JP2019034345A - Tool abnormality detection device and detection method - Google Patents

Abstract

To provide a tool abnormality detection device and a tool abnormality detection method by which tool abnormality can be more suitably detected.SOLUTION: A tool abnormality detection device D is a tool abnormality detection device D which detects abnormality of a tool in a processor WM which relatively rotates the tool and a work-piece, which is processed by the tool, by a motor, thereby processing the work-piece. This device comprises: a power measurement part 1 which measures consumption power of the motor as actual consumption power; and an abnormality detection part 2 which detects abnormality of the tool by comparing a prescribed constant value which has been previously set with the actual consumption power which has been measured by the power measurement part 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tool abnormality detection device and a tool abnormality detection method for detecting a tool abnormality such as tool wear or chipping.

  For example, a tool abnormality detection device that detects a tool abnormality such as tool wear or chipping (for example, blade spillage) has been conventionally known, and is disclosed in, for example, Patent Document 1 and Patent Document 2.

  The cutting force detection method disclosed in Patent Document 1 is based on the tool movement tangent of cutting resistance using the current value of the spindle motor, the motor of the moving shaft, the radius value of the end mill tool, and the cutting participation angle in machining with an end mill tool. Directional cutting resistance and / or tool movement normal direction cutting resistance is detected. In Patent Document 1, it is possible to detect tool wear by monitoring cutting resistance during machining.

  An NC-controlled machining abnormality detection device disclosed in Patent Document 2 includes a cutting force measuring unit 101 that measures a cutting load applied to a tool as a cutting force using a piezoelectric element type force sensor, and a machine A coordinate value acquisition unit 102 that acquires the current processing position of the processing apparatus 10 from the NC control unit 17, a cutting force change amount acquired by the cutting force measurement unit 101, and information stored in the cutting position / processing condition storage unit 107. The cutting force stored in the cutting force calculation value storage unit 108 is extracted based on the cutting force change amount comparison calculation unit 103 for comparison and the cutting force calculation compared with the actual cutting force acquired by the cutting force measurement unit 101. The delay time calculation unit 104 that calculates the delay time between the value (model cutting force pattern) and the cutting that compares the acquired value of the actual cutting force with the calculated value (model value) in consideration of the calculated delay time Force comparison unit 10 And an abnormality determination unit 106 that determines whether or not there is an abnormality by comparing the actual cutting force with which the abnormality detection threshold value calculation unit 110 has obtained a predetermined threshold value from the cutting force threshold value storage unit 109, and a cutting position A cutting position / machining condition storage unit 107 in which machining conditions such as cutting and feed speed based on the cutting angle are stored in association with each other, and a cutting force calculation value storage unit 108 in which a calculation value of the cutting force based on the cutting position is stored. A cutting force threshold value storage unit 109 that stores processing conditions and threshold values in association with each other and an abnormality detection threshold value calculation unit 110 are provided. The force sensor is incorporated in the table 16 or the spindle stage 12 of the machining apparatus 10 or is disposed so as to be sandwiched between the work material 15 and the table 16 (paragraph [0035] to [0038]). In addition, a reference code is a code | symbol provided to each structure in the said patent document 2 in this paragraph.

JP 2004-330368 A JP 2012-254499 A

  By the way, in the technique disclosed in Patent Document 1, since the load fluctuation due to the tool abnormality, such as tool wear or chipping, is small with respect to the load during processing, the current does not fluctuate even if the tool abnormality occurs. It is difficult to detect tool abnormalities. This is because the machine tool normally responds to load fluctuations by controlling the phase difference between voltage and current with an inverter, so if a small load fluctuation occurs relative to the current output, the current value fluctuates greatly. Because it does not.

