamond polycrystalline layer and brazing part is 0.1 to 2 W / cm · K
And a tool support material that supports the tool material by brazing the brazing portion.

The invention according to claim 8 is a method for manufacturing a diamond polycrystalline body cutting tool in which a diamond polycrystalline layer is a rake face, which is formed on a substrate made of a metal or an alloy at room temperature by a low pressure vapor phase method. Has a thermal conductivity of 3 to 20 W /
a step of forming a diamond polycrystalline layer of cm · K,
The thermal conductivity at room temperature is 0.1 on the polycrystalline diamond layer.
A step of forming a heat diffusion preventing layer of 2 W / cm · K, and a step of removing the substrate from the laminate including the substrate, the diamond polycrystalline layer and the heat diffusion preventing layer by a chemical method to produce a tool material. , A step of brazing the tool material to the tool support so that the heat diffusion preventing layer is located between the diamond polycrystal layer and the brazing portion, and a step of processing the cutting edge into a required shape, There is.

According to a ninth aspect of the present invention, there is provided a method for producing a diamond polycrystal cutting tool having a diamond polycrystal layer serving as a rake face, which is formed on a substrate made of a metal or an alloy at room temperature by a low pressure vapor phase method. Has a thermal conductivity of 3 to 20 W /
a step of forming a diamond polycrystalline layer of cm · K,
A step of removing the substrate from the polycrystalline diamond layer by a chemical method, and forming a thermal diffusion preventing layer having a thermal conductivity of 0.1 to 2 W / cmK at room temperature on the growth upper surface of the polycrystalline diamond layer. Then, the step of making the tool material, the step of brazing the tool material to the tool support so that the heat diffusion prevention layer is located between the diamond polycrystal layer and the brazing part, and the required cutting edge shape And the process of processing into.

[0014]

Since the heat diffusion preventing layer is provided between the polycrystalline diamond layer and the brazing portion, the heat of the cutting edge generated when the tool is used as a tool is less likely to be conducted to the brazing portion. Further, since the tool material has a two-layer structure of the diamond polycrystal layer and the heat diffusion preventing layer, the thickness of the tool material is increased as compared with the conventional one, and the strength of the tool material is enhanced.

In the practice of the present invention, any known low-pressure vapor phase method can be applied to the synthesis of the polycrystalline diamond. That is, a method of decomposing / exciting the raw material gas by utilizing thermionic emission or plasma discharge and a film forming method using a combustion flame are also effective. Examples of the raw material gas include hydrocarbons such as methane, ethane, propane, methanol,
It is common to use a mixed gas containing alcohols such as ethanol, organic carbon compounds such as esters, and hydrogen as main components, but other than these, an inert gas such as argon, oxygen, carbon monoxide, Water or the like may be contained in the raw material as long as it does not impair the synthetic reaction of diamond and its characteristics.

As disclosed in Japanese Patent Application Laid-Open No. 1-212767, a substrate made of a metal or an alloy, the surface of which is mirror-finished with Rmax of 0.2 μm or less by any of these methods, is used at room temperature. Thermal conductivity of 3 ~ 20W
/ Cm · K diamond polycrystal layer 0.1-0.5
Synthesize with a thickness of mm. The reason for setting the thickness of the diamond polycrystal body in such a range is that finishing, roughing, etc.
It is specified based on the amount of wear at the end of the life that normally occurs when used as a diamond tool. The average crystal grain size of diamond is preferably 0.5 to 15 μm. This is because when used as a cutting tool, the wear resistance decreases when the particle size is smaller than 0.5 μm, and the chipping tends to occur when the particle size is smaller than 15 μm.

Further, the thermal conductivity at room temperature is 3 to 20 W / c.
The definition of m · K is excluded because it is difficult for the above problems to occur when it is lower than 3 W / cm · K. The upper limit of 20 W / cm · K represents the highest value that can be synthesized by the current technology. Therefore, if a material having a higher thermal conductivity can be produced, it can be applied as the tool material of the present invention.

The substrate preferably has a coefficient of thermal expansion close to that of diamond in order to reduce the internal stress of the diamond polycrystal, and one which dissolves in an acid to recover only the diamond polycrystal. preferable. Mo, W, Si, etc. are mentioned as a thing applicable to this. It is to be noted that the mirror surface of Rmax of 0.2 μm or less is required to finish the substrate surface so that the diamond polycrystal surface can be easily made into such a good surface state without processing the polycrystal diamond surface. Because you can. By making this good surface a rake surface, it is possible to reduce the welding of the work material.

