JPH10556A - Grinding wheel truing time judgement method and its device, grinding wheel truing result judgement method and its device, and grinding wheel automatic truing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To objectively and precisely recognize truing time, the quality of truing, dressing time and the quality of dressing without depending on experience. SOLUTION: Oscillation of a grinder is detected by an oscillation detection means 8 for every specified frequency which is integral times of rotational frequency of a grinding wheel 3 installed on a spindle 2, and truing time of the grinding wheel 3 and the quality of truing are judged by comparing detected amplitude and a designated data with each other at the time of grinding work. Additionally, the amplitude of oscillation generated on the grinder at the time of the grinding work is detected by the oscillation detection means 8 for every specified frequency which is integral times of natural frequency of the grinder, and dressing time of the grinding wheel 3 and the quality of dressing are judged by comparing detected amplitude and a designated data with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for determining the repair time of a grinding wheel, a method and an apparatus for determining the result of repairing a grinding wheel, and an apparatus for automatically repairing a grinding wheel, each of which is used in a grinding machine for grinding a workpiece by rotating a grinding wheel. About.

[0002]

2. Description of the Related Art In a grinding machine, a wheel for grinding a workpiece is deformed due to grinding resistance when grinding operation is continued for a certain period of time or more, and a runout at an outer peripheral portion during rotation is increased. As a result, undulation, scratches (scratches) and chipping occur on the ground surface of the workpiece, and the machining accuracy of the workpiece deteriorates. The same can be said for other general whetstones. Therefore, truing is performed to correct the runout of the outer periphery by shaving off the outer periphery of the wheel.

[0003] Even if the runout of the wheel is small, the sharpness may be deteriorated due to wear. For example, in the case of a diamond wheel where diamond abrasive grains are solidified with a bond, the amount of protrusion of the diamond abrasive grains decreases due to wear,
Retreat the bond surface to make diamond abrasive grains protrude,
Dressing is performed to adjust the shape of diamond abrasive grains and remove clogged chips.

[0004]

In an ultrasonic dressing apparatus, a dressing apparatus incorporating an AE sensor for detecting a contact state between a wheel and a dresser, etc., it has been attempted to sense and monitor the situation of truing and dressing work. However, the truing and dressing conditions are ultimately determined by the operator based on experience. Specifically, the shape of the wheel is measured after the work, or the test piece is actually ground to determine the quality of the wheel.

[0005] Therefore, in the case of an operator other than a skilled operator, wheel repair (truing, tracing)
It is difficult to judge the quality of the repair result at the time, and there is much loss in time.

[0006]

According to a first aspect of the present invention, there is provided a method for determining a repair time of a grindstone, wherein the amplitude of the vibration generated in the grinder during the grinding operation is determined for each specific frequency which is an integral multiple of the rotation frequency of the grindstone mounted on the spindle. The truing timing of the grinding wheel is determined by comparing the detected amplitude with the specified truing timing determination data.

In order to determine the truing time of the grinding wheel, the grinding wheel repair time determining apparatus according to the second aspect of the present invention uses the amplitude of the vibration generated in the grinding machine during the grinding operation to determine the amplitude of the grinding wheel mounted on the spindle of the grinding machine. Vibration detecting means for detecting a specific frequency of an integral multiple of the rotation frequency, and data storage means for storing truing time determination data for determining a truing time corresponding to the amplitude detected by the vibration detecting means,
Truing time determining means for determining the truing time of the grinding wheel by comparing the detected amplitude with the truing time determination data.

Accordingly, as the run-out of the grinding wheel increases, the amplitude of the vibration of the grinding machine changes remarkably at a specific frequency which is an integral multiple of the rotation frequency of the grinding wheel. The truing timing determination means compares the truing timing determination data stored in the data storage means with the truing timing determination data, so that the truing timing can be objectively and accurately recognized.

According to a third aspect of the present invention, there is provided a grinding wheel repair result judging method, wherein the amplitude of vibration generated in a grinding machine during a grinding operation is detected for each specific frequency which is an integral multiple of the rotation frequency of a grinding wheel mounted on a main shaft, and the detected amplitude is determined. Is compared with the designated truing quality determination data to determine the truing quality of the grinding wheel.

In order to determine the quality of the truing of the grinding wheel, the grinding wheel repair result determination apparatus of the invention according to the fourth aspect of the present invention uses the amplitude of the vibration generated in the grinding machine during the grinding operation to determine the amplitude of the grinding wheel mounted on the spindle of the grinding machine. Vibration detecting means for detecting a specific frequency of an integral multiple of the rotation frequency, and data storage means for storing truing quality determination data for determining the quality of truing corresponding to the amplitude detected by the vibration detecting means, Truing quality determination means for determining the quality of truing of the grinding wheel by comparing the amplitude with the truing quality determination data.

Therefore, as the run-out of the grindstone increases, the amplitude of the vibration of the grinder significantly changes at a specific frequency which is an integral multiple of the rotation frequency of the grindstone. By comparing the truing pass / fail judgment data stored in the data storage unit with the truing pass / fail judgment unit, the truing pass / fail is objectively and accurately recognized.

