JPH068136A - Polishing device - Google Patents

Abstract

PURPOSE:To shorten a grinding and machining cycle time without lowering the machining accuracy of a workpiece. CONSTITUTION:Each of assignment data for a cutting amount, a cutting time, a deceleration direction and a computing frequency therefor, is specified by a setting means 110, and an initial cutting speed V (o) and deceleration information V (t) are obtained by the first arithmetic means 120, on the basis of the specified data. Then, a drive means 110 is controlled with the initial cutting speed V (o), thereby starting a cutting process with a wheel spindle stock 13. Thereafter, the second arithmetic means 130 is caused to continuously change the cutting speed of the stock 13 at a constant cycle on the operation of the means 100, using the deceleration information V (t).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding apparatus for controlling a cutting speed to gradually decrease as a workpiece to be ground approaches a predetermined size.

[0002]

2. Description of the Related Art Conventionally, for example, in a numerically controlled grinding machine for cylindrical grinding, a grinding wheel head is idly fed until just before a grinding wheel supported on the grinding wheel comes into contact with a workpiece, and then a grinding wheel head is preset with a notch. By performing rough grinding feed, fine grinding feed, and fine grinding feed at a speed, the workpiece is finished to a predetermined size within a preset grinding time. FIG. 5 is a grinding process cycle diagram at this time.

[0003]

In the cutting control method of the conventional grinding machine as described above, the workpiece is machined in the grinding cycle of the air grinding, the rough grinding, the fine grinding and the fine grinding as shown in FIG. Therefore, the grinding time can be relatively shortened, the processing cost can be reduced, and the processing accuracy such as cylindricity and surface roughness of the workpiece can be improved.

Further, since the cutting speed at the time of fine grinding is high and the elastic deformation of the grinding wheel and the work is increased accordingly, the actual machining diameter of the work is different from the cutting amount of the cutting table shown by the solid line in FIG. Is as shown by the broken line in FIG. 5, and there is a difference between the two, that is, an uncut amount. This uncut amount decreases as the fine grinding process progresses to the fine grinding process, and when the fine grinding feed ends, the actual machining diameter of the workpiece substantially matches the depth of cut.

However, in such a conventional cutting control method, each cutting speed of the idle feed, rough grinding, fine grinding and fine grinding of the cutting table is set based on the characteristics of the workpiece and the grinding wheel and the grinding time. , For example, if you try to shorten the grinding time by increasing the cutting speed of rough grinding, the uncut amount (relief amount) during rough grinding becomes even larger, and this uncut amount becomes the value when the fine grinding is completed. Is not resolved. For this reason, the processing accuracy such as cylindricity and surface roughness of the work is also reduced. On the contrary, if the cutting speed of the rough grinding is reduced, the processing cycle time becomes longer.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a grinding apparatus capable of shortening the grinding cycle time without impairing the machining accuracy of the workpiece.

[0007]

The present invention will be described with reference to FIG. 1, which is a diagram corresponding to claims. The present invention is based on a grinding wheel base 13 having a grinding wheel 19 that is rotationally driven, and the grinding wheel 1 described above.
Drive means 100 for relatively moving the grindstone 13 and the workpiece W in a direction in which the workpiece W to be ground by 9 and the grinding wheel approach and separate from each other, and the cutting amount X from the start of grinding to the target dimension of the workpiece W A specified data setting means 110 for setting a cutting time T required to move the cutting amount X, a deceleration method for obtaining continuous deceleration feed information and the number N of times of calculation thereof, and designated data specified by the setting means 110. The initial cutting speed V (o) and the deceleration information V (t) are obtained based on the first cutting speed V (o), and the initial cutting speed command is sent to the driving means 100.
After starting the cutting by controlling the driving means 100 with the initial cutting speed V (o) obtained by the calculating means 120, the cutting speed is continuously reduced in the deceleration direction at a constant cycle using the deceleration information V (t). And a second calculation means 130 for sending the cutting speed command to the driving means 100.

[0008]

With the above configuration, the first computing means 120 allows the depth of cut X, the depth of cut T specified by the setting means 110,
The initial cutting speed V (o) and the deceleration information V (t) are calculated based on the deceleration method and the number of times N of the calculation. Then, when the driving means 100 operates at the calculated initial cutting speed V (o) to start cutting, the second calculating means 130 is provided.
Changes the cutting speed in the deceleration direction at a constant cycle according to the deceleration information V (t). Therefore, by controlling the drive means 100 on the basis of the cutting speed command, the amount of bending at the time of machining the workpiece is reduced, and the machining cycle time of the workpiece is shortened.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is an overall configuration diagram showing a case where the cutting control method according to the present invention is applied to a cylindrical grinding machine. In FIG. 2, 10 is a grinder, and 30 is a numerical controller for controlling the grinder 10.

The grinder 10 includes a work table 12 and a bed 1 which are installed on a bed 11 so as to be movable in the Z-axis direction.
A grindstone base 13 is installed on the base 1 so as to be movable in the X-axis direction.

