JPH0985585A - Monitoring method and device for state of machining cutter for machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect abnormalities of a machining cutter by starting a warning means when a discriminating means judges that a value corresponds to either peak value upper and lower discriminated values or a cutter break discriminated value. SOLUTION: Either command that the rotation of an electric motor 4 for driving a machining cutter 9 is stopped or that an annunciation means 3 is started is performed according to the wear level of the machining cutter 9 output from a discriminating means 11. The judging values of the absolute value measurement and the relative value measurement and the machining load rise judging value are input in this discriminating means 11, abnormalities such as break of the machining cutter 9, the poor cutting edge, overload, abrasion, etc., are discriminated on the basis of the judging values of the absolute value measurement and the relative value measurement, and the using limit of the machining cutter 9 is discriminated on the basis of the machining load rise judging value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various types of machine tools such as a turning tool for a lathe, a drill for a drilling machine, a milling cutter for a milling machine and the like, which are driven by an electric motor to perform cutting and drilling. A method for monitoring the state of the machining blade, which constantly monitors the state of the blade and detects the normal state of the machining blade or abnormalities such as breakage, defective cutting edge, overload, wear, etc. And its equipment.

[0002]

2. Description of the Related Art In machining blades for machine tools such as cutting tools used for lathes, abnormalities such as overload and breakage due to entrapment of constituent blade tips, blade spills, chips, etc. may occur during machining.
When the usage limit is reached, the operator may continue to process the cutting tool without giving notice of any abnormalities in the cutting tool, and produce a defective product.
In particular, if the operator is in a state where the machined state or the machined item cannot be visually observed, or the machine tool is an automatic machine that continuously processes a large number of products, a large amount of defective products will be generated. There has been proposed a monitoring device capable of constantly monitoring the state of the blade.

This monitoring device includes a touch sensor system in which a sensor bar is attached to a machining blade, an electric leakage system in which a weak current is passed between the machining blade and a workpiece, and a vibration system for detecting vibration generated when the machining blade is broken. There is a ring sensor method in which a processing blade is brought close to or inserted into a ring-shaped sensor using light or infrared rays.

[0004]

Among the above, the touch sensor method includes: a. Since the sensor bar touches the machining blade, the machining cycle becomes longer. b. Since the touch operation is performed for each machining, the sensor bar often wears significantly or malfunctions. c. It is difficult to adjust the operation timing of the sensor bar. d. Since the sensor bar cannot be touched on the cutting edge that comes into contact with the workpiece,
The edge breakage cannot be detected. e. If there is a guide bush in the jig of the processing blade, the sensor bar cannot be attached. There is a problem called.

Further, in the electric leakage system, a. It is not preferable to use it in combination with a water-soluble cutting oil because it energizes the working blade and the work piece. The vibration method of a. It is difficult to distinguish from microtremors during normal processing. b. Only breakage of the processing blade can be detected. c. Since the vibration generated when the blade, which is a vibration measurement object, is broken is monitored, the breakage can be detected only once. In the ring sensor method of a. The accuracy is poor. b. It cannot be detected when the middle of the processing blade is broken. And so on.

Further, most of these systems are breakage monitoring devices only for detecting breakage of a working blade, and the constituent cutting edge before breakage, entrapment of foreign matter such as blade spills or scratches, cutting chips, and concentration of cutting oil. Since it is almost impossible to detect abnormalities such as overload due to deterioration and usage limits, it cannot be an effective means for avoiding the mass production of defective products. Moreover, if expensive cutting blades are replaced every time they are broken, the cost will increase, so unnecessary replacement should be avoided as much as possible.

Therefore, the inventor of the present invention, when the processing blade processes the workpiece, the effective electric power from the electric motor changes during one step from the processing start to the processing end of the workpiece. Focusing on the fact that the effective power has a high rate of change with respect to the load applied to the processing blade due to cutting of the workpiece, etc., monitor this change in active power to know the slight change in the processing load on the processing blade. By doing so, it is intended to provide a state-of-the-art method for monitoring the state of a machining blade for machine tools, which is capable of detecting not only the breakage of the machining blade, but also the abnormal state of the machining blade before it breaks. is there.