According to a fifth aspect of the present invention, there is provided an automatic grinding wheel repairing apparatus for detecting the amplitude of vibration generated in a grinding machine at a specific frequency which is an integral multiple of a rotation frequency of a grinding wheel mounted on a main shaft of the grinding machine during a grinding operation. Means, data storage means storing truing time determination data for determining the truing time corresponding to the amplitude detected by the vibration detection means,
The truing device includes a truing time determining unit that determines the truing time of the grinding wheel by comparing the detected amplitude with the truing time determination data, and a truing driving unit that drives the truing device when the truing time is determined. Therefore, as the wobble of the grindstone increases,
Since the amplitude of the vibration of the grinding machine changes remarkably at a specific frequency that is an integral multiple of the rotation frequency of the grindstone, the amplitude of the vibration of the grinding machine detected by the vibration detecting means and the truing timing determination data stored in the data storage means Is compared by the truing timing determination means, whereby the truing timing is objectively and accurately recognized. Based on this recognition, the truing driving means drives the truing device.

According to a sixth aspect of the present invention, there is provided a grinding wheel repair time determining method, wherein an amplitude of a vibration generated in a grinding machine during a grinding operation is detected for each specific frequency which is an integral multiple of a natural frequency of the grinding machine.
The dressing time of the grinding wheel is determined by comparing the detected amplitude with the designated dressing time determination data.

In order to determine the dressing time of the grinding wheel, the grinding wheel repair time determining apparatus according to the present invention is arranged such that the amplitude of the vibration generated in the grinding machine during the grinding operation is an integral multiple of the natural frequency of the grinding machine. Vibration detecting means for detecting a specific frequency; data storage means for storing dressing time determination data for determining a dressing time corresponding to the amplitude detected by the vibration detecting means; and the detected amplitude and the dressing time determination data. And a dressing timing determining means for determining the dressing timing of the whetstone by comparing.

Accordingly, as the sharpness of the grindstone decreases, the amplitude of the vibration of the grinding machine remarkably changes at a specific frequency which is an integral multiple of the natural frequency of the grinding machine. By comparing the amplitude with the dressing timing determination data stored in the data storage unit, the dressing timing determination unit objectively and accurately recognizes the dressing timing.

According to a eighth aspect of the present invention, there is provided a grinding wheel repair result judging method, wherein the amplitude of a vibration generated in a grinding machine during a grinding operation is detected for each specific frequency which is an integral multiple of the natural frequency of the grinding machine.
The quality of the dressing of the grinding wheel is determined by comparing the detected amplitude with the specified dressing quality determination data.

In order to judge the quality of the dressing of the grinding wheel, the grinding wheel repair result determining apparatus according to the ninth aspect of the present invention determines the amplitude of the vibration generated in the grinding machine during the grinding operation by an integral multiple of the natural frequency of the grinding machine. Vibration detecting means for detecting a specific frequency of the data, data storage means for storing dressing good / bad judgment data for judging dressing quality in accordance with the amplitude detected by the vibration detecting means, and the detected amplitude and dressing good / bad judgment Dressing quality judgment means for judging the quality of dressing of the whetstone by comparing data with the data.

Therefore, as the sharpness of the grindstone decreases, the amplitude of the vibration of the grinding machine remarkably changes at a specific frequency that is an integral multiple of the natural frequency of the grinding machine. By comparing the amplitude with the dressing quality determination data stored in the data storage means, the dressing quality determination means objectively and accurately recognizes the quality of the dressing.

An automatic whetstone repairing device according to a tenth aspect of the present invention comprises:
Vibration detecting means for detecting the amplitude of the vibration generated in the grinding machine during the grinding operation for each specific frequency which is an integral multiple of the natural frequency of the grinding machine; and determining a dressing time corresponding to the amplitude detected by the vibration detecting means. Data storage means in which dressing time determination data is stored, dressing time determination means for comparing the detected amplitude and dressing time determination data to determine the dressing time of the grinding wheel,
Dressing driving means for driving the dressing device when the dressing time is determined. Therefore, as the sharpness of the grindstone decreases, the amplitude of the vibration of the grinding machine changes remarkably at a specific frequency that is an integral multiple of the natural frequency of the grinding machine, and the amplitude of the vibration of the grinding machine detected by the vibration detection means, The dressing time determination means compares the dressing time determination data stored in the data storage means with the dressing time determination data, whereby the dressing time is objectively and accurately recognized. Based on this recognition, the dressing driving means drives the dressing device.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the drawings. In the present embodiment, truing will be mainly described. First, a main mechanical configuration and an electronic circuit of the grinding machine will be described with reference to FIG. 1 is a grinding wheel head. The grindstone head 1 has a main shaft 2 driven by a motor (not shown). A grindstone (hereinafter, described as a wheel in the present embodiment) 3 according to the application is mounted on the main shaft 2. A table 4 is provided below the grindstone head 1 so as to be reciprocated in a direction perpendicular to the plane of the drawing, and a jig 6 for supporting a workpiece 5 is provided on the table 4.
Is fixedly mounted.

The grindstone head 1 is provided with a pickup 7 for detecting the vibration of the main shaft 2, and a vibration detecting means 8 for detecting the amplitude of the vibration of the main shaft 2 according to the output of the pickup 7. In the truing detection mode, the vibration detecting means 8 detects the amplitude of the vibration generated in the grinding machine at the time of the grinding operation for each specific frequency which is an integral multiple of the rotation frequency of the wheel 3 mounted on the main shaft 2, and in the dressing detection mode. The amplitude of the vibration generated in the grinding machine during the grinding operation is detected for each specific frequency that is an integral multiple of the natural frequency of the grinding machine.

