JPH02256461A - Abrasion detecting device for grindstone and abrasion detecting method - Google Patents

Abstract

PURPOSE:To early detect the abrasion of a grindstone and prevent the grinding by the defective grindstone by judging the abrasion quantity of the grindstone of a grinding machine based on the vibration generated at various sections of the grinding machine during the machining of a work. CONSTITUTION:The vibration along the main component force of grinding resistance within the vibration generated at various sections of a grinding machine during the machining of a work is detected by the first vibration means 2. The vibration in the direction along the back component force of grinding resistance within the vibration is detected by the second vibration means 3. The abrasion quantity of the grindstone of the grinding machine is judged by a judging means 10 based on the vibration quantity detected by the detecting means 2 and 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a grindstone wear detection device and a wear detection method.

[Prior Art] Generally, when abrasion, clogging, or cracking (hereinafter collectively referred to as abrasion) occurs in the grinding wheel of a grinding machine, it adversely affects the machined surface of the workpiece. Conventionally, operators have judged tool wear based on the workpiece after machining, and when the workpiece surface becomes rough or grinding burns occur, or when the actual workpiece dimensions change with respect to the depth of cut during grinding. When the grinding wheel is low, it is determined that the grinding wheel is worn out, and the grinding wheel is dressed or replaced.

[Problem to be solved by the invention] However, not only does it require considerable skill to carry out the method described in the above 2, but it is also difficult to judge whether the grinding wheel is wearing out unless it progresses to the point where it adversely affects the workpiece surface. Can not do it. Therefore, by the time the operator grasps the situation and deals with it, there is a problem in that a considerable amount of grinding has already been done with a grindstone that has already progressed in wear.

The above problems occur particularly in the case of unmanned automatic machining, and even though the machining process is automated, the current situation is that it is not possible to automatically control the wear of the grindstone. Therefore, there is a demand for the development of in-process measurement to achieve complete automation and unmanned operation.

The objects of the first and second inventions are to be able to detect wear of a grinding wheel at an early stage without requiring any skill in use, to prevent grinding with a defective grinding wheel, and to provide an infrastructure for unmanned automatic machining. An object of the present invention is to provide a grindstone wear detection device and a grindstone management device that can also handle process measurements.

A third object of the invention is to provide a method for detecting wear of a grindstone, which can detect wear of a grindstone at an early stage without requiring skill in use, and can prevent grinding using a defective grindstone. It is in.

[Means for Solving the Problems 1] The first invention is a first vibration system that detects vibrations in the direction along the principal force of the grinding resistance among the vibrations generated in each part of the grinding machine as the workpiece is processed. The detection means, a second vibration detection means for detecting vibrations in the direction along the thrust force of the grinding resistance among the vibrations generated in each part of the grinding machine as the workpiece is processed; The gist of the present invention is to detect wear of a grindstone Hf1f, which is equipped with a determining means for determining the amount of wear of a grinding wheel of a grinding machine based on the amount of vibration indicated by the second vibration detecting means.

The second invention includes a first vibration detection means for detecting vibrations in a direction along the principal force of the grinding resistance among vibrations generated in each part of the grinding machine as the workpiece is processed; A second vibration detection means detects vibrations in the direction along the thrust force of the grinding resistance among the vibrations generated in each part of the grinding machine due to the a first determination means for determining the amount of wear of the grinding wheel of the grinding machine based on the amount of wear of the grinding wheel of the grinding machine based on the amount of vibration indicated by the first vibration detection means and/or the second vibration detection means; a second determination means for determining the balance state of the grindstone; and a display means for displaying the wear amount of the grindstone determined by the first determination means and the balance state of the grindstone determined by the second determination means. The gist of this is a grindstone management device.

The gist of the third invention is a grindstone wear detection method for determining the amount of wear on the grindstone of a grinding machine based on the vibrations generated in various parts of the grinding machine as the workpiece is processed.