[0008]

According to the above-mentioned object, as a first method of monitoring the state of the machining blade for machine tools of the present invention, the state of the machining blade for machine tools for machining a workpiece is monitored. In the method, in one step from the processing start to the processing end of the work piece, a waveform change of a processing load of active power used by a normal processing blade as power is measured as a reference graph, and a reference peak value of the reference graph. Above and below the
Set a peak value upper limit determination value indicating the overload of the processing blade, and a peak value lower limit determination value indicating the cutting edge defect of the processing blade,
Between the peak value upper limit judgment value and the peak value lower limit judgment value and the normal region of the working blade, and below the peak value lower limit judgment value, the blade breakage judgment value indicating the breakage of the working blade is set. Then, the blade breakage determination value and the peak value upper limit determination value and the peak value lower limit determination value are input to the determination means, and the waveform change of the processing load of active power used by the processing blade during one step is measured graph. Measure, input the measured graph to the determination means, the measured peak value in the measured graph is out of the normal range of the machining blade, the peak value upper limit judgment value, peak value lower limit judgment value and blade breakage judgment value When the determination means determines that any of the above conditions is met, the alarm means such as an alarm sound or a warning light is activated, or the operation of the machine tool is stopped.

As a second method of the present invention, in a method of monitoring the state of a machining blade for a machine tool for machining a workpiece, the machining blade is used from the start to the end of machining of the workpiece. Before performing one step, the idling load of active power used by the machining blade as power is measured for a certain period of time to calculate an idling load average value, and the idling load average value is set to a preset value of the machining blade excess. Peak value upper limit judgment value showing the load, peak value lower limit judgment value showing the cutting edge defect of the working blade, and multiplying each constant of the blade breakage judgment value showing the breakage of the working blade at the lower of the peak value lower limit judgment value The peak value upper limit determination value, the peak value lower limit determination value, and the blade breakage determination value are determined, and the peak value upper limit determination value, the peak value lower limit determination value, and the blade breakage determination value are input to the determination means, and the processing is performed. The blade is used to open the workpiece. The change in the waveform of the processing load of active power used in one process from the process to the end of processing is measured as a measured graph, and the measured graph is input to the determination means so that the measured peak value in the measured graph is the upper limit of the peak value. Departing from the normal range of the processing blade between the judgment value and the peak value lower limit judgment value, the judgment means judged that the peak value upper limit judgment value, the peak value lower limit judgment value or the blade breakage judgment value was met. In this case, warning means such as alarm sounds and warning lights are activated and the machine tool is deactivated.

In the judging means of the first or second method,
The processing load increase judgment value of the processing blade is input, the measured peak values in the measured graph for each process are added, and the measured peak average value is calculated from a predetermined number of measured peak values. Is compared with the processing load increase determination value of the determination means, and when the determination means determines that the measured peak average value exceeds the processing load increase determination value of the determination means, the alarm sound, warning light, etc. It is also possible to activate the notifying means and stop the operation of the machine tool.

Furthermore, as a state monitoring device for a machining blade of a machine tool according to the present invention, in a device for monitoring a state of a machining blade for a machine tool for machining a workpiece by operating the machining blade, the machining of the workpiece is performed. In one step from the start to the end of processing, active power measuring means for measuring the waveform change of the processing load of the active power used as power by the processing blade as an actual measurement graph, and the peak value upper limit judgment indicating the overload of the processing blade. The value and the peak value lower limit determination value indicating the cutting edge defect of the processing blade, and the lower limit of the peak value lower limit determination value, the blade breakage determination value indicating the breakage of the processing blade is input, and the active power measuring means The actual measurement peak value in the actual measurement graph received from deviates from the normal range of the machining blade between the peak value upper limit determination value and the peak value lower limit determination value, and the peak value upper limit determination value and the peak value lower limit determination value. blade Is a determination unit that it has any of the determination values, receiving a judgment of the judging means, and a control means for deactivation operation and machine tools informing means.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In the figure, FIG. 1 is an explanatory view of a machine tool and a machining blade state monitoring device, and FIGS. 2 and 3 show changes in the waveform of active power used by the machining blade as power, and FIG. 2 shows absolute value measurement. Waveform diagram of active power in the case, Fig. 3 is a waveform diagram of active power in the case of relative value measurement, and Fig. 4 is a case where the measured peak value is in the normal range, above the peak value upper limit judgment value and below the peak value lower limit judgment value. FIG. 5, FIG. 5 is an explanatory view when the measured peak value is located below the blade breakage determination value, FIG. 6 is a relationship diagram between the number of times of processing and active power, and FIGS. 7 is a flowchart based on absolute value measurement, and FIG. 8 is a flowchart based on relative value measurement.