The output side of the vibration detecting means 8 is connected to a control circuit 9
It is connected to the. The control circuit 9 includes a ROM 10 in which fixed data such as a program is written, a CPU 11 that monitors the operation state of each unit and controls the operation of each unit based on the program, and a RAM 12 that temporarily stores variable data.
And the like.

In the present embodiment, the RAM 12 stores truing timing data for judging truing timing, truing pass / fail judgment data for judging truing quality, dressing timing judgment data for judging dressing timing, and dressing for judging dressing quality. It functions as data storage means for storing designated data such as pass / fail judgment data. In this case, the truing timing determination data and the truing pass / fail determination data are stored in correspondence with the specified frequency of the specific frequency that is an integral multiple of the rotation frequency of the wheel 3 to be used, and the dressing timing determination data and the dressing pass / fail determination data are stored. Is stored in correspondence with a specified frequency among specific frequencies that are integral multiples of the natural frequency of the grinding machine.

The CPU 11 also stores these data,
Truing timing determining means for determining the truing timing of the wheel 3 by comparing the amplitude of the vibration detected by the vibration detecting means 8, truing quality determining means for determining the truing quality of the wheel 3, dressing of the wheel 3. It functions as dressing timing determining means for determining the timing, and dressing quality determining means for determining the quality of the dressing of the wheel 3.

The CPU 11 includes a drive circuit 14 (truing driving means) for driving the truing device 13 when the CPU 11 (truing time determining means) determines that it is the truing time, and the CPU 1
A drive circuit 16 (dressing drive means) for driving the dressing device 15 when it is determined by 1 (dressing time determination means) that it is the dressing time of the wheel 3.
And the warning means 17 are connected. This warning means 1
Numeral 7 warns the operator of the truing and dressing conditions.

In such a configuration, the cutting depth of the wheel 3 with respect to the workpiece 5 is set, the main shaft 3 is driven to rotate the wheel 3, and the table 4 is reciprocated, whereby the workpiece 5 is ground. . The amplitude of the vibration generated on the main shaft 2 during the grinding is detected by the vibration detecting means 8. In this case, the amplitude of the detected vibration changes depending on the runout and sharpness of the outer periphery of the wheel 3.

Theoretically and according to the results of the embodiments described later, as the run-out of the wheel 3 increases, the amplitude of the vibration of the grinding machine changes significantly at a specific frequency which is an integral multiple of the rotational frequency of the wheel 3. That has been confirmed. Therefore, the grinding machine (spindle 2) detected by the vibration detecting means 8
The CPU 11 (truing timing determining means) compares the amplitude of the vibration with the truing timing determining data stored in the RAM 12 (data storing means), whereby the truing timing is objectively and accurately recognized.

When it is determined that it is the truing time, the state is warned by the warning means,
The drive circuit 14 (truing driving means) drives the truing device 13 (for example, a vertical rotary dresser). Thereby, the truing of the wheel 3 can be performed automatically.

Further, as described above, as the run-out of the wheel 3 increases, the amplitude of the vibration of the grinding machine (main shaft 2) remarkably changes at a specific frequency that is an integral multiple of the rotational frequency of the wheel 3. The amplitude of the vibration of the grinding machine detected by the means 8 and the truing quality determination data stored in the RAM 12 (data storage means) are stored in the CPU 11.
(Truing quality judgment means)
The truing quality can be objectively and accurately recognized.

[0030]

Here, experimental results regarding truing which proves the above-described effects will be described. The experimental conditions are as follows.

Machine used NC surface grinder (using rolling bearings) Static rigidity of main shaft 27.7 N / μm Dynamic rigidity of main shaft 4.3 N / μm Wheel specifications Metal bond wheel (SD140N100M) 200 mm in diameter, 10 mm in thickness Grinding condition Wheel peripheral speed 25 m / sec table speed 0.13 m / sec cutting depth 10 [mu] m / stroke cutting fluid Soryuburu workpiece Si ₃ N ₄ length 100 mm, the peripheral speed 12.5 m / sec wheel circumferential width 5mm truing Vertical rotary dresser dresser grindstone GC60H dresser grindstone Speed 12.5 m / sec Feeding speed 0.006 m / sec Depth of cut 5 μm / 3 pass Under the above-mentioned grinding conditions, vibration detecting means 8
The amplitude of vibration (unit μm) of the grinding machine detected by
2 (a) to 2 (d) show the relationship with the deflection of the wheel 3. FIG. In each figure, the vibration of the main shaft 2 in a certain time period is sampled, and the amplitude of each specific frequency which is an integral multiple of the rotation frequency of the wheel 3 is represented from the sampled data. As the wheel 3 used in the experiment, a wheel whose peripheral run-out was previously set to 30 μm, 15 μm, 5 μm, and 2 μm was used. FIG. 2A shows that the runout of the wheel 3 is 30 μm.
In the case of, the result of FIG.
In the case of m, the result of FIG.
In the case of m, the result of FIG.
This corresponds to the case of m.

