JPH0790466B2 - Grinding wheel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rotation of a grinder, a honing machine, a lathe, a drilling machine, a milling machine, a cutting device, a drilling device, etc. mounted on a machine tool to rotate and reciprocate to machine a workpiece. Alternatively, it relates to a grinding wheel that makes a linear motion.

[0002]

2. Description of the Related Art Fine ceramics are widely used in automobile engines, automobile parts such as turbochargers, machine tool spindles, machine parts such as housings, IC substrates, cutting tools and various electronic parts.

Generally, a grinding wheel for grinding fine ceramics is such that abrasive grains such as diamond and CBN are directly electrodeposited on the outer peripheral portion of the base metal, or the abrasive grains are resinoid,
It is attached to the outer periphery of the base metal as a grindstone layer fired using a binder such as vitrified metal. This base
Is a table or spacer to keep the abrasive layer in the required shape.
From this role, the base metal is generally
High specific strength, low density, high workability, elastic deformation
Small (high elastic modulus), large vibration damping rate, low thermal expansion
It is desired to have various properties such as tonicity. Conventionally, an Al alloy or an Fe alloy (only for cutting) has been used for this base metal, but the linear thermal expansion coefficient α of the Al alloy or the Fe alloy is α = 2.5 to 3.0 × for the Al alloy. 10 ^-5 /
℃, Fe alloy α = 1.0 ~ 1.5 × 10 ^-5 / ℃,
Since the coefficient of thermal expansion is large, the size and shape of the grindstone change due to grinding heat during continuous use, which adversely affects the size and shape accuracy of the workpiece.

For example, an existing practical standard grindstone having a diameter of φ = 300 mm, when used under practical grinding conditions, generally has a room temperature of 70 ° C. at the outer peripheral portion and a central portion of the re-grinding stone. Therefore, according to theoretical calculation, the grindstone is thermally displaced by 20 to 30 μm in the radial direction. Although this value does not directly become the cut amount, about 30% (6 to 10 μm) thereof usually appears as an extra cut amount. Therefore, an error of that amount occurs in the size and shape of the workpiece. Further, the grindstone itself deteriorates due to thermal expansion, and the life of the grindstone is shortened.

[0005]

Hard and brittle materials such as fine ceramics are generally used for expensive structures or functional members that require high precision in size and shape, and thus are generally fired in a state close to the net shape. Generally, the outer surface is mirror finished. for that reason,
The processing accuracy is often on the order of nanometer (nm). Especially Si, GaAs, glass, Si ₃ N ₄ , A
For semiconductors such as l ₂ O ₃ , ZrO ₂ , and SiC, electronic components, and optical components, accuracy of nm to sub-nanometer (1 nm or less) is required.

However, it is the actual situation that no grindstone for processing for finishing to the above-mentioned accuracy is found. This is a conventional whetstone
This is because the size and shape of the workpiece are changed by the grinding heat due to continuous use, and the size and shape accuracy of the workpiece is reduced. In particular, since the grinding point temperature during ceramics processing is 700 to 900 ° C. under practical conditions, it is not possible to obtain a sufficiently high processing accuracy with conventional grinding wheels.

The present invention has been made in view of the above circumstances, and an object of the present invention is, even with a simple structure, thermal deformation of a grindstone during grinding, that is, thermal deformation of a base metal.
It is possible to reduce the heat effect of the shape on the abrasive grain layer, improve the dimensional accuracy of the grinding process, and prolong the life of the grindstone . Moreover, it is possible to easily manufacture by using a new material. > It is to provide a grinding wheel.

[0008]

Means for Solving the Problems In order to achieve the above object, the present invention provides a grinding whetstone having an abrasive grain or a whetstone layer attached to a predetermined outer peripheral portion of the base metal, wherein the base metal is Ni: 20-30%, C: 1-6%, C by weight
o; 3 to 7%, Mn; 0 to 1%, Cu; 0 to 1%, C
r; 0 to 1%, linear thermal expansion coefficient α = mainly composed of residual Fe
It is formed of a Ni—Co cast iron alloy of 0.5 to 3 × 10 ⁻⁶ / ° C., and an abrasive grain or a whetstone layer is attached to a predetermined outer peripheral portion of this base metal.

