JP2000246633A - Grinding device and grinding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding device capable of providing a ground surface having a desired waviness according to required machining accuracy. SOLUTION: When grinding is performed by rotating a grinding wheel 4 and a workpiece 1, a main controller 9 calculates a revolution speed rate allowing the pitch of the waviness of a ground face to be within a specified range. Based on this rotation speed rate, the rotation of a tool spindle 5 to which the grinding wheel 4 is secured and the rotation of a work spindle 2 to which the workpiece 1 is secured are controlled by rotation control units 8 and 7 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding apparatus and a grinding method for performing grinding by rotating a grinding wheel and a workpiece.

[0002]

2. Description of the Related Art In order to maintain the processing accuracy of a workpiece in grinding, the accuracy of movement of a processing apparatus and the accuracy of a grinding wheel are important factors. Regarding the motion accuracy of the processing equipment, it is possible to satisfy the required accuracy by thoroughly examining the rigidity, straightness, rotation accuracy, etc. of the slide spindle on which the workpiece and grinding wheel are mounted. is there.

On the other hand, the accuracy of the grinding wheel includes an outer peripheral runout indicating an error in the outer shape (deviation from a perfect circle) of the disk-shaped grinding wheel which should be a perfect circle, and an imbalance during rotation. If there is such an outer peripheral run-out or imbalance of the grinding wheel, the grinding amount during one rotation of the grinding wheel is not always constant, and undulation may occur on the ground surface. The state of the generated undulation depends on the rotational speed ratio of the grinding wheel and the workpiece, and the moving speed (hereinafter referred to as a feed speed) at a point (processing point) where the grinding wheel and the workpiece come into contact. ing.
Conventionally, as a method of reducing such undulation, a method of reducing the pitch of the undulation by reducing the feed speed and reducing the height of the undulation (the height of the unevenness of the processed surface due to the undulation) is empirically used. Had been.

[0004]

However, reducing the feed rate increases the machining time and causes an increase in cost, which is a problem. In addition, depending on the value of the rotational speed ratio, the feed speed may be reduced to reduce the swell height.

[0005] The object of the present invention is to meet the required processing accuracy,
An object of the present invention is to provide a grinding apparatus and a grinding method capable of obtaining a ground surface having a desired undulation.

[0006]

An embodiment of the present invention will be described with reference to FIGS. 1 and 11. FIG. (1) When described in association with FIG. 1, the invention of claim 1 is a grinding wheel rotating means 5 for driving a grinding wheel 4 to rotate at a designated wheel rotation speed, and a workpiece 1 to which a workpiece 1 is designated. A grinding device for rotating the grinding wheel 4 and the workpiece 1 to perform grinding by rotating the grinding wheel 4 and the workpiece 1, respectively; Calculating means 9 for calculating a ratio between the wheel rotation speed and the workpiece rotation speed in which at least one of the sizes is within a predetermined range; and at least one of the grinding wheel rotation speed and the workpiece rotation speed such that the calculated ratio is obtained. The above-mentioned object is achieved by providing control means 8 and 7 for controlling one of them. (2) When described in association with FIG. 1 and FIG. 11, the invention according to claim 2 is the grinding apparatus according to claim 1, wherein the arithmetic means 9 comprises a grinding surface 22 on which the undulation pitch T is ground. The ratio between the rotation speed of the grindstone and the rotation speed of the workpiece is calculated so as to be smaller than 1/2 of the longitudinal dimension D of the polishing surface 20a of the polishing tool 20 for polishing the workpiece. (3) When described in association with FIG. 1, the invention of claim 3 is applied to a grinding method in which a grinding wheel 4 and a workpiece 1 are respectively rotated to perform a grinding process, and the height of the undulation of the ground surface. And a calculating step for calculating the ratio between the grinding wheel rotation speed and the workpiece rotation speed in which at least one of the size of the pitch is within a predetermined range, and the grinding wheel rotation speed and the workpiece to satisfy the ratio calculated in the calculation step. The above object is achieved by having a processing step of processing the workpiece 1 at the number of rotations of the workpiece.

