JP7084242B2 - Tool blade number estimation device and machine tools equipped with it, and tool blade number estimation method - Google Patents

Description

The present invention relates to a tool blade number estimation device for estimating the number of blades of a tool used when intermittently cutting a work by a machine tool, a machine tool provided with the tool blade number estimation device, and a tool blade number estimation method.

Conventionally, in a machine tool, the number of blades of a tool exists as one of the parameters manually input in advance by the user. This information on the number of blades is used in various situations, for example, it is necessary for calculation for suppressing chatter vibration generated during intermittent cutting. Japanese Patent Application Laid-Open No. 2017-77618 discloses a processing state monitoring method for suppressing chatter vibration by using a manually input number of blades or the like (Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-77618

However, since the information on the number of blades is not essential information for performing cutting, it is often not input at the actual site. Further, for a user who uses a tool of several hundreds, the number of blades is enormous, and there is a problem that it takes a huge amount of time and effort to manually input each one. Further, even if the number of blades is input in advance, there is a problem that some input errors cannot be avoided as long as the number of blades is manually input.

The present invention has been made to solve such a problem, and can estimate the number of blades of a tool used for intermittent cutting, omit manual input work by a user, and reduce the occurrence of input errors. It is an object of the present invention to provide a tool blade number estimation device capable of the tool blade number estimation device, a machine tool equipped with the tool blade number estimation device, and a tool blade number estimation method.

The tool blade number estimation device according to the present invention is
A tool blade number estimation device that estimates the number of tool blades used when cutting workpieces intermittently with a machine tool.
A cutting edge passing frequency estimation unit that estimates the cutting edge passing frequency when executing the intermittent cutting based on the vibration data of the machine tool, and a cutting edge passing frequency estimation unit.
A tool blade number estimation unit that estimates the number of blades of the tool using the following equation based on the estimated cutting edge passing frequency and the spindle rotation speed of the machine tool.
Number of tool blades (sheets) N = Cutting edge passing frequency (Hz) F ・ 60 / Machine tool spindle speed n (min ^-1 )
Have,
The cutting edge passing frequency estimation unit performs an inverse Fourier transform on the power spectrum obtained by Fourier transforming the vibration data to obtain an autocorrelation function, and the main axis of the plurality of peaks appearing in the autocorrelation function makes one rotation. The frequency showing the first peak that appears in between and has the same degree of correlation as that at the time of one rotation is estimated as the cutting edge passing frequency .

The other tool blade number estimation device according to the present invention is
A tool blade number estimation device that estimates the number of tool blades used when cutting workpieces intermittently with a machine tool.
A cutting edge passing frequency estimation unit that estimates the cutting edge passing frequency when executing the intermittent cutting based on the vibration data of the machine tool, and a cutting edge passing frequency estimation unit.
A tool blade number estimation unit that estimates the number of blades of the tool using the following equation based on the estimated cutting edge passing frequency and the spindle rotation speed of the machine tool.
Number of tool blades (sheets) N = Cutting edge passing frequency (Hz) F ・ 60 / Machine tool spindle speed n (min) ^-1 )
When the number of blades estimated by the tool blade number estimation unit and the number of blades input in advance are different, the blade number difference notification unit for notifying that effect and the blade number difference notification unit.
Equipped with.

The method for estimating the number of tool blades according to the present invention is
It is a tool blade number estimation method that estimates the number of tool blades used when cutting workpieces intermittently with a machine tool.
A cutting edge passing frequency estimation step for estimating the cutting edge passing frequency when performing the intermittent cutting based on the vibration data of the machine tool, and a cutting edge passing frequency estimation step.
A tool blade number estimation step for estimating the number of blades of the tool using the following equation based on the estimated cutting edge passing frequency and the spindle rotation speed of the machine tool.
Number of tool blades (sheets) N = Cutting edge passing frequency (Hz) F ・ 60 / Machine tool spindle speed n (min) ^-1 )
Including
In the cutting edge passing frequency estimation step, the autocorrelation function is obtained by performing an inverse Fourier transform on the power spectrum obtained by Fourier transforming the vibration data, and the main axis of the plurality of peaks appearing in the autocorrelation function makes one rotation. The frequency showing the first peak that appears in between and has the same degree of correlation as the one rotation is estimated as the cutting edge passing frequency.