As a result, it is understood that the amplitude of the main shaft 2 is proportional to the magnitude of the runout on the outer periphery of the wheel 3. The rotation frequency of the wheel 3 is 40 rps calculated from the peripheral speed of 25 m / sec, and the rotation frequency of the wheel 3 (40
(rps, 40 Hz), it can be seen that the change in the amplitude for each specific frequency that is an integral multiple of 40 Hz is large.

As described above, as the run-out of the wheel 3 increases, the amplitude of the vibration of the grinding machine (spindle 2) increases.
The CPU 11 compares the amplitude of the vibration of the grinding machine detected by the vibration detecting means 8 with the truing timing determination data stored in the RAM 12 so that the truing is performed. Is accurately and objectively recognized.

As shown in FIG. 2, the frequency at which the amplitude of the main shaft 2 remarkably changes as the deflection of the wheel 3 increases is 80 Hz, which is twice the rotation frequency (40 Hz) of the wheel 3. Therefore, paying attention to the change of the spectrum level of 80 Hz, the wheel 3 during the truing is changed.
The magnitude of the spectrum level was measured for each cutting depth of 100 μm of the dressing grindstone (not shown) with respect to. The result is shown in FIG. According to this result, the spectrum level is such that the deflection of the wheel 3 is from 30 μm to 20 μm.
No significant change was observed up to
When it is less than m, the temperature rapidly decreases. Therefore, based on the spectrum level (amplitude of the spindle 2) at this time, R
The truing pass / fail judgment data stored in the AM 12 is set.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, dressing will be described. The description of the same portions as those described in the previous embodiment will be omitted.

As described above, the run-out of the wheel 3 can be corrected by truing. However, even if the run-out of the wheel 3 is corrected, the grinding from the surface of the wheel 3 is performed as in the case of a super-abrasive wheel. When the amount of protrusion of the grains is small and the chip pockets on the surface are clogged with chips, the sharpness is reduced. In particular, for example, in the grinding of highly brittle materials such as fine ceramics, a decrease in the sharpness of the wheel 3 is associated with an increase in grinding resistance, which may cause chipping on the surface of the workpiece 5 or breakage of the workpiece 5. Become.

Theoretically and according to the results of the embodiments described later, as the sharpness of the wheel 3 decreases, the amplitude of the vibration of the grinding machine (spindle 2) becomes an integral multiple of the frequency of the natural frequency of the grinding machine. It has been confirmed that the frequency significantly changes at a specific frequency. For this reason, during the grinding process, the amplitude of the vibration of the grinding machine (spindle 2) detected by the vibration detecting means 8 and R
By comparing the dressing timing determination data stored in the AM 12 (data storage means) with the CPU 11 (dressing timing determination means), the dressing timing is objectively and accurately recognized.

When it is determined that it is the dressing time, the drive circuit 16 (dressing driving means) drives the dressing device 15 (for example, a twin electrode electrolytic dresser). Thereby, the wheel 3 can be dressed automatically.

Further, as described above, as the run-out of the wheel 3 increases, the amplitude of the vibration of the grinding machine (main shaft 2) remarkably changes at a specific frequency that is an integral multiple of the natural frequency of the grinding machine. The CPU 11 (dressing quality determination means) compares the amplitude of the vibration of the grinding machine detected by the detection means 8 with the dressing quality determination data stored in the RAM 12 (data storage means) to objectively determine the quality of the dressing. Can be accurately recognized.

[0040]

Here, experimental results regarding dressing which prove the above-described effects will be described. The experimental conditions are as follows.

Machine used NC surface grinding machine (using rolling bearings) Static rigidity of main shaft 27.7 N / μm Dynamic rigidity of main shaft 4.3 N / μm Wheel specification Metal bond wheel (SD140N100M) Diameter 200 mm, thickness 10 mm Grinding condition Wheel peripheral speed 30 m / Sec Table speed 0.13m / sec Depth of cut 100μm / stroke Cutting fluid Soluble Workpiece Si ₃ N ₄ Length 100mm, width 5mm Dressing Twin electrode electrolytic dresser Voltage 50V (DC) Gap 0.1mm Electrolyte 30 times dilution Electrolysis Under the above-mentioned grinding conditions, the vibration detecting means 8
The amplitude of vibration (unit μm) of the grinding machine detected by
4 (a) to 4 (d) show the relationship with the grinding amount. In each figure, the vibration of the main spindle 2 in a certain time zone is sampled, and the amplitude of each specific frequency which is an integral multiple of the natural frequency of the main spindle 2 is represented from the sampling data. FIG.
FIG. 4B shows the result of FIG. 4B when the grinding amount per unit width of the grindstone (wheel) 3 reaches 0.5 mm ³ / mm.
Is that when the grinding amount reaches 1400 mm ³ / mm,
Figure 4 (c) if the result of the grinding amount reaches 2450 mm ³ / mm, 4 results grinding amount (d) is 3500 mm ³
/ Mm.

As a result, it is understood that the amplitude of the spindle 2 is proportional to the grinding amount. In this example, the specific frequency of the natural frequency of the grinding machine is 800 Hz in the low frequency component and 5.6 kHz in the high frequency component which is seven times that of the low frequency component, and the amplitude of the main shaft 2 at 800 Hz and the 5.6 kHz A remarkable change was observed in the amplitude of the main shaft 2.

