WO2020067065A1

WO2020067065A1 - Machine tool and operating method for same

Info

Publication number: WO2020067065A1
Application number: PCT/JP2019/037381
Authority: WO
Inventors: 仁志斎藤; 宏顕宇佐美
Original assignee: シチズン時計株式会社
Priority date: 2018-09-28
Filing date: 2019-09-24
Publication date: 2020-04-02
Also published as: TW202019613A; JP7281264B2; JP2020055051A

Abstract

This machine tool is provided with: a clamp capable of a fastening operation for attaching a workpiece or a tool; a control unit for controlling the fastening operation of the clamp; and a detection unit for detecting an abnormality accompanying the fastening operation of the clamp on the basis of predetermined data which starts to be measured at a predetermined timing synchronized with the fastening operation of the clamp and which relates to a vibration or load of the clamp.

Description

Machine tool and its operation method

The present disclosure relates to a machine tool and a method of operating the machine tool.

2. Description of the Related Art Machine tools, such as an NC milling machine and a machining center, for processing a work (workpiece) with a tool are known. Such a machine tool may have a clamp capable of fastening operation for mounting a work or a tool, or may have a main shaft rotatable in a state where the work or the tool is mounted by a clamp or the like. If there is an abnormality such as chip in the mounting portion of the work or the tool, the processing accuracy of the work may be adversely affected.

従来 As conventional techniques for addressing such a problem, for example, those described in Patent Documents 1 to 3 are known. Patent Literature 1 discloses a machine tool configured to detect biting of chips by flowing compressed air between a tool and a clamp and measuring a change in the flow rate or pressure. Patent Literatures 2 and 3 disclose time domain data of vibration of a main shaft measured by a vibration sensor during rotation of the main shaft to obtain frequency domain data by FFT processing, and rotate the main shaft based on the frequency domain data. There is described a machine tool configured to detect run-out due to the above. Patent Literature 3 also describes that such detection is performed based on the intensity of a predetermined frequency band in frequency domain data.

JP 2009-226541 A JP 2009-113160 A JP 2005-74568 A

However, it is desirable to be able to detect an abnormality in a workpiece or a tool mounting portion more effectively than the conventional techniques described in Patent Documents 1 to 3.

目的 An object of the present disclosure is to provide a machine tool capable of effectively detecting an abnormality in a work or a tool mounting portion, and a method of operating the machine tool.

A machine tool according to some embodiments includes a clamp capable of performing a fastening operation for mounting a workpiece or a tool, a control unit that controls the fastening operation of the clamp, and measurement at a predetermined timing synchronized with the fastening operation of the clamp. A detection unit that detects an abnormality associated with the fastening operation of the clamp based on predetermined data related to the vibration or load of the clamp to be started. According to such a configuration, an abnormality associated with the clamping operation can be accurately detected based on data that starts measurement at a predetermined timing synchronized with the clamping operation.

In one embodiment, the measurement of the predetermined data may be terminated at a predetermined timing synchronized with the fastening operation of the clamp. According to such a configuration, based on the quantified data, it is possible to accurately detect an abnormality accompanying the fastening operation of the clamp.

In one embodiment, the predetermined data may relate to vibration of the clamp. According to such a configuration, an abnormality accompanying the fastening operation of the clamp can be accurately detected based on data related to the vibration of the clamp.

In one embodiment, the detection unit may include a vibration sensor that measures the vibration of the clamp. According to such a configuration, it is possible to accurately detect an abnormality associated with the clamping operation of the clamp based on data related to the vibration of the clamp measured by the vibration sensor.

In one embodiment, the machine tool may include a main shaft having a clamp and rotatable when a work or a tool is mounted, and the vibration sensor may be an acceleration sensor disposed on the main shaft. According to such a configuration, it is possible to accurately detect an abnormality accompanying the fastening operation of the clamp with a simple configuration.

In one embodiment, the detection unit is a storage unit that stores data, and a determination unit that determines whether there is an abnormality associated with the fastening operation of the clamp based on predetermined data included in the data stored in the storage unit. May be provided. According to such a configuration, based on data included in the data stored in the storage unit, for example, starting at an appropriate timing before the clamping operation of the clamp, an abnormality associated with the clamping operation of the clamp can be accurately detected. can do.

In one embodiment, the detection unit may detect an abnormality accompanying the fastening operation of the clamp based on the intensity in the predetermined data in the time domain. According to such a configuration, it is possible to easily and accurately detect an abnormality accompanying the fastening operation of the clamp based on the data in the time domain.

In one embodiment, the detection unit may detect an abnormality accompanying the fastening operation of the clamp based on the intensity in the predetermined data in the frequency domain obtained by performing the fast Fourier transform processing on the predetermined data in the time domain. . According to such a configuration, it is possible to accurately detect an abnormality accompanying the fastening operation of the clamp based on the data in the frequency domain.

In one embodiment, the detection unit may detect an abnormality associated with the fastening operation of the clamp based on the strength of a predetermined frequency band in predetermined data in the frequency domain. According to such a configuration, based on the strength of the predetermined frequency band, it is possible to accurately detect an abnormality accompanying the fastening operation of the clamp.

In one embodiment, the machine tool may include a notifying unit that notifies an abnormality accompanying the clamping operation detected by the detecting unit. According to such a configuration, it is possible to notify an abnormality accompanying the fastening operation of the clamp and to urge the user to take measures.