Another method for estimating the number of tool blades according to the present invention is
It is a tool blade number estimation method that estimates the number of tool blades used when cutting workpieces intermittently with a machine tool.
A cutting edge passing frequency estimation step for estimating the cutting edge passing frequency when performing the intermittent cutting based on the vibration data of the machine tool, and a cutting edge passing frequency estimation step.
A tool blade number estimation step for estimating the number of blades of the tool using the following equation based on the estimated cutting edge passing frequency and the spindle rotation speed of the machine tool.
Number of tool blades (sheets) N = Cutting edge passing frequency (Hz) F ・ 60 / Machine tool spindle speed n (min) ^-1 )
Including
If the number of blades estimated in the tool blade number estimation step differs from the number of blades input in advance, a notification to that effect is given.

According to the present invention, the number of blades of a tool used for intermittent cutting can be automatically estimated, the work load on the user can be reduced, and input errors can be prevented.

It is a block diagram which shows one Embodiment of the tool blade number estimation apparatus which concerns on this invention, and the machine tool provided with this. It is a figure which shows the machine tool of this embodiment. It is a flowchart which shows the tool blade number estimation method executed by the tool blade number estimation apparatus of this embodiment. It is a figure which shows the autocorrelation function obtained from the vibration data in this Example 1. It is a figure which plotted the sum of squares of all frequency bands after Fourier transforming the vibration data used in Example 1 in time series. It is a figure which shows the transition of the estimated number of blades in this Example 1.

Hereinafter, an embodiment of a tool blade number estimation device according to the present invention, a machine tool provided with the tool blade number estimation device, and a tool blade number estimation method will be described with reference to the drawings.

The tool blade number estimation device 1 of the present embodiment estimates the number of blades of the tool 12 used when intermittently cutting the work 11 by the machine tool 10. Specifically, as shown in FIG. 1, the tool blade number estimation device 1 outputs a drive signal to the machine tool 10 to perform intermittent cutting, and vibration data obtained from the machine tool 10 during the intermittent cutting. The number of blades of the tool 12 is estimated based on the above. Hereinafter, each configuration will be described.

The machine tool 10 is for performing processing such as intermittent cutting on a work 11 made of metal, wood, stone, resin, or the like. In the present embodiment, as shown in FIG. 2, in the machine tool 10, the spindle 13 on which the tool 12 is mounted and the table 14 on which the work 11 is placed are aligned along the X-axis, Y-axis, and Z-axis directions. It is configured to be relatively movable in the three-dimensional space, and is numerically controlled according to an arbitrary machining program.

Further, as shown in FIG. 1, the machine tool 10 is provided with a vibration detecting means 15 for detecting vibration generated during execution of intermittent cutting. In the present embodiment, the vibration detecting means 15 is composed of an acceleration sensor, and the detected mechanical vibration is output to the tool blade number estimation device 1 as vibration data.

In the present embodiment, the vibration detecting means 15 is configured by an acceleration sensor, but the configuration is not limited to this, and the tool 12 or the work can detect vibration during intermittent cutting. It may be configured by a displacement / velocity sensor that directly or indirectly detects the displacement or velocity of 11 or a microphone that acquires a vibration sound by a sound wave.

The tool blade number estimation device 1 is composed of a computer such as a numerical control device that controls a machine tool 10. As shown in FIG. 1, various data are stored and the arithmetic processing means 3 performs arithmetic processing. By executing the storage means 2 that functions as a working area and the tool blade number estimation program 1a installed in the storage means 2, various arithmetic processes are executed and the arithmetic processing means 3 that functions as each component described later. And have. Hereinafter, each configuration means will be described in detail.

The storage means 2 includes a hard disk, a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, and the like, and as shown in FIG. 1, a program storage unit 21 and a tool blade number storage unit 22. have.