The machine tool 1 shown in FIG. 1 is provided with a machining blade state monitoring device 2 and an informing means 3 at appropriate locations that can be easily confirmed from the operator's working position. Machine tool 1
A lathe, a drilling machine, a milling machine, etc., in which an electric motor 4 is connected to an electromagnetic switch 6 of a control unit 5 and a power supply unit 7 by three-phase wiring 8 for cutting or drilling a workpiece. A machining blade 9 such as a cutting tool, a drill or a milling cutter for machining is driven by an electric motor 4.

The working blade state monitoring device 2 receives the active power measuring means 10 for taking in and measuring the information of the working blade 9 from the electric motor 4, and the active power information from the active power measuring means 10 to receive the working blade 9 Determination means 1 for determining the wear level of
1 and a control means (not shown) that is integrally incorporated in the determination means 11 and that issues an instruction to start the notification means 3 or stop the operation of the machine tool 1 based on the determination of the determination means 11. Abnormalities such as breakage of the processing blade 9, defective cutting edge, overload, wear and the like, and quality of replacement time due to usage limit are constantly monitored. Further, the notifying means 3 is, for example, a warning light such as a patrol light or an alarm sound such as an alarm, and an overload of the processing blade 9, a cutting edge abnormality, a blade break, etc. are set for each abnormality content.

The active power measuring means 10 comprises three-phase wirings 8 and 1.
2 is connected to the electric motor 4 and is also connected to the determination means 11 by the wiring 13, and changes in effective power when the electric motor 4 operates the machining blade 9, that is, the machining blade 9 is a workpiece. The active power information used as a power for the machining of is processed by the active power measuring means 10 from the electric motor 4 and constantly input to the determining means 11. Determination means 11
Is connected to the control unit 5 of the machine tool 1 by the wiring 14, and when the machining by the machining blade 9 is performed,
The trigger signal is taken into the judging means 11 through the judging means 11, and the judging means 11 judges the wear level of the processing blade 9.

The control means integrated with the determination means 11 includes the control section 5 of the machine tool 1, the notification means 3, and the wiring 1.
5 and 16 are connected, and the rotation of the electric motor 4 for driving the machining blade 9 is stopped or the notifying means 3 is activated according to the wear level of the machining blade 9 issued by the determination means 11. Either of these commands is issued.
The absolute value measurement of FIG. 2 and the relative value measurement of FIG. 3 and the processing load increase determination value H of FIG. 6 are input to the determination means 11, and the determination values A to C of the absolute value measurement and the relative value measurement are input. Based on this, abnormality such as breakage, cutting edge defect, overload, wear and the like of the working blade 9 is determined, and based on the working load increase determination value H, the working limit of the working blade 9 is determined.

The measurement diagrams of FIGS. 2 and 3 show the processing load of the active power used by the processing blade 9 for processing the workpiece as the waveform change by the active power measuring means 10. The waveform change of the active power is shown in FIG. Is a waiting period T1 from the detection of the trigger point until the machining blade 9 starts machining, and a machining load measurement period T2 for one process from the machining start to machining of the workpiece by the machining blade 9. have.

Among them, in the absolute value measurement of FIG. 2, during the machining load measuring period T2, the idling load E of the active power, which is the idling operation state of the electric motor 4 after the completion of one step, and the power supply to the electric motor 4 are turned off. include. And
First, the reference peak value P1 for determining the judgment value of the processing blade 9
Is measured by using the normal processing blade 9 to measure the active power 1
Performed by zero. In this measurement, the processing load of active power using the normal processing blade 9 in the processing load measurement period T2 is measured as the reference graph G1, and after the completion of one step in the processing load measurement period T2, the maximum effective from the reference graph G1. A reference peak value P1 which is an electric power value is taken out.

Next, based on the above measurement, the peak value upper limit judgment value A indicating the overload of the working blade 9 and the peak value lower limit indicating the cutting edge defect of the working blade 9 are located above and below the reference peak value P1. The judgment value B is set so that the area between the peak value upper limit judgment value A and the peak value lower limit judgment value B is not the normal range D which is the allowable range of use of the machining blade 9, and the peak value lower limit judgment value B The blade breakage determination value C indicating the breakage of the processing blade 9 is set in the lower order of the. The levels of the judgment values A to C and the range of the normal range D are set based on the durability performance of the processing blade 9, and these are input to the judgment means 11 as basic data of the absolute value measurement program.