[0007] In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used to make the present invention easy to understand. However, the present invention is not limited to the embodiment.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a diagram showing a schematic configuration of a main part of a grinding apparatus for lens processing to which the present invention is applied. A work spindle 2 on which a work 1 made of a lens material is mounted is fixed to a Z-axis slide 3 so that the rotation axis is parallel to the Z-axis. Therefore, the work 1 is driven to rotate in the direction of arrow R <b> 2 by the work spindle 2, and is driven to move straight in the Z-axis direction by the Z-axis slide 3. On the other hand, the tool spindle 5 on which the grinding wheel 4 is mounted is fixed to the X-axis slide 6, and its rotation axis is parallel to the Y-axis direction orthogonal to the rotation axis of the work spindle 2. Therefore, the grinding wheel 4 is driven to rotate in the direction of the arrow R1 and is driven by the X-axis slide 6 to move straight in the X-axis direction orthogonal to the Z-axis.

Reference numerals 7 and 8 denote rotation control units for controlling the rotation of the spindles 2 and 5, respectively, which are connected to a main control unit 9 for controlling the entire grinding machine. The main control unit 9 controls the rotation control units 7 and 8 and the Z-axis slide 3 and the X-axis slide 6 and includes a calculation unit for performing calculations required for the control thereof. Is output. Reference numeral 10 denotes an input device for inputting parameters necessary for grinding, such as the number of revolutions of the grindstone, to the main controller 9. Each of the spindles 2 and 5 is provided with a rotation speed sensor (not shown) such as a rotary encoder, and the sensor signals are sent to rotation control units 7 and 8 and used for rotation control of the spindles 2 and 5. Is done.

FIG. 2 is a view of the work 1 and the grindstone 4 shown in FIG. 1 viewed from the positive direction of the Y axis, and shows the relative movement of the grindstone 4 with respect to the work 1. The grindstone 4 and the work 1 are rotated at a predetermined rotational speed N in the R1 and R2 directions, respectively.
1, while controlling the movement of the Z-axis slide 3 and the X-axis slide 6 in FIG. 1 so that the rotation axis A2 of the grindstone 4 draws a predetermined trajectory L1 with respect to the work 1.
Is processed on the surface 1a. When grinding the convex curved surface 1a as shown in FIG. 2, the workpiece 1 is moved in the minus Z direction while the grindstone 4 is moved in the minus X direction. A1 indicates the rotation axis of the work 1.

As described above, it is known that undulation occurs on the ground surface if the grinding wheel has an outer peripheral runout or imbalance. Next, the mechanism of the undulation will be described. Hereinafter, for the sake of simplicity, the surface 1a of the work 1 is assumed to be a flat surface as shown in FIG.
Is the rotation direction R3 opposite to R2. The trajectory K (X (t), Y (t)) of the processing point P where the workpiece 1 and the grinding wheel 4 come into contact with each other is expressed by the following equations (1) and (2) on the XY plane with the rotation center of the workpiece 1 as the origin. Is represented as

X (t) = r (t) · cos θ (t) (1) Y (t) = r (t) · sin θ (t) (2) where r (t) and θ (t) ) Is

R (t) = r2− (ν1 / 60) · t (3) θ (t) = (2π · N2 / 60) · t (4) where polar coordinates of the processing point P are Represents. Where ν
1 (mm / min) is the wheel feed speed, N2 (rpm) is the number of revolutions of the work, and r2 is the radius of the work 1. The unit of the time t is (min).

As described above, the grindstone 4 has an outer peripheral runout and an imbalance during rotation. Usually, the outer peripheral runout has a undulation for one cycle when the circumference of the grindstone 4 is one cycle. ing. In addition, the unbalance also causes rattling of one cycle while the grinding wheel 4 makes one rotation. Therefore, one failure (eg, a change in the amount of grinding) occurs during one rotation of the grindstone 4 due to outer peripheral runout or imbalance. As shown in FIG. 4, the outer periphery of the grindstone 4 (the radius of the grindstone 4 is r1).
When there is a convex portion 4a at one place, the protrusion amount ε from the outer periphery
1 is the amount of run-out of the outer periphery of the grindstone 4. When the workpiece 1 is ground with such a grindstone 4, a grinding mark Cg having a length CL is formed on the ground surface by the projection 4a. The length CL of the grinding mark Cg is expressed by the following equation (5).

