JPH01295762A - Grinding wheel condition supervisory device and its utilizing method for nc grinding machine - Google Patents

Abstract

PURPOSE:To enhance grinding accuracy of an NC grinding machine by providing a displacement arithmetic circuit for calculating an error for the reference point of an NC unit of a grinding wheel by comparing its displacement, detected by a sensor while rotating the grinding wheel, with a reference level of the NC unit. CONSTITUTION:Contactless displacement sensors S1 to S3 are provided corresponding to a grinding surface of a rotary grinding wheel 1. A displacement amount, detected by these sensors S1 to S3, of the grinding surface of the grinding wheel 1 is compared with the reference level of an NC unit, and an error for a reference point of the NC unit of the grinding wheel is calculated by a displacement amount arithmetic circuit 13. The calculated error is given to an NC part 17 of the NC unit as a correction amount, and controlling a work table 3 to be driven in accordance with a wearing amount of the grinding wheel 1, a workpiece is high accurately ground.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a grindstone condition monitoring device for an NC grinding machine and a method of using the same.

(Prior Art) In recent years, the use of NC in grinding machines has been progressing, but complete automation has not been achieved due to the unique circumstances of grinding machines. That is, in a grinding machine, the grinding wheel gradually wears out and becomes clogged as the grinding process progresses, so the machining accuracy will deteriorate if no correction is made. Furthermore, thermal deformation on the grindstone main shaft side may cause a positional shift between the grindstone and the workpiece.

Therefore, conventionally, processing is sometimes performed without considering the above-mentioned wear or thermal deformation. There is also an example in which processing is performed by manually correcting as appropriate. Alternatively, an optical tracing grinder may be used for the purpose of performing higher precision machining.

(Problem to be Solved by the Invention) However, the amount of wear on the grindstone is quite large, and if this is ignored in many cases, problems will inevitably arise in processing accuracy. Moreover, manual correction requires a considerable amount of effort. Furthermore, optical tracing grinding has the problem that the NC device cannot be used effectively. Furthermore, conventionally, dressing of the grinding wheel was done by visual inspection, but this also failed.
? It is preventing full automation of ill RLJ board.

Therefore, the present invention provides N
An object of the present invention is to provide a grindstone condition monitoring device for an NC grinding machine that can effectively utilize a C device, and a method for using the same.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention provides a non-contact displacement sensor corresponding to the machining surface of a rotary grindstone.
) to (6).

(Operation) In the invention described in claim (1), the error of the grinding wheel with respect to the reference point of the NC device is automatically detected based on the displacement position detected by the non-contact displacement sensor, and the detected error is separated by NC.
It is given as a correction amount to the I position.

In the invention described in claim (2), the state of the abrasive grains is automatically detected based on the displacement position detected by the non-contact displacement sensor, and dressing is automatically performed as necessary.

In the invention described in claim (3), since it is possible to detect both the error of the grindstone with respect to the reference point of the NC device and the state of the abrasive grains, it is possible to give a predetermined correction amount to the NC device, and to adjust the amount of correction as necessary. Dressing can be done.

In the invention described in claim (4), since the non-contact displacement sensor is provided on the grindstone side, the sensor does not interfere with the machining operation, and the mechanical device can be configured compactly. In this case, the li! of the NC device of the detected grindstone! The error caused by a single quasi-point corresponds to the amount of wear on the grinding wheel.

In the invention described in claim (5), since the non-contact displacement sensor is provided on the workpiece side, it is possible to detect thermal strain between the grindstone and the workpiece in addition to detecting the amount of wear on the grindstone. detection, and more advanced correction becomes possible.

In the invention described in claim (6), since the measurement cycle is interposed in the machining cycle, even if the workpiece is relatively large, the error with respect to the reference point of the NC device of the grindstone can be detected before, during, or after the start of machining. Or, the need for dressing can be detected and a higher degree of automation can be performed.

(Example) Hereinafter, the present invention will be described in detail based on the accompanying drawings.

FIGS. 1 and 2 are a plan view and a side view showing an example in which a non-contact displacement sensor (hereinafter simply referred to as a sensor) is provided on a workpiece (hereinafter referred to as a work).

As shown in the figure, a grinding wheel 1 rotates, and a workpiece 5 is mounted on a work table 3 driven by an NC device (not shown).
In addition, a sensor device 7 and a dresser device 9 are attached.

In the NC grinding machine having the above configuration, the NC device (not shown) interprets the N0 statement and moves the work table 3 in the X and Y directions as appropriate to move the grinding wheel 1 to Itli points A and B.
A predetermined grinding process is performed while applying the grinding machine to a predetermined point on the workpiece 5. In this example, considering that the grindstone 1 is a flat grindstone, the sensor device 7 includes three sensors S+, 32
．． Reference numeral 83 indicates attachment corresponding to each machined surface. In FIG. 2, the work table 3 is moved and the sensor device 7 is placed on the grinding wheel 1.
This figure shows the state corresponding to the following.