A tool blade number estimation program 1a for controlling the tool blade number estimation device 1 of the present embodiment is installed in the program storage unit 21. Then, the arithmetic processing means 3 executes the tool blade number estimation program 1a to make the tool blade number estimation device 1 as a computer function as each component described later.

The usage pattern of the tool blade number estimation program 1a is not limited to the above configuration. For example, the tool blade number estimation program 1a may be stored in a non-temporary recording medium such as a CD-ROM or a USB memory that can be read by a computer, and may be directly read from the recording medium and executed. Further, it may be used by a cloud computing method, an ASP (Application Service Provider) method, or the like from an external server or the like.

The tool blade number storage unit 22 stores the number of blades in association with each of the tools 12. Specifically, when the number of blades is estimated by the tool blade number estimation unit 34 described later, the tool blade number storage unit 22 stores the estimated number of blades in association with the tool ID that identifies the tool 12. .. Further, in the present embodiment, when the number of blades is manually input in advance, the tool blade number storage unit 22 stores the manually input number of blades in association with the tool ID. In addition to the number of blades, the tool blade number storage unit 22 may store the date and time when the tool 12 was used, the work ID for identifying the machined work 11, and the like as a history.

Next, the arithmetic processing means 3 is composed of a CPU (Central Processing Unit) or the like, and by executing the tool blade number estimation program 1a installed in the storage means 2, vibration data is as shown in FIG. Acquisition unit 31, cutting edge passing frequency estimation unit 32, spindle rotation speed acquisition unit 33, tool blade number estimation unit 34, blade number difference notification unit 35, natural vibration frequency acquisition unit 36, and optimum rotation speed calculation. It functions as a unit 37 and a drive control unit 38. Hereinafter, each component will be described in more detail.

The vibration data acquisition unit 31 acquires vibration data of the machine tool 10. In the present embodiment, the vibration data acquisition unit 31 acquires vibration data output from the vibration detection means 15 in time series while the machine tool 10 is performing intermittent cutting.

The cutting edge passing frequency estimation unit 32 estimates the cutting edge passing frequency based on the vibration data. Here, the cutting edge passing frequency is also called TPF (Tool Passing Frequency), and means the frequency of periodic vibration generated when the cutting edge (blade edge) of the tool 12 comes into contact with the work 11. In the present embodiment, the cutting edge passing frequency estimation unit 32 estimates the breaking wave passing frequency by analyzing the characteristics (waveform, periodicity, transition, etc.) of the vibration data.

Specifically, the cutting edge passing frequency estimation unit 32 first Fourier transforms the vibration data acquired by the vibration data acquisition unit 31 to acquire a power spectrum. Next, the inverse Fourier transform is performed on the power spectrum to obtain the autocorrelation function. In this autocorrelation function, the autocorrelation becomes high in the cycle in which the spindle 13 makes one rotation, and the same peak appears even in the cycle in which the cutting edge contacts the work 11. Further, since the peak appearing in the cycle in which the cutting edge comes into contact with the work 11 during one rotation corresponds to the number of blades, the cutting edge passing frequency can be estimated from the cycle between the peaks. Therefore, the cutting edge passing frequency estimation unit 32 is a frequency that appears during one rotation of the spindle 13 among the plurality of peaks appearing in the autocorrelation function, and shows the first peak having the same degree of correlation as that of the one rotation. Is estimated as the cutting edge passing frequency.

The method for estimating the cutting edge passing frequency is not limited to the above-mentioned method, and various estimation methods based on vibration data can be applied. For example, in the present embodiment, the autocorrelation function is obtained by Fourier transforming the vibration data, but the present invention is not limited to this, and the autocorrelation function is directly obtained from the time-series vibration data without Fourier transform. You may ask.

Further, in the present embodiment, among the plurality of peaks appearing in the autocorrelation function, the frequency that appears during one rotation of the spindle 13 and shows the first peak having the same degree of correlation as that of the one rotation is passed through the cutting edge. Although it is estimated as a frequency, the frequency is not limited to this, and the frequency showing the maximum peak value may be estimated as the cutting edge passing frequency, and the frequency when the peak value exceeds a predetermined threshold is cut off. It may be estimated as the blade passing frequency.