After depositing the diamond polycrystal,
Subsequently, a thermal diffusion preventing layer having a thermal conductivity of 0.1 to 2 W / cm · K at room temperature is formed. Thermal conductivity of 0.1-2 W / cm
-K is specified because moderate cutting heat is not efficiently dissipated when the energy is lower than 0.1 W / cmK. If the cutting heat is not efficiently dissipated, the cutting edge of the diamond polycrystal becomes high in temperature, which is not preferable. Further, when the thermal conductivity is higher than 2 W / cm · K, the amount of cutting heat radiated to the brazed portion increases and the heat diffusion preventing layer does not exhibit an effective action.

The thickness of the heat diffusion preventing layer is from 0.05 to
0.5 mm is preferable. This is because if it is thinner than 0.05 mm, the effect of preventing heat diffusion becomes weak and the effect of improving the strength of the tool material becomes weak. Further, if the thickness is 0.5 mm, the role of preventing heat diffusion and the effect of improving the strength of the tool material are sufficiently fulfilled, and therefore, a further thickness is unnecessary.

Materials for the heat diffusion preventing layer include Ti, W,
Those containing a carbide of at least one element selected from the group containing Ta, Mo and Si are preferable.

Thus, the laminate obtained by depositing the heat diffusion preventing layer on the growth upper surface of the diamond polycrystalline layer and then removing only the substrate by a chemical method can be used as a tool material. .. As the chemical method, a method of dissolving the substrate in at least one liquid selected from the group containing hydrochloric acid, sulfuric acid, nitric acid and hydrofluoric acid is preferable.

As a method for producing the above tool material,
It is also possible to form a thermal diffusion prevention layer by the vapor phase method on the growth upper surface of the diamond polycrystal simple substance obtained by removing the substrate by a chemical method after forming the diamond polycrystal layer on the substrate Is. For the formation of the thermal diffusion prevention layer, any means such as a vapor phase synthesis method such as CVD or PVD, a thermal spraying method, a method of laminating a solid material with a diamond polycrystal body and heating it can be applied.

Then, the tool material is brazed to the tool support so that the heat diffusion preventing layer is located between the diamond polycrystal layer and the brazing portion. The tool manufactured through the above steps is bladed by grinding or laser processing.

[0025]

【Example】

(Example 1) As shown in FIG. 2, microwave plasma C
According to the VD method, the diamond polycrystalline layer 3 is formed on the Si substrate 1 whose surface has a mirror surface state of Rmax of 0.03 μm.
Was synthesized. The synthesis was performed under the following conditions.

[0026]

[Table 1]

After the synthesis, as shown in FIG. 3, by immersing it in hydrofluoric nitric acid 5 to dissolve and remove only the Si substrate 1, a diamond polycrystal layer 3 having an average crystal grain size of 3 μm and a thickness of 0.15 mm. Could be recovered. The surface 7 of the polycrystalline diamond layer 3 facing the Si substrate 1 has Rmax
Was 0.03 μm. As shown in FIG. 4, TiC was formed in a thickness of 0.2 mm on the growth upper surface 9 of the polycrystalline diamond layer 3 by a vapor phase method. The production of TiC was performed under the following conditions.

[0028]

[Table 2]

The laminate obtained by the above method is used as a tool material 1
As shown in FIG. 5, as shown in FIG. 5, the tool material 19 is placed on the cemented carbide shank 13 and the melting point is 680 ° C. so that the TiC 11 is located between the diamond polycrystalline layer 3 and the brazing part 17. It joined using the material 15. At this time, the rake face is the Si of the surface of the diamond polycrystalline body 7.
Bonding was performed so that the surface 7 facing the substrate 1 was formed. Then, as shown in FIG. 6, the blade was attached by a grinding process using a diamond grindstone. FIG. 7 is a perspective view thereof. This tool is A. Tool No. FIG. 1 is an enlarged view of the portion of the blade edge of A.

For comparison, a brazing filler metal similar to that described above was used to join a single diamond polycrystal body without TiC and a cemented carbide shank. This tool is B.