Each sensor S+, S2, S3 outputs a predetermined voltage signal according to the amount of displacement from the sensor reference position with respect to the grinding wheel 1 (for example, LC-2010 of Keyence Corporation,
PA1810).

FIG. 3 is a block diagram illustrating a grindstone condition monitoring device applied to the NC grinding machine.

As shown in the figure, the grinding wheel condition monitoring device of this example includes an amplifier section 11 which inputs the voltage signals output from the sensors S+ and S2.33 and outputs an appropriate analog or digital signal.
, a displacement calculating section 13 and an abrasive grain state detecting section 15 connected in parallel to the amplifier section 11. The output lines of both calculation sections 13 and 15 are connected to the N0 section 17 of the NC device that drives the work table 3. Also, the abrasive grain state detection unit 15 indicates alarm 1! It is also connected to i location 19.

FIG. 4 and FIG. 5 are explanatory diagrams showing the calculation method of the displacement calculation section 13.

The displacement calculation section 13 averages the input signal of displacement with respect to the grinding wheel shaft rotation angle θ shown in FIG. 4 as shown in FIG. 5, calculates the difference between this and the reference level LO, and sends the correction amount to the N0 section 17 Output δ. Reference level 0 is N0 part 1 when setting the whetstone
This is the regular grindstone reference position taught to No. 7.

In this example, the correction amount δ obtained by 1q is calculated by the sensor device 7.
Since the grinding wheel is attached to the work table, the amount of wear on the grinding wheel is the sum of the thermal strain between the work table 3 and the grinding wheel 1. Incidentally, when the sensor device 7 is fixed to the grindstone 1, although the device is compact, this thermal distortion is not taken into consideration.

In detail, the tip of the grinding wheel 1 and the work table are now dX in the X direction with respect to the sensor S+ due to thermal strain.

Assume that it is displaced by dY in the Y direction. Also, due to grinding or dressing, the diameter of the grinding wheel is dR, the width of the grinding wheel is sensor S+,
Suppose that dll+ and dH3 are displaced from 83.

Then, the read data L+, L2, L3 from the reference value (usually zero) of each sensor S+, S2, S3 is L, =d t-1+ +d becomes.

゛Therefore, when giving a correction amount to each machined surface, the displacement calculation unit 13 uses the notation values L+, L2, L3
However, in reality, point A shown in Figure 1 is output.

Since a correction value is given for 已, for point A (L+
, L2), which gives (13, 12) for point B.

As described above, since the N0 section 17 can recognize the actual coordinate values of points A and B, it is possible to continue high-precision machining that is unrelated to the amount of grindstone wear and thermal strain.

6 and 7 are explanatory diagrams showing the calculation method of the abrasive calculation section 15. FIG.

The abrasive grain condition detection section 15 inputs the displacement signal with respect to the grinding wheel rotation angle θ shown in FIG. 6 from the amplifier section 11, filters this signal, and removes the low frequency part as shown in FIG. , the abrasive grain protrusion m is recognized from the average value of the signal after removal, and this is a constant Ii! determined by experience. [In the following cases, the address request signal Q is output to the N0 unit 17 along with the alarm output.

Due to the above-described operation of the abrasive grain condition calculation section 15, the N0 section 17 can automatically dress the grindstone 1 using the dresser device W9.

FIG. 8 is a flowchart showing the correlation between processing cycles and measurement cycles.

After the machining cycle of the unit machined surface is completed in step 801, a measurement cycle is executed in step 802.

In the measurement cycle, the grindstone is rotated at a low speed, and during this period, the sensor S+, 82.83 detects the displacement according to the rotation angle θ of the grindstone shaft.

In step 803, the displacement calculation unit 13 and the abrasive grain state calculation unit 1
5, and if a dressing request is issued in step 804, dressing is performed in step 806. In this case, measurement is performed again in the measurement cycle of steps 802 and 803, and then correction is performed in step 805. . The reason why step 804 is provided is that the condition of the grindstone changes due to dressing.

As described above, since the measurement cycle can be interposed between any machining cycles, all machining can be performed with precision and fully automatically.

Fig. 9 shows an example in which the present invention is applied to a ■ grindstone, and Fig. 10 shows an example in which the present invention is applied to an R grindstone. ■ Considering that the tip of the grindstone is also the processed surface, ■ three sensors S+, 82.83 are attached to both end surfaces and the tip surface. Also, R
The grindstone uses three sensors S+ to accurately measure the R shape.
, 82.83. Sensor S+, 32
．． The same applies to what is called a distance sensor as 33.

The present invention is not limited to the above embodiments, but can be implemented in other embodiments by making appropriate design changes.

[Effect of the invention] As mentioned above, the invention described in claim (1) has the following effects:
NC of the grinding wheel based on the displacement position detected by the non-contact displacement sensor
Since the error with respect to the reference point of the device can be automatically detected and the detected error can be given to the NC device as a correction amount, the accuracy of the NG grinder can be improved and automation can be advanced.