The work table 12 is designed to be moved in the Z-axis direction by a servo motor and a feed screw (not shown).
A headstock 14 and a tailstock 16 that support 5 are located opposite to each other on the left and right. Both ends of the work W are supported by the centers 15a and 16a provided on the spindle 15 and the tailstock 16, respectively, and the left end portion of the work W is engaged with a detent member 17 protruding from the spindle 15. As a result, the work W is rotated integrally with the spindle 15. Further, the spindle 15 is rotationally driven by a motor 18 provided on the spindle stock 14.

The grindstone base 13 is a grindstone 19 such as a CBN grindstone for grinding the cylindrical portion Wa of the workpiece W, and this grindstone 19
It has a grindstone shaft 20 that supports the spindle parallel to the main shaft 15, and a motor 22 that rotationally drives the grindstone wheel 20 via a rotation transmission mechanism 21 such as the grindstone shaft 20 and a belt. The grindstone base 13 is moved in the X-axis direction (direction orthogonal to the axis of the workpiece W) by the servomotor 23 provided on the bed 11 and a feed screw (not shown) rotated by the servomotor 23. To be done.

The numerical controller 30 is a central processing unit (hereinafter CPU) that controls and manages the entire grinding machine as shown in FIG.
31), a memory 32, an interface 33 for exchanging data with the outside, and a pulse distribution circuit 34 for distributing and transmitting drive pulses in response to a command from the CPU 31. An input device 40 including a keyboard or the like for inputting setting data and control data is connected to the interface 33, and a driving circuit 41 that operates based on a driving pulse sent from the pulse distributing circuit 34 is connected to the input device 40. The whetstone head servo motor 23 is connected.

In the memory 32, as shown in FIG. 2, an arithmetic processing program for calculating continuous deceleration feed information, an arithmetic processing program for grinding the workpiece W based on the calculated speed information, and a grinding start. Amount (movement amount) X of the grindstone 13 from reaching to the target dimension, and this cutting amount X
A preset cutting time (grinding time) T required to move the machine, a deceleration method for obtaining continuous deceleration feed information,
Data such as the number of calculations N is stored.

As a deceleration method for obtaining the continuous deceleration feed information, a linear method shown in FIG. 3 (a) and a linear method shown in FIG. 3 (b) corresponding to the characteristics of the workpiece W and the grinding wheel 19 are shown. There are a hyperbolic method and a quadratic curve method shown in FIG. 3 (c), which determine a function V (t) of the cutting speed with respect to the cutting time.

In the correspondence between the present embodiment and the claims, the servomotor 23 and the drive circuit 42 serve as the drive means 100,
The input device 40, the CPU 31, and the memory 32 configure the data setting means 110, and the CPU 31 and the memory 32 configure the first and second computing means 120, 130, respectively.

Next, according to the flow chart shown in FIG.
The operation of this embodiment will be described. At the start of cutting, first, the input device 40 is operated to set the cutting amount X, the cutting time T, the number of calculations N, and the deceleration method (step S1). The deceleration system in this embodiment is the linear deceleration system shown in FIG. 3A, and its speed function (deceleration information) is given by V (t) = Vo + at.

In the next step S2, the initial speed V (o) at the start of the cutting feed is calculated. Here, the speed at the completion of cutting is given by Equation 1, and the cutting amount X by the time T
Is given by the equation 2.

[0019]

[Equation 1]

[0020]

[Equation 2]

From the equations (1) and (2), a = -2 · X / T ² Vo = 2 · X / T. Therefore, the initial velocity V (o) is Vo = 2 · X / T
Required from. For example, if X = 5 mm and T = 50 sec, V (o) will be 0.2 (mm / sec).

In the next step S3, a deceleration information calculation time interval to is calculated. This calculation time interval to is obtained from to = T / N based on the cutting time T and the number of times of calculation N. For example, if T = 50 sec and N = 100, t
o = 0.5 sec. In the next step S4, deceleration information V (t) is set. This deceleration information V (t) can be obtained by using equations 1 and 2
Obtained from V (t) = it is given by ^{2X / T-2Xt / T 2} .

In step S5, the CPU 31 and the memory 3
A timer (not shown) for counting the calculation time interval, which is configured by software by 2, is set to zero. Then, in the next step S6, a counter n for counting the number of calculations
The value of is set to n = 1. This counter n is CPU3
1 and the memory 32 are configured as software and are not shown.

In step S7, the calculated initial velocity V
The grindstone base 13 is moved forward at (o). That is, the CPU 31
When the initial speed command value calculated in step 3 is input to the pulse distribution circuit 34, the pulse distribution circuit 34 sends out a driving pulse having a pulse number and a frequency corresponding to the initial speed command value, and this driving pulse is supplied to the driving circuit 42. By being applied to the servo motor 23 via, the grindstone base 13 is advanced in the direction of the workpiece W at the initial speed V (o). Then, in the next step S8, the timer t for counting the calculation time interval is started, and in the next step S9, it is determined whether the count value of the timer t has reached the calculation time interval to. here,
When a positive determination is made that to = t, step S1
The process proceeds to 0 to calculate the actual cutting cumulative time ta = t × n by multiplying the counting time t of the timer t by the number of times of calculation n. In the next step S11, it is determined whether the actual cut cumulative time ta has reached the set cut time T.

