JPH02109683A - Automatic measuring device for grindstone dimension in numerical control grinder - Google Patents

Abstract

PURPOSE:To correctly measure the diameter, length and shape change of a grindstone by arranging a contact detecting means detecting the contact of a grindstone, a main shaft indexing means indexing the grindstone at optional angle and an arithmetic means operating the dimension of the grindstone from the position detected by the contact detecting means. CONSTITUTION:In case of measuring the diameter and length of a grindstone T, the grindstone T is fitted to a main shaft 1 and moved toward a contact detecting means 6. The moving amt. of the grindstone is calculated by an arithmetic means 8 by the contact of the grindstone T with this contact detecting means 6. This calculated value is then subtracted from the reference distance between a preknown main shaft origin and the contact detecting means 6 by the arithmetic means 8 to find the dimension of the grindstone T. As a result, the diameter, length and shape change of the grindstone T can correctly be measured without accompanying any interference with the probe of the contact detecting means 6 and any wear of the probe.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a measuring device that automatically measures dimensions such as the diameter and length of a grinding wheel, changes in shape, etc. in a numerically controlled grinding machine.

[Conventional technology]

In a numerically controlled grinding machine, as shown in Fig. 8, a touch machine is conventionally used as a device for remeasuring so-called dimensions such as the diameter and length of a grinding wheel that has become smaller due to workpiece grinding, automatic truing, automatic dressing, etc. By fixing the sensor 2o to the side of the table, moving the main shaft 21 from a predetermined position and bringing the grindstone T into contact with the contact 20a of the touch sensor 2o, the diameter and length of the grindstone T are measured from the distance the main shaft 21 has moved. What it does is known.

In addition, as a device for automatically replacing the grinding wheel and measuring changes in shape due to grinding work, as shown in Fig.
It is known that the amount of deformation of the grindstone T is measured by touching the grindstone 2a and detecting the swinging of the lever 22 about the pivot shaft 23 with a displacement meter 24.

[Problem to be solved by the invention]

In the former dimension measuring device shown in FIG.
It is intended for measuring points only, and diameters and lengths can be measured, but if you try to measure changes in the shape of the grinding wheel by measuring multiple points, as shown in Figure 9, the grinding wheel T can be Oh! , 0. When the contactor 20a of the touch sensor 20 interferes with the grindstone T when the contactor 20a of the touch sensor 20 is moved to a portion of Ol other than the above, changes in shape etc. cannot be measured.

Furthermore, although the latter device shown in FIG. 1θ can measure changes in the shape of the grinding wheel T, since the contact 22a is brought into contact with the circumferential surface of the rotating grinding wheel T, the contact 22a is subject to severe wear. There is a problem that measurement accuracy is significantly reduced.

Furthermore, if it is necessary to measure the dimensions and shape changes of one grinding wheel, it is necessary to install two devices as shown in Figures 8 and 10 in the work area, which is not economical and the work area is narrow. There is a certain inconvenience.

The present invention can measure the diameter and length of a grindstone, as well as changes in shape, etc., and has almost no contact wear.
The purpose of the present invention is to provide an automatic grindstone size measuring device for a numerically controlled grinding machine that can measure accurately and does not significantly narrow the working area.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a main shaft on which a grindstone is mounted, and the main shaft is configured to be moved in at least seven of the X-axis, Y-axis, and Z-axis in one direction by a drive motor. In the numerically controlled grinding machine, a contact detection means for detecting contact of the grindstone, a spindle indexing means for indexing the grindstone at an arbitrary angle, and a calculation means for calculating the dimensions of the grindstone from the position detected by the contact detection means. The configuration includes the following.

[Effect]

When measuring the diameter or length of a grindstone, (the stone is attached to the main shaft and moved toward the contact detection means), the amount of movement of the grindstone is calculated by the calculation means by the contact of the grindstone with the contact detection means. The calculation means calculates the dimensions of the grindstone by subtracting the above calculated value from a previously known reference distance between the spindle starting point and the contact detection means.

