JP4032422B2 - Method for determining abnormality of mounting state of tool holder in machine tool and apparatus having rotating shaft - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tool holder mounting state abnormality determination method in a machine tool and an apparatus having a rotating shaft, and more particularly to a tool holder in a machine tool using a tool holder such as a machining center (hereinafter abbreviated as “MC”). The present invention relates to a tool holder mounting state abnormality determining method in a machine tool and an apparatus having a rotating shaft that can automatically detect an abnormality in the mounting state of the main shaft.
[0002]
[Prior art]
The MC is an apparatus that automatically selects various tools according to a machining process and automatically attaches them to a spindle to perform various types of machining. In this MC, tool change is performed by an automatic tool change (ATC: auto tool holder change) device. This ATC device is a device that automatically takes out a tool holder to which a tool is attached from a tool magazine and automatically attaches it to a spindle.
[0003]
FIG. 14 is a cross-sectional view showing a state in which the tool holder 2 is mounted on the spindle 1. As shown in the figure, the tool holder 2 has a conical fitting portion 2A, and this fitting portion 2A is fitted to a conical fitting portion 1A formed on the main shaft 1. Is attached.
[0004]
This procedure is as follows. By pulling the shaft rod 3 to the right, the ball holder 4 and the ball 5 move accordingly. By the movement of the ball 5, the pull stud (drawing bolt) 6 is pulled, whereby the conical fitting portion 2 </ b> A of the tool holder 2 is pressed against the conical fitting portion 1 </ b> A of the main shaft 1. Due to this pressed pressure, the fitting portion 2A comes into close contact with the fitted portion 1A, and mounting with high precision (chucking) is performed.
[0005]
FIG. 15 is an explanatory diagram showing a mounted state of the tool holder 2 that holds the tool T. FIG. Normally, the tool holder 2 is properly mounted, and a state as shown in FIG. However, as shown in FIG. 5B, when chips 7 and the like adhere to this fitting portion, the shaft is bent and attached. When machining is performed in this state, there is a drawback that the tool T is shaken and the machining accuracy of the workpiece is remarkably lowered. As a technique for automatically detecting the presence or absence of such a chuck error in the tool holder, the applicant of the present application has proposed (see Patent Document 1 above).
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-200542
[0007]
[Problems to be solved by the invention]
However, in addition to the above-mentioned chuck mistakes, there are some phenomena that cause abnormalities in the mounting state of the tool holder on the spindle. This phenomenon is often seen after operation for about two years after delivery of a new MC. And the frequency is about once a month.
[0008]
As a phenomenon, it has been confirmed that the pulling force of a pull stud (drawing bolt) of about 2 tons usually drops to about 0.8 tons for some reason, resulting in an abnormal mounting state of the tool holder. This is presumed to be due to deterioration of the mounting mechanism, such as a disc spring (not shown) in the mounting portion of the tool holder 2 to the main shaft 1 and a decrease in gripping force, but the details are not known. There is a current situation.
[0009]
That is, at present, it is difficult to determine from the frequency that the cause is determined to be a decrease in the clamping force of the tool holder when the workpiece machining accuracy is reduced.
[0010]
For this reason, the only way to deal with such an abnormal mounting state is to replace the parts around the spindle 1 with new ones. In addition, in order to prevent such an abnormality in the mounting state, it is also possible to replace parts around the spindle 1 with a new one as soon as possible by looking at the total operating time and the transition of the machining accuracy of the workpiece in advance. It was. Due to these various problems, there has been a strong demand for improvement of the clamping force of the tool holder.
[0011]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a machine tool that can easily and reliably detect a chuck error and thereby eliminate the occurrence of defective products.
[0024]
[Means for Solving the Problems]
  In order to achieve the above-mentioned object, the present invention provides a machine tool in which a tool holder to which a tool is attached is mounted on a main shaft and the main shaft is rotationally driven to process a workpiece. Measuring means for measuring the displacement of the surface; and mounting state determining means for determining an abnormality in the mounting state of the tool holder on the spindle due to deterioration of the mounting mechanism from the measurement data obtained by the measuring unit, State judgment means,in frontThe eccentric amount of the first round immediately after the start of rotation of the tool holdernumberCompare with the eccentric amount of the circumferenceThen, it is detected that the eccentric amount of the several rounds is smaller than a predetermined threshold value than the eccentric amount of the first round.By wearing stateAbnormalA machine tool characterized by determining the above is provided. The inventor of the present application has found that when the mounting state of the tool holder is poor, the amount of eccentricity is large immediately after the start of rotation of the tool holder, and thereafter the amount of eccentricity after a predetermined time has returned to normal. Therefore, by making such a determination, it is possible to reliably determine the suitability of the mounting state of the tool holder.
