JPH08300265A - Cutting grinding wheel - Google Patents

Abstract

PURPOSE: To provide a cutting grinding wheel that epochally improves the cutting accuracy and cutting yield rate of a workpiece in checking any possible deformation value of this diamond and carbon nitride cutting grinding wheel being thin in blade thickness. CONSTITUTION: In this cutting grinding wheel made up of sticking diamond or carbon nitride abrasive grains tight to a grinding wheel spindle stock plate end, the surface of a grinding wheel spindle stock plate made of sheet steel is coated with a cemented carbide material layer of 0.5 to 50μm in thickness by a carbide vitrified process in advance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond or CBN cutting grindstone used for slicing various hard materials.

[0002]

2. Description of the Related Art Recently, for cutting various hard materials,
Wheels containing fine particles of diamond abrasive grains or CBN (cubic boron nitride) abrasive grains are widely used. this is,
This is because the fine particles of diamond abrasive grains and CBN abrasive grains have a large hardness, and in recent years, these fine particles have been industrially produced at low cost. For various diamond grindstones (hereinafter, including CBN grindstone unless otherwise specified), a thin circular plate made of steel plate as shown in Fig. 1 is used as a grindstone base plate and outer peripheral cutting is performed by adhering diamond abrasive grains to the outer peripheral portion. There are a diamond grindstone and an inner peripheral cutting diamond grindstone in which diamond abrasive grains are adhered to the inner peripheral part of a thin doughnut-shaped disc made of a steel plate as shown in FIG.
It is an object of the present invention. As the grinding stone base plate material, a steel material, a cemented carbide, a ceramics or the like is used, but from the viewpoint of material cost and mechanical strength, the steel material such as alloy tool steel is exclusively used. In the case of a cutting whetstone, shocking stress is continuously applied to the whetstone base plate by high-speed rotation, and brittle materials such as cemented carbide and ceramics are not used often because they have insufficient mechanical strength and are easily damaged.

When cutting a hard material using a cutting grindstone, for example, when cutting a block of a certain size to cut out a large number of products, the blade thickness of the cutting grindstone and the material yield of the material to be cut are The relationship becomes important, and it is important to use as thin a blade as possible to reduce the cutting cost, increase the number of products to be obtained, increase the material yield, and improve the productivity. In order to obtain a thin cutting blade, it is necessary to make the whetstone base plate thin. At present, by using the highest possible mechanical strength among various steel materials, it is possible to manufacture grindstone base plates as thin as about 0.2 mm for outer cutting wheels and about 0.05 mm for inner cutting wheels. As the grinding stone base plate material, an appropriate type is selected and used from the above-mentioned steel materials in consideration of material cost, heat treatment cost and mechanical strength.

[0004]

In such a cutting whetstone, the following problems have occurred as the whetstone base plate has become thinner. Generally, as shown in the peripheral cutting grindstone of FIG. 1, a diamond abrasive grain layer is formed from the surface of the grindstone base plate.
0.02 to 0.2 mm is projected so that a gap (hereinafter, also referred to as escape) is provided between the workpiece and the object to be cut. This gap serves to eliminate cutting grinding powder generated from the cut object when the cutting grindstone cuts into the cut object and the cutting depth becomes deeper than the band width of the diamond abrasive grain layer of the outer peripheral cutting blade. ing. To reduce the cutting allowance, that is, the blade thickness, it is necessary to make this gap and the grindstone base plate as thin as possible.For example, when the thickness of the grindstone base plate is 0.7 mm or less, the gap is only 0.02 on one side. It will be about 0.05 mm. The problem of cutting with a thin plate grinding wheel base plate is that this gap is too small to remove cutting grinding powder, and this cutting grinding powder is sandwiched between the object to be cut and the grinding wheel base plate and scratches the grinding wheel base plate. It is to end up. When the material to be cut is a hard material, it is generally harder and brittle than the steel material used for the grinding wheel base plate. Cutting fragments of these hard and brittle materials are not removed from the gap and accumulate, and are sandwiched between the grinding stone base plate and the object to be rotated at high speed, which damages the grinding stone base plate. Due to the plastic deformation of, the stress balance between the front and back of the steel plate is disturbed, and deformation such as bending and waviness occurs in the whetstone base plate. The thinner the whetstone base plate, the smaller the scratches, and the larger the bending and waviness. Once the whetstone base plate is deformed by such scratches,
Since the stress at the time of cutting is applied so as to further deform the deformed whetstone base plate, and the bending and waviness are promoted, the dimensional accuracy of the obtained cut product is largely lost.
This phenomenon also applies to the inner circumference cutting grindstone shown in FIG. The present invention is intended to provide a diamond cutting grindstone or a CBN cutting grindstone in which a diamond or CBN abrasive grain is strongly bonded to a grindstone base plate having improved mechanical strength, which solves the above problems.