Further, in order to know the amount of change in the shape of the grindstone, the spindle indexing means operates to rotate the grindstone by a predetermined angle every time the above dimension measurement is completed. The calculation means calculates the amount of change in the shape of the grindstone from the maximum and minimum values of the plurality of dimensions thus obtained.

〔Example〕

The present invention will be explained below based on the drawings.

Figures 1 and 2 show an embodiment of the automatic grinding wheel dimension measuring device of the present invention, and A in the figure shows a numerically controlled grinding machine (hereinafter referred to as NC grinding machine) having an automatic tool changer (not shown). (referred to as a board). This NC grinding machine A has the same basic structure as a so-called grinding center, and the grindstone T is taken out from a tool magazine (not shown) and mounted on the main spindle 1, and the NC control device 2
Each drive motor 3.4.5 for the X-axis, Y-axis, and Z-axis is controlled respectively.

The automatic grindstone dimension measuring device of the present invention is attached to this NC grinding machine A, and includes a touch sensor (contact detection means) 6 that detects contact with the grindstone T, and a servo amplifier (main shaft The indexing means (indexing means) 7 is composed of an operator stage 8 which performs predetermined calculations to be described later based on the detection signal obtained by the touch sensor 6 to determine the diameter of the grindstone T, etc.

The touch sensor 6 includes a contactor (tip ball) 6a that detects the contact of the grindstone T, a photoelectric sensor 6b that detects that the grindstone T approaches the contactor 6a to a predetermined position, and a photoelectric sensor 6b that detects when the grindstone T approaches the contactor 6a. It has a switch 6c that outputs a contact signal when the switch 6a is touched. The signal output from the photoelectric sensor 6b is input to the signal processing section 9, and when the amount of received light reflected from the grindstone T exceeds a set value, a contact signal is sent from the signal processing section 9 to the NC control device 2. The detection signal outputted from the switch 6c of the touch sensor 6 is converted into a contact signal by the signal processing unit IO, and then guided to the NC control device 2.

The servo amplifier 7 also includes an angle indexing circuit 7 that receives the indexing angle and rotation start signal output from the NC control device 2.
a, and an amplifier unit 7b that receives the signal output from the angle indexing circuit 7a and sends a signal for rotation to the spindle motor 11, The angle indexing circuit 7a compares the number of pulses output according to the rotation angle of the main shaft l, and when the latter number of pulses matches the former number of pulses, the output of the amplifier section 7b is stopped, and the output of the main shaft 1 is stopped. It is configured to stop the rotation of.

The calculation means 8 is provided inside the NC@valve device t2, and as shown in FIG.
AND gate 8a that transmits
An interpolator 8b generates an output turn for controlling the servo device of the Z-axis drive motor 5 using the feed pulse f, and a position detection signal from the photoelectric sensor 6b, or a switch of the touch sensor 6. By inputting the contact signal from 6c, a counter inside the interpolator 8b causes the grinding wheel T(
Alternatively, the position Z (coordinate value on the Z axis) when the reference block 14), which will be described later, reaches a position a certain distance away from the contact 6a or when the grindstone T contacts the contact 6a is taken in, and the The AND gate 8a is turned OFF to stop the movement of the main shaft 1, that is, the grindstone T, in the Z-axis direction,
Additionally, a CPU (
It consists of a central processing unit 8c and a storage device 8d connected to the CPU 8c. This storage device 8d has N
A control program that controls the C control device 2 and the various devices that measure the dimensions of the grindstone is registered.

Further, when the main spindle index is executed by the control program, the CPU 8c sends an index angle and a rotation start signal to the servo amplifier 7. In addition, in Fig. 1, the reference numeral 13
is an NC tape.

Next, the operation of the automatic grindstone dimension measuring device for the NC grinding machine of the present invention will be explained.

3 and 4 explain the principle of measuring the length of the grinding wheel T, from the end face 1a of the main axis l to the plane 14 perpendicular to the Z axis. A reference block 14 whose distance εZo in the Z-axis direction to a is measured in advance is installed on the spindle head 15.

Distance between the end surface 1a of the main shaft 1 at the starting point and the contact 6a of the touch sensor 6 outputting a contact signal (reference distance)
Lo is given by the following equation.