Further, in the present embodiment, the cutting edge passing frequency is estimated by using the autocorrelation function, but the present invention is not limited to this. For example, the cutting edge passing frequency may be estimated based on the fundamental frequency detected by a method such as cepstrum analysis used for voice analysis. Alternatively, the cutting edge passing frequency may be estimated by machine learning the vibration data, the power spectrum, the autocorrelation function, and the like.

The spindle rotation speed acquisition unit 33 acquires the spindle rotation speed of the machine tool 10. In the present embodiment, the spindle rotation speed acquisition unit 33 refers to a machining program related to intermittent cutting during execution, and acquires the spindle rotation speed set in the machining program.

The tool blade number estimation unit 34 estimates the number of blades of the tool 12. In the present embodiment, the tool blade number estimation unit 34 uses the tool 12 based on the cutting edge passing frequency estimated by the cutting edge passing frequency estimation unit 32 and the spindle rotation speed acquired by the spindle rotation speed acquisition unit 33. The number of blades is estimated. Specifically, the tool blade number estimation unit 34 calculates the number of blades using the following equation (1).
N = F ・ 60 / n ・ ・ ・ Equation (1)
However, each code represents the following.
N: Number of tool blades (sheets)
F: Cutting edge passing frequency (Hz)
n: Spindle speed of machine tool (min ^-1 )

However, the number of blades N of the tool calculated by the above equation (1) is not necessarily an integer value. Therefore, the tool blade number estimation unit 34 outputs an integer value obtained by rounding off the decimal point of the value calculated by the above equation (1) as the blade number N. Further, when the fractional part of the value calculated by the above equation (1) is close to 5, the tool blade number estimation unit 34 considers that the estimation is unreliable and notifies the user by a display screen or voice. , Subsequent processing may be skipped, or measures such as adopting the number of blades that are often used in practice may be taken. Further, even if the estimation results vary in time series, it may be considered that the reliability of the estimation is low and the same measures may be taken.

When the estimated number of blades and the number of pre-input blades are different, the blade number difference notification unit 35 notifies that fact. As described above, the tool blade number storage unit 22 can store the number of blades manually input in advance. Therefore, in the present embodiment, when the number of blades is estimated by the tool blade number estimation unit 34, the blade number difference notification unit 35 refers to the number of blades stored in the tool blade number storage unit 22 and refers to the tool blade number. It is determined whether or not the number of blades estimated by the estimation unit 34 and the number of blades input in advance match. If the two match as a result of the determination, the estimated number of blades is stored in the tool blade number storage unit 22 as it is.

On the other hand, if the number of blades estimated by the tool blade number estimation unit 34 and the number of blades input in advance are different as a result of the above determination, the user is notified by a display screen or voice to that effect. It is designed to accept instructions from the user. The instruction may be an instruction for selecting either the number of blades estimated by the tool blade number estimation unit 34 or the number of blades input in advance as the correct number of blades. Alternatively, if the number of blades is different due to a missing blade, an instruction may be given to stop the cutting process in order to replace the tool 12.

The natural vibration frequency acquisition unit 36 acquires the natural vibration frequency of the machine tool 10. In the present embodiment, the natural vibration frequency acquisition unit 36 determines the chatter vibration frequency based on the vibration data acquired by the vibration data acquisition unit 31 when chatter vibration occurs in the machine tool 10 during intermittent cutting. Identify. Then, the chatter vibration frequency is acquired as the natural vibration frequency of the machine tool 10.

In the present embodiment, the natural vibration frequency acquisition unit 36 acquires the chatter vibration frequency by regarding it as the natural vibration frequency, but the method for specifying the natural vibration frequency is not limited to this. For example, as in the method described in Japanese Patent Application Laid-Open No. 2017-94463, the natural vibration is based on the displacement spectrum and the cutting power spectrum obtained by frequency analysis of the displacement data of the tool 12 and the cutting power data acting on the tool 12. You may get the frequency. Further, the machine tool 10 is vibrated by an impulse hammer in advance, the vibration generated as a result is detected by an accelerometer, and the natural vibration frequency obtained by the hammering test measured by the FFT analyzer is input from the input means. You may.