For comparison, a sintered diamond having a grain size of 5 μm and containing 12% by volume of Co as a binding material is used as a tool material, and the same brazing material as described above is used to superharden the tool material to form a shank. A bonded tool was also made. This tool is Let be C. The performance evaluation of these throw-away insert 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: 1.0 mm Feeding Speed: 0.1 mm / rev. Coolant: Water-soluble oil (Evaluation method) Comparison of cutting edge states after 5 minutes of cutting and 60 minutes of cutting. As a result, as shown in Table 3, the tool No. of Example 1 of the present invention was used. A is a sintered diamond tool No. of Comparative Example 2. It was revealed that a sharp cutting edge was maintained for a long time as compared with C. Further, the tool No. which is the comparative example 1 using the diamond polycrystalline body in which the thermal diffusion preventing layer made of TiC is not formed. It was revealed that B has a large defect as the brazing material flows out, which causes fatal damage as a tool.

[0033]

[Table 3]

(Embodiment 2) The thermionic emission material has a diameter of 0.2 m.
As shown in FIG. 8, a diamond polycrystalline layer 3 was synthesized on a W substrate 21 having a surface of Rmax of 0.12 μm by a thermal CVD method using a linear tungsten filament having a length of m and a length of 200 mm. The synthesis conditions are shown below.

[0035]

[Table 4]

After the synthesis, as shown in FIG. 9, a TaC23 having a thickness of 0.1 mm was continuously formed on the diamond polycrystalline layer 3 by the vapor phase method under the following conditions.

[0037]

[Table 5]

As shown in FIG. 10, by immersing this laminate in hot aqua regia 25, only the W substrate 21 is dissolved and removed, and as shown in FIG. 11, the average crystal grain size is 3 μm and the thickness is 0. 25 mm diamond polycrystal layer 3 and thickness 0.1
It was possible to recover a laminate consisting of mm of TaC23. Incidentally, the surface 7 of the diamond polycrystalline layer 3 among the surfaces of the laminated body was a mirror surface having Rmax of 0.12 μm. This laminate was brazed to a cemented carbide shank in the same manner as in Example 1. This tool is Let be D. A brazing material having a melting point of 850 ° C. was used.

For comparison, a brazing material similar to the above is used,
Bonding was also performed between the single-piece diamond polycrystalline body not having TaC formed thereon and the cemented carbide shank. The conditions for synthesizing the diamond polycrystal were the same as in Example 2. This tool is Let E.

For comparison, a sintered diamond having a grain size of 5 μm and containing 12% by volume of Co as a binder is used as a tool material, and this tool material is bonded to a cemented carbide shank using the same brazing material as above. A tool was also made. This tool is Let it be F. Tool No. D and E are tool numbers for the YAG laser. F was bladed by grinding. The performance evaluation of these throw-away insert tools was performed under the following conditions.

(Cutting conditions) Work material: A390-T6 (A1-17% Si) Round bar having eight V-shaped grooves in the axial direction Cutting speed: 900 m / min Cutting amount: 0.8 mm Feed Speed: 0.12 mm / rev. Coolant: Water-soluble oil (Evaluation method) Comparison of cutting edge states after 5 minutes of cutting and 60 minutes of cutting. As a result, as shown in Table 6, the tool No. of Example 2 of the present invention was used. D is a tool No. using the sintered diamond of Comparative Example 4. As compared with F, it became clear that a sharp cutting edge was maintained for a long time. Further, in Comparative Example 3, a tool No. using a polycrystalline diamond body in which a thermal diffusion preventing layer made of TaC was not formed was used. It was revealed that in the case of E, the brazing material flows out and a large defect occurs, which causes fatal damage as a tool.

[0042]

[Table 6]

(Example 3) A raw material gas was supplied into a reaction tube on which a Mo substrate having a Rmax of 0.06 μm and which had been mirror-finished was placed. Next, a high frequency was applied from a high frequency oscillator to excite the source gas to generate plasma and synthesize a diamond polycrystal layer on the Mo substrate. The synthesis was performed under the following conditions.

[0044]

[Table 7]

After the synthesis, by immersing it in hot aqua regia to dissolve and remove only the Mo substrate, a diamond polycrystal layer having an average crystal grain size of 3 μm and a thickness of 0.35 mm could be recovered. The surface of the polycrystalline diamond layer facing the Mo substrate was a mirror surface with Rmax of 0.06 μm. A thickness of 0.
A W plate of 25 mm was placed, and W was heated and melted by an electron beam in a short time to react and bond with the diamond polycrystal. The recovered joint has a thickness of W of 0.1 mm at the joint.
C and the remaining 0.15 mm were metal W.

[0046]

[Table 8]

The laminate obtained by the above method was used as a tool material, and a brazing filler metal having a melting point of 870 ° C. was used to join the cemented carbide shank. This tool is Let G.