Using the above absolute value program, the processing blade 9
When monitoring the state of, the waveform change of the processing load of the active power used by the processing blade 9 during one process during the processing load measurement period T2 is measured as the actual measurement graph G2.
Measurement is performed at 0, and this measured graph G2 is input to the determination means 11. Then, after the machining load measurement period T2, the determination means 11 compares the measured peak value P2 in the measured graph G2 with the determination values A to C of the basic data, and the determination means 11 detects an abnormality in the processing blade 9. In this case, the control means is operated to activate the notification means 3 or stop the operation of the machine tool 1.

In the relative value measurement shown in FIG. 3, after the last machining load measuring period T2 to the next machining load measuring period T2, that is, the machining blade 9 starts machining the workpiece in the machining load measuring period T2. Immediately before performing one step from to the end of processing,
Idling load measurement period T3 for determining the judgment value of the processing blade 9
Is set. In the idling load measurement period T3, the idling load E of the active power in the idling operation state of the electric motor 4 is measured by the active power measuring means 10, and the determining means 11 is used.
Then, the idling load average value F is calculated, and in the judging means 11, a peak value upper limit judgment value A indicating a preset overload of the machining blade 9 and a peak value lower limit judgment value B indicating a cutting edge defect of the machining blade 9 are set. And the processing blade 9 below the peak value lower limit judgment value B
Peak coefficient upper limit judgment value A by multiplying each coefficient X, Y, Z of the blade breakage judgment value C indicating the breakage of
The peak value lower limit determination value B and the blade breakage determination value C are determined.

Between the peak value upper limit judgment value A and the peak value lower limit judgment value B, as in the case of the above-mentioned absolute value measurement, the normal range D which is the allowable range of use of the working blade 9 is determined, and the idling is performed. Judgment values A to C obtained relative to the load average value F and normal range D
Is input to the determination means 11 as an absolute value program.

Using the relative value program described above, the machining blade 9
In the case of monitoring the above condition, the idle blade load E of active power is set to the active power measuring means 1 in the idle load measurement period T3 immediately before the processing load measurement period T2 in which the processing blade 9 performs one step of the workpiece.
0, and the determination means 11 calculates the idling load average value F from the idling load E, and the idling load average value F is multiplied by the coefficient of the determination values A to C to determine the determination values A to C and the normal range D. Determine the range of. Then, the actual measurement graph G2 is measured during the processing load measurement period T2, and the actual measurement peak value P2 in the actual measurement graph G2 is compared with the determination values A to C after the processing load measurement period T2.
When the determination means 11 detects an abnormality in the processing blade 9, the control means is operated to activate the notification means 3 or the machine tool 1
Stop the operation of.

Next, the determination based on the measurement diagrams of FIGS. 2 and 3 will be described with reference to FIGS. 4 and 5. First, in FIG. 4, the processing load of the active power when the processing blade 9 actually processes the workpiece in one processing in the processing load measurement period T2 shows three types of measured graphs G2-1, G2-2. P2-3 indicates the peak values P2-1 and P from the respective measured graphs G2-1 to G2-1 after the end of one machining in the machining load measurement period T2.
2-2 and P2-3 are measured.

Of these, the actual measurement graph G2-1 indicated by the solid line
Then, the peak value P2-1 is located in the normal region D between the peak value upper limit determination value A and the peak value lower limit determination value B, and the determination means 11 determines that the processing blade 9 is normal. Further, in the actual measurement graph G2-2 of the broken line in which the peak value P2-2 is located higher than the peak value upper limit judgment value A, the judgment means 11
Detects an overload caused by the inclusion of chips in the processing blade 9 or abnormal concentration of cutting oil. Further, in the actual measurement graph G2-3 of the alternate long and short dash line in which the peak value P2-3 is located lower than the peak value lower limit judgment value B, the judgment means 11 is attributed to the processing blade 9 such as blade spill, cutting edge damage, and constituent cutting edge. The occurrence of defective cutting edge is detected.

In FIG. 5, the actual measurement graph G2-4 in (A) shows the case where the machining blade 9 is broken due to overload in the previous one step.
In addition, the case of measuring this breakage in the next step is shown in the measured graph G2-4 of (B). FIG. 5 (A)
In the previous one step, when the processing blade 9 breaks at the peak value P2-4 due to overload, the active power loses the processing load and remains as the idling load E equal to or less than the blade breakage determination value C, completing one step. Next, in the next step of FIG. 5B, the processing blade 9
Is a broken state, the active power does not reach the blade breakage determination value C with the idling load E. Therefore, the determination means 11 determines that the machining blade 9 has been broken after the end of the next step.