The optimum rotation speed calculation unit 37 calculates the optimum spindle rotation speed for suppressing chatter vibration. In the present embodiment, the optimum rotation speed calculation unit 37 suppresses chatter vibration based on the number of blades estimated by the tool blade number estimation unit 34 and the natural vibration frequency acquired by the natural vibration frequency acquisition unit 36. The rotation speed of the main shaft is calculated. Specifically, the optimum rotation speed calculation unit 37 calculates the spindle rotation speed using the following equation (2).
n = 60 ・ f / (k ・ N) ・ ・ ・ Equation (2)
However, each code represents the following.
n: Spindle speed of machine tool (min ^-1 )
f: Natural vibration frequency (Hz)
k: Integer greater than or equal to 1 N: Number of tool blades (sheets)

The drive control unit 38 drives and controls each axis provided in the machine tool 10. In the present embodiment, the drive control unit 38 generates a drive signal for causing the machine tool 10 to execute intermittent cutting of the work 11 based on the machining program, and outputs the drive signal to the motor of each axis. Further, when chatter vibration occurs during execution of intermittent cutting, the drive control unit 38 outputs a drive signal based on the spindle rotation speed calculated by the optimum rotation speed calculation unit 37.

Next, the operation of the tool blade number estimation device 1 of the present embodiment and the machine tool 10 provided with the tool blade number estimation device 1 and the tool blade number estimation method will be described with reference to FIG. In the following description, after estimating the number of blades of the tool 12, a case where chatter vibration is suppressed by using the estimated number of blades will be described.

When estimating the number of blades of the tool 12 by using the tool blade number estimation device 1 of the present embodiment, the machine tool 10 provided with the tool blade number estimation device 1, and the tool blade number estimation method, first, the vibration data acquisition unit 31 performs the machine tool 10 The machine tool 10's vibration data is acquired from the vibration detecting means 15 provided in the machine tool 10 (step S1). This makes it possible to grasp the vibration state of the machine tool 10 performing intermittent cutting.

Next, the cutting edge passing frequency estimation unit 32 estimates the cutting edge passing frequency of the tool 12 based on the vibration data acquired in step S1 (step S2). As a result, the cutting edge passing frequency as a parameter necessary for estimating the number of blades is acquired. Further, in the present embodiment, the cutting edge passing frequency estimation unit 32 performs an inverse Fourier transform on the power spectrum obtained by Fourier transforming the vibration data to obtain an autocorrelation function, and a plurality of peaks appearing in the autocorrelation function. Of these, the frequency that appears during one rotation of the spindle 13 and shows the first peak that has the same degree of correlation as that of the one rotation is estimated as the cutting edge passing frequency. As a result, a more accurate cutting edge passing frequency is estimated, so that the estimation accuracy of the number of blades is improved.

Subsequently, when the spindle rotation speed acquisition unit 33 acquires the spindle rotation speed of the machine tool 10 (step S3), the tool blade number estimation unit 34 acquires the cutting edge passing frequency estimated in step S2 and the cutting edge passing frequency in step S3. The number of blades of the tool 12 is estimated based on the calculated spindle rotation speed (step S4). As a result, the number of blades of the tool 12 used for intermittent cutting is automatically detected, so that it is not necessary to manually input the number of blades, and the work load on the user is reduced. In addition, since human errors such as input errors are prevented, chatter vibration is suppressed with high certainty.

Next, in the present embodiment, the tool blade number storage unit 22 determines whether or not the number of blades has been input in advance (step S5). As a result of the determination, when the number of blades has not been input in advance (step S5: NO), the number of blades estimated in step S4 is stored in the tool blade number storage unit 22 (step S9). On the other hand, when the number of blades is pre-input as a result of the determination in step S5 (step S5: YES), whether or not the estimated number of blades and the pre-input number of blades match with the blade number difference notification unit 35. (Step S6).

If the results of the determination match (step S6: YES), the matching number of blades is stored in the tool blade number storage unit 22 (step S9). On the other hand, if the result of the determination in step S6 is different (step S6: NO), the user is notified to that effect (step S7). As a result, if the number of blades manually input in advance is incorrect, or if the blade of the tool 12 is missing, the user is urged to confirm the number of blades.