L o = a o + t Z o A−−°”°”
°°° (1) Here, ao is the amount of axial movement of the reference block 14 until it touches the contact 6a of the touch sensor 6 and the contact signal is turned ON.

Next, the grindstone T is inserted into the main shaft l and brought into contact with the contact 6a of the touch sensor 6. If the axis movement amount at this time is a, then
The grindstone length Lx at the position Ta of the grindstone T is given by the following equation.

LX=LO-a ・・・・・・・・・・・・・・・
(2) When the measurement of the position Ta is completed, return to the starting point that is a minute distance away from the touch sensor 6, and calculate the main axis l by the starting angle set in the control program.

Make contact again and return to the starting point. Thereafter, the indexing and contacting operations of the main shaft l are repeated in the same manner.

At the end of one contact operation, the grindstone length at each measurement position is calculated by the calculation means 8 and stored in the storage device 8d. The calculation means 8 calculates the maximum value LI11! for the plurality of measured grindstone lengths. ! The minimum value L min ΔL = L maw -1, miQ is determined and compared with the allowable value set in the control program. If the allowable value is exceeded, a warning is output. NC LIIlax
Register in the grinding wheel length offset of the control device.

The operation of the apparatus when measuring the grindstone length LX using the control program in the storage device 8d based on the above principle will be explained with reference to the flowcharts shown in FIGS. 5 to 7.

First, when the apparatus is started and a measurement counter (not shown) is reset (step Sl), the position of the starting point of the main axis l is stored in the storage device 8d of the calculation means 8 (
Step S2), it is determined whether the mode is the reference distance acquisition mode (Step S3).

In the case of the reference distance collection mode, the number of measurement points is set to "l" (step 84), and the main shaft 1 moves in the Z-axis direction by the operation of the Z-axis drive motor 5 to move the reference block 14 to the third
Move to the left in the figure at a faster feed rate (step S6)
. Then, the gate signal of the AND gate 8a of the calculation means 8 becomes ON, and the feed pulse f passes through the AND gate 8a and enters the interpolator 8b. The interpolator 8b outputs a control signal for the two-axis drive motor 5 based on this feed pulse f, and the Z-axis drive motor 5 continues to operate.

Then, when the reference block 14 enters the detection area of the photoelectric sensor 6b (step S7), the photoelectric sensor 6b detects an increase in the amount of light reflected from the reference block 14, and the signal is converted into a contact signal by the signal processing unit 9 and output. and enters the CPU 8c of the calculation means 8.

When the CPU 8c detects this contact signal, it
) The gate signal 8a is momentarily turned off to stop inputting the feed pulse f to the interpolator 8b, and the Z-axis drive motor 5 is temporarily stopped. Then, the calculation means 8 restarts the two-axis drive motor 5 according to the control program registered in the storage device 8d, and moves it to a position in front of the contactor 6a, for example, at 2 am (this distance of 2 m is the maximum shape of the grindstone expected). The main shaft l is moved at a fast speed until it reaches a value (a little larger than the amount of change) (step S8). Note that since the distance between the contactor 6a and the photoelectric sensor 6b is known, the distance between the contactor 6a and the photoelectric sensor 6b is known.
After the movement of the reference block 14 is detected by
Whether it reaches 2III11 before a is calculated in advance by the calculation means 8.

If it is the reference distance collection mode (step S4) and the amount on the measurement counter is less than the number of measurement points calculated in step S5 (step S9), the main shaft 1 is not rotated and the 2mm distance is It moves toward the contact 6a at a slow feed speed (step 311). When the reference block 14 comes into contact with the contact 6a of the touch sensor 6,
The switch 6c outputs a contact signal, and the signal is detected by the signal processing section 10 (step 312), and the C of the calculation means 8 is detected.
Enter PU8c.

When this contact signal is input, the CPU 8c operates the interpolator 8.
The parless number of the feed pulse f is taken in from the counter inside b as the position of the reference block 14, and stored in the storage device 8.
d (step 513), the gate signal of the AND gate 8a is turned off, the input of the feed pulse f to the interpolator 8b is stopped, and the Z-axis drive motor 5 is stopped.