Therefore, focusing on the spectrum levels at the natural vibration frequencies of 800 Hz and 5.6 kHz,
The relationship between the spectrum level and the grinding amount will be discussed based on FIG. Regarding the spectrum level of 5.6 kHz, the level is high during the period when the grinding amount is small (initial grinding after dressing), but gradually decreases as the grinding amount increases. On the other hand, the spectrum level at 800 Hz is low when the grinding amount is small, shows a high level as the grinding amount increases, and rapidly increases when the grinding amount reaches 2450 mm ³ / mm. . Therefore, at this point, it is determined that the amplitude of the vibration generated on the main shaft 2 is dominated by the low frequency component (800 Hz) of the natural vibration frequency of the grinding machine. Therefore, with a clear increase in the spectrum level at 800 Hz, the grinding amount is 2450 mm ³ / mm.
Can be determined that the wheel 3 has reached the dressing time. Further, at the time when the spectrum level of 800 Hz increases, 5.6 kHz
, The dressing time can be determined by the change in the spectrum level of 5.6 kHz.

As is clear from the above results, the amplitude of the vibration generated on the main spindle 2 is detected to measure the change in the spectrum level of the natural vibration frequency of the test grinding machine, so that the grinding process is performed (in-process). The dressing time of the wheel 3 can be recognized.

Here, the cause of the difference in the vibration generation phenomenon in the main shaft 2 will be considered. The vibration of the main shaft 2 described so far is caused by the wheel 3 being moved by the workpiece 5 as shown in FIG.
At the point C in the center of FIG. In this case, the state where the wheel 3 has reached the point C is detected by a proximity sensor (not shown) provided on the table 4, and the detection signal is used as a trigger to detect the vibration of the main shaft 2. Therefore,
The wheels 3 are each 5 mm from the end of the workpiece 5 and 25
mm, 50 mm apart, points A, B, and C are detected by the proximity sensor, and the detection signal is used as a trigger to detect the main spindle 2
7 (a) to 7 (a) to 7 (c) show the differences in the amplitude of
(C) and FIGS. 8 (a) to 8 (c).

FIG. 7 shows the amplitude of the spindle 2 at the start of grinding when the grinding amount is as small as 0.5 mm ³ / mm. FIG. 7A shows the measurement result at point A, and FIG. As a result, (c) is a measurement result at point C. According to this result, even if the grinding amount is as small as 0.5 mm ³ / mm, at point A, as in the case where the grinding amount increases,
The amplitude at 00 Hz increases, and a high level of 800 Hz and 5.6 kHz is detected at point B as at point C.

FIG. 8 shows the amplitude of the spindle 2 when the grinding amount increased to 1400 mm ³ / mm. FIG. 8A shows the measurement result at the point A, FIG. 8B shows the measurement result at the point B, and FIG. c) is the measurement result at point C. According to this result, at points A and B, the amplitude at 800 Hz increases, and at point C, the amplitude at 5.6 kHz increases.

From the above results, even at the start of grinding after dressing has been performed well, 800
It can be seen that the amplitude of the main shaft 2 in Hz exceeds a certain level, and at point C, the amplitude at 800 Hz decreases and the amplitude at 5.6 kHz is dominant.

Therefore, when determining the dressing timing and the quality of the dressing described later, the timing for detecting the vibration of the spindle 2 (the wheel 3 on the workpiece 5).
Position).

As described above, when it is determined that the dressing time has been reached, dressing is performed by a dressing device (twin electrode electrolytic dressing). The determination of the quality of the result will be described. This determination is made by grinding the workpiece 5 with the wheel 3 after dressing, the amplitude of the vibration of the main shaft 2 generated at that time (the amplitude at a specific frequency which is an integral multiple of the natural frequency of the grinding machine), and the RA as described above.
This is performed by comparing the dressing quality determination data stored in M12 (see FIG. 1).

First, when the dressing time has been reached, the change in the amplitude of the vibration of the main shaft 2 during the grinding process in which the depth of cut into the workpiece 5 is changed to 5 μm, 10 μm, and 15 μm using the wheel 3 which has not been dressed is performed. 9 (a) and 9 (b)
As shown in (c), using the wheel 3 after dressing, the depth of cut into the workpiece 5 was 5 μm, 10 μm, and 15 μm.
FIGS. 10A, 10B, and 10C show changes in the amplitude of vibration of the main shaft 2 during the grinding process. In each figure, the vibration of the main spindle 2 in a certain time zone is sampled, and the amplitude of each specific frequency which is an integral multiple of the natural frequency of the main spindle 2 is represented from the sampling data.

From the results of FIGS. 9A, 9B and 9C,
When grinding is performed using the wheel 3 on which dressing has not been performed, the low frequency component 800 Hz
Is large, and the amplitude at a high frequency component of 5.6 kHz is small. On the other hand, from the results of FIGS. 10 (a), (b) and (c), when grinding is performed using the wheel 3 after dressing, the amplitude at 800 Hz has a low level,
The level of the amplitude of 5.6 kHz is high. In addition, the amplitude of the main shaft 2 increases as the cutting depth increases. FIG.
It is clear from FIG. 10 that the low frequency component 800 Hz
Is large, and the amplitude at a high frequency component of 5.6 kHz is small. Conversely, when grinding with a good wheel 3 after dressing, the amplitude of the main shaft 2 at a low frequency component of 800 Hz is small, and the amplitude at a high frequency component of 5.6 kHz is large. Therefore, the amplitude of the vibration of the main shaft 2 at least at 800 Hz is detected, and the detection result is stored in the RAM 12.
The quality of the dressing can be objectively and accurately determined by comparing with the dressing quality determination data set in.