After that, when an instruction from the user is received (step S8), the correct number of blades is selected, or the tool is replaced with a new tool 12, the correct number of blades is stored in the tool blade number storage unit 22 (step S9). As a result, the reliability of the number of blades is improved, and the safety of avoiding chatter vibration is improved. In addition, it becomes possible to obtain history information useful for traceability of the tool 12, quality control of the work 11, investigation of the cause of a defect, and the like. For example, when a quality defect occurs in the work 11, it may be possible to identify the timing at which the cutting edge is missing by paying attention to the change point of the estimated number of blades of the tool 12.

Subsequently, in the present embodiment, when the natural vibration frequency acquisition unit 36 acquires the natural vibration frequency of the machine tool 10 (step S10), the optimum rotation speed calculation unit 37 determines the number of blades saved in step S9 and the step. The spindle rotation speed is calculated based on the natural vibration frequency acquired in S10 (step S11). As a result, the optimum spindle rotation speed that can suppress the chatter vibration generated in intermittent cutting is calculated.

Then, the drive control unit 38 controls the machine tool 10 according to the spindle rotation speed calculated in step S11 (step S12). As a result, the period in which the cutting edge of the tool 12 comes into contact with the work 11 is controlled to be an integral multiple of the natural vibration frequency, so that the occurrence of chatter vibration is suppressed.

According to the tool blade number estimation device 1 of the present embodiment as described above, the machine tool 10 provided with the tool blade number estimation device 1, and the tool blade number estimation method, the following effects are obtained.
1. 1. The number of blades of the tool 12 used for intermittent cutting can be estimated, the manual input work of the user can be omitted, and the occurrence of input errors can be reduced.
2. 2. In particular, when chatter vibration occurs, the avoidance operation can be immediately executed without manually inputting the number of blades in advance, and the convenience can be improved.
3. 3. It is possible to calculate the optimum spindle rotation speed that can suppress the chatter vibration that occurs in intermittent cutting.
4. It is possible to estimate the cutting edge passing frequency more accurately and improve the estimation accuracy of the number of blades.
5. The user can be made aware of the possibility that the number of blades manually input in advance is incorrect or that the blade of the tool 12 is missing.
6. It is possible to improve the reliability of the number of blades and improve the safety by avoiding chatter vibration.
7. The traceability of the tool 12 used for intermittent cutting can be realized.

Next, a specific embodiment of the tool blade number estimation device 1 according to the present invention, the machine tool 10 provided with the tool blade number estimation device 1, and the tool blade number estimation method will be described.

In the first embodiment, the number of blades of the tool 12 used when performing intermittent cutting by using the tool blade number estimation device 1 of the present embodiment described above, the machine tool 10 provided with the tool blade number estimation device 1, and the tool blade number estimation method is used. An experiment was conducted to estimate. In the first embodiment, the tool 12 having four blades was used, and the spindle rotation speed was set to 2777 min ^-1 .

Specifically, first, vibration data was acquired from the machine tool 10 during intermittent cutting at a predetermined sampling cycle. Then, the acquired vibration data was Fourier transformed, subjected to appropriate filtering processing, and then squared to acquire a power spectrum. Next, the autocorrelation function was obtained by inverse Fourier transforming the power spectrum. A graph of the autocorrelation function is shown in FIG. In FIG. 4, the horizontal axis of the graph shows the index value obtained by dividing the sampling frequency (the reciprocal of the sampling cycle) by the frequency, and the vertical axis shows the correlation.

The frequency corresponding to the spindle rotation speed is 46.28 Hz, and when this is converted into an index value, it becomes 177.0. Therefore, the peak appearing at 175 corresponds to the peak appearing when the main shaft 13 makes one rotation. Therefore, paying attention to the peak appearing before the peak, three peaks (index values: 44, 88, 131) appear, and among these peaks, 44 indicating the first appearing peak is converted into a frequency. The obtained 186.1818 Hz was estimated as the cutting edge passing frequency.