When the contact position is stored in this way, the CPU 8c calculates the moving distance ao from the starting point to the contact with the contact 6a (step 514). Here, it is again determined whether the mode is the reference distance acquisition mode (step 315), and if the mode is the reference distance acquisition mode, the CPU 8c calculates aO+εZ.

is calculated and the reference distance Lo is calculated (step 316
), its value is stored in the storage device 8d (step 51
7).

Once the above memorization is completed, the operation of the two-axis drive motor 5 will cause
The reference block 14 is moved back to 2 cm in front of the contactor 6a (step 520), and the number of measurements is counted up on the counter (step 521).

When the result of step S9 is No, the main shaft l is returned to the starting point by the operation of the two-axis drive motor 5 (step S522).
), it is determined whether or not it is the reference distance acquisition mode (step l
+3), if YES, it is the end.

In step S3, if it is not the reference distance acquisition mode, the number of measurement points is calculated from the starting angle and pitch angle by the calculating means 8.
At the same time, the grindstone T is taken out from the tool magazine and inserted into the spindle I. From then on,
Similarly to the above, the main shaft 1 is moved to Z by the operation of the two-axis drive motor 5.
The grindstone T is moved in the axial direction to the left in FIGS. 1 and 4 at a high feed rate (step S6). Then, the gate signal of the controller 8a of the calculation means 8 becomes ON, and the feed pulse f passes through the controller 8a and enters the interpolator 8b. The interpolator 8b uses this feed pulse f
A control signal for the Z-axis drive motor 5 is output, and the Z-axis drive motor 5 continues to operate.

Then, when the grindstone T enters the detection area of the photoelectric sensor 6b (step 87), the photoelectric sensor 6b detects an increase in the amount of light reflected from the grindstone T, and the signal is converted into a contact signal by the signal processing section 9 and output. It enters the CPU 8c of the calculation means 8. The calculation means 8 controls the Z-axis drive motor 5 according to the control program registered in the storage device 8d, and moves the main shaft 1 at a fast speed until it reaches 2 mm in front of the contact 6a (step S8). In step S9, if the amount on the measurement counter is less than the number of measurement points calculated in step S5, the NC control device 2 issues a command to the servo amplifier 7, and the spindle motor 11 rotates to move the grindstone T at a predetermined angle. Determine (step 510).

On the other hand, after the above detection signal is input, the CPU 8c continues to move the main spindle 1 so that the grindstone T is moved at a fast speed to the contactor 6a for 2 m.
When the rotational speed approaches m, the rotational speed of the two-axis drive motor 5 is reduced and the main shaft 1 is moved in the Z-axis direction at a slow feed speed (step 5ll). Then, when the grindstone T comes into contact with the contact 6a of the touch sensor 6, as in the case of the reference block 14,
The switch 6c outputs a contact signal, and the signal is detected by the signal processing unit io (step 512), and the
Enter PU8c. When this contact signal is input, the CPU 8c takes in the pulse number of the feed pulse f as the position of the grindstone T from the counter inside the interpolator 8b, registers it in the storage device 8d (step 513), and also registers it in the AND gate 8a. The gate signal is turned OFF to stop inputting the feed pulse f to the interpolator 8b, and the two-axis drive motor 5 is stopped.

When the contact position of the grindstone T with respect to the contact 6a is stored in this way, the CPU 8c calculates the moving distance a from the starting point to the contact with the contact 6a (step 514).

It is determined whether the mode is reference distance acquisition mode (step 515).
, if the mode is not the reference distance collection mode, the CPU 8c calculates o-a to calculate the grinding wheel length LX (step 518), and stores the grinding wheel length in the storage device 8d (step 519).
. After the above memorization is completed, the grindstone T is moved back to 2 mm before the contact 6a by the operation of the Z-axis drive motor 5 (step 520), and the number of measurements is counted up on the counter (step 521).

The above operation. are repeated until the number of measurement points matches the number of measurement points set in the measurement number counter, and when they match and the result in step S9 is NO, the main axis l is returned to the starting point (step 522). It is also determined whether it is the reference distance collection mode (step 523), and if No, the maximum value (L max) and minimum value (Lmin) of the grinding wheel length measured and stored above are calculated (step 524), The amount of variation is calculated (step 525).