A method for operating a machine tool according to some embodiments is based on predetermined data related to vibration or load of a clamp that starts measurement at a predetermined timing synchronized with a fastening operation of a clamp for mounting a workpiece or a tool. A clamp abnormality detecting step of detecting an abnormality associated with the clamping operation of the clamp. According to such a configuration, an abnormality associated with the clamping operation can be accurately detected based on data that starts measurement at a predetermined timing synchronized with the clamping operation.

In one embodiment, in the clamp abnormality detecting step, the vibration of the clamp may be measured by a vibration sensor. According to such a configuration, it is possible to accurately detect an abnormality associated with the clamping operation of the clamp based on data related to the vibration of the clamp measured by the vibration sensor.

In one embodiment, in the clamp abnormality detecting step, the vibration of the clamp may be measured by an acceleration sensor having a clamp and arranged on a main shaft rotatable when a work or a tool is mounted. According to such a configuration, it is possible to accurately detect an abnormality accompanying the fastening operation of the clamp with a simple configuration.

In one embodiment, the clamp abnormality detection step includes a storage step of storing data, and a determination step of determining the presence or absence of an abnormality associated with the clamping operation of the clamp based on predetermined data included in the data stored in the storage step. And may be provided. According to such a configuration, based on the data included in the stored data, for example, starting at an appropriate timing before the clamping operation of the clamp, for example, it is possible to accurately detect the abnormality associated with the clamping operation of the clamp. it can.

In one embodiment, in the clamp abnormality detecting step, an abnormality associated with the clamping operation of the clamp may be detected based on the intensity in the predetermined data in the time domain. According to such a configuration, it is possible to easily and accurately detect an abnormality accompanying the fastening operation of the clamp based on the data in the time domain.

In one embodiment, in the clamp abnormality detection step, based on the intensity in the predetermined data in the frequency domain obtained by performing fast Fourier transform processing on the predetermined data in the time domain, an abnormality associated with the clamping operation of the clamp is detected. Is also good. According to such a configuration, it is possible to accurately detect an abnormality accompanying the fastening operation of the clamp based on the data in the frequency domain.

In one embodiment, in the clamp abnormality detection step, an abnormality associated with the clamping operation of the clamp may be detected based on the intensity of a predetermined frequency band in predetermined data in the frequency domain. According to such a configuration, based on the strength of the predetermined frequency band, it is possible to accurately detect an abnormality accompanying the fastening operation of the clamp.

In one embodiment, the operating method of the machine tool may include a clamp abnormality reporting step of reporting an abnormality associated with the clamp fastening operation detected in the clamp abnormality detection step. According to such a configuration, it is possible to notify an abnormality accompanying the fastening operation of the clamp and to urge the user to take measures.

According to the present disclosure, it is possible to provide a machine tool capable of effectively detecting an abnormality in a work or a tool mounting portion, and a method of operating the machine tool.

It is a schematic diagram showing a machine tool according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a peripheral portion of a main shaft of the machine tool illustrated in FIG. 1 in more detail. It is a figure which shows an example of predetermined | prescribed data of the time domain regarding the vibration of a clamp when there is no abnormality accompanying the fastening operation of the clamp. FIG. 3B is a diagram illustrating an example of predetermined data in the frequency domain obtained by performing FFT processing on the time domain data illustrated in FIG. 3A. It is a figure which shows an example of the predetermined | prescribed data of the time domain regarding the vibration of a clamp, when there is abnormality accompanying the fastening operation | movement of a clamp (when small chips bite arises). FIG. 4B is a diagram illustrating an example of predetermined data in the frequency domain obtained by performing FFT processing on the time domain data illustrated in FIG. 4A. It is a figure which shows an example of the predetermined | prescribed data of the time domain regarding the vibration of a clamp, when there is abnormality accompanying the fastening operation | movement of a clamp (when large chip bites occur). FIG. 4B is a diagram illustrating an example of predetermined data in the frequency domain obtained by performing FFT processing on the time domain data illustrated in FIG. 4A. FIG. 9 is a diagram illustrating an example of an index value distribution of predetermined data when not synchronized with a clamp fastening operation. It is a figure showing an example of index value distribution of predetermined data at the time of synchronizing with clamp fastening operation. FIG. 7 is a diagram illustrating an example of frequency domain data on vibration of the main shaft when there is substantially no run-out due to rotation of the main shaft. FIG. 6 is a diagram illustrating an example of frequency domain data relating to vibration of the main shaft when there is a shake accompanying rotation of the main shaft. 5 is a flowchart showing steps (detection of a clamp abnormality based on intensity in predetermined data in a time domain) for dealing with an abnormality associated with a clamp fastening operation in the method of operating a machine tool according to an embodiment of the present invention. . 5 is a flowchart showing steps (detection of a clamp abnormality based on intensity in predetermined data in a frequency domain) for dealing with an abnormality associated with a clamp fastening operation in the method of operating a machine tool according to an embodiment of the present invention. . 6 is a flowchart showing steps (no preliminary operation) for coping with run-out due to rotation of the spindle in the method of operating a machine tool according to an embodiment of the present invention. 5 is a flowchart showing steps (preliminary operation is performed) for coping with a run-out due to rotation of a spindle in the method for preliminary operation of a machine tool according to an embodiment of the present invention.

Hereinafter, a machine tool and an operation method thereof according to an embodiment of the present invention will be described in detail with reference to the drawings.