When it is determined in step S11 that T = ta is not satisfied, the process proceeds to step S12, and the deceleration cutting speed V (ta) at ta is set to V (ta) = 2 (X / T-
X * ta / T). Then, after resetting the timer in the next step S13, the value of the operation number counter n is incremented by n + 1 in the next step S14.
After that, the deceleration cutting speed V calculated in step S12
The grinding wheel base 13 is moved forward at (ta), and the cylindrical portion Wa of the workpiece W is ground by the rotating grinding wheel 19 (step S15). In the next step S16, the calculation time interval counting timer t is activated again from the start point of the cutting feed at the speed V (ta), and in the next step S17, it is determined whether the count value of the timer t becomes the calculation time interval to. judge. If it is determined that to = t, step S
In step 10, the cutting speed V (ta) is decelerated again by executing the processing of step S10 and thereafter, and the grinding wheel head 13 is further advanced at the decelerated cutting speed.
In the same manner, the cutting speed is continuously decelerated in the constant calculation time interval to until the set cutting time T is reached. As a result, the cutting speed of the grindstone base 13 is linearly reduced as shown in FIG.

On the other hand, when it is determined in step S11 that the actual cumulative cutting time ta has reached the set cutting time T, the process proceeds to step S18, in which the cutting control of the wheel head 13 is stopped and the wheel head 13 is retracted. The operation is completed, and the grinding of the workpiece W is completed.

In this embodiment as described above, the cutting depth X, the cutting time T, the deceleration method and the number of times N of calculation are designated, and based on these designated data, the initial cutting speed V (o) and Obtain deceleration information V (t), and
After the cutting of the grinding wheel head is started, the cutting speed is utilized by using the deceleration information V (t) so that the cutting speed is a constant cycle sufficiently smaller than the cutting time in the conventional rough grinding and fine grinding, for example, 1/10 or less of the cutting time T. Since it is configured to continuously change in the deceleration direction at every cycle, even if the initial cutting speed is increased compared to the conventional cutting methods such as rough grinding, fine grinding, and fine grinding, the cutting amount of the grinding wheel head and the workpiece The difference from the actual machining diameter, that is, the uncut amount caused by the bending deformation of the workpiece does not increase, but rather decreases. As a result, the machining cycle time of the workpiece is shortened, and the workpiece can be surely finished to the target dimension within the set cutting time.
It is possible to improve the processing accuracy such as cylindricity and surface roughness of the workpiece.

In the above embodiments, the case where the present invention is applied to a cylindrical grinder has been described, but the present invention is not limited to this. For example, it can be similarly applied to an inner surface grinder, a surface grinder, and other grinders. Further, the deceleration method of the present invention is not limited to the method shown in FIG. Furthermore, the cutting control system of the present invention is not limited to the configuration shown in the above embodiment, but can be variously modified without departing from the scope described in the claims.

[0029]

As described above, according to the present invention, the cutting amount, the charging time, the deceleration method and the number of times of calculation thereof are designated, and the initial cutting speed V is set based on these designated data.
(o) and deceleration information V (t) are obtained, and after the cutting is started, the deceleration information V (t) is used to continuously change the cutting speed in the deceleration direction at a constant cycle until the set cutting time is reached. As a result, the bending amount of the workpiece is reduced, and the processing cycle time can be shortened.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of the present invention.

FIG. 2 is an overall configuration diagram showing an example of a cylindrical grinder to which the cutting method of the present invention is applied.

FIG. 3 is an explanatory diagram showing an example of a deceleration method in this embodiment.

FIG. 4 is a flowchart showing an operation procedure of a cutting control method in the present embodiment.

FIG. 5 is an explanatory diagram showing a conventional grinding cycle.

[Explanation of symbols]

 10 Grinder 11 Bed 12 Worktable 13 Grindstone Head 14 Spindle Head 15 Spindle 16 Tailstock 18 Motor 19 Grindstone Wheel 22 Motor 23 Servomotor 30 Numerical Control Device 31 CPU 32 Memory 34 Pulse Distribution Circuit 40 Input Device 41 Drive Circuit 100 Driving means 110 Setting means 120 First calculating means 130 Second calculating means

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[Procedure amendment]

[Submission date] August 3, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (1)

[Claims] 1. A grindstone base having a grindstone wheel driven to rotate, and a drive means for relatively moving the grindstone mount and the workpiece in a direction in which a workpiece ground by the grindstone wheel and a grindstone wheel move toward and away from each other. A specified data setting means for setting a cutting amount from the start of grinding to a target dimension of a workpiece, a cutting time required to move the cutting amount, a deceleration method for obtaining continuous deceleration feed information and the number of times of calculation thereof, First computing means for obtaining an initial cutting speed V (o) and deceleration information V (t) on the basis of designated data designated by the setting means, and sending the initial cutting speed command to the driving means; After starting the cutting by controlling the driving means with the initial cutting speed obtained by the computing means, the cutting speed is continuously changed in the deceleration direction at a constant cycle using the deceleration information V (t). A grinding device comprising: a second arithmetic means for sending a cutting speed command to the driving means.