[Function] In the first invention, when the grindstone is worn and becomes dull, the main force of the grinding resistance decreases and the thrust force increases. Of the vibrations generated in each part of the grinding machine during machining, as the principal force decreases, the amount of vibration in the direction along this force decreases, and as the back force increases, the amount of vibration in the direction along this force decreases. The amount increases. The amount of vibration in each direction is detected by the first and second vibration detection means, and the determining means determines the amount of wear of the grindstone based on the detected amount of vibration.

In the second invention, the first determination means determines the wear amount of the grindstone in the same way as in the first invention. In addition, the second determination means determines the balance state of the grindstone based on the vibration ω indicated by at least one of the detection signals from the first and second vibration detection means, and performs this determination. The display means displays the value. Further, the display means also displays the wear amount of the grindstone determined by the first determination means. The user can easily grasp the current amount of wear and balance of the grindstone by means of the display means.

In the third invention, the vibrations generated in each part of the grinding machine due to processing of the workpiece change depending on the amount of wear of the grinding wheel that is performing the grinding. Therefore, the amount of wear on the grindstone can be determined based on the vibrations generated in the grinder.

[Embodiment] Hereinafter, a first embodiment of the present invention in which the present invention is embodied in a display device for displaying the wear amount of a grindstone will be described with reference to FIGS. 1 to 5.

As shown in Fig. 1.2, a lateral acceleration pickup 2 as a first vibration detection means is attached to the right side of the spindle head 1 of the grinding machine. As shown, only the horizontal vibration of the spindle head 1 is detected. Further, a vertical acceleration pickup 3 as a second vibration detection means is attached to the upper surface of the spindle head 1, and due to its directional characteristics, the pickup 3 detects vibrations in the vertical direction of the spindle head 1 as shown by arrows. It is designed to detect only . A rotation speed sensor 6 is installed inside the motor 5 for driving the main shaft 4 on which the grindstone 4a is attached, and detects the rotation of the motor 5.

A display panel 7 to which both the acceleration pickups 2 and 3 and the rotation speed sensor 6 are connected includes a display section 7 composed of an LED.
A is provided below the display section 7a, a grindstone designation dial 8 for specifying the type of the grindstone 4a whose wear amount is to be measured, a power switch 9, and a grinding wheel 8 for specifying the type of grindstone 4a whose wear amount is to be measured, a power switch 9, and the grinding wheel 4a that is grinding the workpiece W. A measurement instruction button 14 for indicating the time is provided.

As shown in FIG. 3, a central processing unit (hereinafter referred to as CPU) 1 is installed in the display panel 7 and serves as a determination means.
0 is connected to the rotation speed sensor 6, and both acceleration pickups 2 and 3 are connected via a bandpass filter 11. Further, the display section 7a of the display panel 7 is connected to the CPU10 via the display section drive circuit 15, and a grindstone designation dial 8 and a measurement command button 14 are also connected thereto, and a random access memory (hereinafter referred to as RAM) 1
2, and a read-only memory 13 (hereinafter referred to as ROM) 13 are connected. The ROM 13 stores a program for determining the wear amount of the grinding wheel 4a based on the vibration of the spindle head 1 during grinding, and the CPLll
o is designed to determine the amount of wear according to this program. Note that the RAM 12 is configured to temporarily store data for processing performed by the CPU 10.

Next, the operation of the grindstone wear display device configured as described above will be described, but before that, it will be explained how the grinding resistance generated during grinding affects the vibration of the grindstone 4a.

As shown in FIG. 4, when the grinding wheel 4a is rotated clockwise to grind the workpiece W, the main component force F1 of the grinding resistance acts to move the grinding wheel 4a to the right, and also the grinding resistance The thrust force F2 acts to move the grindstone 4a upward.

Generally, the ratio of the principal force F1 and back force F2 of the grinding resistance is 1.
:1.5 to 1:2.5, and this value is
It changes as the wear of a progresses.