In the invention described in claim (2), the state of the abrasive grains can be automatically detected based on the amount of displacement detected by the non-contact displacement sensor, and dressing can be performed automatically as necessary. , automation can be achieved with less effort.

In the invention described in claim (3), since it is possible to detect the error of the grindstone with respect to the reference point of the NC device as well as the abrasive grain condition, it is possible to give a predetermined correction to the NC device and to perform dressing as necessary. This allows more complete automation to be achieved.

In the invention described in claim (4), since the non-contact displacement sensor is provided on the grindstone side, the sensor can be installed in a manner that does not interfere with the processing operation, and the mechanical device can be configured compactly.

In the invention described in claim (5), since the non-contact displacement sensor is provided on the workpiece side, it is also possible to detect thermal strain between the grindstone and the workpiece to detect the amount of wear on the grindstone. More advanced correction is possible, and processing accuracy can be further improved.

In the invention described in claim (6), since the measurement cycle is interposed in the machining cycle, even when processing a relatively large workpiece, the NC of the grindstone is adjusted before, during, or before the start of machining.
Errors relative to the reference point of the device or the need for dressing can be detected, allowing for higher automation.

[Brief explanation of the drawing]

The drawings all show embodiments of the present invention, and FIG. 1 and FIG.
The figures are an explanatory plan view and a side view showing the mounting state of the sensor, Fig. 3 is an explanatory block diagram of the grinding wheel condition monitoring device, Figs. 4 and 5 are explanatory views showing the signal processing method of the displacement calculation section, and Fig.
7 and 7 are explanatory diagrams showing the signal processing method of the grindstone-like i calculation unit, FIG. 8 is a flowchart showing the positioning of the measurement cycle, and FIG. 9 is a plan explanatory diagram showing an example of application to a grindstone.
FIG. 10 is an explanatory plan view showing an example of application to an R grindstone. 1.21.23... Grindstone 3... Work table 5... Machining work 9... Dresser device 1
3... Displacement calculation section 15... Abrasive grain state calculation section S+, 82, S3... Non-contact displacement sensor agent
Patent Attorney Yasuo Miyoshi Figure 3 1.21.23...Whetstone 3...Work Q:5.
・Workpiece 9... Dresser device 13 ・Displacement l1lI calculating section 15... Abrasive grain shape! IεS+
, Ss, S3...Non-contact displacement sensor ruru ♂ Town stomach part

Claims (6)

[Claims] (1) A non-contact displacement sensor is provided corresponding to the machining surface of the rotary grindstone, and the displacement detected by the non-contact displacement sensor obtained while rotating the grindstone is compared with the reference level of the NC device. A grindstone condition monitoring device for an NC grinding machine, characterized in that it is provided with a displacement calculation circuit that calculates an error with respect to a reference point of an NC device. (2) A non-contact displacement sensor is provided corresponding to the machining surface of the rotary whetstone, and the state of the abrasive grains of the whetstone is detected based on minute changes in the displacement detected by the non-contact sensor obtained while rotating the whetstone. N characterized by being provided with an abrasive grain state calculation circuit.
Grinding wheel condition monitoring device for C grinding machine. (3) A non-contact displacement sensor is provided corresponding to the machining surface of the rotary whetstone, and the detected displacement of the non-contact displacement sensor obtained while rotating the whetstone is compared with the reference level of the NC device. NC grinding characterized in that a displacement calculation circuit is provided for calculating an error with respect to a reference point of the NC device, and an abrasive grain state calculation circuit is provided for detecting the abrasive grain state of the grindstone based on a minute change in the detected displacement position. Grinding wheel condition monitoring device. (4) A non-contact displacement sensor is provided corresponding to the processing surface of the rotary grindstone, and based on the detected displacement of the non-contact displacement sensor obtained while rotating the grindstone, the error of the grindstone relative to the reference point of the NC device or and a grinding wheel condition monitoring device for an NC grinding machine that detects the condition of abrasive grains, characterized in that the non-contact sensor is provided on the grinding wheel side via an appropriate movable means. (5) A non-contact displacement sensor is provided corresponding to the processing surface of the rotary grindstone, and based on the detected displacement of the non-contact displacement sensor obtained while rotating the grindstone, the error of the grindstone relative to the reference point of the NC device or and a grindstone condition monitoring device for an NC grinder that detects the condition of abrasive grains, characterized in that the non-contact sensor is provided on a workpiece side. (6) A non-contact displacement sensor is provided corresponding to the processing surface of the rotary grindstone, and based on the detected displacement of the non-contact displacement sensor obtained while rotating the grindstone, the error of the grindstone relative to the reference point of the NC device or and a method of using a grinding wheel condition monitoring device for an NC grinding machine that detects an abrasive grain condition,
A method of using a grinding wheel condition monitoring device for an NC grinder, characterized in that a measurement cycle for detecting an error with respect to a reference point of the device or the condition of the abrasive grain is interposed at least once during a processing cycle of the NC grinder.