Among the hard and brittle materials, in order to improve the size and shape accuracy of a ceramic work, it is necessary to minimize the size and shape deformation of the grindstone due to the grinding heat.
That is, it is necessary to prevent the fired ceramics supplied in a dimension close to the net shape from becoming defective as a result of grinding and finishing due to over-grinding of the ceramics due to thermal deformation of the grindstone.

In the grinding wheel, not only those in which the abrasive grains are directly attached to the base metal by electrodeposition but also those in which the grindstone layer is attached to the base metal have a very large proportion of the base metal in the whole grindstone. For example, in the case of a grinding wheel in which a whetstone layer is attached to the outer periphery of a base metal, the whetstone layer has a thickness of 0.1 to 3 mm, whereas the whetstone base metal has a diameter φ of 100 to 600 mm as a general size. Become. Therefore, it was found that the thermal deformation of the base metal had a great influence on the size and shape change of the grindstone. Accordingly, the present inventors have found the study, as base metal of the grinding wheel, high rigidity and vibration absorption properties, moreover Chi also low chemical components of linear thermal expansion coefficient alpha, and other of the properties desired in the metal base Stuff
The inventors have found that a cast iron alloy is used, and completed the present invention.

On a weight basis, Ni: 20-30%, C: 1-
6%, Co; 3 to 7%, Mn; 0 to 1%, Cu; 0-1
%, Cr; 0 to 1%, Ni—Co containing Fe as the main component
According to the result of the experiment, the cast iron alloy has a coefficient of linear thermal expansion α = 0.
It is 5 to 3.0 × 10 ⁻⁶ / ° C. (−50 to 300 ° C.) and has an extremely low a value as compared with Al alloys and Fe alloys used for the base metal of conventional grinding wheels. For example, Ni≈26%, C≈2%, Co≈5%, Mn≈1%, and
The coefficient of linear thermal expansion α of the cast iron alloy made of Fe containing Cu <1%, Cr <1% and residual impurities is α≈1.6 × 10 ⁻⁶ / ° C. If the a value is within the range of the above component composition, it is F
It does not change even if e contains unavoidable impurities. And
Grinding whetstone that formed the base metal by the cast iron alloy of the above components, even if it is a whetstone with abrasive grains directly attached to the outer peripheral portion of the base metal, also with a whetstone layer with a whetstone layer obtained by sintering the abrasive grains with a binder. However, under practical grinding conditions, thermal deformation is 0.5-
Reduce to about 1.0 μm or less.

Moreover, the elastic modulus E showing the rigidity of the Al alloy, which occupies most of the base metal of the conventional grinding wheel, is E = 70.3G.
While Pa, the elastic modulus of the base metal made of the cast iron alloy having the above components is E = 130 GPa. Therefore, although it is lower than E = 200 GPa of steel, it has sufficient rigidity as a base metal for a grinding wheel.

The abrasive grains used in the present invention may be any as long as they are commonly used as abrasive grains such as diamond abrasive grains and CBN abrasive grains. Further, the abrasive grains may be directly attached to the base metal formed of the cast iron alloy of the above components by electrodeposition or the like, or may be sintered with a binder and attached as a grindstone layer.

In the case of a grinding wheel in which a grindstone layer obtained by sintering abrasive grains using a binding material is attached to the outer periphery of a base metal, the binding material may be bronze, Ag, Co, Cu, Fe, Ni, Sn, W.
One or more of metals such as c and Zn or alloys thereof, bakelite, epoxy, polyurethane, phenol, polyamide, resinoids such as PVA, and vitrified materials such as feldspar and clay can be used. Further, as the binder, it is also possible to use the powder of the cast iron alloy having the same components as the base metal, or to mix the cast iron alloy powder with another binder, and in this case, the effect of the thermal expansion of the binder. Can be reduced.

Abrasive grains and binder are vacuum, hydrogen or 3H ₂ +
It is preferable to sinter under an atmosphere such as N ₂ . At that time, the optimum sintering temperature and pressure are selected according to the types of abrasive grains and binder used.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of a grinding wheel, and 1 is a base metal. The base metal 1 has, for example, an outer diameter of 160 and an inner diameter of 1
27 and a ring portion 2 having a thickness of 24.5 mm, and a collar portion 3 integrally provided on the outer peripheral surface of the ring portion 2 and having an outer diameter of 210 including the ring portion 2 and a thickness of 1.5 mm. . An abrasive grain layer 4 is attached to the outer peripheral portion of the collar 3 of the base metal 1.

The base metal 1 is made of Ni on a weight basis; 20 to 3
0%, C; 1-6%, Co; 3-7%, Mn; 0-1
%, Cu; 0 to 1%, Cr; 0 to 1%, and a coefficient of linear thermal expansion having residual Fe as a main component α = 0.5 to 3 × 10 ⁻⁶ / ° C. (−5
(0 to 300 ° C.) Ni-Co cast iron alloy.

The abrasive grain layer 4 is formed by directly adhering # 140 diamond abrasive grains to the collar portion 3 of the base metal 1 by electrodeposition, but may be CBN abrasive grains.

[0019]

[Table 1]

Table 1 shows that the grinding wheel of the first embodiment (hereinafter referred to as "development wheel") is repeatedly used four times, the wheel peripheral speed Vs = 1800 m / min, and the table speed Vw = 10.
m / min, grindstone cutting amount d = 10 μm, and a substantial cutting amount when a cutting experiment of 120 μm in total was performed using plunge grinding with silicon nitride (two sparkouts). For comparison, a commercially available metal bond grindstone (SD
140J75 φ300 B = 10 mm. Base metal 1 is Al
Alloyed with Cu: Sn = 6: 4 mixed fine powder with W
C; 0.4 Wt%, TiB2; 0.3 Wt%, Ni;
Binders added with 0.2 wt% of # 140 diamond abrasive grains that are fired and adhered to the outer periphery of the base metal. Hereinafter referred to as "comparison grindstone". ) Also shows the data when the same experiment is performed. As is clear from Table 1, the number of repeated experiments was 4
On average, the cutting amount is 119/120 with the developed grindstone.
0.99, 110.3 / 120 = 0.92 for the comparative grindstone, so the uncut amount is 1% for the developed grindstone (grindstone of the first embodiment) and for the comparative grindstone (commercially available metal bond grindstone). It was 8%.

From the results of the above experiment, in the comparative grindstone exposed to high temperature, since the high heat source portion is cooled by the grinding liquid during grinding, large shrinkage and expansion are repeated, resulting in a large uncut amount. It is recognized that the grinding wheel of the present invention, that is, the developed wheel, has a small amount of deformation with respect to heating and cooling, and therefore the dimensional accuracy is improved eight times as compared with the comparative wheel.

FIG. 2 shows a second embodiment of the grinding wheel, 5
Is the base metal. The base metal 5 has an outer diameter of 210 mm and a thickness of 1
It has a disk shape of 0 mm, and a grindstone layer 6 having a thickness of 3 mm is attached to the outer peripheral portion thereof.

Similar to the first embodiment, the base metal 5 is Ni; 20 to 30%, C; 1 to 6%, Co; 3 on a weight basis.
~ 7%, Mn; 0-1%, Cu; 0-1%, Cr; 0
1%, coefficient of linear thermal expansion α = 0.5 to 3 mainly composed of residual Fe
× is formed by ^{10 -6} / Ni-Co iron alloy ℃ (-50~300 ℃).

The grindstone layer 6 is composed of abrasive grains mainly composed of diamond having a grain size of # 140, bronze 80 Wt% and Ni 10 W.
t% and a binder mixed with 10 Wt% of the cast iron alloy powder having the above components, and is formed by sintering the abrasive grains and the binder in a high-purity vacuum under high temperature and high pressure.

The same experiment as described above for the first embodiment was conducted on the grinding wheel of the second embodiment.
Results similar to those of the example were obtained.

Further, a grinding wheel similar to that of the second embodiment except that the binder is a mixture of 70 wt% phenol and 30 wt% Fe, and the binder is 70% bronze and 10% Ni10.
When the same experiment as in the above-described first example was conducted on the same grinding wheel as in the second example except that it was a mixture of Wt% and Fe20Wt%, the same result as in the first example was obtained. It was

FIGS. 3 and 4 show a grinding wheel of the first embodiment (developing wheel) and the commercially available metal bond wheel (comparative wheel) under the respective processing conditions shown in FIGS. It shows the result of an experiment for examining the normal line and tangential grinding resistance when grinding silicon and alumina. From the results of the above experiment, the tangential grinding resistance of the developed grindstone is about the same as that of the comparative grindstone, but the normal grinding resistance of the developed grindstone is 1/2 to 1/5 of that of the comparative grindstone, which is a considerably small value. It can be seen that the grindstone is expected to have a reduction in normal grinding resistance due to thermal deformation of 2 to 5 times that of the comparative grindstone. This means that the grinding wheel of the present invention does not need to be strongly pressed against the workpiece to be elastically deformed, unlike the comparative wheel, so that 8
It shows that there is less unfolding left. That is,
In the grinding wheel of the present invention, the grinding process can be advanced with a small grinding wheel pushing force, and as a result, high dimensional accuracy can be obtained smoothly.

[0028]

As described above, according to the present invention, it is possible to reduce the size and shape change of the work piece due to the size and shape change of the grindstone due to the grinding heat, and to reduce the work piece by 2 to 5 times. Under normal grinding force of pressing and desired dimensional accuracy in design with much less uncut amount than before,
Ceramics can be processed efficiently. In particular, when exposed to severe grinding conditions where high-temperature grinding heat is generated, the present invention can further exert the effect of preventing thermal deformation of the workpiece. Further, in the case of plunge grinding using a form electrodeposition grindstone, there is an effect that even more excellent performance can be exhibited because the number of grindstone layers is small.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a grinding wheel according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional side view of a grinding wheel according to a second embodiment of the present invention.

FIG. 3 is a graph comparing a normal line and a tangential grinding resistance with respect to respective ceramics of a grinding wheel (developing wheel) according to an embodiment of the present invention and a commercially available metal bond wheel (comparative wheel).

FIG. 4 is a graph comparing the normal and tangential grinding resistances of respective ceramics of a grinding wheel (developing wheel) according to an embodiment of the present invention and a commercially available metal bond wheel (comparative wheel).

[Explanation of symbols]

1, 5 ... Base metal, 4. ..Abrasive particles, 6 ...
Whetstone layer.

Claims (3)

[Claims] 1. A grinding wheel in which abrasive grains or a grindstone layer is attached to a predetermined outer peripheral portion of a base metal, wherein the base metal is Ni; 20 to 30%, C; 1 to 6%, Co; 3-7
%, Mn; 0-1%, Cu; 0-1%, Cr; 0-1
%, Coefficient of linear thermal expansion α = 0.5 to 3 × containing residual Fe as a main component
A grinding wheel formed of a ^10-6 / ° C Ni-Co cast iron alloy and having abrasive grains or a wheel layer adhered to a predetermined outer peripheral portion of the base metal. 2. The grindstone layer comprises abrasive grains and N by weight.
i; 20 to 30%, C; 1 to 6%, Co; 3 to 7%, M
n; 0 to 1%, Cu; 0 to 1%, Cr; 0 to 1%, balance F
coefficient of linear thermal expansion α = 0.5 to 3 × 10 ⁻⁶ containing e as a main component
/ ° C Ni-Co cast iron alloy powder, a metal other than the cast iron alloy powder, a resinoid, and a binder containing one or more kinds of vitrified materials. Grinding wheel. 3. The grindstone layer is formed by vacuuming abrasive grains and a binder.
The grinding wheel according to claim 1, which is formed by sintering in an atmosphere of hydrogen, 3H ₂ + N ₂ or the like.