For comparison, a brazing material similar to the above is used,
Bonding of a single-piece diamond polycrystalline body not formed with WC and a cemented carbide shank was also performed. The synthesis conditions of the polycrystalline diamond were the same as in Example 3. This tool is N
o. Let H.

For comparison, sintered diamond having a grain size of 5 μm and containing 12% by volume of Co as a binder was used as a tool material, and this tool material was joined to a cemented carbide shank using the same brazing material as above. .. This tool is I. In addition, the tool No. G, H, and I were bladed with a # 1500 grindstone. The performance evaluation of these throw-away insert tools was performed under the following conditions.

(Cutting Conditions) Work Material: Hard Carbon Cutting Speed: 1000 m / min Cutting Depth: 0.8 mm Feeding Speed: 0.2 mm / rev. Cutting time: 20 minutes Coolant: Water-soluble oil (Evaluation method) Comparison of cutting edge states after 5 minutes of cutting and 60 minutes of cutting. As a result, as shown in Table 9, the tool No. of Example 3 according to the present invention was used. G is a tool No. using the sintered diamond of Comparative Example 6. It was revealed that a sharp cutting edge was maintained for a long time as compared with I. In addition, the tool No. of Comparative Example 5 was used. It has been clarified that H causes fatal damage as a tool as the brazing filler metal flows out.

[0051]

[Table 9]

[0052]

According to the present invention, since the thermal diffusion preventing layer having a low thermal conductivity is provided between the diamond polycrystal layer and the brazing portion, the cutting edge is generated by the heat generated when it is used as a tool. Even if the heat becomes high, the strength of the brazed portion will not decrease. Further, since the thickness of the tool material is increased as compared with the conventional one, the strength of the tool material can be increased.

[Brief description of drawings]

FIG. 1 is an enlarged view of a first embodiment of a diamond polycrystalline body cutting tool according to the present invention.

FIG. 2 is a schematic view of a Si substrate on which a diamond polycrystalline layer is formed, showing the first step of the manufacturing steps of Example 1 of the diamond polycrystalline cutting tool according to the present invention. is there.

FIG. 3 shows a second step of the manufacturing steps of Example 1 of the diamond polycrystalline body cutting tool according to the present invention, showing a state where the laminate is immersed in a nitric fluoride solution. It is a schematic diagram.

FIG. 4 shows a third step of the manufacturing steps of Example 1 of the polycrystalline diamond cutting tool according to the present invention, which is a schematic diagram of a tool material composed of a polycrystalline diamond layer and TiC. Is.

FIG. 5 is a view showing a fourth step of the manufacturing steps of Example 1 of the polycrystalline diamond cutting tool according to the present invention, showing a state where the laminate is brazed to the cemented carbide shank. It is a schematic diagram.

FIG. 6 is a schematic view showing a fifth step of the manufacturing steps of Example 1 of the diamond polycrystalline body cutting tool according to the present invention, in a state in which blade cutting is performed.

FIG. 7 is a perspective view of the diamond polycrystalline body cutting tool shown in FIG.

FIG. 8 is a schematic view of a W substrate on which a diamond polycrystalline layer is formed, showing a first step of the manufacturing steps of Example 2 of the diamond polycrystalline cutting tool according to the present invention. is there.

FIG. 9 is a view showing a second step of the manufacturing steps of Example 2 of the diamond polycrystalline body cutting tool according to the present invention, in which TaC and a diamond polycrystalline layer are laminated on each other;
It is a schematic diagram of a board | substrate.

FIG. 10 is a view showing a third step of the manufacturing steps of Example 2 of the polycrystalline diamond cutting tool according to the present invention, in which the W substrate shown in FIG. 9 is immersed in hot aqua regia. It is a schematic diagram which shows.

FIG. 11 shows a fourth step of the manufacturing steps of Example 2 of the polycrystalline diamond cutting tool according to the present invention, and is a schematic view of a tool material composed of a polycrystalline diamond layer and TaC. is there.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Si substrate 3 Diamond polycrystal layer 5 Fluorine nitric acid 11 TiC 13 Cemented carbide shank 17 Brazing part 19 Tool material 21 Mo substrate 23 TaC 25 Thermal aqua regia

Claims (18)