[0025]
  Further, the present invention provides a tool holder mounting state abnormality determination method in a device for mounting a tool holder on a shaft and rotationally driving the shaft, and measuring the displacement of the outer peripheral surface of the flange of the tool holder, whereby the tool holder The amount of eccentricity ofin frontThe eccentric amount of the first round immediately after the start of rotation of the tool holdernumberCompare with the eccentric amount of the circumferenceThen, it is detected that the eccentric amount of the several rounds is smaller than a predetermined threshold value than the eccentric amount of the first round.Accordingly, there is provided a tool holder mounting state abnormality determining method in an apparatus having a rotating shaft, wherein abnormality of a mounting state of the tool holder on the shaft due to deterioration of a mounting mechanism is determined.
[0026]
  By applying each of the above-described configurations of the present invention, it is possible to determine whether the tool holder is in an abnormal state even in various apparatuses having a rotation axis other than a machine tool.
  In the present specification, the problem described in Patent Document 1 is referred to as “chuck error”, and the problem in the present invention is referred to as “chuck error” (mounting state abnormality).
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a machine tool according to the present invention will be described in detail with reference to the accompanying drawings.
[0028]
FIG. 1 is a block diagram showing a first embodiment of a chuck error detection device incorporated in a machine tool according to the present invention. This chuck error detection device 10 is a device that automatically detects a chuck error (mounting state abnormality) of the tool holder 2 mounted on the spindle 1 by an ATC device, and mainly includes a sensor 12 that is a measuring unit and a mounting state determination unit. A certain data processing device 14 is used.
[0029]
The sensor 12 is attached via a bracket 6 to the head 5 to which the main shaft 1 is attached. This sensor 12 is an eddy current sensor, and detects the distance d to the outer peripheral surface of the flange portion 2B of the tool holder 2 attached to the spindle 1 as an electrical signal.
[0030]
The data processing device 14 detects a chuck error of the tool holder 2 based on the measurement data measured by the sensor 12, and includes an A / D converter 16, a CPU 18, a memory 20, an input / output circuit 22, and the like.
[0031]
The A / D converter 16 converts the electrical signal indicating the distance d output from the sensor 12 into a digital signal and outputs it to the CPU 18. The CPU 18 calculates the amount of eccentricity of the tool holder 2 based on the measurement data of the sensor 12 converted into the digital signal. Then, the calculated amount of eccentricity is compared with a threshold value stored in advance in the memory 20. A chuck error is determined when the change in the amount of eccentricity exceeds the threshold value. Then, the result is output to the MC control device 24 that controls the MC via the input / output circuit 22. Details of this will be described later.
[0032]
As described above, the CPU 18 calculates the amount of eccentricity of the tool holder 2 based on the measurement data of the distance d measured by the sensor 12, and the calculation process and the mounting state determination of the tool holder 2 are performed as follows. .
[0033]
First, the CPU 18 receives a measurement start command from the MC control device 24 via the input / output circuit 22. Then, the measurement data of the distance d output from the sensor 12 is stored in the memory 20 in correspondence with the rotation angle θ of the tool holder 2. This measurement is performed for two rounds of the tool holder immediately after the start of rotation. Among these, the measurement data of the distance d for the first round of the tool holder is displayed in a graph, for example, as shown in FIG.
[0034]
Next, the CPU 18 performs FFT analysis on the measurement data of the distance d for the first round of the tool holder stored in the memory 20. That is, the measurement data for one round of the tool holder is Fourier-analyzed and decomposed into each frequency component.
[0035]
Note that the FFT analysis may be performed simultaneously with the measurement. When the result of the FFT analysis is displayed as a power spectrum, for example, it is as shown in FIG.