[0005]

Means for Solving the Problems The inventors of the present invention have made extensive studies as a solution to such problems, and as a result, on the surface of a whetstone base plate made of a steel plate such as an alloy tool steel, a TiC film was previously formed by CVD (chemical vapor deposition). , TiN, Ti (C, N), AlN, Al ₂ O ₃ etc., a layer of ultra-hard material is deposited, and then diamond or CBN abrasive grains are selected from metal bond, resin bond, vitrified bond, electroformed bond, etc. We have found that a cutting grindstone bonded to the end of the grindstone base plate by this method is extremely effective, and completed the present invention.The gist is that diamond abrasive grains or CBN abrasive grains are fixed to the end of the grindstone base plate. In the cutting grindstone, the surface of the steel stone grindstone base plate is pre-formed with a superhard material layer by the CVD method.
A cutting grindstone characterized by being coated to a thickness of 5 to 50 μm.

The present invention will be described in detail below. The greatest feature of the present invention is TiC, TiN, Ti (C, N), AlN, a superhard substance layer such as Al ₂ O ₃ on a whetstone base plate surface made of steel plate such as alloy tool steel.
The coating is applied in advance to a thickness of 0.5 to 50 μm by the CVD method, and then diamond or CBN abrasive grains are fixed to the whetstone base plate with a binder, which causes the steel plate whetstone base plate generated during cutting work. Suppresses scratches on the steel plate grinding stone base plate caused by cutting and grinding powder of a hard and brittle cemented carbide or ceramics, and prevents deformation such as bending and waviness of the grinding stone base plate However, it is to secure the cutting dimension accuracy of the cut object and reduce the cutting processing allowance.

The material of the whetstone base plate which is the object of the present invention is various steel materials, particularly alloy tool steel, and JIS standards SK, SKS, S
Alloy tool steels such as KD, SKT, SKH are used. Ultra-hard materials that are coating materials include carbides such as TiC, nitrides such as TiN and AlN, carbonitrides such as Ti (C, N), and Al.
Oxides such as ₂ O ₃ are used. One type selected from these coating materials may be used in a single layer or two or more types may be used in a multi-layer combination to form 0.5 to 50 μm, preferably 1 to 40 μm.
Coat to a thickness of μm. Coating thickness
The coating thickness is 0.5 to 50 μm.
If it is less than μm, the grindstone base plate is likely to be scratched during cutting, and the effect of the present invention cannot be sufficiently obtained.
This is because if it exceeds m, it takes too much time and cost for coating, which is not preferable.

The CVD method used for coating may be basically a known method, and the reaction conditions are appropriately selected depending on the type of substance to be coated. A grindstone base plate made of various steel plates is placed in a reaction vessel inside an electric furnace maintained at about 1000 ° C, and a reaction gas, which is a raw material of an ultra-hard substance to be coated, generated by a chemical reaction is introduced. The reaction gas is
In Ti-based coating, titanium tetrachloride (TiCl ₄ ) is mainly used as evaporative gas, and in the case of TiC, carbon dioxide (C
O ₂ ) or methane (CH ₄ ) or nitrogen gas in the case of TiN
(N ₂ ) or ammonia gas (NH ₃ ), a mixed gas of CO ₂ or CH ₄ and Ti or N ₂ or NH ₃ in the case of Ti (C, N), and hydrogen (H ₂ ) Or argon (Ar) mixed with a carrier gas and introduced into the reaction vessel.
In the case of AlN, vaporized gas of aluminum trichloride (AlCl ₃ ) is used instead of titanium tetrachloride gas. In the case of Al ₂ O ₃ , hydrogen gas and carbon dioxide are reacted with aluminum trichloride gas. The introduced mixed gas reacts on the surface of the whetstone base plate to deposit an ultra-hard substance. Each precipitation reaction formula is as follows. TiCl ₄ + CH ₄ → TiC ＋ 4HCl TiCl ₄ ＋ (1/2) N ₂ ＋ 2H ₂ → TiN ＋ 4HCl AlCl ₃ ＋ NH ₃ → AlN ＋ 3HCl TiCl ₄ ＋ (1-x) CH ₄ ＋ (x / 2) N ₂ → Ti ( C _1-x N _x ) + 4HCl 2 AlCl ₃ ＋ 3CO ₂ ＋ 3H ₂ → Al ₂ O ₃ ＋ 3CO ＋ 6HCl The magnet grindstone base plate is held in the space of the reaction vessel by passing the stainless wire through the central shaft hole. As a result, the whetstone base plate is coated simultaneously on the front and back, and it is not necessary to coat the front and back twice separately. In the case of multi-layer coating, it is possible by changing the composition of the introduced gas during coating.