! J'+i, lt, etc., when grinding at a certain depth of cut is performed and a back force F2 is generated, a principal force F1 is generated according to the amount of wear of the grindstone 4a at this point. For example, as shown by the broken line in FIG. 5, an unused grindstone 4a has good sharpness, so the ratio of the principal force F1 to the back force F2 is large. When the sharpness deteriorates due to wear, the principal force F1 decreases and the thrust force F2 increases, reaching the wear limit shown by hatching in FIG.

On the other hand, when the workpiece W is ground by the grindstone 4a, the countless abrasive grains on the surface layer act as cutting edges, and the workpiece W is ground by the grinding wheel 4a.
This is done by scraping the machined surface into countless chips. When each abrasive grain shaves the workpiece W, vibrations having unspecified directionality occur in the grindstone 4a and the workpiece W.

Among the vibrations in various directions generated in the grindstone 4a and the workpiece W, the amount of vibration in the direction along the principal force F1 is the principal force F1.
1, and the amount of vibration in the direction along the thrust force F2 increases or decreases according to the thrust force F2. Therefore, when the grinding wheel 4a wears out as described above, the amount of vibration in that direction increases as the thrust force F2 increases, and as the principal force F1 decreases, the amount of vibration in that direction decreases. The ratio of vibration t changes.

Therefore, assuming that the above phenomenon occurs,
A case will be described in which the wear of the grindstone 4a is measured using this wear display device.

First, the type of grindstone 4a for measuring the amount of wear is indicated on the display panel 7.
The grinding wheel 4a is used to start grinding a workpiece W of a predetermined material at a predetermined depth of cut, workpiece feed speed, and grindstone rotation speed.
Operate the power switch 9 on the display panel 7 to activate it. Then, the measurement instruction button 14 is pressed during grinding when the workpiece W is being ground by the grindstone 4a as the workpiece W moves back and forth.

Then, the lateral acceleration pickup 2 detects the lateral vibration of the spindle head 1 during grinding, that is, the lateral vibration of the grinding wheel 4a, and the vertical acceleration pickup 3 detects the lateral vibration of the spindle head 1 during grinding. The vibration in the t5 direction, that is, the vibration in the vertical direction of the t5 grindstone 4a is detected. Then, the CPU 10 detects the grindstone 4a detected by the rotation speed detection sensor 6.
The bandpass filter 11 is controlled so that the center frequency is set to the rotational speed of
The ratio of the vibration openings indicated by each of the acceleration pickups 2 and 3 is determined. As mentioned above, since the ratio of the amount of vibration in the principal force F1 direction and the amount of vibration in the back force F2 direction changes as the grinding wheel 4a wears, each of the horizontal and vertical acceleration pickups 2.3 indicates The ratio of swing tlJI is also the grindstone 4a.
It can be assumed that this changes with wear.

Note that the rotational speed of the grindstone 4a changes due to changes in load due to contact and separation with the workpiece W, and the CPU 10 controls the bandpass filter 11 according to this change.
Therefore, horizontal and vertical acceleration pickup 2.3
Among the vibrations of all frequencies detected by the CPU, only the vibrations of a predetermined width of frequencies centered around the rotation speed of the grindstone 4a are always detected by the CPU.
It will be input to io.

The ROM 13 stores, for each grindstone 4a that can be selected with the grindstone designation dial 8, what value the ratio of the above-mentioned vibration amount will be when it is not in use and when it is at the limit of wear, and the CPU 10 Check where the calculated ratio is between the ratio when unused and the ratio at the wear limit stored in the ROM 13, with the ratio when unused being 100% and the ratio at the wear limit being 0%. It is shown as a percentage and displayed on the display section 7a of the display panel 7. For example, if the grindstone is close to the wear limit, a value close to 0% will be displayed, and the user will have to replace the grindstone or perform a predetermined dressing operation.

In addition, as mentioned above, setting the material of the workpiece W, the depth of cut, the workpiece feed speed, and the number of rotations of the grindstone to predetermined values is as follows.
This is because these factors affect the ratio between the principal force F1 and the thrust force F2, causing errors in the judgment results. The reason why this ratio is used differently is because this ratio differs depending on each grindstone 4a.