First, a machine tool according to an embodiment of the present invention will be described by way of example. As shown in FIGS. 1 and 2, the machine tool 1 according to the present embodiment includes a spindle 2 and a headstock 3 that rotatably supports the spindle 2. The main shaft 2 includes a clamp 4 that can be fastened to mount the workpiece W thereon. In the present embodiment, the machine tool 1 is configured to work (work) with the tool T while rotating the work W mounted on the clamp 4. However, the clamp 4 may be configured to be able to perform a fastening operation for mounting a tool T such as a drill. In this case, the machine tool 1 can be configured to process the workpiece W by rotating the tool T mounted on the clamp 4.

In the present embodiment, the clamp 4 causes the sleeve 5 having the tapered surface 5a to move toward the distal end side in the axial direction (hereinafter, also referred to as forward movement, and movement in the opposite direction is also referred to as retreating), thereby forming the tapered surface 5a. It is configured as a substantially cylindrical chuck for reducing the diameter by applying a pressing force to the inside in the radial direction from, and gripping the mounted object (work W in this example). Therefore, the fastening operation of the clamp 4 is caused by the advance of the sleeve 5, and the opening operation of the clamp 4 is caused by the retreat of the sleeve 5. The advance and retreat of the sleeve 5 can be caused by a clamp actuator (not shown) composed of, for example, a cylinder and a piston.

The main shaft 2 includes a cover 6 surrounding the clamp 4 and the sleeve 5 in the circumferential direction. For example, a vibration sensor 7 that measures the vibration of the clamp 4 is disposed on the cover 6 while the machine tool 1 is operating. The vibration sensor 7 constantly measures the vibration of the clamp 4 during the operation of the machine tool 1. However, the timing of measurement by the vibration sensor 7 can be changed as appropriate. The vibration sensor 7 is disposed on the cover 6, so that the vibration of the clamp 4 can be measured effectively. However, the vibration sensor 7 may be arranged at a portion other than the cover 6 on the main shaft 2. In the present embodiment, the vibration sensor 7 is configured as an acceleration sensor. The acceleration sensor performs acceleration in each of three axial directions shown in FIG. 2 in an x-axis direction (circumferential direction of the main shaft 2), a y-axis direction (radially outer side of the main shaft 2), and a z-axis direction (axial end side of the main shaft 2). Can be measured. However, it may be possible to measure acceleration of one axis, two axes, four axes or more. The vibration sensor 7 is not limited to an acceleration sensor, and may be, for example, a distance sensor or the like. Further, a plurality of sensors may be used.

The machine tool 1 includes a control unit 8, a detection unit 9 having a storage unit 10 and a determination unit 11, an input unit 12, and a notification unit 13.

The control unit 8 is configured to control the rotation of the main shaft 2 and the fastening operation and the opening operation of the clamp 4. The control unit 8 can be configured by a central control panel or the like including a processor such as a CPU (Central Processing Unit) or a memory. The control unit 8 can control a rotation drive unit (not shown) that drives the main shaft 2 to rotate, for example, includes an electric motor or a fluid pressure motor. Further, the control unit 8 can control the clamp actuator to cause the clamp 4 to perform the fastening operation and the opening operation.

The detecting unit 9 is started at a predetermined timing synchronized with the fastening operation of the clamp 4 and starts with a fastening operation of the clamp 4 based on predetermined data P (see FIG. 3A and the like) related to the vibration of the clamp 4. It is configured to detect an abnormality such as chip entrapment. In the present embodiment, the predetermined data P ends at a predetermined timing synchronized with the fastening operation of the clamp 4. However, the predetermined data P does not have to end at a predetermined timing synchronized with the fastening operation of the clamp 4. The storage unit 10 of the detection unit 9 is configured to store data (acceleration) relating to the vibration of the clamp 4 measured by the vibration sensor 7 when the work W is mounted (when the main shaft 2 is not rotating). The determination unit 11 of the detection unit 9 performs the fastening operation of the clamp 4 based on the predetermined data P that starts and ends at a predetermined timing synchronized with the fastening operation of the clamp 4 in the data stored in the storage unit 10. It is configured to determine the presence or absence of an abnormality associated with. However, the detection unit 9 may be configured to directly acquire the predetermined data P from the vibration sensor 7 without going through the storage unit 10.

The determination unit 11 is configured to determine the presence or absence of an abnormality due to the fastening operation of the clamp 4 based on the intensity in the predetermined data P in the time domain with the horizontal axis as time, as shown in FIG. 3A. You may. In this case, the determination unit 11 may detect an abnormality accompanying the fastening operation of the clamp 4 by comparing a predetermined index value based on the intensity in the predetermined data P in the time domain with a threshold value, for example. The predetermined index value may be, for example, an integral value or a maximum value of any of the intensity in the x-axis direction, the intensity in the y-axis direction, and the intensity in the z-axis direction, or the intensity in the x-axis direction, the y-axis direction. May be the sum of the integrated values or the maximum values of the intensities in the z-axis and the intensities in the z-axis direction, or may be feature values calculated from statistical processing or the like, or may be other values. However, a plurality of predetermined index values may be used. Further, the predetermined index value may be a dimensionless amount.