Then, by substituting the spindle rotation speed (2777 / min) and the estimated cutting edge passing frequency (186.1818 Hz) into the above equation (1), 4.0226 is obtained as an estimated value of the number of blades, and the blade is obtained. It was shown to estimate the number correctly.

Here, FIG. 5 shows vibration data used when estimating the number of blades in the first embodiment. In FIG. 5, the horizontal axis represents the elapsed time, and the vertical axis represents the sum of squares of the vibration amounts in the entire frequency band after the Fourier transform. Further, FIG. 6 shows the transition of the estimated number of blades in the first embodiment. In FIG. 6, the horizontal axis represents the elapsed time, and the vertical axis represents the estimated value of the number of blades.

As shown in FIG. 5, in the vibration data, vibration was observed between 0.8 seconds and 11 seconds, and it can be seen that the intermittent cutting process was performed during this period. Therefore, as shown in FIG. 6, it was shown that the number of blades of the tool 12 is estimated to be four, which is the same as the actual number of blades, from the start to the end of the intermittent cutting.

Further, in FIG. 5, it can be seen that the vibration amount suddenly increased and chatter vibration occurred in the vicinity of 2 seconds after the start of observation. Also at this time, as shown in FIG. 6, the number of blades of the tool 12 is estimated to be four, which is the same as the actual number of blades, and it is shown that the estimation accuracy is not affected by the presence or absence of chatter vibration. rice field.

According to the first embodiment as described above, the tool blade number estimation device 1 of the present embodiment, the machine tool 10 provided with the tool blade number estimation device 1, and the tool blade number estimation method are based on the vibration data of the machine tool 10 that executes intermittent cutting. Based on this, it was shown that the number of blades of the tool 12 can be estimated accurately and stably.

The tool blade number estimation device 1 according to the present invention, the machine tool 10 provided with the tool blade number estimation device 1, and the tool blade number estimation method are not limited to the above-described embodiments and examples, and can be appropriately changed. ..

For example, in the above-described embodiment, the tool blade number estimation device 1 is realized as one function of the numerical control device, but the present invention is not limited to this configuration. That is, the tool blade number estimation device 1 may be configured by a computer separate from the numerical control device.

Further, in the present embodiment described above, since the tool blade number estimation device 1 has a function of suppressing chatter vibration, it has a natural vibration frequency acquisition unit 36, an optimum rotation speed calculation unit 37, and a drive control unit 38. is doing. However, if the function of suppressing chatter vibration is not required, it is not necessary to provide the natural vibration frequency acquisition unit 36, the optimum rotation speed calculation unit 37, and the drive control unit 38. In this case, in the flowchart shown in FIG. 3, the processes from step S10 to step S12 are unnecessary.

Further, in the above-described embodiment, the tool blade number estimation device 1 has a blade number difference notification unit 35, but it is not always necessary to provide the tool blade number difference estimation device 1. In this case, in the flowchart shown in FIG. 3, the processes from step S5 to step S8 are unnecessary.

Further, in the present embodiment described above, the tool blade number estimation device 1 has the tool blade number storage unit 22, but the present invention is not limited to this configuration, and the tool blade number estimation device 1 is not limited to this configuration, and may be used in an external storage device, an external server, or the like. The number of blades may be transmitted.

The description of the embodiments described above is exemplary in all respects and is not restrictive. Modifications and changes can be made as appropriate for those skilled in the art. The scope of the invention is indicated by the claims, not by the embodiments described above. Further, the scope of the present invention includes modifications from the embodiments within the scope of the claims and within the scope of the claims.