As described above, the wheel 3 used is a diamond wheel, and the bond for solidifying the diamond abrasive grains is a metal bond. Experiments have shown that the frequency at which the amplitude of the main shaft 2 changes significantly also changes depending on what the bond is required for. As an example, an experimental result when a resin bond wheel is used as the wheel 3 will be described. The experimental conditions are as follows.

Wheel Specifications Resin bond wheel (SD140N100B) Diameter 200 mm, thickness 10 mm Grinding conditions Wheel peripheral speed 30 m / sec Table speed 0.13 m / sec Cutting depth 10 μm / stroke Cutting fluid Soluble Workpiece Si ₃ N ₄ Length 100 mm , Width 5mm Dressing Vertical rotary dresser Dresser grindstone WA150G Peripheral speed of dresser grindstone 12.5m / sec Wheel peripheral speed 12.5m / sec Feed speed 0.006m / sec Depth of cut 5μm / 3pass Total cutting depth 400μm In the above grinding conditions Vibration detecting means 8 during the grinding process
The amplitude of vibration (unit μm) of the grinding machine detected by
FIGS. 11A to 11D show the relationship with the grinding amount.
In each figure, the vibration of the main spindle 2 in a certain time zone is sampled, and the amplitude of each specific frequency which is an integral multiple of the natural frequency of the main spindle 2 is represented from the sampling data. Results of the measured amplitude, FIG. (A) grinding amount 0.3 mm ³
/ B, (b) grinding amount 700 mm ³ / mm, (c) grinding amount 1225 mm ³ / mm, (d) grinding amount 1750
mm ³ / mm.

As apparent from FIG. 11, when the grinding is started by the wheel 3 after the dressing, also in this example, the amplitude of the spindle 2 is small at the start of the grinding and increases as the grinding amount increases. . Looking at the results of the frequency analysis, 3.2 kHz and 1.6 kHz were obtained in the initial stage of grinding (grinding amount: 0.3 mm ³ / mm).
It can be seen that the amplitude of the main shaft 2 at z is significantly detected. Then, as the grinding amount increases, 3.2 kHz
, The amplitude of the main shaft 2 tends to decrease, the amplitude of 1.6 kHz is detected at substantially the same level, and the amplitude of 800 Hz shows a high value. Thus, even when the resin bond wheel is used as the wheel 3, the grinding amount is 175.
It can be seen that at the point of time when it increases to 0 mm ³ / mm, the amplitude of the low frequency component 800 Hz of the natural vibration frequency of the grinding machine is detected at a high level.

As described in the previous embodiment, when the metal bond wheel was used, the amplitude at 800 Hz and 5.6 kHz was detected. However, when the resin bond wheel was used as in this embodiment, The amplitudes at 800 Hz and 3.2 kHz were detected, and there was a difference in the appearance of the amplitude of the high frequency component. This is thought to be due to the difference in contact stiffness, etc., which depends on the mechanical properties of the bond that solidifies the diamond abrasive grains. Incidentally, it was evident from experiments that the frequency at which the amplitude was detected did not change even when the peripheral speed of the wheel 3 was changed.

Next, as the wheel 3, the particle size is set to # 23.
FIG. 12 and FIG. 13 show the results of experiments on the generation of vibration when using a resin bond wheel changed to 0 and # 400.
Shown in This experiment also detects the frequency at which the main shaft 2 vibrates during grinding. The peripheral speed of the wheel 3 is 30 m / sec, the speed of the table 6 is 0.13 m / sec,
The cutting depth is 6 μm / stro for wheel 3 of # 230.
ke, 4 μm / stroke for wheel # 400.

Under these grinding conditions, the relationship between the amplitude (unit: μm) of the vibration of the grinding machine detected by the vibration detecting means 8 during the grinding and the amount of grinding is shown in FIGS. (A) and (b). In each figure, the vibration of the main spindle 2 in a certain time zone is sampled, and the amplitude of each specific frequency which is an integral multiple of the natural frequency of the main spindle 2 is represented from the sampling data. FIG. 12 shows a wheel 3 having a grain size of # 230, and FIG. 12 (a) shows a grinding amount of 0.18 mm ³ /
mm, the amplitude is reached, and FIG.
The state of occurrence of the amplitude when it reaches 0 mm ³ / mm is shown. FIG. 13 shows a wheel 3 having a grain size of # 400. FIG. 13A shows the occurrence of amplitude when the grinding amount reaches 0.12 mm ³ / mm, and FIG. 13B shows the case where the grinding amount reaches 440 mm ³ / mm. The state of occurrence of the amplitude is shown.

When grinding is performed using the wheel 3 having a grain size of # 230, as can be seen from the results in FIG. 12, at the start of grinding (grinding amount 0.18 mm ³ / mm), 3.2 kHz, 1.6 kHz.
The amplitude of z appears remarkably, and when the grinding amount increases to 660 mm ³ / mm, the amplitude of 3.2 kHz decreases and 1.6 kHz.
It can be seen that the amplitude at 800 Hz appears at a high level.