Further, as described above, the processing load increase determination value H shown in FIG. 6 is used to determine the use limit of the processing blade 9. This processing load increase determination value H is input to the determination means 11 by replacing the durability of the processing blade 9 with the value of the processing load of active power based on the performance and processing content of the processing blade 9. Then, the measured peak value P2 for each machining sent from the active power measuring means 10 is recorded in the judging means 11, the measured peak average value P3 is calculated from the predetermined number n of measured peak values P2, and the measured peak average value P3. Is compared with the processing load increase determination value H.

Each measured peak value P2 used for the measured peak average value P3 is in the normal range D of the above absolute value measurement and relative value measurement programs, and when the measured peak value P2 deviates above and below the normal range D, As described above, the abnormality is notified by the determination means 11 and the control means. Also, the measured peak average value P
3 is calculated by always taking in a new value while discarding the oldest value from the predetermined number of actually measured peak values P2 each time the number of machining is increased. Therefore, the machining blade 9 at the time of replacement with a new one also gradually wears as the number of machining increases, and therefore the actually measured peak average value P3 calculated by always incorporating the new actually measured peak value P2 gradually increases the machining load judgment value H. Approach to. When the determination means 11 determines that the measured peak average value P3 exceeds the processing load increase determination value H, the control means is operated to activate the notification means 3 or the operation of the machine tool 1 is started. It stops and notifies that the processing blade 9 has reached the use limit.

To judge the machining blade 9, one of the above-mentioned two programs inputted to the judging means 11 is selected. For example, in the absolute value measurement of FIG. 2, the difference between the idling load E of the active power and the measured peak value P2 of the actual measurement graph G2 that actually measures the processing load of the active power is so large that the variation of the idling load E can be ignored. Used in some cases and also in FIG.
In the relative value measurement of, the idle load E of the active power and the actually measured peak value P2 are not so different from each other, and the idle load E of the active power varies, or the processing load rises and falls with the fluctuation of the idle load E. To the actual peak value P
Used when 2 is difficult to measure. Therefore, in the relative value measurement of FIG. 3, the idling load average value F is obtained from the idling load E of active power, and the determination value A based on the idling load average value F is obtained.
~ C and the range of normal range D is the processing load measurement period T2
At every time immediately before performing one step of the workpiece.

Next, two more specific operation examples of the machining blade state monitoring device 2 configured as described above will be described with reference to the flowcharts of FIGS. 7 and 8. The absolute value measurement program in which the basic data by the absolute value measurement of FIG. 2 and the processing load increase determination value H set in FIG. 6 are combined is input to the flowchart of FIG. 7, and the flowchart of FIG. A relative value measurement program in which the basic data obtained by the relative value measurement of FIG. 3 and the processing load increase determination value H set in FIG. 6 are combined is input. As described above, for the determination of the machining blade 9, one of the above-mentioned two programs input to the determination means 11 is selected. In describing these flowcharts, FIGS. 1 to 6 will be referred to as appropriate.

In the flow chart of FIG. 7 using the absolute value measuring program, when the program starts in step S1, the electric motor 4 starts up, the trigger point is detected in step S2, and the waiting period T1 is waited in step S3, and then step S4. And the processing blade 9 is 1
The active power measuring means 10 starts measuring the processing load of active power used in processing as the actual measurement graph G2. Then, in step S5, the actually measured graph G2 is measured during the processing load measurement period T2, and after entering the step S6 and ending the measurement, in step S7, the actually measured peak value P2 that is the maximum active power is extracted from the actually measured graph G2.

In the blade breakage determination in step S8, the determination means 11 compares the measured peak value P2 with the blade breakage determination value C, and when the measured peak value P2 is equal to or smaller than the blade breakage determination value C, that is, P2≤C. In the case of, the process goes to step S9 and the blade breakage lamp which is the notification means 11 is turned on. If the actually measured peak value P2 is larger than the blade breakage determination value C, that is, if P2> C, the blade edge abnormality determination at step S10 is entered, and the actually measured peak value P2 and the peak value lower limit determination value are determined by the determination means 11. If the measured peak value P2 is equal to or smaller than the peak value lower limit determination value B, that is, if P2 ≦ B, the process goes to step S11 to turn on the cutting edge abnormality lamp that is the notification means 11.