[0036]
Here, among the frequency components subjected to the FFT analysis as described above, the amplitude value of the fundamental frequency component (one peak component) can be regarded as twice the amount of eccentricity of the tool holder 2, so the CPU 18 obtains the result of the FFT analysis. The fundamental frequency component is extracted from the signal, the amplitude value is calculated, and the eccentric amount T of the first round of the tool holder 2 is calculated.₁To get.
[0037]
The same measurement as above is performed for the second round of the tool holder immediately after the start of rotation. Thereby, the eccentric amount T of the second round of the tool holder 2₂To get.
[0038]
The obtained eccentricity T₁And T₂Based on the above, the chuck error is determined. Specifically, the eccentric amount T₁And eccentricity T₂Whether or not there is a chuck error is determined based on whether or not the difference is greater than or equal to a predetermined threshold value. When the difference is equal to or larger than the threshold value, it is determined as a chuck error, and when the difference is less than the threshold value, it is determined as normal. This predetermined threshold is determined by the specifications of the MC. This determination was introduced because the present inventor discovered the phenomenon described below.
[0039]
That is, regardless of whether or not there is a chuck error in the tool holder 2, the eccentric amount T of the first round immediately after the rotation of the tool holder 2 is started.₁Is big. On the other hand, the eccentric amount T of the second turn of the tool holder 2 with no chuck error.₂Is a small value. On the other hand, the eccentric amount T of the second round of the tool holder 2 causing the chuck error₂Is the eccentricity T of the first lap₁Although it is smaller than the above, it is sufficiently larger than the value without the chuck error.
[0040]
This phenomenon will be described by showing the amount of eccentricity measured using a specific MC. FIG. 16 is a table showing the amount of eccentricity of the tool holder in each state of MC. In the table, “normal” means that there is no chuck error, “abnormal” means that a chuck error occurs, and “NG” means that the mechanism around the spindle is in a state requiring replacement. T_mIndicates the amount of eccentricity during workpiece machining. The number of eccentricity in the table indicates an approximate order, and fine values are rounded and displayed.
[0041]
In normal condition, eccentricity T₁Is 10 μm, T₂Is 2μm, T_mIs at the level of 1 μm. On the other hand, in an abnormal state, the eccentric amount T₁Is 100 μm, T₂Is as large as 10 μm, T_mIs at the level of 1 μm as in the normal state. In the NG state, eccentricity T₁Is 100 μm, T₂Is 50μm, T_mIs as large as 30 μm.
[0042]
Thus, the eccentric amount T₁And eccentricity T₂Whether or not there is a chuck error can be determined. Similarly, eccentricity T₁And eccentricity T₂The ratio of T₁/ T₂Whether or not there is a chuck error can also be determined by looking at how much is.
[0043]
In the above example, the eccentric amount T of the first round of the tool holder 2₁And eccentric amount T in the second lap₂However, depending on the device, T₂Instead of the eccentric amount T of the third round of the tool holder 2_ThreeOr the eccentric amount T in the fourth lap_FourIn some cases, it is easier to determine whether or not there is a chuck error. Therefore, the suitability of the mounting state may be determined by comparing the amount of eccentricity immediately after the start of the rotation of the tool holder with the amount of eccentricity after the lapse of a predetermined time according to the device characteristics.
[0044]
Further, it is possible to employ a method of performing statistical processing such as calculating the standard deviation of the eccentricity for several rounds of the tool holder 2 and determining the suitability of the wearing state from the result.
[0045]
Next, a chuck error detection method for the tool holder 2 by the chuck error detection apparatus 10 of the present embodiment configured as described above will be described with reference to the flowchart shown in FIG.
[0046]
The chuck error detection device 10 is activated when the MC is started (step S1). When tool change (ATC) is performed by the ATC device (step S2), the MC control device 24 rotates the spindle at a preset rotation speed (step S3).
[0047]
The sensor 12 measures the distance d to the outer peripheral surface of the flange portion 2B of the rotating tool holder 2. The CPU 18 stores the measurement data of the distance d measured by the sensor 12 in the memory 20 in association with the rotation angle θ of the tool holder 2.
[0048]
The measurement is performed for two rounds immediately after the rotation of the tool holder 2 is started (steps S4 and S7), and this measurement data is obtained.