When grinding is performed using the wheel 3 having a grain size of # 440, as can be seen from the results of FIG. 13, at the start of grinding (grinding amount 0.12 mm ³ / mm), an amplitude of 3.2 kHz appears at a high level. The level of amplitude at lower frequencies is low. When the grinding amount increases to 440 mm ³ / mm, 3.2
It can be seen that the amplitude of kHz decreases and the amplitude of 1.6 kHz, which did not appear remarkably in the initial stage of grinding, appears at a high level. When the grinding is performed using the wheel 3 having the grain size of # 440, unlike the previous experiments, the frequency that remarkably appears with the increase in the grinding amount is not 800 Hz, but 1.6 times twice that frequency.

However, as can be seen from previous experiments,
Even if the type of the wheel 3 is different, it can be said in common that the detected amplitude is detected for each specific frequency that is an integral multiple of the natural frequency of the grinding machine. Therefore, the timing of dressing, the quality of the dressing is determined by the detection result. Is considered appropriate.

[0062]

According to the first and second aspects of the present invention, the amplitude of the vibration generated in the grinding machine during the grinding operation is detected for each specific frequency which is an integral multiple of the rotation frequency of the grinding wheel mounted on the spindle, and the detected amplitude is determined. The truing time of the grindstone is determined by comparing the specified truing time determination data.As the wobble of the grindstone increases, the amplitude of the vibration of the grinder becomes a specific frequency that is an integral multiple of the rotation frequency of the grindstone. Truing timing is objectively determined by comparing the amplitude of the vibration of the grinding machine detected by the vibration detecting means with the truing timing determination data stored in the data storage means. Can be accurately recognized.

According to the third and fourth aspects of the present invention, the amplitude of the vibration generated in the grinding machine during the grinding operation is detected for each specific frequency which is an integral multiple of the rotation frequency of the grinding wheel mounted on the spindle, and the detected amplitude is designated. Since the quality of the truing of the grindstone was determined by comparing the truing good / bad judgment data, the amplitude of the vibration of the grinding machine is increased at a specific frequency that is an integral multiple of the rotation frequency of the grindstone as the deflection of the grindstone increases. Since the truing quality changes significantly, the truing quality determination means compares the amplitude of the vibration of the grinding machine detected by the vibration detection means with the truing quality determination data stored in the data storage means, thereby objectively determining the quality of the truing. Accurate recognition is possible.

According to the fifth aspect of the present invention, the truing device is driven by the truing drive means when the truing timing is recognized, so that the truing can be automatically performed when the truing timing is reached. Operability can be improved.

According to the invention of claims 6 and 7, the amplitude of the vibration generated in the grinding machine during the grinding operation is detected for each specific frequency which is an integral multiple of the specific frequency of the natural frequency of the grinding machine, and the detected amplitude and Since the dressing time of the grindstone is determined by comparing it with the specified dressing time determination data, as the sharpness of the grindstone decreases, the amplitude of the vibration of the grinder is specified as an integral multiple of the natural frequency of the grinder. Since the frequency significantly changes, the dressing time determination means compares the amplitude of the vibration of the grinding machine detected by the vibration detection means with the dressing time determination data stored in the data storage means, so that the dressing time can be objectively determined. It can be recognized with high accuracy.

According to the eighth and ninth aspects of the invention, the amplitude of the vibration generated in the grinding machine during the grinding operation is detected for each specific frequency that is an integral multiple of the specific frequency of the natural frequency of the grinding machine, and the detected amplitude and Since the quality of the dressing of the grindstone was determined by comparing it with the specified dressing pass / fail judgment data, as the sharpness of the grindstone decreases, the amplitude of the vibration of the grinder becomes an integral multiple of the natural frequency of the grinder. The dressing quality is significantly changed at the specific frequency, so that the dressing quality is compared by the dressing quality determination means comparing the amplitude of the vibration of the grinding machine detected by the vibration detection means with the dressing quality determination data stored in the data storage means. It can be objectively and accurately recognized.

According to the tenth aspect of the present invention, the dressing device is driven by the dressing driving means when the dressing time is recognized, so that the dressing can be automatically performed when the dressing time has been reached. Operability can be improved.

[Brief description of the drawings]

FIG. 1, showing a first embodiment of the present invention, is an explanatory diagram showing a main mechanical configuration of a grinding machine and an electronic circuit.

FIG. 2 shows an example according to the first embodiment of the present invention, and is a graph showing the relationship between wheel runout and vibration of a grinding machine through experiments.

FIG. 3 is a graph showing a relationship between a wheel runout and a spectrum level at 800 Hz.

FIG. 4 shows an example according to the second embodiment of the present invention, and is a graph showing an experiment showing a relationship between a grinding amount and a vibration of a grinding machine when performing grinding using a metal bond wheel. is there.

FIG. 5 is a graph showing the relationship between the grinding amount and the spectrum level by an experiment.

FIG. 6 is an explanatory diagram showing a position where a wheel contacts a workpiece.

FIG. 7 is a graph showing experimentally the relationship between the grinding amount and the vibration of the grinding machine when the position where the wheel contacts the workpiece is changed.