[Claims] 1. A diamond polycrystal cutting tool having a diamond polycrystal layer as a rake face, the diamond polycrystal layer having a thermal conductivity of 3 to 20 W / cm · K at room temperature, and brazing. Part, and a tool material having a heat diffusion preventing layer having a thermal conductivity of 0.1 to 2 W / cm · K at room temperature, which is located between the diamond polycrystalline layer and the brazing part, and the brazing material. A diamond polycrystal cutting tool, comprising: a tool support that supports the tool material by brazing the brazing part. 2. The diamond polycrystalline body cutting tool according to claim 1, wherein the diamond polycrystalline layer has a thickness of 0.1 to 0.5 mm. 3. The thickness of the heat diffusion prevention layer is from 0.05 to
The diamond polycrystalline body cutting tool according to claim 1, which is 0.5 mm. 4. The thermal diffusion preventing layer comprises Ti, W, Ta,
The diamond polycrystalline body cutting tool according to claim 1, comprising a carbide of at least one element selected from the group containing Mo and Si. 5. The rake face is the surface in contact with the substrate when the diamond polycrystal is synthesized, and Rm
The diamond polycrystalline body cutting tool according to claim 1, which has a mirror surface state of 0.2 μm or less in ax. 6. The diamond polycrystalline cutting tool of claim 1, wherein the tool support comprises cemented carbide. 7. The grain size of the diamond polycrystal is 0.
The polycrystalline diamond cutting tool according to claim 1, which has a thickness of 5 to 15 μm. 8. A method for manufacturing a diamond polycrystal cutting tool having a diamond polycrystal layer as a rake face, which has a thermal conductivity of 3 to 3 at room temperature on a substrate made of metal or alloy by a low pressure vapor phase method. Forming a diamond polycrystal layer of 20 W / cm · K, and forming a thermal diffusion preventing layer having a thermal conductivity of 0.1 to 2 W / cm · K at room temperature on the diamond polycrystal layer. A step of removing the substrate from the laminate including the substrate, the diamond polycrystalline layer and the thermal diffusion preventing layer by a chemical method to produce a tool material, and the diamond polycrystalline layer and brazing Of the diamond polycrystalline body cutting tool, which comprises a step of brazing the tool material to a tool support so that the heat diffusion preventing layer is located between Production method. 9. A method for manufacturing a diamond crystal cutting tool having a diamond polycrystal layer as a rake face, which has a thermal conductivity of 3 to 20 W at room temperature on a substrate made of metal or alloy by a low pressure vapor phase method. / Cm · K, forming a diamond polycrystal layer, removing the substrate from the diamond polycrystal layer by a chemical method, and applying heat at room temperature on the growth upper surface of the diamond polycrystal layer. A step of forming a heat diffusion preventing layer having a conductivity of 0.1 to 2 W / cm · K and producing a tool material; and the heat diffusion preventing layer is located between the diamond polycrystalline layer and the brazing portion. As described above, a method for manufacturing a diamond polycrystalline body cutting tool, comprising: a step of brazing the tool material to a tool support; and a step of processing a cutting edge into a required shape. 10. The method for manufacturing a diamond polycrystalline body cutting tool according to claim 8, wherein the diamond polycrystalline layer has a thickness of 0.1 to 0.5 mm. 11. The thickness of the heat diffusion preventing layer is from 0.05 to
The method for manufacturing a diamond polycrystalline body cutting tool according to claim 8 or 9, which has a thickness of 0.5 mm. 12. The thermal diffusion preventing layer comprises Ti, W, T
at least 1 selected from the group including a, Mo and Si
The method for manufacturing a diamond polycrystalline body cutting tool according to claim 8 or 9, which contains carbides of one or more elements. 13. The rake face is the surface in contact with the substrate when the polycrystalline diamond is synthesized, and R
The method for producing a diamond polycrystalline body cutting tool according to claim 8 or 9, which has a mirror-finished state with a maximum of 0.2 µm or less. 14. The method for manufacturing a diamond polycrystalline body cutting tool according to claim 8, wherein the tool support contains cemented carbide. 15. The method for manufacturing a diamond polycrystalline body cutting tool according to claim 8, wherein the grain size of the diamond polycrystalline body is 0.5 to 15 μm. 16. The method for manufacturing a diamond polycrystalline body cutting tool according to claim 8, wherein the substrate contains at least one selected from the group containing Mo, W and Si. 17. The chemical method for removing the substrate is to dissolve the substrate in at least one liquid selected from the group containing hydrochloric acid, sulfuric acid, nitric acid and hydrofluoric acid. A method for manufacturing a diamond polycrystalline body cutting tool according to 1. 18. The method for manufacturing a diamond polycrystalline body cutting tool according to claim 8, wherein the cutting edge is formed by laser processing.