[0049]
The CPU 18 performs FFT analysis on the measurement data stored in the memory 20, extracts one peak component, and calculates the amplitude value. Since the amplitude value of the single peak component is equal to twice the eccentric amount T of the tool holder 2, the eccentric amount T of the tool holder 2 is thereby calculated.₁, T₂Is acquired (steps S6 and S8). The CPU 18 obtains the obtained eccentricity T₁And T₂Is compared with a predetermined threshold value to determine the presence or absence of a chuck error (step S9).
[0050]
The FFT analysis may be performed simultaneously with the measurement. The predetermined threshold value is input by an operator from an input device (not shown) prior to the start of operation of the MC. The input predetermined threshold value is stored in the memory 20. The predetermined threshold value is selected and set as appropriate based on the processing accuracy required by the user.
[0051]
The determination result is output to the MC control device 24, and the MC control device 24 determines that the state is normal with no chuck error (the amount of eccentricity T₁And T₂(Step S10), the machining is started as it is (step S11). On the other hand, when the chuck error is determined (the eccentric amount T₁And T₂(Step S12), a command to display that fact on the display unit (not shown) of the MC control device 24 (or to sound an alarm or blink the patrol) (step S12). S13).
[0052]
As described above, according to the chuck error detection device 10 of the present embodiment, the amount of eccentricity of the tool holder 2 is measured, and the chuck error of the tool holder 2 is detected based on the amount of eccentricity. A chuck error of the holder 2 can be detected. In addition, the apparatus configuration is extremely simple and does not require complicated control, so that detection can be performed easily.
[0053]
Next, a second embodiment of the machine tool according to the present invention will be described. The apparatus used is the same as that in the first embodiment described above.
[0054]
The first embodiment is a case where the flange portion 2B of the tool holder 2 which is the measurement point of the sensor 12 is circular. Generally, the flange portion 2B of the tool holder 2 is shown in FIG. Thus, notches 2C and 2C for the chuck are often formed. The chuck error detection method of the second embodiment is a detection method when notches 2C and 2C are formed in the flange portion 2B of the tool holder 2 that is a measurement point.
[0055]
When there are two cutouts 2C and 2C in the flange portion 2B of the tool holder 2, the measurement data for one round of the tool holder is as shown in FIG. As shown in the figure, the measurement data changes rapidly at the two notches 2C and 2C. The measurement data of the notches 2C and 2C is corrected by, for example, linear interpolation. FIG. 6B is a graph showing the measurement data after linear interpolation of the notches 2C and 2C.
[0056]
Thus, when there are notches 2C and 2C in the flange portion 2B of the tool holder 2, which is the measurement point of the sensor 12, the measurement data of the portions of the notches 2C and 2C is complemented, and the complemented measurement data An FFT analysis is performed on the image (FIG. 6C), and one peak component is extracted to calculate an eccentric amount (amplitude value). Based on the calculation result, a chuck error is determined. Thereby, a chuck error can be detected effectively even for a tool holder having a notch in the flange portion.
[0057]
Next, a third embodiment of the machine tool according to the present invention will be described. Note that the apparatus used is the same as that of the first embodiment.
[0058]
When an eddy current sensor is used as the sensor, the electrical signal from the eddy current sensor may not be in the shape of the tool holder due to the influence of magnetization or the change in the thickness (area) of the measurement portion of the tool holder. If the amount of eccentricity is calculated in this state, an error is included and the detection accuracy may be reduced.
[0059]
Therefore, in order to perform detection with higher accuracy, a chuck error is detected by the following method. That is, as shown in FIG. 7, the amount of eccentricity of the tool holder 2 mounted in a state where there is no chuck error is measured in advance, and this is regarded as the basic amount of eccentricity unique to the tool holder and stored. Then, the true eccentricity is calculated by comparing the basic eccentricity with the measured eccentricity measured at the time of ATC, and the chuck error is determined based on the calculated true eccentricity.
[0060]
Hereinafter, the chuck error detection method of the third embodiment will be described with reference to the flowcharts shown in FIGS. First, setup is performed to detect the basic eccentricity (step S20). The setup is performed before the operation of the MC is started according to the flowchart shown in FIG.