1 Tool blade number estimation device 1a Tool blade number estimation program 2 Storage means 3 Arithmetic processing means 10 Machine tool 11 Work 12 Tool 13 Spindle 14 Table 15 Vibration detection means 21 Program storage unit 22 Tool blade number storage unit 31 Vibration data acquisition unit 32 Cutting edge passing frequency estimation unit 33 Spindle rotation speed acquisition unit 34 Tool blade number estimation unit 35 Blade number difference notification unit 36 Intrinsic vibration frequency acquisition unit 37 Optimal rotation speed calculation unit 38 Drive control unit

Claims (7)

A tool blade number estimation device that estimates the number of tool blades used when cutting workpieces intermittently with a machine tool.
A cutting edge passing frequency estimation unit that estimates the cutting edge passing frequency when executing the intermittent cutting based on the vibration data of the machine tool, and a cutting edge passing frequency estimation unit.
A tool blade number estimation unit that estimates the number of blades of the tool using the following equation based on the estimated cutting edge passing frequency and the spindle rotation speed of the machine tool.
Number of tool blades (sheets) N = Cutting edge passing frequency (Hz) F ・ 60 / Machine tool spindle speed n (min ^-1 )
Have,
The cutting edge passing frequency estimation unit performs an inverse Fourier transform on the power spectrum obtained by Fourier transforming the vibration data to obtain an autocorrelation function, and the main axis of the plurality of peaks appearing in the autocorrelation function makes one rotation. A tool blade number estimation device that estimates as the cutting edge passing frequency the frequency that appears in between and shows the first peak that has the same degree of correlation as during one rotation . A tool blade number estimation device that estimates the number of tool blades used when cutting workpieces intermittently with a machine tool.
A cutting edge passing frequency estimation unit that estimates the cutting edge passing frequency when executing the intermittent cutting based on the vibration data of the machine tool, and a cutting edge passing frequency estimation unit.
A tool blade number estimation unit that estimates the number of blades of the tool using the following equation based on the estimated cutting edge passing frequency and the spindle rotation speed of the machine tool.
Number of tool blades (sheets) N = Cutting edge passing frequency (Hz) F ・ 60 / Machine tool spindle speed n (min ^-1 )
When the number of blades estimated by the tool blade number estimation unit and the number of blades input in advance are different, the blade number difference notification unit for notifying that effect and the blade number difference notification unit.
Tool blade number estimation device equipped with. An optimum rotation speed calculation unit that calculates the spindle rotation speed that can suppress chatter vibration generated in the intermittent cutting based on the number of blades estimated by the tool blade number estimation unit and the natural vibration frequency of the machine tool. The tool blade number estimation device according to claim 1 or 2 . The tool blade number estimation device according to any one of claims 1 to 3, further comprising a tool blade number storage unit that stores the number of blades estimated by the tool blade number estimation unit in association with each of the tools. .. A machine tool provided with the tool blade number estimation device according to any one of claims 1 to 4. It is a tool blade number estimation method that estimates the number of tool blades used when cutting workpieces intermittently with a machine tool.
A cutting edge passing frequency estimation step for estimating the cutting edge passing frequency when performing the intermittent cutting based on the vibration data of the machine tool, and a cutting edge passing frequency estimation step.
A tool blade number estimation step for estimating the number of blades of the tool using the following equation based on the estimated cutting edge passing frequency and the spindle rotation speed of the machine tool.
Number of tool blades (sheets) N = Cutting edge passing frequency (Hz) F ・ 60 / Machine tool spindle speed n (min ^-1 )
Including
In the cutting edge passing frequency estimation step, the autocorrelation function is obtained by performing an inverse Fourier transform on the power spectrum obtained by Fourier transforming the vibration data, and the main axis of the plurality of peaks appearing in the autocorrelation function makes one rotation. A method for estimating the number of tool blades, in which a frequency showing an initial peak that appears in between and has a correlation similar to that at one rotation is estimated as the cutting edge passing frequency . It is a tool blade number estimation method that estimates the number of tool blades used when cutting workpieces intermittently with a machine tool.
A cutting edge passing frequency estimation step for estimating the cutting edge passing frequency when performing the intermittent cutting based on the vibration data of the machine tool, and a cutting edge passing frequency estimation step.
A tool blade number estimation step for estimating the number of blades of the tool using the following equation based on the estimated cutting edge passing frequency and the spindle rotation speed of the machine tool.
Number of tool blades (sheets) N = Cutting edge passing frequency (Hz) F ・ 60 / Machine tool spindle speed n (min ^-1 )
Including
A tool blade number estimation method for notifying when the number of blades estimated in the tool blade number estimation step differs from the number of blades input in advance.

Images