As described above, according to the grinding wheel wear detection device of this embodiment, since the amount of wear on the grinding wheel 4a is displayed as a numerical value, even an unskilled person can easily judge the wear. Since the ratio of the component force F24 changes sharply according to the wear of the grindstone 4a, it is possible to accurately grasp the wear state of the grindstone in the ninth period.

Therefore, the wear of the grindstone 4a is not noticed too late, and the workpiece W is not continued to be ground with the grindstone 4a which has progressed to wear.

In addition, in the wear display device of this embodiment, out of the vibrations of all frequencies detected by the horizontal and vertical acceleration pickups 2 and 3, the vibration is based only on SvJ of a predetermined range of frequencies centered around the rotational speed of the grindstone 4a. The amount of wear on the grindstone 4a is determined. In general, it has been confirmed that vibrations caused by wear of the grindstone 4a often have frequency components synchronized with the rotation speed of the grindstone 4a, and this embodiment determines the amount of wear of the grindstone 4a based only on such vibrations. This wear display device does not cause errors due to vibrations caused by other factors, and can display the amount of wear more accurately than when the band pass filter 11 is not used.

In this embodiment, the wear detection device of the present invention is embodied as a display device that displays the amount of wear on the grindstone 4a, but the wear detection device of the present invention is not limited to this, and for example,
The present invention is embodied as a wear detection device that determines the amount of wear on a grinding wheel 4a in an NC grinding machine, and the NC grinding machine side automatically takes predetermined measures based on the judgment value of the device, such as notifying a manager with a buzzer, The dressing process may also be executed automatically. With this configuration, the wear condition of the grindstone 4a can be automatically managed, and completely unmanned automatic machining can be achieved.

In addition, in the wear display device of this embodiment, in order to make the determination value of the wear m more accurate, the amount of wear of the band pass filter 11 was determined based only on the vibration caused by the wear of the grindstone 4a obtained at the eaves. However, it is not necessary to use this bandpass filter 11, and even when the bandpass filter 11 is not used, a determination value that is sufficiently accurate for practical purposes can be obtained.

Furthermore, in the wear display device of this embodiment, the cpuio distinguishes between grinding and idle running by pressing the measurement instruction button 14. In addition to normal limit switches, there are also limit switches that detect the position where a moving workpiece contacts the grindstone and the position where the workpiece separates from the grindstone as the workpiece moves back and forth. A limit switch may be provided, and the grinding time may be determined based on whether the limit switch is turned on or off.

Next, a second embodiment of the present invention will be described with reference to FIG. 6.7, in which the present invention is embodied in a magnet management device that displays the wear amount and balance state of the grindstone 4a.

Note that this grindstone management device is a wear display device of the first embodiment with an added function of determining and displaying the unbalanced state of the magnet 4a, so we focused on this added part. Cover the explanation.

As shown in FIG. 6, the motor 5 of the grinding machine is equipped with an origin detection sensor 21 in place of the rotation speed sensor 6 of the first embodiment. The detection signal is output once.

The display panel 7 is provided with a position display section 22 in which a large number of iEDs are arranged in a ring, and in the center of this position display section 22 is a numerical display section for displaying numerical values as in the above-mentioned first addition example. 23 are provided. Further, on the lower side of both display sections 22 and 23, a grindstone designation dial 8, a power switch 9, and a measurement instruction button 14 similar to those in the first embodiment are provided (but are blanked out). In this management device, the position display section 22 and the numerical display section 23 constitute display means.

As shown in FIG. 7, the origin detection sensor 21 is connected to a CPU 10 serving as first and second determination means, and the CPU 10 is connected to the position display section 22 and numerical values via a display drive circuit 15. A display section 23 is connected.