When the measured peak value P2 is larger than the peak value lower limit judgment value B, that is, when P2> B, the overload judgment in step S12 is entered, and the judgment means 11 determines the measured peak value P2 and the peak value. The upper limit judgment value A is compared.
If the measured peak value P2 is equal to or larger than the peak value upper limit determination value A, that is, if P2 ≧ A, then step S
If the measured value P2 is smaller than the peak value upper limit judgment value A, that is, if the actually measured peak value P2 is smaller than the peak value upper limit judgment value A, that is, if P2 <A, the process directly proceeds to the addition processing of step S16. To do. When each lamp is turned on in the above steps S9, S11 and S13, the process goes to step S14 and the alarm 1 which is the notification means 11 is entered.
Is output, and then step S15 is entered and the machine tool 1
Stop the operation of.

In the addition processing of step S16, the processing blade 9
Measured peak value P to measure the degree of wear of the
2 is added, and if the number of times the actually measured peak value P2 is added is less than the predetermined number n in the number of times of addition in step S17, the program for one machining is ended as it is. If the number of additions in step S17 is sufficient for the predetermined number n,
As described above, the oldest value is discarded from the measured peak values P2, a new value is taken in, the measured peak average value P3 is calculated from the measured number of peak values P2 of a predetermined number n, and this measured peak average value P3 is calculated in step S18. By comparing the processing load increase determination value H in the processing load determination, the wear level of the processing blade 9 is determined.

When the measured peak average value P3 is equal to or larger than the processing load increase determination value H, that is, when P3 ≧ H, the process goes to step S19 and the wear lamp which is the notification means 3 is turned on and the step is performed. In S20, the alarm 2 of the notifying means 3 is activated, and when the measured peak average value P3 is smaller than the machining load increase determination value H, that is, when P3 <H, the program for one machining is ended as it is.

In the flow chart of FIG. 8 using the relative value measuring program, when the program starts in step S1, the electric motor 4 starts up, and when the trigger point is detected as an external signal, the external signal is detected in step S2, In step S3, the waiting period T1 and the processing load measurement period T
Wait for two. Then, the measurement of the idling load E is started from step S4, the trigger point is detected in step S5, the waiting period T1 is waited for in step S6, and the measurement of the idling load E is ended in step S7. In S8, the idling load average value F based on the idling load E is calculated.

In step S9, an abnormality of the electric motor 4, the bearing, the drive transmission portion, etc. is determined as an abnormality of the idling load E. When it is determined that the idling load is abnormal, the idling load of the notification means 3 is determined in step S10. The abnormality lamp is turned on, and in step S11, the alarm 2 which is also the notification means 3 is activated.

If there is no abnormality determination of the idling load E in step S9, the process proceeds to step S12 as it is, and the processing load of the active power used by the processing blade 9 for one processing of the workpiece is measured by the active power measuring means. 10 starts measurement as a measured graph G2. In step S13, the processing load measurement period T
During 2, the measurement of the actual measurement graph G2 by the active power measuring means 10 is continued, and after entering the step S14 and ending the measurement, the actual measurement peak value P2 which is the maximum active power is taken out from the actual measurement graph G2 in step S15.

In the blade breakage determination in step S16, the actually measured peak value P2 is compared with the coefficient X of the idling load average value F × the blade breakage determination value C = the blade breakage determination value C, and the actually measured peak value P2 is determined as the blade breakage determination value. When it is the same as or smaller than C, that is, P2 ≦ F × X
In case of = C, step S17 is entered to turn on the blade breakage lamp which is the notification means 3, and when the actually measured peak value P2 is larger than the blade breakage determination value C, that is, P2> FxX = C.
In this case, the process proceeds directly to the blade edge abnormality determination in step S18.

In the blade edge abnormality determination in step S18, the actually measured peak value P2 is compared by the determination means 11 with the coefficient Y of the idling load average value F × the peak value lower limit determination value B = the peak value lower limit determination value B to obtain the actually measured peak value. If P2 is equal to or smaller than the peak value lower limit determination value B, that is, if P2 ≦ F × Y = B, the process goes to step S19, the blade abnormality lamp that is the notification means 3 is turned on, and the actually measured peak value P2 is When it is larger than the peak value lower limit determination value B, that is, when P2> F × Y = B, the process directly proceeds to the overload determination of step S20.

In the overload determination of step S20, the determination means 11 compares the actually measured peak value P2 with the idling load average value F × the coefficient Y of the peak value upper limit determination value A = the peak value lower limit determination value A to obtain the actually measured peak value. When P2 is equal to or larger than the peak value upper limit judgment value A, that is, when P2 ≧ F × Y = A, the procedure goes to step S21, the overload lamp which is the notification means 3 is turned on, and the actually measured peak value P2 is When it is smaller than the peak value lower limit determination value B, that is, when P2 <F × Y = A, the process directly proceeds to the addition process of step S24. When each lamp is turned on in steps S17, S19, and S21 described above, next, step S22 is entered to output the alarm 1 which is the notification means 3, and then step S23 is entered to stop the operation of the machine tool 1. .