The determination unit 11 obtains predetermined data P in the frequency domain having a frequency on the horizontal axis, as shown in FIG. 3B, obtained by performing fast Fourier transform (FFT) processing on the predetermined data P in the time domain. The presence or absence of an abnormality associated with the fastening operation of the clamp 4 may be determined on the basis of the strength within the '. In this case, the determination unit 11 is configured to detect an abnormality associated with the fastening operation of the clamp 4 based on the strength of a predetermined frequency band B (see FIG. 3B and the like) in the predetermined data P ′ in the frequency domain. Is also good. The determining unit 11 may detect an abnormality associated with the fastening operation of the clamp 4 by comparing a predetermined index value based on the intensity of the predetermined frequency band B with a threshold value, for example. The predetermined index value may be, for example, an integral value or a maximum value of any of the intensity in the x-axis direction, the intensity in the y-axis direction, and the intensity in the z-axis direction, or the intensity in the x-axis direction, the y-axis direction. May be the sum of the integrated values or the maximum values of the intensities in the z-axis and the intensities in the z-axis direction, or may be feature values calculated from statistical processing or the like, or may be other values. However, a plurality of predetermined index values may be used. Further, the predetermined index value may be a dimensionless amount. It is preferable that the predetermined frequency band B is set in a range in which a change in intensity between a case where there is an abnormality associated with the fastening operation of the clamp and a case where there is no abnormality is as large as possible.

3A, 4A, and 5A show examples of data stored in the storage unit 10. FIG. FIG. 3A is an example in a case where there is no abnormality due to the fastening operation of the clamp 4. FIG. 4A is an example of a case where there is an abnormality associated with the fastening operation of the clamp 4 (a case where small chips are bitten). FIG. 5A is an example of a case where there is an abnormality associated with the fastening operation of the clamp 4 (a case where large chips are bitten). In FIGS. 3A, 4A, and 5A, predetermined data that starts and ends at a predetermined timing is indicated by a symbol P, a predetermined start timing is indicated by a symbol S, and a predetermined end timing is indicated by a symbol E.

The predetermined start timing S may be simultaneous with the start of the fastening operation of the clamp 4, may be before the start of the fastening operation of the clamp 4 (for example, one second before), or may be after the start of the fastening operation of the clamp 4. . The predetermined end timing E may be the same as the end of the fastening operation of the clamp 4, may be before the end of the fastening operation of the clamp 4, or may be after the end of the fastening operation of the clamp 4 (for example, after one second). . It is preferable that both the predetermined start timing S and the predetermined end timing E are synchronized with the fastening operation of the clamp 4, but only the predetermined start timing S may be synchronized with the fastening operation of the clamp 4.

3B, 4B, and 5B show examples of the predetermined data P ’in the frequency domain. FIG. 3B is obtained by performing the FFT processing on the predetermined data P shown in FIG. 3A. FIG. 4B is obtained by performing the FFT processing on the predetermined data P shown in FIG. 4A. FIG. 5B is obtained by performing FFT processing on the predetermined data P shown in FIG. 5A.

A time lag between the start of the fastening operation of the clamp 4 and a predetermined start timing S, a time lag between the start of the fastening operation of the clamp 4 and a predetermined end timing E, and a predetermined index based on the intensity in the predetermined data P in the time domain. The method of calculating the value, the predetermined frequency band B, the method of calculating the predetermined index value based on the intensity of the predetermined frequency band B, and the threshold may be set in advance when the machine tool 1 is shipped, or may be input. It may be set by a user or the like via the unit 12, or may be automatically set by statistical processing, deep learning, machine learning, AI: Artificial Intelligence, or the like.

The storage unit 10 may be configured to store data relating to the load of the clamp 4 instead of or in addition to the data relating to the vibration of the clamp 4. The data relating to the load of the clamp 4 may be, for example, a drive current value or a drive voltage value when the clamp actuator is an electric type, and a drive fluid flow value when the clamp actuator is a hydraulic drive type. Alternatively, it may be a driving fluid pressure value, or another value. In this case, the determination unit 11 performs the fastening operation of the clamp 4 based on the predetermined data that is included in the data on the load of the clamp 4 stored in the storage unit 10 and that starts at a predetermined timing synchronized with the fastening operation of the clamp 4. May be configured to determine the presence / absence of an abnormality associated with. The predetermined data may end at a predetermined timing synchronized with the fastening operation of the clamp 4. The determination unit 11 may be configured to determine the presence or absence of an abnormality associated with the fastening operation of the clamp 4 based on the intensity in the predetermined data in the time domain, or may perform FFT processing on the predetermined data in the time domain. The presence or absence of an abnormality associated with the fastening operation of the clamp 4 may be determined based on the intensity in the predetermined data in the frequency domain obtained as described above. The determination of the presence or absence of an abnormality accompanying the fastening operation of the clamp 4 can be performed by comparing the above-described predetermined index value with the threshold.

FIG. 6 shows an example of an index value distribution of predetermined data when not synchronized with the fastening operation of the clamp. When the fastening operation of the clamp is not synchronized at a predetermined timing, the predetermined index value is scattered, and erroneous detection is likely to occur when the index value is located near the threshold value 14.

FIG. 7 shows an example of index value distribution of predetermined data when synchronized with the clamping operation of the clamp. When the clamping operation of the clamp is synchronized at a predetermined timing, as shown in FIG. 7, the distribution of the predetermined index value is divided into a normal case and an abnormal case. Become. Therefore, when the fastening operation is synchronized, the accuracy of detecting an abnormality accompanying the fastening operation of the clamp increases.