Further, in the ROM 13, a program for determining the unbalanced state of the grinding wheel 4a is stored in the program for determining the amount of wear of the grinding wheel 4a, and the CPU 10 determines the amount of wear and unbalanced state according to these programs. It is supposed to be done.

In addition, CP (Jlo) calculates the rotation speed of the grinding wheel 4a based on the pulse period of the origin detection signal from the origin detection sensor 21 and controls the bandpass filter 11. The detection signals from the acceleration pickups 2 and 3 are input, and the above-described determination operation is performed based on these detection signals and the origin detection signal from the origin detection sensor 21.

Further, the CPU 10 is configured to switch 19 between two types of modes, a wear amount display mode and a balance state display mode, and maintains the balance state display mode unless the measurement instruction button 14 is pressed. ing. Then, when the measurement instruction button 14 is pressed,
The cpuio switches to the wear amount display mode and operates, and the built-in timer 10a starts counting, and after a predetermined period of time has elapsed, it automatically displays the balanced state r'f! It is designed to return to the A display mode.

Next, the case where this grindstone management device is used will be explained.

When the measurement instruction button 14 is pressed during grinding of the workpiece in order to measure the amount of wear on the grindstone 4a, the CPU 10 switches to the wear amount display mode, and similarly to the first embodiment, the wear amount is measured in the left and right directions and through the band pass filter 11. Detection signals from the vertical acceleration pickup 2°3 are input, and the ratio of the following motion ω indicated by each signal is determined. Furthermore, C.P.L.
IIO indicates where this ratio falls between the ratio when not in use and the ratio at the wear limit stored in the ROM 13, with the ratio when not in use being 100% and the ratio at the wear limit being 0%. , is displayed on the numerical display section 23 of the display panel 7. Then, as described above, the CPU 10 switches to the balance state display mode after a predetermined period of time has elapsed, and stops the display on the numerical display section 23. The user determines whether dressing work or the like is necessary based on the display on the numerical display section 23.

Next, when the CPUIO is in the wear amount display mode, that is, other than until a predetermined time has elapsed after pressing the measurement instruction button 14, the CPU 14 displays the vertical direction input via the bandpass filter 11. Detection signal from acceleration pickup 3 and origin detection sensor 2
Based on the detection signal from 1, the unbalance of the grinding wheel 4a and the phase in which it occurs are determined. This unbalanced suspension is the magnitude of vibration generated in the grindstone 4a, and the phase is a phase indicating a heavy portion of the grindstone 4a. In addition, whetstone 4
The unbalanced state of a and the phase in which it occurs are collectively referred to as the balanced state of the grindstone 4a.

Further, the CPU 10 displays the determined unbalance of the grindstone 4a on the numerical display section 23, and lights up the LED of the position display section 22 corresponding to the similarly determined phase. The user then corrects the imbalance of the grinding wheel 4a by, for example, changing the position of the balance piece provided on the whetstone 7 flange (not shown) based on the display on the image display section 22.23. .

As described above, the grindstone management device of this embodiment can accurately measure the wear state of the grindstone 4a, which is the measurement target, as in the first embodiment.
Not only can it be grasped at an early stage (and its balance status can also be easily grasped), but the above-mentioned wear and imbalance account for most of the common troubles that occur with the grinding wheel 4a, so this grinding wheel According to the management device, it is possible to comprehensively manage the grindstone 4a and prevent such troubles from occurring.

In addition, in the grindstone management device of this embodiment, the grindstone 4a is controlled based on the detection signal from the vertical acceleration pickup 3.
Instead, the balance state of the grinding wheel 4a is determined based on the detection signal from the left-right acceleration pickup 2, or the balance state of the grinding wheel 4a is determined based on the detection signal from both acceleration pickups 2.3. The state may also be determined.