CL = 2 · ((r1 + ε1) ² −r1 ² ) ^0.5 (5)

FIG. 5 shows a processing point P (FIG. 3) on the work surface.
(A) is a view schematically showing the entire grinding surface of the work 1, and FIG.
(B) is an enlarged view of the area indicated by the symbol B in (a). As shown in FIG. 3, since the grindstone 4 is moved in the minus X direction to grind the work 1 rotating in the R3 direction, the trajectory K is shifted from the processing start point Ps to the work 1 as shown in FIG. It spirals toward the center. In FIG. 5B,
If the trajectory K is represented from the outside as K1, K2, K3, K4, K5,...
1, K2, K3, K4, K5,...), And the time interval t1 (min) at which the grinding mark Cg is formed
Is represented by the following equation (6). The position of the grinding mark Cg on the grinding surface is represented by t = N · t1 (where N = 1, 2, 3,...) In t of Expressions (1) and (2) or Expressions (3) and (4). It is obtained by substituting. In addition, N1 (rpm) is a grindstone rotation speed.

## EQU4 ## t1 = 60 / N1 (6)

The grinding marks Cg formed on the grinding surface are shown in FIG.
A grinding mark pattern W (shaded area) as shown in FIG. The portion of the grinding mark pattern W is a region where the amount of grinding is larger than other portions (regions between adjacent grinding mark patterns W), and the grinding surface of the work 1 is formed by forming such a grinding mark pattern W. Undulation will occur.

FIGS. 6A and 6B are diagrams showing an example of a grinding trace pattern W obtained by a simulation calculation. FIG. 6A is a plan view of a grinding surface, and FIG. 6B is a diagram showing a undulation height h along the X axis. It is. When this calculation was actually performed under the same conditions and the waviness of the ground surface was compared, it was confirmed that the grinding trace patterns W were very consistent. Grinding trace pattern W
Is the rotation speed ratio α between the grinding wheel rotation speed N1 and the work rotation speed N2.
(= N2 / N1) and the feed rate F, and FIG. 7 is a diagram showing a grinding trace pattern W when the feed rate is lower than that in FIG. In FIG. 7B, the swell height h and the pitch T are smaller than in the case of FIG. On the other hand, FIG. 8 is a diagram showing a grinding trace pattern W when the rotation speed ratio is changed, and the undulation height h and the pitch T are almost the same as those in the case where the grinding wheel feed speed in FIG. 7 is reduced. Generally, as the pitch T of the undulation decreases, the swell height h also decreases.

In the present embodiment, the input device 10 shown in FIG.
2. The required swell height h and pitch T or any of h, T together with the radii r1 and r2 and the feed speed F) are input in advance. Hereinafter, the upper limit value Tma of the pitch T will be described.
A case where x is input as the required accuracy will be described. Then, those data (N1, N2, r1, r2, Tma
Based on x), main controller 9 calculates optimum rotation speeds N1 'and N2' and feed speed F ', and controls the rotation speeds of the tool spindle and the work spindle to N1' and N2 'via the control unit, respectively. At the same time, the X-axis slide 6 and the Z-axis slide 3 are adjusted so that the feed rate becomes F '.
To control the straight travel of the vehicle.

Next, the control performed by the main controller 9 is shown in FIG.
This will be described with reference to the flowchart of FIG. First, before describing each step of the flowchart, an outline of the entire flow will be described. In the first stage, the grinding conditions according to the work 1 and the grindstone 4 are simulated with respect to the initial conditions (N1 (0), N2 (0), F0), and the obtained undulation pitch T is equal to or less than an allowable upper limit value Tmax. , The initial conditions (N1 (0), N2 (0),
Grinding is performed by F0). On the other hand, if T> Tmax, the process proceeds to the second stage. In the second stage, simulation calculation is performed by changing the size of the rotation speed ratio α (= N2 / N1), and if a pitch T satisfying T ≦ Tmax is obtained, grinding is performed at the rotation speed ratio α at that time. If the pitch T satisfying the condition is not obtained, the process proceeds to the third stage. In the third stage, the feed speed F is set to a value lower than the initial condition F0, and the procedure of the second stage is performed. If a pitch T satisfying T ≦ Tmax is obtained, grinding is performed at the rotation speed ratio α and feed rate F at that time, and if a pitch T satisfying the conditions is not obtained, only a calculation result is output. .