The storage unit 10 is configured to store data (acceleration) relating to the vibration of the clamp 4 measured by the vibration sensor 7 when the main shaft 2 rotates with the workpiece W mounted thereon. The determination unit 11 acquires the data (time domain data) from the storage unit 10 and performs FFT processing to convert the data into frequency domain data (frequency domain data). Based on the intensity of the predetermined natural frequency F (see FIG. 8A and the like) of the main shaft 2 or the intensity of a predetermined frequency band Bf including the predetermined natural frequency F, the main shaft 2 and / or the eccentricity of the work W may be used. Is configured to detect a shake associated with the rotation of. It is preferable that the predetermined natural frequency F is set to a natural frequency at which a change in intensity between a case where the main shaft 2 rotates and a case where there is no vibration is as large as possible. The time domain data is measured at the time of machining by rotation of the main shaft 2. However, the time domain data may be measured during a preliminary operation prior to the work by the rotation of the main shaft 2.

(4) The measurement at the time of the preliminary operation may be performed by matching the harmonic frequency of the rotation frequency of the main shaft 2 (a frequency that is an integral multiple of the rotation frequency) to the predetermined natural frequency F and emphasizing the acquired waveform.

8A and 8B show examples of frequency domain data. FIG. 8A shows an example of frequency domain data in a case where there is substantially no shake accompanying rotation of the main shaft 2. FIG. 8B shows an example of frequency domain data in a case where there is a shake accompanying rotation of the main shaft 2.

The determination unit 11 may determine, for example, whether or not there is a shake associated with the rotation of the main shaft 2 by comparing the intensity of the predetermined natural frequency F with a threshold.

The determination unit 11 may determine, for example, whether there is a shake due to the rotation of the main shaft 2 by comparing the intensity of the predetermined frequency band Bf with a threshold. In this case, the determination unit 11 may determine, for example, whether there is a shake due to the rotation of the main shaft 2 by comparing a predetermined index value based on the intensity of the predetermined frequency band Bf with a threshold. The predetermined index value may be, for example, an integral value or a maximum value of any of the intensity in the x-axis direction, the intensity in the y-axis direction, and the intensity in the z-axis direction, or the intensity in the x-axis direction, the y-axis direction. May be the sum of the integrated values or the maximum values of the intensities in the z-axis and the intensities in the z-axis direction, or may be feature values calculated from statistical processing or the like, or may be other values. However, a plurality of predetermined index values may be used. Further, the predetermined index value may be a dimensionless amount.

所定 The predetermined natural frequency F of the main spindle 2 with the workpiece W or the tool T mounted thereon can be measured or calculated in advance by, for example, vibration using a vibration member or simulation. In addition, the upper limit value and the lower limit value of the predetermined frequency band Bf are measured or calculated in advance by, for example, exciting or simulating the natural frequency of the main shaft 2 and the natural frequency of the main shaft 2 itself measured or calculated in this way. It can be set based on:

所定 The predetermined natural frequency F of the spindle 2 with the work W or the tool T mounted thereon may fluctuate slightly depending on the type of the work W or the tool T mounted. For example, when the protrusion amount or weight of the work W or the tool T becomes large, a predetermined value is obtained from the natural frequency equation (F = 1 / 2π√k / m, F: frequency, k: spring constant, m: weight). The natural frequency F tends to be small. Conversely, when the amount of protrusion or weight of the workpiece W or the tool T decreases, the predetermined natural frequency F tends to increase from the natural frequency equation (F = 1 / 2π√k / m). Therefore, in consideration of such a tendency, a predetermined natural frequency F or an upper limit value and a lower limit value of a predetermined frequency band Bf may be set based on the natural frequency of the spindle 2 itself measured or calculated in advance. Good.

The predetermined natural frequency F, the upper limit value / lower limit value of the predetermined frequency band Bf, the method of calculating the predetermined index value based on the intensity of the predetermined frequency band Bf, and the threshold value are set in advance when the machine tool 1 is shipped. Alternatively, it may be set by a user or the like via the input unit 12, or may be automatically set by statistical processing, deep learning, machine learning, AI: Artificial Intelligence, or the like.

The detecting unit 9 is configured to process a sensor signal from the vibration sensor 7 to convert the measured value into a measured value of vibration, an analyzer that performs an FFT process on the measured value, and to execute these based on a command from the control unit 8. And a controller including a processor that performs integrated control.

The input unit 12 is configured to receive an input of a predetermined natural frequency F, a threshold, and the like. The input unit 12 can be composed of, for example, a button, a keyboard, a touch panel, and the like.

The notifying unit 13 is configured to notify the presence / absence of an abnormality associated with the fastening operation of the clamp 4 determined by the determining unit 11 and the presence / absence of a shake associated with the rotation of the main shaft 2 by, for example, a display or a sound. The notification unit 13 can be configured with, for example, a display, a warning light, a speaker, or the like.

The determination unit 11 determines not only the presence or absence of an abnormality due to the fastening operation of the clamp 4 but also the mode of the abnormality due to the fastening operation of the clamp 4 (specification of the biting position of the chip, whether it is an abnormality due to the biting of the chip, or other It may also be configured to determine whether an abnormality is caused by the cause. In addition, the determination unit 11 determines not only the presence / absence of the shake due to the rotation of the main shaft 2 but also the mode of the shake due to the rotation of the main shaft 2 (for example, which part of the work W or the main shaft 2 has the shake). It may be configured as follows.

Next, an operation method of the machine tool according to one embodiment of the present invention will be described by way of example. In the present embodiment, the operation method of the machine tool 1 described above will be described as an example, but the operation method can be applied to an operation method of another machine tool.

The operation method according to the present embodiment includes a step for coping with an abnormality associated with the fastening operation of the clamp 4 as shown in FIGS. 9 and 10, and a step associated with the rotation of the main shaft 2 as shown in FIGS. And a step for coping with the shake. The step for coping with the abnormality accompanying the fastening operation of the clamp 4 and the step for coping with the run-out due to the rotation of the main shaft 2 are performed independently of each other.