It is examined whether the amount of variation is within the tolerance set in the control program (step 7, step 526), and if it is within the tolerance, the maximum value is registered in the tool offset of the NC control device 2 (step 526). 527) If the limit is exceeded, an alarm signal is output (step 828) and the process ends.

In addition, in the above, the grindstone T is moved in the Z-axis direction.
We have explained the case of measuring and determining the length of the grindstone.
The diameter of the grindstone can also be measured by moving it in the axial direction (direction perpendicular to the plane of the paper in FIG. 1) or Y-axis direction (vertical direction). In this case, it goes without saying that the touch sensor 6 is rearranged in the direction of movement of the grindstone. Furthermore, in the above embodiment,
When the reference block 14 approaches the contact 6a, the grindstone T or I; moves at a fast speed to 2 mm before the contact 6a, then moves at a slow speed and contacts the contact 6a, and the grindstone T
The retracted position is 2 mm in front of the contact 6a, but this is to make the dimension measurement work as efficient as possible, and is not limited to 2 mm. Furthermore, in the above embodiment, when the photoelectric sensor 6b outputs a position detection signal, the movement of the spindle 1 in the two-axis directions is temporarily stopped, but the movement of the spindle 1 is continued without being stopped. You can do it like this.

〔Effect of the invention〕

As explained above, the present invention provides a numerically controlled grinding machine comprising a main shaft to which a grindstone is attached, and the main shaft is configured to be moved by a drive motor in at least one direction of the X-axis, Y-axis, and Z-axis. A configuration in which the disc includes a contact detection means for detecting contact with a grindstone, a spindle indexing means for indexing the grindstone at an arbitrary angle, and an arithmetic means for calculating the dimensions of the grindstone from the position detected by the contact detection means. Therefore, by rotating the main shaft to a predetermined angle for indexing and contacting the touch sensor from one direction, multiple positions can be measured individually. As a result, the following effects can be obtained.

(a) The amount of variation and the diameter or length can be measured without problems such as interference with the contact of the touch sensor or wear of the contact. That is, at the measured positions of multiple points, the amount of variation is obtained from the maximum difference between them, and the actual length when attached to the spindle is determined from the distance to the end of the spindle or the farthest position from the center of the spindle.
Alternatively, the diameter can be obtained.

(b) In the past, in order to measure diameter and length dimensions and runout, it was necessary to install two devices in the grinding work area as described above, but in the present invention, one device is required to be installed in the grinding work area. Since only five touch sensors need to be placed within the work area, the work area is expanded.

(C) Since the positions of multiple points can be known, there is a function to automatically check for abnormalities in the grinding wheel, such as parts falling off or deformation of the grinding wheel. For example, a certain threshold value can be set for the amount of variation. It is easy to provide a function such as setting a limit and issuing a warning when the limit is exceeded.

[Brief explanation of drawings]

FIG. 1 is a side view showing an embodiment of an automatic grinding wheel dimension measuring device for a numerically controlled grinding machine according to the present invention, FIG. 2 is a block diagram showing an example of a calculation means, and FIGS. 3 and 4 are Explanatory diagrams for explaining the principle of measuring dimensions, Figures 5 to 7
The figure is a flow chart of the present invention. FIG. 8 is a side view of a conventional dimension measuring device, FIG. 9 is a front view thereof, and FIG. 1θ is a side view of a conventional dimension measuring device. T... Grindstone, l... Main shaft, 3, 4.5... Drive motor, 6... Touch sensor (contact detection means), 7...
- Servo amplifier (spindle indexing means), 8... calculation means.

Claims (1)

[Claims] A numerically controlled grinding machine comprising a main shaft to which a grindstone is attached, and the main shaft is configured to be moved by a drive motor in at least one direction of the X-axis, Y-axis, and Z-axis,
It is characterized by comprising a contact detection means for detecting contact with the grindstone, a spindle indexing means for indexing the grindstone at an arbitrary angle, and an arithmetic means for calculating the dimensions of the grindstone from the position detected by the contact detection means. Automatic grinding wheel size measurement device for numerically controlled grinding machines.