Hereinafter, each step of the flowchart of FIG. 9 will be described in order. First, initial conditions such as grinding parameters required for grinding are input to the main controller 9 by the input device 10. The initial conditions include the rotation speed N1 (0) and the radius r1 of the grinding wheel 4, the rotation speed N2 (0) and the radius r2 of the work 1, the feed speed F0, the upper limit Tmax of the undulation pitch, and the like. When an instruction to start simulation calculation is input from the operator, the flowchart of FIG.
Proceed to.

In step S1, a simulation calculation is performed based on the input initial conditions to determine the pitch T of the undulation of the ground surface. Step S2 is a step of determining whether or not the pitch T calculated in step S1 is equal to or smaller than an upper limit value Tmax input as an initial condition.
The pitch upper limit value Tmax obtained as a result of the simulation and the undulation pattern of the ground surface as shown in FIG. Thereafter, the process proceeds to step S10 to perform a grinding process based on the initial conditions.

On the other hand, if the pitch T is larger than the upper limit Tmax, the process proceeds from step S2 to step S3. In step S3, a rotation speed ratio α, which is a ratio between the work rotation speed N2 and the grinding wheel rotation speed N1, is set as in the following equation (7).

Α = αmin−Δα (7) where Δα is given by Δα = (αmax−αmin) / m. Here, αmax and αmin are a calculation upper limit value and a calculation lower limit value of the rotation speed ratio α at the time of performing the simulation calculation, and an upper limit value N1 () of the grinding wheel rotation speed N1 and the work rotation speed N2 that can perform good grinding. max), N2 (max) and lower limit values N1 (min), N2 (min) are expressed as in the following equations (8) and (9). In addition, the natural number m in the above-described equation of Δα
When obtaining a pitch T satisfying T ≦ Tmax, αmin ≦ α ≦
This indicates that m kinds of simulation calculations are to be performed within the range of αmax, and is input in advance.

Αmax = N2 (max) / N1 (min) (8) αmin = N2 (min) / N1 (max) (9)

FIG. 10 shows the range of the rotation speeds N1 and N2 on the (N1, N2) coordinate plane when performing the simulation calculation, and the area S is the range of the rotation speeds N1 and N2. In FIG. 10, three straight lines L passing through the coordinate origin
0, Lmin, and Lmax are the rotational speed ratios α in the initial condition, respectively.
0 (= N2 (0) / N1 (0)) (N1, N2), points (N1, N2) that satisfy the lower limit αmin (N1, N2), and satisfy the upper limit αmax. , The inclination of the straight line represents the rotation speed ratio α.

Returning to the flowchart of FIG. 9, step S4 is a step for determining whether or not the rotational speed ratio α is equal to or greater than an upper limit αmax. If α ≧ αmax, the process proceeds to step S11, where α <αmax In the case of, the process proceeds to step S5. When proceeding from step S4 to step S5,
In step S5, the rotation speed ratio α is changed to Δα (= (αmax−
αmin) / m). Next, step S6
The simulation calculation is performed using the rotational speed ratio α set in step S5, and the swell pitch T at that time is obtained.

Step S7 is a step for determining whether or not the pitch T calculated in step S6 is equal to or smaller than the upper limit value Tmax.
Is larger than Tmax, the process returns to step S4. That is, step S4 is performed until T ≦ Tmax or α ≧ αmax and the process proceeds from step S4 to step S11.
Steps 4 to S7 are repeated. If the process proceeds from step S7 to step S8, step S5
The grinding wheel rotation speed N1 'and the workpiece rotation speed N2' are set so as to satisfy the α set in the above.

In FIG. 10, a straight line L1 is a straight line corresponding to the rotation speed ratio α, and a portion (thick solid line) included in the region S in the straight line L1 can be used as the optimum rotation speeds N1 'and N2'. Range. Among the rotation speeds N1 and N2 included in the thick line portion, the rotation speeds at which the grinding conditions are good are set as rotation speeds N1 'and N2'. As an example, there is a method of selecting the rotation speed as high as possible. In this case, the rotation speed N1 ′ is set to N1 (max), and the rotation speed N
2 ′ is set to α · N1 (max). Further, the work rotation speed may be fixed to the initial value N2 (0) and only the grinding wheel rotation speed N1 may be changed, or vice versa.

In step S8, the optimum rotation speeds N1 'and N2'
Is set, the process proceeds to step S9, and the calculation result is output to the output device 11. In this case, the data output as the calculation results include the calculated rotation ratio α and the rotation speeds N1 ′ and N2 ′, initial conditions other than the rotation ratio and the rotation speed, the pitch T obtained by the simulation calculation, and the ground surface. There are undulation patterns. Subsequent step S11
Then, grinding is performed under the conditions displayed on the output device 11, and a series of steps is completed.