At the end of the whetstone base plate which has been coated with the ultra-hard material, a diamond abrasive grain or CBN abrasive grain is fixed in a U-shape using a binder to obtain the cutting stone of the present invention. The binder may be a known metal bond, resin bond, vitrified bond or electrodeposition bond, and an appropriate one is used depending on the application of the cutting grindstone. The metal bond is obtained by mixing an alloy powder such as bronze (Cu-Sn) with diamond abrasive grains or CBN abrasive grains, baking the mixture at a temperature of 1000 ° C or less, and fixing it to the whetstone base plate. Further, in the resin bond, a thermosetting phenol resin is generally used as a binder. This resin is mixed with diamond abrasive grains or CBN abrasive grains, pressure-formed at 50 to 500 kg / cm ² , and heated at 100 to 500 ° C to adhere to the stone base plate. Vitrified bond uses a vitreous bond and is mixed with abrasive grains
Melt the vitreous binder at 0-900 ℃ and fix it to the wheel base plate. Electrodeposition bond mixes and disperses diamond abrasive grains and CBN abrasive grains in the plating bath and electroplates the stone base plate in the plating bath to incorporate the abrasive grains into the plating film and fix them to the stone base plate. Let Further, diamond abrasive grains or CBN abrasive grains may be sprinkled on the surface of the grindstone base plate, and the grindstone base plate may be electroplated as it is to fix the abrasive grains to the grindstone base plate.

[0010]

[Function] The cutting wheel with the steel plate whetstone base plate surface coated with a super-hard material by the CVD method improves the wear resistance by increasing the hardness of the whetstone base plate surface. It does not occur, for example, 0.2 mm thick
~ 0.7 mm, 60 mm ~ 150 mm in diameter Ultra-thin steel plate grinding wheel Even on the outer and inner diamonds of the base plate, CBN cutting wheel, no bending or waviness occurs. This ultra-hard material layer prevents scratches on the surface of the grinding stone base plate due to chips and debris of the work to be cut and maintains its cutting accuracy for a long time, improving material yield by thin blade cutting and reducing manufacturing cost Can be realized.

[0011]

EXAMPLES The embodiments of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. (Example 1, Comparative Example) A 150 mmφ × 0.6 mmt SKD whetstone base plate was coated with TiC, TiN and Al ₂ O ₃ on both sides by the CVD method. The thickness of the coating film was about 10 μm on each side. The reaction conditions of the CVD method were as follows. Coating material Reaction gas Reaction temperature Reaction pressure TiC TiCl ₄ , CH ₄ 1000 ℃ Atmospheric pressure TiN TiCl _4, N ₂ , H ₂ 1000 ℃ Atmospheric pressure Al ₂ O ₃ AlCl ₃ , CO ₂ , H ₂ 1000 ℃ 100 Torr Next diamond grinding Range binder was used as the binder for the grains. Put the above coated whetstone base plate in a disc whetstone-shaped die, and use 120 μm artificial diamond abrasive grains with 120 μm Ni coating of 12 μm with thermosetting phenolic resin as a binder on the outer periphery. 3 (abrasive): 1
(Binder) is filled with the mixed powder. After forming into a grindstone shape with a press, 180 ° C with it set in the mold
After heat-curing for 30 minutes, the blade thickness was finished with a lapping machine after cooling, and a peripheral cutting whetstone with a blade thickness of 0.7 mmt was produced. As a comparative example, a peripheral cutting grindstone of the same size, which was not coated with an ultra-hard material, was also manufactured. For these four types of resin-bonded diamond peripheral cutting grindstones, a cutting test was conducted using quartz glass as the cut object, and Table 1 shows the relationship between the cutting time, the amount of deformation of the grindstone, the cutting accuracy of the cut object, and the cutting yield. It was Table 2 shows the results when the rare earth magnet was cut.