  On the other hand, in machining, particularly free-form surface machining, the load fluctuates from moment to moment depending on the machining part. Therefore, in order to detect tool abnormalities, load fluctuations due to machining parts are separated from load fluctuations caused by tool abnormalities. Therefore, it is necessary to set a processing abnormality determination threshold. In Patent Document 2, a force sensor for measuring a cutting force is attached between a work material and a table of a machining apparatus, and the calculated value of the cutting force analyzed in advance and the obtained value (measured value) of the actual cutting force are used. The presence or absence of abnormality is determined by comparison. However, when machining large parts or parts with complex shapes from the cutting material, the distance between the table and the tool edge becomes longer, or the cutting force direction changes depending on the machining site, so the measured value of the cutting force May be different from the force actually applied to the tool edge. Further, a force sensor that accurately measures the cutting force is very expensive, and its application to a machine tool is not practical.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a tool abnormality detection device and a tool abnormality detection method capable of more appropriately detecting a tool abnormality and a machine tool using the tool abnormality detection device. Is to provide.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. That is, the tool abnormality detection device according to one aspect of the present invention detects an abnormality of the tool in a processing machine that processes the workpiece by relatively rotating the tool and the workpiece processed by the tool with a motor. A tool abnormality detection device, a power measurement unit that measures the power consumption of the motor as actual power consumption, a predetermined predetermined scheduled power consumption, and the actual power consumption measured by the power measurement unit And an abnormality detection unit that detects an abnormality of the tool by comparing. A tool abnormality detection method according to another aspect of the present invention detects an abnormality of the tool in a processing machine that processes the workpiece by relatively rotating a tool and a workpiece processed by the tool with a motor. A tool abnormality detection method, a power measurement step of measuring the power consumption of the motor as actual power consumption, a predetermined predetermined scheduled power consumption, and the actual power consumption measured in the power measurement step And an abnormality detection step of detecting an abnormality of the tool by comparing with the above. Preferably, in the above description, the processing machine is a 3-axis or 5-axis apparatus. Preferably, in the above, the tool is an end mill.

  Such a tool abnormality detection device and a tool abnormality detection method detect a tool abnormality with power consumption, so that a tool abnormality can be detected even if the voltage and current are controlled by an inverter. In the tool abnormality detection device and the tool abnormality detection method, since the planned power consumption is preset at a constant value, in order to detect the tool abnormality, the load fluctuation due to the machining part of the workpiece and the load fluctuation due to the tool abnormality are detected. There is no need to separate them. Therefore, the tool abnormality detection device and the tool abnormality detection method can detect a tool abnormality more appropriately.

  In another aspect, in the above-described tool abnormality detection device, the planned power consumption is obtained in advance by a simulation using a mathematical model representing the motor.

  Since such a tool abnormality detection apparatus calculates | requires planned power consumption by simulation previously, it can set planned power consumption appropriately.

  In another aspect, in the above-described tool abnormality detection device, the abnormality of the tool includes wear of the tool and a loss of the tool, and the abnormality detection unit is configured to reduce the actual power consumption to the planned power consumption. A predetermined value that is equal to or greater than a first addition value obtained by adding a predetermined first determination threshold value that is set in advance and that the actual power consumption is greater than the first determination threshold value in the scheduled power consumption The wear of the tool is detected when it is less than the second added value obtained by adding the second determination threshold value, and the tool loss is detected when the actual power consumption is equal to or greater than the second added value.

  Since such a tool abnormality detection device detects a tool abnormality using the first and second determination thresholds, it can detect tool wear and tool chipping (blade spillage).

  In another aspect, in these above-described tool abnormality detection devices, when the abnormality detection unit further detects the abnormality of the tool, the tool and the workpiece are rotated at a preset rotation speed at the time of abnormality. A first control signal for relatively rotating is output to the processing machine.

  In the processing machine, if the movement of the tool is stopped during the processing, the tool may be bitten into the workpiece. If the tool is bitten into the workpiece, it takes time and effort to cope with it. When the tool abnormality detection device detects a tool abnormality, the tool abnormality detection device outputs a first control signal for relatively rotating the tool and the workpiece at a rotation speed at the time of the abnormality to the processing machine. Since the tool can be rotated without stopping the movement, the possibility that the tool bites into the workpiece can be reduced.

  In another aspect, in these above-described tool abnormality detection devices, the processing machine further processes the workpiece by relatively moving the tool and the workpiece, and the abnormality detection unit further includes: When an abnormality of the tool is detected, a second control signal for relatively moving the tool and the workpiece at a preset moving speed at the time of abnormality is output to the processing machine.