First, steps for coping with an abnormality accompanying the fastening operation of the clamp 4 will be described. As shown in FIGS. 9 and 10, the steps for responding to the abnormality associated with the fastening operation of the clamp 4 include a clamp abnormality detection step S1 or S1 'and a clamp abnormality notification step S2. In the clamp abnormality detection steps S1 and S1 ', the detection unit 9 starts and ends the vibration measurement at a predetermined timing synchronized with the fastening operation command of the clamp 4 for mounting the work W output by the control unit 8. The detecting unit 9 detects an abnormality (hereinafter, also referred to as “clamp abnormality”) accompanying the fastening operation of the clamp 4 based on predetermined data P related to the vibration of the clamp 4. As shown in FIG. 9, in the clamp abnormality detection step S1, the detection unit 9 detects a clamp abnormality based on the intensity in the predetermined data P in the time domain. As shown in FIG. 10, in the clamp abnormality detection step S1 ′, the detection unit 9 performs the FFT processing on the predetermined data P in the time domain based on the intensity in the predetermined data P ′ in the frequency domain. , To detect a clamp abnormality. In this case, in the clamp abnormality detection step S1 ', the detection unit 9 may detect the clamp abnormality based on the intensity of the predetermined frequency band B in the predetermined data P' in the frequency domain.

As shown in FIG. 9, when a clamp abnormality is detected based on the intensity in the predetermined data P in the time domain, the clamp abnormality detection step S1 includes a clamp fastening operation step S11, a storage step S12, and a determination step. S13. In the clamp fastening operation step S11, the control unit 8 outputs a fastening operation command of the clamp 4 for mounting the work W. In the storage step S12, the storage unit 10 stores data including predetermined data P at a predetermined timing synchronized with the clamp fastening operation command output in the clamp fastening operation step S11. In the determination step S13, the determination unit 11 determines whether or not there is a clamp abnormality based on the predetermined data P included in the data stored in the storage step S12.

More specifically, in the determination step S13, the determination unit 11 calculates a predetermined index value based on the intensity in the predetermined data P in the time domain, and compares the predetermined index value with a threshold value. There is a clamp abnormality determination step S132 for determining the presence or absence of abnormality.

(4) When it is determined that there is an abnormality in the clamp abnormality determination step S122, the process proceeds to a clamp abnormality notification step S2. In the clamp abnormality reporting step S2, the reporting unit 13 reports the occurrence of the clamp failure.

クランプ If it is determined that there is no abnormality in the clamp abnormality determination step S132, the clamp abnormality detection step S1 ends.

As shown in FIG. 10, when a clamp abnormality is detected based on the intensity in the predetermined data P ′ in the frequency domain, the clamp abnormality detection step S1 ′ includes a clamp fastening operation step S11, a storage step S12, Determination step S13 ′. In the clamp fastening operation step S11, the control unit 8 outputs a fastening movement command of the clamp 4 for mounting the work W. In the storage step S12, the storage unit 10 stores data including predetermined data P at a predetermined timing synchronized with the clamp fastening operation output in the clamp fastening operation step S11. In the determination step S13, the determination unit 11 determines whether or not there is a clamp abnormality based on the predetermined data P included in the data stored in the storage step S12.

More specifically, the determination step S13 includes an analysis step S131 in which the determination unit 11 performs FFT processing on the predetermined data P to obtain predetermined data P ′ in the frequency domain, and a determination step S13 in which the determination unit 11 obtains the analysis data in the analysis step S131. A predetermined index value based on the intensity of the predetermined frequency band B in the predetermined data P ′ in the frequency domain obtained, and comparing the predetermined index value with a threshold value to determine the presence or absence of a clamp abnormality. Step S132 ′.

When it is determined that there is an abnormality in the clamp abnormality determination step S132 ’, the process proceeds to a clamp abnormality notification step S2. In the clamp abnormality reporting step S2, the reporting unit 13 reports the occurrence of the clamp failure.

The clamp abnormality may be detected based on the intensity in the predetermined data P in the time domain, or the clamp abnormality may be detected based on the intensity in the predetermined data P ′ in the frequency domain. It may be used or may be carried out plural times.

クランプ Note that the clamp abnormality detection steps S1 and S1 'of the present embodiment are not limited to the case where the workpiece W is mounted on the clamp 4, but can be applied to the case where the tool T is mounted on the clamp 4. Further, the clamp abnormality detecting steps S1 and S1 'of the present embodiment are not limited to the case where both the start timing S and the end timing E of the predetermined data P are synchronized with the fastening operation of the clamp 4, and are not limited to the predetermined cases. The present invention can also be applied to a case where only the start timing S of the data P is synchronized with the fastening operation of the clamp 4. Further, the clamp abnormality detecting steps S1 and S1 'of the present embodiment are not limited to the case where data relating to the vibration of the clamp 4 is used, but can also be applied to the case where data relating to the load of the clamp 4 is used.

Next, steps for coping with run-out due to rotation of the main shaft 2 will be described. As shown in FIG. 11, the steps for coping with the runout caused by the rotation of the main shaft 2 include an input step S4, a runout detection step S3, and a runout notification step S5, which are performed in the working step S6. . Further, as shown in FIG. 12, the steps for coping with the run-out due to the rotation of the main spindle 2 include a run-out detection step S3 ′ and a run-out notification step S5 performed in a preliminary operation step S7 performed before the working step S6. 'May be provided. When performing the shake detection step S3 'and the shake notification step S5' in the preliminary operation step S7, the shake detection step S3 and the shake notification step S5 may or may not be performed in the working step S6.

In the shake detection steps S3 and S3 ′, the detection unit 9 performs the FFT processing on the time domain data related to the vibration of the main shaft 2 measured by the vibration sensor 7 when the main shaft 2 rotates with the workpiece W mounted thereon, and converts the frequency domain data. At the same time, the rotation of the main shaft 2 is performed based on the strength of the predetermined natural frequency F of the main shaft 2 in a state where the work W is mounted or the strength of the predetermined frequency band Bf including the predetermined natural frequency F in the frequency domain data. The accompanying shake is detected. In the shake detection step S3, the time domain data is measured at the time of machining by rotation of the main shaft 2. In the shake detection step S <b> 3 ′, the time domain data is measured at the time of the preliminary operation prior to the work by the rotation of the main shaft 2.

When the preliminary operation is not performed, first, as shown in FIG. 11, before the start of the machining step S6, the input step S4 is performed. In the input step S4, a predetermined natural frequency F (or a method of calculating an upper limit value / lower limit value of a predetermined frequency band Bf and a predetermined index value) and a threshold value are input by a user or the like via the input unit 12. Is set. The setting may be automatically performed by statistical processing, deep learning, machine learning, AI: Artificial Intelligence, or the like. Further, the setting may be made in advance when the machine tool 1 is shipped, and in this case, the input step S4 becomes unnecessary. When the input step S4 is completed, the work is started in step S61 (start of the work step S6).

The shake detection step S3 includes a measurement / analysis step S32 performed after step S61, and a shake determination step S33 performed after the measurement / analysis step S32. In the measurement / analysis step S32, the frequency domain data is obtained by performing FFT processing on the time domain data relating to the vibration of the main spindle 2 measured by the vibration sensor 7 during the machining (when the main spindle 2 is rotating). In the shake determination step S33, it is determined whether there is a shake accompanying the rotation of the main shaft 2 based on the frequency domain data.

In the measurement / analysis step S32, the storage unit 10 stores time domain data on the vibration of the main shaft 2 measured by the vibration sensor 7. In the measurement / analysis step S32, the determination unit 11 acquires the time domain data from the storage unit 10 and performs FFT processing to obtain frequency domain data.

In the shake determination step S33, the determination unit 11 compares the strength of the predetermined natural frequency F in the frequency domain data or the strength of the predetermined frequency band Bf including the predetermined natural frequency F with a threshold value, thereby obtaining the It is determined whether or not there is vibration due to rotation.

場合 If it is determined that there is an abnormality in the shake determination step S33, the process proceeds to a shake notification step S5. In the shake notification step S5, the notification unit 13 notifies the occurrence of the shake accompanying the rotation of the main shaft 2.

If it is determined that there is no abnormality in the runout determination step S33, the machining is continued until the currently executed machining pass of the plurality of machining passes constituting the machining is completed. When the current machining pass is completed in step S62, it is determined in step S63 whether all the machining passes have been completed. If it is determined in step S63 that all machining passes have not been completed, the process returns to the measurement / analysis step S32. If it is determined in step S63 that all machining passes have been completed, the machining step S6 ends.

When performing the preliminary operation, as shown in FIG. 12, first, the input step S4 is performed, and then the preliminary operation step S7 is performed. The preliminary operation step S7 includes a shake detection step S3 'and a shake notification step S5'. The shake detection step S3 'includes a rotation step S31, a measurement / analysis step S32', and a shake determination step S33 '.

In the rotation step S31, the control unit 8 rotates the main shaft 2 at a predetermined rotation speed with the work W mounted. At this time, in the present embodiment, the control unit 8 adjusts the predetermined rotation speed such that the predetermined rotation speed or its harmonic frequency input in the input step S4 matches the predetermined natural frequency F. By adjusting the rotation speed in this manner, the waveform of the frequency domain data acquired in the measurement / analysis step S32 'is emphasized, and the accuracy of the determination in the shake determination step S33' can be improved. However, without adjusting the rotation speed to make the predetermined rotation speed correspond to the predetermined natural frequency F, the main shaft 2 is rotated at a rotation speed that does not correspond to the predetermined natural frequency F to obtain the frequency domain data. May be.

In the 'measurement / analysis step S32', the time domain data on the vibration of the main shaft 2 measured by the vibration sensor 7 while rotating the main shaft 2 in the rotation step S31 is subjected to FFT processing to obtain frequency domain data. In the measurement / analysis step S <b> 32 ′, the storage unit 10 stores time domain data on the vibration of the main shaft 2 measured by the vibration sensor 7. In the measurement / analysis step S32 ', the determination unit 11 acquires the time domain data from the storage unit 10 and performs FFT processing to obtain frequency domain data.

In the "vibration determination step S33", it is determined whether or not there is a vibration accompanying the rotation of the main shaft 2 based on the frequency domain data. In the shake determination step S33 ′, the determination unit 11 compares the strength of the predetermined natural frequency F in the frequency domain data or the strength of the predetermined frequency band Bf including the predetermined natural frequency F with a threshold value, thereby obtaining the main shaft 2. It is determined whether or not there is a shake accompanying the rotation of.

If it is determined that there is an abnormality in the shake determination step S33 ', the process proceeds to a shake notification step S5'. In the shake notification step S <b> 5 ′, the notification unit 13 notifies the occurrence of the shake accompanying the rotation of the main shaft 2.

When it is determined that there is no abnormality in the runout determination step S33 ’, the preliminary operation step S7 ends, and the work is started in step S61 (start of the work step S6).

As described above, the run-out may be detected during the preliminary operation, may be performed during the machining, or may be performed both during the preliminary operation and during the machining. Further, the run-out may be detected a plurality of times during the preliminary operation and during the work, respectively.

振 Note that the shake detection steps S3 and S3 'of the present embodiment are not limited to the case where the workpiece W is mounted on the clamp 4, but can be applied to the case where the tool T is mounted on the clamp 4.

The above-described embodiment is merely an example of the embodiment of the present invention, and it goes without saying that various modifications can be made without departing from the spirit of the invention.

工作 In the machine tool according to the above-described embodiment, the detection unit is configured to detect the run-out due to the rotation of the main shaft, but the detection unit may not have such a configuration. Further, the method of operating a machine tool according to the above-described embodiment includes a step for coping with a run-out due to rotation of the main spindle, but may not include such a step.

DESCRIPTION OF SYMBOLS 1 Machine tool 2 Spindle 3 Headstock 4 Clamp 5 Sleeve 5a Tapered surface 6 Cover 7 Vibration sensor 8 Control part 9 Detection part 10 Storage part 11 Judgment part 12 Input part 13 Notification part 14 Threshold value W Work T Tool P, P 'Predetermined Data S Predetermined start timing E Predetermined end timing B, Bf Predetermined frequency band F Predetermined natural frequency

Claims

A clamp capable of fastening operation for mounting a work or a tool,
A control unit for controlling the fastening operation of the clamp,
Based on predetermined data related to the vibration or load of the clamp that starts measuring at a predetermined timing synchronized with the clamping operation of the clamp, a detection unit that detects an abnormality associated with the clamping operation of the clamp,
A machine tool.
2. The machine tool according to claim 1, wherein the measurement of the predetermined data ends at a predetermined timing synchronized with a fastening operation of the clamp. 3.
The machine tool according to claim 1, wherein the predetermined data is related to vibration of the clamp.
The machine tool according to claim 3, wherein the detection unit includes a vibration sensor that measures vibration of the clamp.
A spindle having the clamp and rotatable in a state where the work or the tool is mounted,
The vibration sensor is an acceleration sensor arranged on the main shaft,
The machine tool according to claim 4.
The detection unit,
A storage unit for storing data,
Based on the predetermined data included in the data stored in the storage unit, a determination unit that determines whether there is an abnormality associated with the fastening operation of the clamp,
The machine tool according to any one of claims 1 to 5.
The work according to any one of claims 1 to 6, wherein the detection unit detects an abnormality associated with a fastening operation of the clamp based on an intensity in the predetermined data in a time domain. machine.
The detection unit, based on the intensity in the predetermined data in the frequency domain obtained by performing the fast Fourier transform processing of the predetermined data in the time domain, based on the strength of detecting the abnormality associated with the fastening operation of the clamp, The machine tool according to any one of claims 1 to 6, wherein
9. The machine tool according to claim 8, wherein the detection unit detects an abnormality associated with a fastening operation of the clamp based on an intensity of a predetermined frequency band in the predetermined data in the frequency domain. 10.
The machine tool according to any one of claims 1 to 9, further comprising: a reporting unit that reports an abnormality associated with the clamping operation of the clamp detected by the detection unit.
Starting the measurement at a predetermined timing synchronized with the clamping operation of the clamp for mounting the work or the tool, detecting an abnormality accompanying the clamping operation of the clamp based on predetermined data related to the vibration or load of the clamp. An operation method of a machine tool, comprising a clamp abnormality detecting step.
The method according to claim 11, wherein the measurement of the predetermined data ends at a predetermined timing synchronized with a fastening operation of the clamp.
The method according to claim 11, wherein the predetermined data is related to vibration of the clamp.
The method according to claim 13, wherein in the clamp abnormality detecting step, vibration of the clamp is measured by a vibration sensor.
15. The clamp abnormality detecting step according to claim 14, wherein in the clamp abnormality detecting step, the vibration of the clamp is measured by an acceleration sensor arranged on a main shaft having the clamp and rotatable in a mounted state of the work or the tool. How a machine tool works.
The clamp abnormality detection step includes:
A storage step for storing data;
A determination step of determining whether there is an abnormality associated with the fastening operation of the clamp based on the predetermined data included in the data stored in the storage step,
An operation method for a machine tool according to any one of claims 11 to 15.
17. The clamp abnormality detecting step according to claim 11, wherein an abnormality associated with a fastening operation of the clamp is detected based on an intensity in the predetermined data in a time domain. How to operate machine tools.
In the clamp abnormality detecting step, based on the intensity in the predetermined data in the frequency domain obtained by performing the fast Fourier transform processing on the predetermined data in the time domain, detecting an abnormality associated with the fastening operation of the clamp. The method for operating a machine tool according to any one of claims 11 to 16, characterized in that:
19. The machine tool according to claim 18, wherein in the clamp abnormality detecting step, an abnormality associated with a fastening operation of the clamp is detected based on an intensity of a predetermined frequency band in the predetermined data in a frequency domain. How it works.
The method of operating a machine tool according to any one of claims 11 to 19, further comprising: a clamp abnormality notification step of notifying an abnormality associated with the fastening operation of the clamp detected in the clamp abnormality detection step.