In addition, in the wear display device of the first embodiment and the grindstone management device of the second embodiment, the wear is determined based on the vibration of the grindstone 4a indicated by the acceleration pickups 2 and 3 attached to the spindle head 1. However, for example, horizontal and vertical acceleration pickups 2 and 3 are attached to the table so as to detect vibrations in the horizontal and vertical directions, respectively, and the grinding wheel 4 is adjusted based on the ratio of the amount of vibration indicated by each acceleration pickup.
The wear amount of a may be determined. In this case, the main component force F of the vibration generated on the table during machining is
The vibration in one direction increases or decreases according to the principal force F1, and the back force F2
Since the vibration in both directions increases and decreases according to the thrust force F2, the amount of wear can be determined based on the ratio of the amount of vibration in both directions.

[Effects of the Invention] As detailed above, according to the grindstone wear detection device of the first invention and the grindstone management device of the second invention, the wear of the grindstone can be quickly prevented without requiring the user to be skilled. 114, which has the excellent effect of preventing grinding with a defective grindstone and being able to support in-process measurement for unmanned automatic machining.

In addition, the 1f wear detection head of the grindstone of the third invention can detect wear of the grindstone at an early stage without requiring skill from the user.
This has the excellent effect of preventing grinding with a defective whetstone.

[Brief explanation of drawings]

1 to 5 show a first embodiment of the present invention as a wear display device, FIG. 1 is a front view showing the wear display device connected to a grinding machine, and FIG. 2 is an acceleration ILT. A partial side view showing the spindle head with a pickup attached, FIG. 3 is a block diagram showing the electrical configuration, and FIG. 4 is an explanatory diagram showing the principal force and thrust force generated between the grindstone and the workpiece. , FIG. 5 is an explanatory diagram showing changes in principal force and thrust force due to wear of the grindstone, and FIGS. 6 and 7 show a second embodiment in which the present invention is embodied in a management device. FIG. 6 is a front view showing the management device connected to the grinding machine, and FIG. 7 is a block diagram showing the electrical configuration. 2 is a horizontal acceleration pickup as a first vibration detection means; 3 is a vertical acceleration pickup as a second vibration detection means; 4a is a grindstone; 10 is a CPU as first and second determination means; 22 is a A position display section is used as a display means, 23 is a numerical display section as a display means, W is a workpiece, Fl is a principal force, and F2 is a thrust force. Patent Applicant Nagase Iron Works Co., Ltd. Representative Patent Attorney On 1) Bo Prize Figure 4 Figure 5 (Imitation of WJ Yu J

Claims (1)

[Claims] 1. Each part (4a) of the grinding machine during processing of the workpiece (W)
The first vibration detection means (2) detects the vibration in the direction along the principal force (F1) of the grinding resistance among the vibrations generated in (4
a), a second vibration detection means (3) for detecting the vibration in the direction along the thrust force (F2) of the grinding resistance among the vibrations generated in the above-mentioned first and second vibration detection means (2, 3) A grindstone wear detection device comprising: determination means (10) for determining the amount of wear of a grindstone (4a) of a grinding machine based on the amount of vibration indicated by 3). 2. Each part of the grinder (4a) is removed as the workpiece (W) is processed.
The first vibration detection means (2) detects the vibration in the direction along the principal force (F1) of the grinding resistance among the vibrations generated in the grinding machine. (4
a), a second vibration detection means (3) for detecting the vibration in the direction along the thrust force (F2) of the grinding resistance among the vibrations generated in the above-mentioned first and second vibration detection means (2, a first determining means (10) for determining the amount of wear of the grinding wheel (4a) of the grinding machine based on the amount of vibration indicated by (3); and the first vibration detecting means (10);
2) and/or a second determination means (10) for determining the balance state of the grinding wheel (4a) of the grinding machine based on the amount of vibration indicated by the second vibration detection means (3); A grindstone management device comprising display means (22, 23) for displaying the wear amount of the grindstone (4a) determined by the determination means and the balance state of the grindstone (4a) determined by the second determination means. 3. Each part of the grinder (4a) is removed as the workpiece (W) is processed.
A grindstone wear detection method for determining the amount of wear of a grinding wheel (4a) of a grinding machine based on vibrations generated in the grinding wheel.