[0061]
First, the tool holder 2 is mounted on the main shaft 1. Since it is before the start of operation, chips are not sandwiched, and the tool holder 2 is properly attached to the spindle 1. In this state, the tool holder 2 is rotated, and a change in the distance d for one round of the tool holder is measured by the sensor 12 in a state where the rotation is sufficiently stable (step S21). The measured data of the distance d for one round of the tool holder having a notch is displayed in a graph, for example, as shown in FIG.
[0062]
Next, when the tool holder 2 has a notch, as shown in FIG. 10B, the center of one of the two notches 2C and 2C becomes 0 °. Thus, the phase of the measurement data is corrected (step S22). Then, as shown in FIG. 10C, the measurement data of the two notches 2C and 2C are corrected (step S23). Here, the measurement data is corrected by linear interpolation.
[0063]
If the tool holder 2 has no notch, the phase correction (step S22) and the notch correction (step S23) are not performed, and the process proceeds to the next process (step S24).
[0064]
Next, FFT analysis is performed on the measurement data, and the amplitude and phase (angle) of one peak component are calculated. Then, as shown in FIG. 12A, the eccentricity and phase calculated from the amplitude are stored in the memory 20 as a basic eccentricity u and a basic eccentric direction α (hereinafter referred to as “basic eccentricity vector U”). (Step S24).
[0065]
Next, as shown in FIG. 10D, a sine wave is restored from the calculated amplitude and phase of one peak component. Then, a waveform obtained by subtracting the restored sine wave data from the measurement data (original data) after the notch correction shown in FIG. 10C is calculated (the waveform in FIG. 10E). The calculated waveform is regarded as a magnetic uneven pattern of the measured point sequence data and stored in the memory 20 (step S25).
[0066]
Thus, the setup work is completed (step S26). This setup operation is performed for all tool holders required by the user among the tool holders set in the tool magazine, and is stored in the memory 20 as data unique to each tool holder.
[0067]
When the operation of the MC is started, the chuck error of the tool holder is detected according to the flowchart shown in FIG. 9 (step S30).
[0068]
When the tool is exchanged by the ATC device (step S31), the tool holder 2 attached to the spindle 1 starts to rotate at a specified number of rotations (step S32), and data for one round of the tool holder is measured by the sensor 12. (Step S33). When the tool holder 2 has a notch, notch correction is performed on the measurement data (step S34), and then a magnetic uneven pattern is obtained (step S35). If the tool holder 2 has no notch, the notch correction process (step S34) is unnecessary.
[0069]
Note that the method for acquiring measurement data and the method for correcting notch when the tool holder 2 has a notch are the same as those in the first and second embodiments, and the magnetic unevenness. The method for obtaining the pattern is the same as that in the above-described setup.
[0070]
Next, as shown in FIG. 11, the calculated magnetic concavo-convex pattern (magnetic pattern during processing) is compared with the magnetic concavo-convex pattern during setup (magnetic pattern during setup) stored in the memory 20. In the calculated magnetic concavo-convex pattern, it is determined which position is located at 0 ° (step S36).
[0071]
If the tool holder 2 has a notch, it is determined here which of the two notches 2C and 2C is located at 0 °. Then, the phase correction of the measurement data subjected to the cutout correction is performed so that the determined position becomes 0 ° (step S37).
[0072]
Next, the phase-corrected measurement data is subjected to FFT analysis, and the amplitude and phase of one peak component are calculated. Then, as shown in FIG. 12B, the eccentricity and phase calculated from this amplitude are stored in the memory 20 as a measured eccentricity v and a measured eccentric direction β (hereinafter referred to as “measured eccentricity vector V”). (Step S38).
[0073]
Next, as shown in FIG. 12C, the difference between the calculated measurement eccentricity vector V and the basic eccentricity vector U stored in the memory 20 is calculated by vector calculation (step S39). Then, the calculated vector is set as a true eccentricity vector R, the magnitude r of the true eccentricity vector R is obtained, and this is calculated as the true eccentricity r₁(Step S40).
[0074]
The same measurement (steps S33 to S40) is performed for the second round (or the third, fourth, etc.) of the tool holder 2, and the second round (or the third, fourth, etc.) is true. Eccentricity r₂Is obtained (step S41). CPU 18 obtains the true eccentricity r₁And r₂Is compared with a predetermined threshold value to determine the presence or absence of a chuck error (step S42).