Next, when the actually measured peak value P2 is added in the addition processing of step S24 and the number of times of addition of the actually measured peak value P2 is less than the predetermined number n in the number of times of addition in step S25, the program for one machining is directly performed. To finish. Also,
If the number of times of addition in step S25 is sufficient for the predetermined number n, the oldest value is discarded from the measured peak values P2, and a new value is fetched to obtain the measured peak value P for the predetermined number n.
The actual measurement peak average value P3 is calculated from 2, and the actual measurement peak average value P3 is compared with the processing load increase determination value H in the processing load determination in step S26 to determine the wear level of the processing blade 9.

When the measured peak average value P3 is equal to or larger than the processing load increase determination value H, that is, when P3 ≧ H, the process goes to step S27, the wear lamp as the notification means 3 is turned on, and step S28. Then, the alarm 2 of the notifying means 3 is activated, and when the measured peak average value P3 is smaller than the machining load increase determination value H, that is, when P3 <H, the program for one machining is ended as it is.

[0044]

As described above, according to the method and apparatus for monitoring the state of the machining blade for machine tools according to the present invention, a.
Since it is not necessary to make the sensor bar touch the machining blade, there is almost no time effect on the machining and the machining cycle can be shortened. b. Since no touch operation is performed, there are no parts to wear and malfunction does not occur. c. There is no need to set operation timing. d. It can be used in combination with water-soluble cutting oil. e. Not affected by microtremors during processing. f. There is no limit to the number of measurements and repeated measurements are possible. And so on.

Further, not only the breakage of the working blade, but also the abnormality such as the overload due to the inclusion of foreign material such as the cutting edge, blade spill, scratches, chips, etc. before the breakage and the concentration of cutting oil, and the usage limit are accurately detected. Therefore, the expensive machining blade can be effectively used for a long period of time. Moreover, since a large number of defective products can be avoided in advance, a high productization rate can be obtained while achieving cost reduction.

[Brief description of drawings]

FIG. 1 is an explanatory view of a machine tool and a machining blade state monitoring device showing an embodiment of the present invention.

FIG. 2 is a waveform diagram of active power in the case of absolute value measurement showing one embodiment of the present invention.

FIG. 3 is a waveform diagram of active power in the case of relative value measurement showing one embodiment of the present invention.

FIG. 4 is an explanatory view showing a case where an actually measured peak value is located in a normal range, above a peak value upper limit judgment value and below a peak value lower limit judgment value, showing one embodiment of the present invention.

FIG. 5 is an explanatory diagram of an example of an embodiment of the present invention in which an actually measured peak value indicating an example of the embodiment of the present invention is positioned below a blade breakage determination value

FIG. 6 is a diagram showing the relationship between the idling load average value and the machining load increase determination value showing one embodiment of the present invention.

FIG. 7 is a flowchart based on an absolute value measurement showing an embodiment of the present invention.

FIG. 8 is a flowchart based on relative value measurement showing an embodiment of the present invention.

[Explanation of symbols]

1 ... Machine tools such as lathes and drilling machines 2 ... Condition monitoring device for machining blades 3 ... Warning lamps such as patrol lights and notification means by alarm sounds such as alarms 4 ... Electric motors 5 ... Control unit 6 ... Electromagnetic switch 7 ... Power supply unit 9 ... Machining blade such as bite, drill, milling cutter, etc. 10 ... Active power measuring means 11 ... Judgment means A ... Peak value upper limit judgment value B ... Peak value lower limit judgment value C ... Blade breakage judgment value D ... Peak value upper limit judgment value A Normal range between the peak value lower limit judgment value B and the peak value E ... Idle load of active power F ... Idle load average value G1 ... Reference graph G2, G2-1, G2-2, P2-3 ... Actual measurement graph H ... Machining load Increase determination value T1 ... Standby period T2 ... Machining load measurement period T3 ... Idling load measurement period P1 ... Reference peak value P2, P2-1, P2-2, P2-3 ... Measured peak value P3 ... Measured peak average value

Claims (4)