  When such a tool abnormality detection device detects a tool abnormality, it outputs a second control signal for relatively moving the tool and the workpiece at the movement speed at the time of abnormality to the processing machine. Since the tool can be moved without stopping the movement of the tool, the possibility that the tool bites into the workpiece can be reduced.

  The tool abnormality detection device and the tool abnormality detection method according to the present invention can detect a tool abnormality more appropriately.

It is a block diagram which shows the structure of the tool abnormality detection apparatus in embodiment. It is a flowchart which shows the operation | movement regarding detection of a tool abnormality in the tool abnormality detection apparatus of embodiment. It is a figure which shows the time change of power consumption as one Example.

  Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted suitably. In this specification, when referring generically, it shows with the reference symbol which abbreviate | omitted the suffix, and when referring to an individual structure, it shows with the reference symbol which attached the suffix.

  The tool abnormality detection device according to the present embodiment is, for example, worn or broken (for example, blade spillage) in a processing machine that processes the workpiece by relatively rotating the tool and the workpiece processed by the tool with a motor. It is an apparatus for detecting an abnormality (tool abnormality) of the tool. Such a tool abnormality detection device includes a power measuring unit that measures the power consumption of the motor as actual power consumption, a predetermined predetermined scheduled power consumption that is set in advance, and the actual consumption measured by the power measuring unit. And an abnormality detection unit that detects an abnormality of the tool by comparing with electric power. Hereinafter, the tool abnormality detection device in these embodiments will be described more specifically.

  FIG. 1 is a block diagram illustrating a configuration of a tool abnormality detection device according to an embodiment. For example, as shown in FIG. 1, the tool abnormality detection device D in the embodiment includes a power measurement unit 1 and an abnormality detection unit 2. In the present embodiment, the input unit 3 and the NC program creation unit 4 are further provided. And a simulation unit 5 to detect tool abnormality in the processing machine WM.

  The processing machine WM is a machine tool that processes the workpiece by rotating the tool and the workpiece processed by the tool relative to each other by a motor (electric motor) using, for example, one axis, three axes, and five axes. . In the present embodiment, the processing machine WM further processes the workpiece by relatively moving the tool and the workpiece by a moving device such as an XYZ stage or a multi-axis arm. Such a processing machine WM includes, for example, a control panel 6 and a processing unit 7 as shown in FIG.

  The processing unit 7 is connected to each of the control panel 6 and the power measurement unit 1, and processes the workpiece by relatively rotating the tool and the workpiece, and relatively moving the tool and the workpiece. An apparatus for processing the workpiece. In the present embodiment, the processing unit 7 includes a so-called spindle motor and a moving device. The tool is attached to the spindle motor by, for example, a chuck device, the rotational force of the spindle motor is transmitted to the tool, and the tool rotates with respect to the workpiece. Conversely, the workpiece may be attached to the spindle motor, the rotational force of the spindle motor may be transmitted to the workpiece, and the workpiece may rotate with respect to the tool. Moreover, the said workpiece | work is attached to moving apparatuses, such as an XYZ stage, for example, and the said workpiece | work moves with respect to the said tool. Conversely, the tool may be attached to a moving device such as a multi-axis arm, and the tool may move relative to the workpiece.

  The tool is, for example, a bite, a milling cutter (for example, an end mill such as a ball end mill or a flat end mill), a grindstone, and the like, and an appropriate type of tool is selected and used depending on a processing method such as cutting or polishing. The In the present embodiment, as an example, the tool is an end mill.

  The control panel 6 is connected to each of the tool abnormality detection device D and the machining unit 7 so as to machine the workpiece with the tool in accordance with an NC program acquired from the tool abnormality detection device D (an implementation NC program described later in the present embodiment). This is a device for controlling the processing section 7. In this embodiment, when the control panel 6 receives from the tool abnormality detection device D the first control signal for relatively rotating the tool and the workpiece at the rotational speed at the time of abnormality, the control panel 6 executes the executed NC program. On the other hand, the machining unit 7 is controlled so as to relatively rotate the tool and the workpiece at the rotation speed at the time of the abnormality by interruption.