[0075]
The determination result is output to the MC control device 24, and the MC control device 24 determines that the normal state without a chuck error (true eccentricity r₁And r₂(Step S43), machining is started as it is (step S44). On the other hand, when the chuck error is determined (true eccentricity r₁And r₂(Step S45), a command to display that fact on a display unit (not shown) of the MC control device 24 (or to sound an alarm or blink a patrol) (step S45). S46).
[0076]
As described above, in the chuck error detection method according to the present embodiment, the chuck error is determined based on the true eccentricity r obtained by removing the eccentricity specific to the tool holder. Detection can be performed. In this embodiment, since the eccentric direction can be specified from the true eccentric vector R, it is convenient for specifying the abnormal part on the apparatus.
[0077]
As mentioned above, although the example of embodiment of the machine tool which concerns on this invention was demonstrated, this invention is not limited to the example of the said embodiment, Various aspects can be taken. For example, in the series of embodiments described above, an eddy current sensor is used as the sensor 12, but the sensor 12 is not limited to an eddy current sensor as long as it can measure the distance from a specific measurement point to the outer peripheral surface of the tool holder 2. Other sensors may be used. In this case, not only a non-contact type sensor such as an eddy current sensor but also a contact type sensor may be used.
[0078]
Further, in the above series of embodiments, when the CPU 18 determines that a chuck error has occurred, an error display is instructed to the MC display unit. However, as shown in FIG. It is also possible to adopt a form that can be distinguished from a chucking error of the tool holder caused by chips 7 or the like adhering to the mating portion.
[0079]
That is, the CPU 18 determines that the chuck error is to occur (the eccentric amount T₁And T₂First, ATC is performed again, and the same measurement is performed again. As a result, it is possible to determine whether the chuck error is caused by the apparatus or the chuck error due to chips 7 or the like adhering to the fitting portion, and it is difficult to make an error in subsequent countermeasures.
[0080]
In the present embodiment, the displacement of the outer circumference of the tool holder is measured, the measurement data is subjected to FFT analysis, one peak component is extracted, and the amplitude value is obtained to obtain the eccentric amount. However, the method of acquiring the amount of eccentricity is not limited to this method.
[0081]
Furthermore, in the present embodiment, the eccentricity is obtained by performing FFT analysis on the measurement data, extracting one peak component, and obtaining the amplitude value, but the maximum and minimum values of the measurement data are obtained. The eccentric amount of the tool holder may be obtained by calculating and calculating the eccentric amount from the difference.
[0082]
Similarly, the presence / absence of a chuck error can be determined by detecting an abnormality in the amplitude value of the other peak component other than the one peak component obtained by the FFT analysis. It is also possible to determine the presence or absence of a chuck error by comprehensively determining the amplitude values of a plurality of peak components obtained by FFT analysis.
[0083]
Moreover, in this Embodiment, although the flange part 2B of the tool holder 2 is used as a measurement point of the sensor 12, the measurement point of the sensor 12 is not limited to this, According to a measurement condition etc. You may change suitably. For example, as shown in FIG. 13, the cutting edge of the tool T (the part where the workpiece is cut) may be used as the measurement point. In this way, by using the cutting edge of the tool T as a measurement point, the amount of eccentricity of the portion to be directly processed can be measured, so that a chuck error can be detected more reliably.
[0084]
In the present embodiment, the sensor 12 is attached to the head 5, but the installation location of the sensor 12 is not limited to this, and may be attached to a place other than the head 5. For example, the sensor 12 may be fixed at a predetermined position other than the head 5, and the head 5 may be moved to the measurement position of the sensor 12 to detect a chuck error. As the installation position of the sensor 12 other than the head, for example, it may be installed at the first origin of the MC (the reference point (starting point) on the coordinates where the head 5 is always located during machining) or at any other position. Can do. In this case, in order to ensure more stable and highly accurate measurement, it is preferable to install the sensor 12 at a position where it is not affected by the coolant (a position where the coolant is not applied).
[0085]
In the present embodiment, the example in which the present invention is applied to the MC has been described. However, the present invention is not limited to the MC, and can be applied to any machine tool as long as the machine tool uses an ATC device.
[0086]
In the above-described series of embodiments, the amount of eccentricity of the tool holder attached to the spindle is measured, and a chuck error is detected based on this amount of eccentricity. The tool runout is measured by measuring the amount of eccentricity of the tool holder.
[0087]
【The invention's effect】
As described above, according to the present invention, the displacement of the outer peripheral surface of the flange of the tool holder mounted on the spindle is measured, and an abnormality in the mounting state is determined from the measurement data. Thereby, the chuck error (mounting state abnormality) of the tool holder can be reliably detected, and the occurrence of defective products can be eliminated.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a first embodiment of a chuck error detection device.
Fig. 2 Graph of measurement data for one tool holder
FIG. 3 is a graph showing power analysis results of FFT analysis.
FIG. 4 is a flowchart illustrating a processing procedure of the chuck error detection method according to the first embodiment.
FIG. 5 is a plan view of a tool holder having a notch in a flange portion.
6A is a graph of measurement data of a tool holder having a notch in a flange portion, FIG. 6B is a graph of corrected measurement data, and FIG. 6C is a graph in which the result of FFT analysis is displayed in a power spectrum.
FIG. 7 is a conceptual diagram of a chuck error detection method according to a third embodiment.
FIG. 8 is a flowchart for setup.
FIG. 9 is a flowchart for detection.
FIGS. 10A and 10B are graphs of measurement data for one rotation of a tool holder mounted without a chuck error, FIG. 10B is a graph of measurement data with phase correction, and FIG. 10C is measurement data with notch correction. (D) is a graph showing a restored sine wave, (e) is a graph showing a magnetic uneven pattern.
FIG. 11 is a conceptual diagram during phase correction.
FIG. 12 is a conceptual diagram of vector operation.
FIG. 13 is a block diagram showing another embodiment of the chuck error detection device.
FIG. 14 is a cross-sectional view showing a mounting state of the tool holder
FIG. 15 is an explanatory view showing a mounting state of the tool holder.
FIG. 16 is a table showing the amount of eccentricity of the tool holder in each state of MC
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Main shaft, 1A ... Part to be fitted, 2 ... Tool holder, 2A ... Fitting part, 2B ... Flange part, 2C ... Notch, 7 ... Chip, 10 ... Chuck error detection device, 12 ... Sensor, 14 ... Data processor, 16 ... A / D converter, 18 ... CPU, 20 ... memory, 22 ... input / output circuit, 24 ... MC controller, d ... distance, .theta .... rotation angle, U ... basic eccentric vector, u ... basic eccentricity. Amount, α: basic eccentric direction, V: measurement eccentric vector, v: measurement eccentric amount, β: measurement eccentric direction β, R: true eccentric vector, r: true eccentric amount, T: tool

Claims (2)

In a machine tool that mounts a tool holder to which a tool is attached to a spindle and drives the spindle to rotate the workpiece,
Measuring means for measuring the displacement of the flange outer peripheral surface of the tool holder attached to the spindle;
A mounting state determination unit that determines an abnormality in a mounting state of the tool holder on the spindle due to deterioration of a mounting mechanism from measurement data obtained by the measurement unit;
The attachment state determination means compares the previous SL 1 lap eccentricity immediately after the start of rotation of the tool holder and the number lap eccentricity, towards the number lap eccentricity than eccentricity of 1 lap A machine tool characterized in that an abnormality in a mounted state is determined by detecting that is smaller than a predetermined threshold value . In the tool holder mounting state abnormality determination method in a device that attaches a tool holder to a shaft and rotationally drives the shaft,
Measure the displacement of the outer peripheral surface of the flange of the tool holder, thereby obtaining the amount of eccentricity of the tool holder,
Comparing the pre-Symbol 1 lap eccentricity immediately after the start of rotation of the tool holder and the number lap eccentricity, towards the number lap eccentricity than eccentricity of the first lap is smaller than a predetermined threshold value An abnormality determination method of a tool holder in a device having a rotating shaft, wherein abnormality of the attachment state of the tool holder to the shaft due to deterioration of the attachment mechanism is determined by detecting the state of being.

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