[Claims] 1. A method for monitoring the state of a machining blade for a machine tool for machining a workpiece, wherein a normal machining blade (9) is provided in one step from the start to the end of machining of the workpiece.
Measure the waveform change of the processing load of the active power used as power by the standard graph (G1).
Above and below the reference peak value (P1) of 1), a peak value upper limit judgment value (A) indicating an overload of the machining blade (9),
The peak value lower limit judgment value (B) indicating the cutting edge defect of the processing blade (9) is set, and these peak value upper limit judgment values (A) are set.
Between the peak value lower limit judgment value (B) and the machining blade (9)
And the normal range (D) of the above, and a lower limit of the peak value lower limit determination value (B), a blade breakage determination value (C) indicating a breakage of the processing blade (9) is set, and the blade breakage determination value is set. (C) and the peak value upper limit determination value (A) and the peak value lower limit determination value (B) are input to the determination means (11), and the processing blade (9) processes active power used in one step. The waveform change of the load is measured as a measured graph (G2), the measured graph (G2) is input to the determination means (11), and the measured peak value (P2) in the measured graph (G2) is the machining blade (G2). The determination means (11) is determined to be outside the normal range (D) of 9) and to correspond to any of the peak value upper limit determination value (A), the peak value lower limit determination value (B), and the blade breakage determination value (C). If) is determined, the alarm sound, warning light, or other notification means is started or the machine tool is stopped. State monitoring method of a machine tool for machining blade characterized. 2. A method for monitoring the state of a machining blade for a machine tool for machining a workpiece, wherein the machining blade (9) performs one step from the start to the end of machining of the workpiece. , The idle load (E) of active power used by the machining blade (9) as power is measured for a certain period of time to calculate the idle load average value (F), which is preset to the idle load average value (F). The peak value upper limit judgment value (A) indicating the overload of the machining blade (9), the peak value lower limit judgment value (B) indicating the cutting edge defect of the machining blade (9), and the peak value lower limit judgment value (B ) Is multiplied by each constant of the blade breakage determination value (C) indicating the breakage of the processing blade (9), and the peak value upper limit determination value (A), the peak value lower limit determination value (B), and the blade breakage determination value are multiplied. (C), the peak value upper limit judgment value (A) and the peak value lower limit judgment value (B ) And the blade breakage determination value (C) are input to the determination means (11), and the processing load (9) of the processing load of the active power used for one step from the processing start to the processing end of the workpiece. The waveform change is measured as an actual measurement graph (G2), the actual measurement graph (G2) is input to the determination means (11), and the actual measurement peak value (P) in the actual measurement graph (G2) is measured.
2) deviates from the normal range (D) of the machining blade (9) between the peak value upper limit determination value (A) and the peak value lower limit determination value (B), and the peak value upper limit determination value (A) When the determination means (11) determines that either the peak value lower limit determination value (B) or the blade breakage determination value (C) is met, the alarm means such as an alarm sound or a warning light is activated, or the machine tool A method for monitoring the state of a machining blade for a machine tool, characterized by stopping the operation. 3. A processing load increase determination value (J) of the processing blade (9) is input to the determination means (11), and an actually measured peak value (in the actually measured graph (G2) for each step ( P
2) is added to calculate a measured peak average value (P3) from a predetermined number of measured peak values (P2), and the measured peak average value (P3) is used as the processing load increase judgment value ( H), when the determination means (11) determines that the measured peak average value (P3) exceeds the processing load increase determination value (H) of the determination means (11), the alarm sound is generated. 3. The method for monitoring the state of a machining blade for a machine tool according to claim 1 or 2, wherein a notification means such as a warning light or a warning light is activated or the operation of the machine tool is stopped. 4. An apparatus for monitoring the state of a machining blade for a machine tool, which performs machining of a workpiece by operating a machining blade (9), wherein 1 from the start to the end of machining of the workpiece.
In the process, active power measuring means (10) for measuring the waveform change of the processing load of active power used by the processing blade (9) as power, as an actual measurement graph (G2), and the processing blade (9).
Peak value upper limit determination value (A) indicating the overload of No. 1, peak value lower limit determination value (B) indicating the cutting edge defect of the processing blade (9), and lower than the peak value lower limit determination value (B) The blade breakage determination value (C) indicating the breakage of the blade (9) is input, and the measured peak value (P2) in the measured graph (G2) received from the active power measuring means (10) is the peak. The peak value upper limit determination value (A) and the peak value lower limit determination value deviate from the normal range (D) of the machining blade (9) between the value upper limit determination value (A) and the peak value lower limit determination value (B). (B) and the blade breakage determination value (C), a determination unit (11) for determining whether the determination unit (11) determines whether or not the determination unit (11) determines that the notification unit is activated or the machine tool is stopped. A state monitoring device for a machining blade for machine tools, comprising: