JP2019034372A - Grinding wheel and grinding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding whetstone capable of changing a surface roughness Rz after processing of a workpiece according to a speed of the grinding whetstone at the time of grinding, and a grinding device provided with the above grinding whetstone. To provide. A grinding wheel having a change rate of elastic modulus represented by the following formula A of 1.5 or more, preferably a grinding wheel base having an abrasive grain layer containing abrasive grains as an outermost layer, A grinding wheel in which the rate of change of the elastic modulus represented by the formula A of the base is 1.5 or more, and a grinding device including the grinding wheel. Formula A: (Elastic modulus at load speed of 50 mm / min) / (Elastic modulus at load speed of 1 mm / min) [Selection diagram] None

Description

  The present disclosure relates to a grinding wheel and a grinding apparatus.

Abrasive processing is intended to finish a workpiece to a predetermined shape size and surface quality, and is one of the important processing methods that must represent machining as well as cutting. Abrasive grains are generally composed of hard mineral particles, and particle sizes (grain sizes of abrasive grains) of various sizes can be used. When abrasive grains with a large particle size are used, the amount of processing is large, so that the shape can be created efficiently, but the surface roughness after processing (maximum height roughness, Rz) is large and the surface is cloudy. End up. On the other hand, when small abrasive grains are used, the processing amount is small, but a smooth glossy surface with a small surface roughness Rz can be obtained.
Usually, in part processing, a grindstone with a large amount of processing is used, and the size of the abrasive grains is gradually changed to a grindstone with a small amount of processing but a small surface roughness after processing. Processing method is performed.

  Patent Document 1 includes “a disc-shaped coarse grindstone portion including abrasive grains and abrasive grains having a diameter smaller than that of the coarse grindstone portion, and is adjacent to the coarse grindstone portion in the thickness direction of the coarse grindstone portion. A disk-shaped finishing grindstone part, and the outer diameter dimension of the rough grindstone part is smaller than the outer diameter dimension of the finishing grindstone part.

Japanese Patent Laid-Open No. 2006-78165

Abrasive processing is roughly divided into a free abrasive processing method and a fixed abrasive processing method.
The loose abrasive processing method is a processing method using abrasive particles that are free from each other such as sand and dust. On the other hand, the fixed abrasive processing method is a processing method in which abrasive grains are fixed with a binder or the like, and the representative tool is a “whetstone”.
In the grinding process, which is a process using a grindstone, as described above, a method of changing the size of the abrasive grains step by step is performed when the process proceeds. However, in such a method, it is necessary to change to a grindstone having a different particle size for each process, and there is a problem that work efficiency is lowered.
Therefore, Patent Document 1 proposes a method in which disk-shaped grindstones having different particle diameters are adjacent to each other and processing having different particle diameters can be performed without exchanging the grindstones. Specifically, the grinding wheel described in Patent Document 1 has two grinding wheel parts having different grain sizes, so that the grinding wheel for roughing processing has a large grain size without replacing the grinding wheel. And a grinding wheel for finishing that has abrasive grains having a small particle size can be used properly.
However, as a result of intensive studies, the present inventor has found that, according to the method described in Patent Document 1, when one of the grinding wheels deteriorates due to use, even if the other is usable, the grindstone It has been found that there is a problem that extra time is required for the maintenance of the grindstone due to the need for dressing and truing.
Further, according to the method described in Patent Document 1, the present inventor can only change to a stage corresponding to the number of grindstones having different particle diameters (for example, if there are two kinds of grindstones, it can only be changed to two stages). ) Was found.

As a result of intensive studies, the present inventors have used a grinding wheel whose elastic modulus change rate represented by Formula A is 1.5 or more, so that the workpiece is processed according to the speed of the grinding wheel during grinding. It has been found that the surface roughness (maximum height roughness, Rz) after processing of an object can be changed.
Although the details of the mechanism for obtaining the above effect are unknown, it is considered that the grinding wheel becomes hard when the rate of change of the elastic modulus represented by Formula A is 1.5 or more, for example, when the speed of the grinding wheel is high. . For this reason, when the speed of the grinding wheel is high, the abrasive grains are difficult to sink into the grinding wheel, so that the surface roughness after processing of the workpiece is reduced as in the case of grinding with a large grain size. Is estimated to be large.
In addition, when the speed of the grinding wheel is slow, the grinding wheel becomes soft, and for example, the abrasive grains are likely to sink into the grinding wheel, so that the apparent height of the abrasive grains is reduced, and abrasive grains having a small particle size are used. It is presumed that the surface roughness after processing of the work piece is reduced as in the case of performing grinding.

  The problem to be solved by the embodiments of the present disclosure is to provide a grinding wheel capable of changing the surface roughness Rz after processing of the workpiece according to the speed of the grinding wheel during grinding, and It is providing the grinding device provided with the said grinding wheel.

Means for solving the above problems include the following aspects.
<1> A grinding wheel whose elastic modulus change rate represented by the following formula A is 1.5 or more.
Formula A: Change rate of elastic modulus = (elastic modulus at a load speed of 50 mm / min) / (elastic modulus at a load speed of 1 mm / min)
<2> including a grindstone base having an abrasive layer containing abrasive grains in the outermost layer, and the rate of change of the elastic modulus represented by the formula A of the grindstone base is 1.5 or more, <1> The grinding wheel according to 1>.
<3> The grinding wheel according to <1> or <2>, which has a cylindrical shape, a spindle shape, or a conical shape.
<4> A grinding apparatus comprising the grinding wheel according to any one of <1> to <3>.

  According to the embodiment of the present disclosure, it is possible to provide a grinding wheel capable of changing the surface roughness Rz after processing of the workpiece according to the speed of the grinding wheel at the time of grinding, and the grinding wheel Can be provided.

It is a result of the compression test of the grinding wheel concerning this indication. It is a result of the compression test of the grinding wheel whose particle size is # 400. It is a result of the compression test of the grinding wheel whose particle size is # 800. It is a result of the compression test of the grinding wheel whose particle size is # 1500. It is the result of the compression test of the impact-absorbing pad used in the Example. It is a figure which shows the outline of the preparation procedure of the grinding wheel which concerns on this indication in an Example. It is a roughness curve of the surface of the workpiece before a process. It is a roughness curve after processing with a grinding wheel concerning this indication. It is a roughness curve after processing with a grinding wheel having a particle size of # 400. It is a roughness curve after processing by a grinding wheel having a particle size of # 800. It is a roughness curve after processing with a grinding wheel having a particle size of # 1500. It is a graph which shows the relationship between the surface roughness Rz after a process at the time of using the grinding wheel which concerns on this indication, and a grindstone rotation speed. It is a graph which shows the relationship between the surface roughness Rz after a process with a commercial grindstone, and a particle size. It is a graph which shows the surface roughness of the to-be-processed object when using the grinding wheel which concerns on this indication, and making processing load into 200gf. It is a graph which shows the surface roughness of the to-be-processed object when using the grinding wheel which concerns on this indication, and making processing load into 50 gf. It is a graph which shows the surface roughness of a to-be-processed object when using a commercially available grinding wheel and making process load into 200gf. It is a graph which shows the surface roughness of a to-be-processed object when a commercially available grinding wheel is used and a process load is 50 gf.

Hereinafter, the present disclosure will be described in detail.
In the present disclosure, the description “xx to yy” represents a numerical range including xx and yy.
In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.
In this specification, the term “process” is not only an independent process, but is included in this term if the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes.
Hereinafter, the present disclosure will be described in detail.

(Grinding wheel)
The grinding wheel according to the present disclosure has an elastic modulus change rate represented by the following formula A of 1.5 or more.
Formula A: Change rate of elastic modulus = (elastic modulus at a load speed of 50 mm / min) / (elastic modulus at a load speed of 1 mm / min)

Here, the rate of change of the elastic modulus represented by the formula A is 1.5 or more means that the elastic modulus is high when the deformation speed is high and the elastic modulus is low when the deformation speed is slow. Show.
When the grinding wheel has the above properties, the grinding wheel speed during grinding (for example, when using the grinding wheel as a rotating wheel with a grinding wheel attached) is high. When the processing amount is large and the surface roughness Rz after processing of the obtained workpiece is large and the speed is low, the processing amount is small and the surface roughness Rz is small.
As described above, by using the grinding wheel according to the present disclosure, it is possible to obtain the same effect as when a plurality of grinding stones having different particle sizes are used properly.

<Change rate of elastic modulus represented by Formula A>
The change rate of the elastic modulus represented by the formula A is 1.5 or more, preferably 1.8 or more, more preferably 2.0 or more, and further preferably 2.5 or more. preferable.
The amount of change is preferably 5.0 or less, more preferably 4.5 or less, and still more preferably 4.0 or less.

The elastic modulus at a load speed of 50 mm / min and the elastic modulus at a load speed of 1 mm / min are measured by the following methods.
Using a universal testing machine (manufactured by Shimadzu Corporation: AG 100 kNX), a compression test is performed at a load speed of 50 mm / min or a load speed of 1 mm / min, and a stress value (MPa) with respect to the displacement (mm) is at least Measure at 5 points of displacement.
The displacement amount of at least 5 points may be set as appropriate according to the hardness and size of the material. For example, the displacement amount is in the range of 0.5 mm to 1 mm, or the stress value is 1 MPa to A displacement amount in the range of 5 MPa is selected.
For the obtained stress values for at least 5 points of displacement, create a stress-displacement diagram with the vertical axis representing stress and the horizontal axis representing displacement, creating a regression line using the least squares method, and the slope Is the elastic modulus at each load rate.

1 to 4 show the results of the compression test.
FIG. 1 is a result (stress-displacement diagram) of a compression test of a grinding wheel according to the present disclosure. The elastic modulus at a load speed of 50 mm / min is 0.1679, and the elastic modulus at a load speed of 1 mm / min is 0.0655. Yes, the rate of change of the elastic modulus represented by Formula A is 0.1679 / 0.0655 = 2.6.
2 to 4 are results (stress-displacement diagrams) of a compression test of a grinding wheel that is not a grinding wheel according to the present disclosure.
FIG. 2 shows the results of a compression test of a grinding wheel having a particle size of # 400 (manufactured by Monotaro, GCME-612). The elastic modulus at a load speed of 50 mm / min is 24.312, and the elastic modulus at a load speed of 1 mm / min. Is 22.688, and the rate of change of the elastic modulus represented by the expression A is 22.688 / 24.312 = 0.93.
FIG. 3 shows the results of a compression test of a grinding wheel having a particle size of # 800 (manufactured by Monotaro, GCME-614). The elastic modulus at a load speed of 50 mm / min is 18.514, and the elastic modulus at a load speed of 1 mm / min. Is 18.68, and the change rate of the elastic modulus represented by the formula A is 18.68 / 18.514 = 1.0.
FIG. 4 shows the results of a compression test of a grinding wheel having a particle size of # 1500 (manufactured by Monotaro Co., Ltd., GCME-617). The elastic modulus at a load speed of 50 mm / min is 26.173, and the elastic modulus at a load speed of 1 mm / min. Is 24.172, and the rate of change of the elastic modulus represented by Formula A is 26.173 / 24.172 = 1.1.

<Whetstone base>
The grinding wheel according to the present disclosure preferably includes a grinding wheel base (hereinafter also simply referred to as “base”).
Here, in order to set the change rate of the elastic modulus represented by the formula A of the grinding wheel according to the present disclosure to 1.5 or more, for example, a grinding wheel base having an abrasive layer containing abrasive grains in the outermost layer And having an elastic modulus change rate represented by the formula A of 1.5 or more (hereinafter also referred to as “first embodiment”) and an abrasive layer containing abrasive grains at least in the outermost layer. And an aspect (hereinafter also referred to as “second aspect”) in which the abrasive layer contains a binder and the change rate of the elastic modulus represented by the formula A of the binder is 1.5 or more. Is mentioned.

In the first aspect, the grinding wheel base used in the present disclosure preferably has a change rate of the elastic modulus represented by the formula A of 1.5 or more, preferably 1.8 or more. Is more preferably 0.0 or more, and further preferably 2.5 or more.
The amount of change is preferably 5.0 or less, more preferably 4.5 or less, and still more preferably 4.0 or less.
Although it does not specifically limit as a grindstone base in a 1st aspect, For example, a shock absorption pad (D3O by D3O lab company) etc. are mentioned.

In the second embodiment, the grinding wheel does not include a grindstone base, and may be formed only by an abrasive layer including abrasive grains and a binder, or may include a grindstone base. That is, at least the outermost layer may be an abrasive layer containing abrasive grains, and the entire grinding wheel may be an abrasive layer containing abrasive grains.
When a grindstone base is included, it is not particularly limited, and a known grindstone base can be used.

<Abrasive layer>
It is preferable that the abrasive grain layer in this indication contains an abrasive grain and exists in the outermost layer of a grinding wheel.
In the first aspect, the abrasive layer may further contain a binder, or may have a form in which the abrasive grains are directly bonded to the grindstone base like an electrodeposited grindstone.
Moreover, when an abrasive grain layer further contains a binder, it may have pores inside.
When the abrasive grain layer contains a binder, the abrasive grain layer can be formed by a known method, for example, the abrasive grains and the binder are stirred and applied to the grindstone base and then cured.
In the second aspect, the abrasive layer includes abrasive grains and a binder, and may further have pores therein.
In the second embodiment, when the grinding wheel does not include a grinding wheel base, the abrasive layer is formed by, for example, a method in which the abrasive grains and the binder are molded after being molded and then cured.

[Abrasive]
The abrasive grains used in the present disclosure are not particularly limited, and it is possible to use known abrasive grains in the field of grinding wheels.
Moreover, it is preferable to use the abrasive grain suitable for a workpiece.
Although it does not specifically limit as a material of an abrasive grain, For example, diamond, boron compounds, such as CBN (cubic boron nitride), cerium oxide, an alumina, silicon carbide, etc. are mentioned. The abrasive grains may be particles made of these materials, or particles containing these materials (for example, those obtained by coating the above compound with nickel, copper, titanium, or the like).

The grain size of the abrasive grains used in the grinding wheel according to the present disclosure is not particularly limited, but is preferably # 240 to # 2000, and more preferably # 320 to # 1500.
The grain size of the abrasive grains is measured by the method described in JIS R 6001: 1998.

  It is preferable that the usage-amount of the abrasive grain in the grinding wheel which concerns on this indication is 50 mass%-150 mass% with respect to the total mass of a binder.

[Binder]
The binder is not particularly limited, and a known binder is used.

In the first aspect, the binder used in the present disclosure is not particularly limited, and may be selected from known binders so that the rate of change of the elastic modulus represented by Formula A of the grinding wheel is in the above range. .
The binder in the first embodiment is preferably soft to some extent so that the amount of change is in the above range. For example, a hardened silicone adhesive (Supermed X, manufactured by Cemedine Co., Ltd.) is used.

In the second aspect, the binder used in the present disclosure preferably has a change rate of the elastic modulus represented by the formula A of 1.5 or more, preferably 1.8 or more. It is more preferably 0 or more, and further preferably 2.5 or more.
The amount of change is preferably 5.0 or less, more preferably 4.5 or less, and still more preferably 4.0 or less.

[Other ingredients]
In the first aspect and the second aspect, the abrasive layer may contain other components as long as the change rate of the elastic modulus represented by the formula A of the grinding wheel is in the above range.
Examples of other components include known fillers and colorants.

[Thickness of abrasive layer]
In both the first aspect and the second aspect, the thickness of the abrasive layer is not particularly limited, and may be set as appropriate so that the rate of change of the elastic modulus represented by the formula A of the grinding wheel is in the above range. .

<Shaping of grinding wheel>
The shape of the grinding wheel is not particularly limited, and may be a thin paper shape, a plate shape, a rod shape, a spherical shape or a combination thereof for use as a file, or a grinding device such as a leuter or a grinder. Cylindrical shape (including disc shape), spindle shape, conical shape, spherical shape, etc., or a shape having a rotating shaft attached thereto, or a belt shape having a grinding surface It may be a grinding wheel.
When used as a rotating grindstone, the grinding wheel according to the present disclosure preferably has the above-described abrasive layer on the outermost layer on the outer peripheral surface with respect to the rotation axis of the grinding wheel.
Although an abrasive grain layer should just exist in at least one part of the outer peripheral surface of a grinding stone, it is preferable that it exists in the whole surface.
The grinding wheel according to the present disclosure is preferably a grinding wheel having a cylindrical shape, a spindle shape, or a conical shape from the viewpoint of being used in a rotating grindstone, and the abrasive layer in the present disclosure is provided on the outermost layer of these outer peripheral surfaces. More preferably a grinding wheel having

By using the grinding wheel according to the present disclosure as a rotating wheel, the surface roughness Rz after processing of the workpiece can be adjusted by changing the number of rotations (rotation speed) per unit time. .
That is, by rotating at a high speed, it is possible to perform processing with both a large processing amount and a surface roughness Rz, and by rotating at a low speed, processing with a small surface roughness Rz can be performed although the processing amount is small. .
Thus, by using the grinding wheel according to the present disclosure as a rotating grindstone, the surface roughness Rz can be arbitrarily adjusted according to the number of rotations.
In addition, when the grinding wheel according to the present disclosure is used as a rotating grindstone, it can also be obtained by changing the load that presses the grinding wheel against the workpiece while keeping the rotation speed constant, or the load that presses the workpiece against the grindstone. It becomes possible to change the surface roughness Rz of the workpiece after processing.
Increasing the load increases the surface roughness Rz, and decreasing the load decreases the surface roughness Rz.

  The size of the grinding wheel is not particularly limited, and may be appropriately designed according to the processing desired to be performed on the workpiece.

(Grinding device)
A grinding apparatus according to the present disclosure includes a grinding wheel according to the present disclosure.
The grinding apparatus according to the present disclosure is not particularly limited, and examples thereof include an apparatus in which a grinding wheel of a known grinding apparatus is changed to a grinding wheel according to the present disclosure.
Specific examples include, but are not limited to, grinding apparatuses such as a grinder and a leuter.

  Hereinafter, the present disclosure will be described in detail by way of examples, but the present disclosure is not limited thereto.

(Production of grinding wheel)
For the grinding wheel base, shock absorbing pad (D3O lab: D3O) is used. Alumina # 400 (Fujimi Incorporated: FO) is used for the abrasive. Used a silicone-based adhesive (manufactured by Cemedine Co., Ltd .: Super X).

The shock absorbing pad is a product that sells shock absorption using dilatancy, and is judged to be suitable for setting the rate of change of the elastic modulus expressed by the formula A of the grinding wheel to be 1.5 or more. did.
In the present disclosure, dilatancy refers to the property that the elastic modulus is high for a fast shape change and the elastic modulus is low for a slow shape change.
FIG. 5 shows the results of a compression test measured using an impact absorbing pad (D3O lab: D3O). The elastic modulus at a load speed of 50 mm / min is 0.0924, the elastic modulus at a load speed of 1 mm / min is 0.0582, and the rate of change of the elastic modulus represented by Formula A is 0.0924 / 0.0582 = 1. 6.
Abrasive alumina is commonly used in the fields of grinding and polishing.
Since the silicone adhesive of the adhesive is relatively long to cure, it can be sufficiently stirred with the abrasive grains and is relatively soft after curing. It was determined that the change rate of the elastic modulus represented by the formula A of the grinding wheel was 1.5 or more.

An outline of the manufacturing procedure is shown in FIG.
Details of grinding wheel preparation in the examples will be described.
First, a shock absorbing pad serving as a base was cut into a rectangular parallelepiped of 8 mm × 8 mm × 15 mm. A hole having a diameter of 2.8 mm and a depth of 10 mm for attaching a grindstone shaft was formed in the center of the cut end face of the rectangular parallelepiped ("Cut &Drill" in FIG. 6). A grindstone shaft was inserted into the hole on the end face of the rectangular parallelepiped and bonded with an instantaneous adhesive (“bonding of the grindstone shaft” in FIG. 6). After that, the grindstone shaft is attached to an electric grinding machine (manufactured by Japan Precision Machine Tool Co., Ltd .: Luther Minilite ML-51), pressed against abrasive paper while rotating at 15,000 rpm, and the base is φ6 mm using the rotational force. Molded into a cylindrical shape (“molding” in FIG. 6).
The abrasive grains and the adhesive were mixed and stirred at a mass ratio of 1: 1, and the mixture was applied to the base cylindrical surface. After the adhesive is dried, the grindstone shaft is again attached to the electric grinding machine, pressed against the abrasive paper while rotating at 15,000 rpm, and the abrasive grain adhesive body is formed into a cylindrical shape of φ6.2 mm by using the rotational force. ("Abrasive grain adhesion and molding" in FIG. 6).

(Evaluation of rate of change of elastic modulus represented by Formula A)
The grindstone produced by the above method uses a material having a dilatancy on the base, but the abrasive grains are applied to the surface layer with an adhesive, and the change in the elastic modulus represented by the formula A in that state It is necessary to check the rate. Then, the compression test was done with respect to the produced grindstone, and the said change rate was evaluated.
The test specimen was the grindstone produced in the previous section. The compression test was performed using a universal testing machine (manufactured by Shimadzu Corporation: AG100kNX). The test conditions were a load speed of 1 mm / min, 5 mm / min, and 50 mm / min.
The stress-displacement diagram obtained by the compression test is shown in FIG.
FIG. 1 shows that in the compression test for the manufactured grinding wheel, the slope of the stress-displacement diagram increases as the load speed increases. An increase in the slope of the stress-displacement diagram means an increase in the elastic modulus. In general, since the hardness increases as the elastic modulus increases, it can be said that the manufactured grinding wheel becomes harder as the load speed increases.
Moreover, the change rate of the elastic modulus represented by Formula A was 0.1679 / 0.0655 = 2.6, which was 1.5 or more.

(Evaluation of processing performance)
In order to evaluate the processing performance of the manufactured grindstone and compare it with a commercially available grindstone, a machining experiment was performed using an electric grinding machine (manufactured by Nippon Seimitsu Machine Co., Ltd .: Luther Minilite ML-51). Steel (SS400), which is a workpiece, was polished in advance to adjust the surface roughness Rz to 0.1 μm. The grindstone used in this experiment is a grinding grindstone according to the present disclosure produced by the above-described method, and commercially available rubber grindstones # 400, # 800, # 1500 (manufactured by Monotaro, GCME-612, GCME-614, GCME- 617).
The stress-displacement diagram for the # 400 rubber wheel is shown in FIG. 2, the stress-displacement diagram for the # 800 rubber wheel is shown in FIG. 3, and the stress-displacement diagram for the # 1500 rubber wheel is as shown in FIG. In all the grindstones, the rate of change of the elastic modulus represented by the formula A was less than 1.5.
Table 1 shows the processing conditions. As shown in Table 1, the rotational speed of the grindstone was changed to 4 types, and the surface roughness of the workpiece after processing at each rotational speed was evaluated.
Moreover, the roughness curve before processing with a grindstone is shown in FIG.

The roughness curve after processing by the manufactured grinding wheel according to the present disclosure is shown in FIG.
It described in FIG. 9 (# 400), FIG. 10 (# 800), and FIG. 11 (# 1500) by a commercially available grindstone, respectively. In addition, since the change of the processing result by a grindstone rotational speed was not recognized in the processing by a commercially available grindstone, the processing was stopped at 5,000 to 15,000 rpm, and the processing at 3,700 rpm was not performed.
FIG. 12 shows the relationship between the processed surface roughness Rz and the grinding wheel rotational speed when the grinding wheel according to the present disclosure is used. Each graph in FIG. 12 indicates the average value of the surface roughness Rz in three tests, and the error bar indicates the maximum value and the minimum value of the measurement results.
FIG. 13 shows the relationship between the surface roughness Rz after processing with a commercially available grindstone and the particle size (revolutions were 5000 rpm, 10000 rpm, and 15000 rpm, and the test was performed three times each). Each graph in FIG. 13 shows an average value of the surface roughness Rz in nine tests, and error bars represent the maximum value and the minimum value of the measurement results.

From the results of FIGS. 8 to 11, no change in the processing result due to the rotational speed of the grindstone is recognized in the processing using the commercially available grindstone, but the processing result varies depending on the rotational speed of the grindstone in the processing using the manufactured grinding wheel according to the present disclosure. You can see that
When the grinding wheel according to the present disclosure is used, the maximum height of the roughness curve increases as the grinding wheel rotational speed increases, and the maximum height of the roughness curve decreases as the grinding wheel rotational speed decreases. That is, it can be seen that when the rate of change of the elastic modulus represented by Formula A is 1.5 or more, a grinding wheel is obtained in which the surface roughness of the workpiece changes due to the change in the rotational speed.
Moreover, it can confirm that the variation | change_quantity of the processing result by the grindstone rotation speed of the grindstone produced from FIG. 12 and FIG. 13 is substantially equivalent to commercially available grindstone # 400- # 1500. That is, when the grinding wheel according to the present disclosure is used, the same processing as when four types of commercially available grinding stones # 400 to # 1500 are used can be performed with one type of grinding stone by changing the rotational speed of the grinding wheel. It turns out that it becomes.
That is, when using the grinding wheel according to the present disclosure, after performing processing with a larger grinding wheel speed to increase the processing amount, the use of reducing the grinding wheel speed to reduce the surface roughness of the workpiece. A method is possible.

Next, the influence by changing the load at the time of a process at the time of using the grinding wheel which concerns on this indication was examined.
The grinding conditions were as shown in Table 2 below.

FIG. 14 shows the surface roughness of the workpiece when the processing load is 200 gf and the grinding wheel rotational speed is 5,000, 10,000, or 15,000 rpm.
Further, FIG. 15 shows the surface roughness of the workpiece when the processing load is 50 gf and the grindstone rotational speed is 5,000, 10,000, or 15,000 rpm.
From the results of FIGS. 14, 15 and 12, when the grinding wheel according to the present disclosure is used, the surface roughness Rz increases as the processing load increases even at the same rotation speed, and the processing load is reduced. It was found that the surface roughness Rz decreases as the value decreases.

Further, with respect to the above-described commercially available grindstones # 400, # 800, and # 1500, the processing load was 50 gf or 200 gf, the surface roughness of the workpiece was evaluated, and the results are shown in FIGS. 16 and 17.
From the results of FIGS. 16, 17, and 13, when using a grinding wheel that is not a grinding wheel according to the present disclosure and whose elastic modulus change rate represented by Formula A is less than 1.5, the processing load It can be seen that the surface roughness of the workpiece remains almost unchanged even when the value is changed.

Claims (4)

A grinding wheel whose rate of change in elastic modulus represented by the following formula A is 1.5 or more.
Formula A: Change rate of elastic modulus = (elastic modulus at a load speed of 50 mm / min) / (elastic modulus at a load speed of 1 mm / min) Including a grindstone base having an abrasive layer containing abrasive grains in the outermost layer,
The grinding wheel according to claim 1, wherein a rate of change of an elastic modulus represented by the formula A of the grinding wheel base is 1.5 or more.   The grinding wheel according to claim 1 or 2, which has a cylindrical shape, a spindle shape or a conical shape.   A grinding apparatus comprising the grinding wheel according to any one of claims 1 to 3.