(Cutting Test Method and Conditions) Eight peripheral cutting grindstones were assembled in a multi-mold at intervals of 2 mm, and an object to be cut was cut at a rotation speed of 4500 rpm and a cutting speed of 8 mm / min. 36 mm wide
The test piece had a size of 40 mm in length and 10 mm in height and was attached to a carbon plate and cut together with the carbon plate. 500, 1000, 2 after cutting starts
After 000 and 3000 hours, the cutting grindstone was disassembled and the flatness from the inner peripheral edge of each grindstone base plate to immediately before the abrasive grain layer at the outer peripheral edge was measured, and the average was taken as the amount of deformation of the grindstone. . In addition, the thickness of 4 points at the corners and 5 points at the center of the cut product is measured with a micrometer, and the difference between the maximum value and the minimum value is used as the cutting accuracy. The yield was specified.

[0013]

[Table 1]

[0014]

[Table 2]

(Example 2, Comparative Example) 4 similar to Example 1
Electrodeposited bond diamond peripheral cutting whetstones were produced using various types of whetstone base plates. After insulating with a tape and masking agent except for the outer periphery of the whetstone base plate and the electrode connection part, 5% by weight of 120 mesh artificial diamond abrasive grains with a Ni coating of 12 μm on the Ni watt bath was applied to the total amount of the plating bath. The electrodeposition treatment was performed for 10 hours in the mixed electrodeposition plating bath. The thickness of the electrodeposition layer was about 100 μm. The electrodeposition plating bath was stirred with a stirrer and ultrasonic waves were applied to maintain the dispersion of diamond abrasive grains in the liquid. As a comparative example, a peripheral cutting grindstone of the same size, which was not coated with an ultra-hard material, was also manufactured. With respect to these four kinds of electrodeposited bond diamond peripheral cutting grindstones, a cutting test was performed using quartz glass as the cut object in the same manner as in Example 1, and Table 3 shows the cutting time, the amount of deformation of the grindstone, the cutting accuracy of the cut object, and the cutting. The relationship with yield was shown.
Table 4 shows the results when the rare earth magnet was cut.

[0016]

[Table 3]

[0017]

[Table 4]

(Example 3, Comparative Example) 4 similar to Example 1
An electrodeposited bond CBN peripheral cutting grindstone was prepared using various kinds of grindstone base plates. After insulating with tape and masking agent except for the outer periphery of the grinding wheel base plate and the electrode connection part, in an electrodeposition plating bath in which 5% by weight of 120 mesh CBN abrasive grains were mixed with Ni watt bath to the total amount of plating bath. It was electrodeposited for 10 hours. The thickness of the electrodeposition layer was about 100 μm. The electrodeposition plating bath was stirred with a stirrer and ultrasonic waves were applied to maintain the dispersion of diamond abrasive grains in the liquid. As a comparative example, a peripheral cutting grindstone of the same size, which was not coated with an ultra-hard material, was also manufactured. With respect to these four kinds of electrodeposited bond CBN peripheral cutting grindstones, a cutting test was carried out using quartz glass as an object to be cut in the same manner as in Example 1.
The relationship between the cutting accuracy of the material to be cut and the cutting yield was shown. Table 6
Shows the result when the rare earth magnet was cut.

[0019]

[Table 5]

[0020]

[Table 6]

[0021]

INDUSTRIAL APPLICABILITY The present invention is applicable to diamond and C having a thin blade thickness.
The cutting precision of the BN cutting grindstone is epoch-making, and if the cutting grindstone of the present invention is used for cutting, even if the blade thickness is thin, the cutting machining cost can be narrowed down while maintaining the cutting precision. Therefore, the product yield can be improved, the rationalization effect of the manufacturing process is great, and its utility value is extremely high in industry.

[Brief description of drawings]

FIG. 1 is a view showing a structure of a peripheral cutting grindstone. (A) is a top view, (b) is a vertical sectional view taken along the line AA, and (c) is an enlarged view of an outer peripheral end portion.

FIG. 2 is a view showing a structure of an inner circumference cutting grindstone. (A) is a top view, (b) is a vertical cross-sectional view taken along line BB, and (c) is an enlarged view of an outer peripheral end portion.

[Explanation of symbols]

1 Peripheral cutting whetstone 2
Inner circumference cutting whetstone 3 Super hard material coating layer 4
Abrasive layer 5 Grindstone base plate p Blade thickness or cutting cost q
Abrasive grain layer width r Gap or clearance

Claims (1)

[Claims] 1. A cutting grindstone in which diamond abrasive grains or CBN abrasive grains are fixed to the end of the grindstone base plate, the surface of the grindstone base plate made of a steel plate is 0.5 to 50 μm in advance as a super-hard material layer formed by the CVD method.
A cutting grindstone characterized by being coated to a thickness of m.