On the other hand, when the process proceeds from step S4 to step S11, that is, when the rotational speed ratio α is αmin ≦ α ≦ αmax
If the pitch T does not become less than or equal to the upper limit value Tmax after m simulations in the range
11, the feed speed F and the rotation speed ratio α are calculated by the following equation (1).
0) and (11).

F = F0−ΔF (10) α = αmin (11) ΔF in equation (10) is given by ΔF = (F−Fmin) / n. Here, Fmin is a lower limit value of the feed speed F, and n is an arbitrary natural number, all of which are set in advance and input to the main controller 9.

Next, in step S12, it is determined whether or not the feed speed F is smaller than a lower limit value Fmin.
In the case of (1), the process proceeds to step S6 to perform a simulation calculation, and in the case of F <Fmin, the process proceeds to step S13 and, if the calculation result is output, ends without performing grinding.

As described above, in the present embodiment, a simulation calculation of the swell is performed based on the initial conditions before the actual grinding is performed, and when the swell pitch T is larger than the upper limit Tmax, the rotation is calculated. By changing the numerical ratio α or the feed speed F from the initial conditions α0 and F0, the pitch T becomes T
The rotation speed ratio α or the feed speed F satisfying ≦ Tmax
, And grinding was performed under the conditions. Therefore, a ground surface with small undulation can be easily obtained.

Further, only the rotation speed ratio α or the rotation speed ratio α
Thus, the desired grinding surface is obtained by changing the feed speed F, so that the grinding time can be reduced as compared with the conventional grinding process in which only the feed speed F is reduced to reduce the undulation. Further, conventionally, it has been difficult to obtain a desired ground surface by a single grinding process because the feed speed F has been appropriately reduced to obtain a ground surface with a small undulation. Although it had to be performed, since the grinding of the apparatus according to the present embodiment requires only one time, the operation time can be greatly reduced including the calculation time in the main controller 9.

By the way, in the case of lens processing, a polishing step is performed after the grinding step. However, if the undulation height h is too large as shown in FIG. 6, it is difficult to remove the undulation in the polishing step. Become. In addition, as shown in FIG. 11A, when the undulation pitch T of the grinding surface 22 is increased to about the size of the polishing tool 20, the polishing surface 20a of the polishing tool 20 is inclined, and desired polishing cannot be performed. There was a problem. However, in the above-described embodiment, if the upper limit value Tmax of the undulation pitch T is set as in the following equation (12), the above-described problem in the polishing process does not occur.

Tmax <D / 2 (12) In the equation (12), D represents the diameter when the polishing tool 20 is circular.

If Tmax is set as in equation (12),
Regardless of the position of the polishing tool 20, FIG.
As shown in (b), two or more undulating convex portions 21 always contact the polishing surface 20a of the polishing tool 20.
That is, in the flowchart described above, the expression (1)
Tmax that satisfies 2) may be input as an initial condition. Alternatively, the dimension D of the polishing tool 20 is input as an initial condition, and the Tma used in step S2 is used.
The main controller 9 may calculate Tmax = D / 2 as x.

In the above-described embodiment, the undulation (grinding trace pattern W) is controlled by controlling the rotation speed ratio α and the feed speed F.
Is set to be within a predetermined pitch Tmax, but only the rotation speed ratio α may be controlled. Further, instead of controlling with the pitch of the undulation, control may be performed such that the height h of the undulation is within a predetermined height hmax. In addition, the rotational speed ratio α at which the grinding marks Cg are randomly formed on the entire grinding surface is held as data in the main controller 9, and the rotational speed ratio α corresponds to the work 1 and the grindstone 4 based on the rotational speed ratio α. Rotation speed N1, N2 or N1,
Either one of N2 may be selected.

In the correspondence between the embodiment described above and the elements of the claims, the work 1 is a workpiece, the main control unit 9 is an arithmetic unit, the tool spindle 5 is a grinding wheel rotating unit, and the work spindle 2 is Denotes a workpiece rotating unit, the rotation control units 7 and 8 constitute a control unit, and the Z-axis slide 3 and the X-axis slide 6 constitute a moving unit.

[0034]

As described above, according to the present invention,
For example, based on (a) the rotation speed and radius of the grinding wheel, (b) the rotation speed and radius of the workpiece, and (c) the moving speed of the processing point, for example, the amount of runout and rotation of the outer periphery of the grinding wheel are determined. Calculate the ratio between the wheel rotation speed and the workpiece rotation speed at which at least one of the height of the undulation and the size of the pitch of the ground surface due to the unbalance amount is within a predetermined range, and adjust the grinding wheel so as to satisfy the ratio. Since the grinding is performed by controlling at least one of the number of rotations and the number of rotations of the workpiece, a ground surface having a desired undulation can be obtained. As a result, a ground surface with small undulation can be easily obtained, and the grinding operation time can be reduced. In particular, according to the second aspect of the present invention, the size of the undulation pitch of the grinding surface is set to be の of the longitudinal dimension of the polishing surface of the polishing tool.
Good polishing can be performed in the polishing process.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a grinding apparatus according to the present invention.

FIG. 2 is a view of a work 1 and a grindstone 4 shown in FIG. 1 as viewed from a positive direction of a Y axis.

FIG. 3 is a diagram illustrating a mechanism of undulation generation;
The work 1 and the grindstone 4 are shown.

FIG. 4 is a diagram showing a relationship between a grinding wheel 4 and grinding marks Cg.

5A and 5B are diagrams schematically showing a trajectory K of a processing point P and a grinding mark Cg on a work surface, wherein FIG.
(B) is an enlarged view of a portion indicated by a symbol B in (a).

6A and 6B are diagrams illustrating an example of a grinding trace pattern W obtained by a simulation calculation, wherein FIG. 6A is a plan view of a ground surface, and FIG. 6B is a diagram illustrating a swell height h along the X axis.

FIGS. 7A and 7B are diagrams showing a grinding trace pattern W when a feed speed is reduced, wherein FIG. 7A is a plan view of a grinding surface, and FIG. 7B is a diagram showing a swell height h along the X axis.

FIGS. 8A and 8B are diagrams showing a grinding mark pattern W when a rotation speed ratio is changed, wherein FIG. 8A is a plan view of a grinding surface, and FIG. 8B is a diagram showing a swell height h along the X axis.

FIG. 9 is a flowchart illustrating control performed by main controller 9.

FIG. 10 is a diagram showing a range of rotation speeds N1 and N2 on a (N1, N2) coordinate plane.

11A and 11B are diagrams showing a relationship between a polishing tool 20 and a grinding surface 22, wherein FIG. 11A shows a conventional case and FIG. 11B shows a case of the present embodiment.

[Explanation of symbols]

 Reference Signs List 1 work 2 work spindle 3 Z-axis slide 4 grinding wheel 5 tool spindle 6 X-axis slide 7, 8 rotation control unit 9 main control device 10 input device 11 output device Cg grinding mark T pitch W grinding mark pattern

Claims (3)

[Claims] A grinding wheel rotating means for rotating a grinding wheel at a designated number of rotations of a grinding wheel; and a workpiece rotating means for rotating a workpiece at a designated number of rotations of a workpiece.
In a grinding apparatus that performs grinding by rotating the grinding wheel and the workpiece, at least one of the height of the undulation and the magnitude of the pitch of the grinding surface is a predetermined range, the grinding wheel rotation speed and the workpiece rotation speed. And a control means for controlling at least one of the rotational speed of the grinding wheel and the rotational speed of the workpiece so as to achieve the calculated ratio. 2. The grinding apparatus according to claim 1, wherein the calculating means is configured to set the waviness pitch to one of a longitudinal dimension of a polishing surface of a polishing tool for polishing the ground surface having been ground.
A grinding machine for calculating a ratio between the rotation speed of the grinding wheel and the rotation speed of the workpiece so as to be smaller than / 2. 3. A grinding method for performing grinding by rotating a grinding wheel and a workpiece, respectively, wherein at least one of the waviness height and the pitch size of the grinding surface is within a predetermined range, and the grinding wheel rotation number and the workpiece rotation speed. An arithmetic step of calculating a ratio to the workpiece rotation speed, and a processing step of processing the workpiece with a grindstone rotation speed and a workpiece rotation speed that satisfy the ratio calculated in the arithmetic step. A grinding method characterized by the following.