FIG. 8 is a graph showing experimentally the relationship between the grinding amount and the vibration of the grinding machine when the position where the wheel contacts the workpiece is changed.

FIG. 9 is a graph showing experimentally the relationship between the depth of cut and the vibration of the grinding machine when grinding is performed with a wheel that has not been dressed.

FIG. 10 is a graph showing the relationship between the depth of cut and the vibration of the grinder when grinding with a wheel after dressing is performed by experiment.

FIG. 11 is a graph showing experimentally the relationship between the grinding amount and the vibration of the grinding machine when grinding is performed using a resin bond wheel.

FIG. 12 is a graph showing experimentally the relationship between the grinding amount and the vibration of a grinding machine when grinding is performed using a resin bond wheel having a particle size of # 230.

FIG. 13 is a graph showing experimentally the relationship between the amount of grinding and the vibration of the grinding machine when grinding is performed using a resin bond wheel having a grain size of # 400.

[Explanation of symbols]

2 Spindle 3 Grinding wheel 8 Vibration detecting means 11 Truing timing determining means, Truing good / bad determining means Dressing timing determining means, Dressing good / bad determining means 12 Data storage means 13 Truing device 14 Truing driving means 15 Dressing device 16 Dressing driving means

Claims (10)

[Claims] An amplitude of vibration generated in a grinding machine during a grinding operation is detected for each specific frequency that is an integral multiple of a rotation frequency of a grinding wheel mounted on a spindle, and the detected amplitude is compared with designated truing timing determination data. And determining a truing time of the grinding wheel. 2. A vibration detecting means for detecting an amplitude of vibration generated in a grinding machine during a grinding operation for each specific frequency which is an integral multiple of a rotation frequency of a grindstone mounted on a spindle of the grinding machine, and the vibration detecting means detects the amplitude. Truing time determination data for determining the truing time corresponding to the amplitude, and a truing time determination means for comparing the detected amplitude and the truing time determination data to determine the truing time of the grinding wheel. A grindstone repair time judging device characterized by comprising: 3. The amplitude of a vibration generated in a grinding machine during a grinding operation is detected for each specific frequency that is an integral multiple of the rotation frequency of a grinding wheel mounted on a spindle, and the detected amplitude is compared with designated truing pass / fail judgment data. Determining whether the truing of the whetstone is good or not. 4. A vibration detecting means for detecting an amplitude of a vibration generated in a grinding machine during a grinding operation for each specific frequency which is an integral multiple of a rotation frequency of a grindstone mounted on a main shaft of the grinding machine, and the vibration detecting means detects the amplitude. Truing quality determination data for storing truing quality determination data for determining the quality of truing in accordance with the amplitude, and truing quality determination for comparing the detected amplitude with the truing quality determination data to determine the truing quality of the grinding wheel. Means for determining a wheel repair result. 5. A vibration detecting means for detecting an amplitude of vibration generated in a grinding machine during a grinding operation for each specific frequency which is an integral multiple of a rotation frequency of a grindstone mounted on a spindle of the grinding machine, and the vibration detecting means detects the amplitude. Truing time determination data for determining the truing time corresponding to the amplitude, and a truing time determination means for comparing the detected amplitude and the truing time determination data to determine the truing time of the grinding wheel. Truing drive means for driving a truing device when a truing time is determined. 6. The amplitude of a vibration generated in a grinding machine during a grinding operation is detected for each specific frequency that is an integral multiple of the natural frequency of the grinding machine, and the detected amplitude is compared with designated dressing time determination data. A dressing time of the grinding wheel is determined by using the method. 7. A vibration detecting means for detecting the amplitude of vibration generated in a grinding machine at the time of a grinding operation for each specific frequency which is an integral multiple of the natural frequency of the grinding machine, and corresponding to the amplitude detected by the vibration detecting means. It is provided with data storage means in which dressing time determination data for determining dressing time is stored, and dressing time determination means for comparing the detected amplitude with the dressing time determination data to determine the dressing time of the grinding wheel. Characteristic whetstone repair time determination device. 8. An amplitude of vibration generated in a grinding machine during a grinding operation is detected for each specific frequency which is an integral multiple of a natural frequency of the grinding machine, and the detected amplitude is compared with designated dressing pass / fail judgment data. Determining whether the dressing of the whetstone is good or not. 9. A vibration detecting means for detecting the amplitude of vibration generated in a grinding machine during a grinding operation for each specific frequency which is an integral multiple of the natural frequency of the grinding machine, and corresponding to the amplitude detected by the vibration detecting means. A dressing unit for storing dressing quality determination data for determining dressing quality; and a dressing quality determination unit for comparing the detected amplitude with the dressing quality determination data to determine the dressing quality of the grindstone. A grindstone repair result determining device. 10. A vibration detecting means for detecting the amplitude of vibration generated in a grinding machine at the time of grinding operation for each specific frequency which is an integral multiple of the natural frequency of the grinding machine, and corresponding to the amplitude detected by the vibration detecting means. Data storage means for storing dressing time determination data for determining the dressing time; dressing time determination means for comparing the detected amplitude with the dressing time determination data to determine the dressing time of the grinding wheel; and determining the dressing time. And a dressing driving means for driving the dressing device when the operation is completed.