  The power measuring unit 1 is connected to each of the processing unit 7 and the abnormality detecting unit 2 and is a device that measures the power consumption of the spindle motor of the processing unit 7 as an actual power consumption Wr. For example, the power measuring unit 1 is externally attached to the processing machine WM. A wattmeter or the like for measuring power flowing in an inverter circuit included in a drive circuit for driving the spindle motor. The power measurement unit 3 outputs the measured actual power consumption Wr to the abnormality detection unit 2.

  The abnormality detection unit 2 is connected to each of the power measurement unit 1, the simulation unit 5, and the control panel 6, and the predetermined power consumption Wc that is set in advance and the actual power consumption Wr measured by the power measurement unit 1. Is a device that detects an abnormality of the tool by comparing More specifically, in the present embodiment, the tool abnormality includes wear of the tool and chipping of the tool (for example, blade spillage), and the abnormality detection unit 2 determines that the actual power consumption Wr is the planned power consumption Wc. It is equal to or greater than a first addition value (Wc + Th1) obtained by adding a predetermined first determination threshold value Th1, and the actual power consumption Wc is preset to the planned power consumption Wc to be greater than the first determination threshold value Th1. When the predetermined second determination threshold value Th2 (Th2> Th1) is less than the second added value (Wc + Th2), the wear of the tool is detected as a tool abnormality, and the actual power consumption Wr becomes the second added value ( If it is equal to or greater than Wc + Th2), a tool defect is detected as a tool abnormality.

  The scheduled power consumption Wc may be set to an appropriate value in advance by, for example, the user's experience, but in the present embodiment, the planned power consumption Wc is determined and set in advance by simulation using a mathematical model representing the spindle motor of the processing unit 7. Is done. The scheduled power consumption Wc is set to 2/3 or 1/2 of the maximum power consumption obtained by simulation using the mathematical model, for example. The mathematical model is represented by a known equivalent circuit using, for example, a resistor and a coil corresponding to the type of the spindle motor. The first and second determination threshold values Th1 and Th2 are appropriately set in advance from a plurality of samples.

  In the present embodiment, when the abnormality detection unit 2 detects the abnormality of the tool, the first control signal that relatively rotates the tool and the workpiece at a preset rotation speed at the time of abnormality. Is output to the control panel 6 of the processing machine WM. The rotational speed at the time of abnormality is appropriately set in advance from a plurality of samples.

  The abnormality detection unit 2 sends a second control signal for relatively moving the tool and the workpiece to the processing machine at a preset moving speed when the abnormality of the tool is detected. It may be output. Upon receiving the second control signal from the abnormality detection unit 2 of the tool abnormality detection device D, the control panel 6 interrupts the execution NC program being executed, and moves the tool and the workpiece at the moving speed at the time of the abnormality. The processing unit 7 is controlled so as to relatively move the. The moving speed at the time of abnormality is appropriately set in advance from a plurality of samples. Alternatively, when the abnormality detection unit 2 detects an abnormality of the tool, the abnormality detection unit 2 relatively rotates the tool and the workpiece at a preset rotation speed at the time of the abnormality, and moves when the abnormality is set in advance. A third control signal for relatively moving the tool and the workpiece at a speed may be output to the control panel 6 of the processing machine WM. When the third control signal is received from the abnormality detection unit 2 of the tool abnormality detection device D, the control panel 6 interrupts the execution NC program being executed, and the tool and the workpiece are rotated at the rotation speed at the time of the abnormality. And the machining unit 7 is controlled so that the tool and the workpiece are relatively moved at the moving speed at the time of the abnormality. Such a tool abnormality detection device D provides a second control signal or a third control signal for moving the tool and the workpiece relative to each other at a moving speed at the time of abnormality when a tool abnormality is detected. Since it outputs to WM, the said tool can be moved without stopping the movement of the said tool, Therefore The possibility that a tool may bite into a workpiece | work can be reduced. In the above description, the abnormality detection unit 2 detects tool wear and tool chipping (blade spillage) using the first and second determination threshold values Th1 and Th2. However, the tool abnormality is not classified by type. From the viewpoint of detecting only the presence / absence of the tool abnormality, the abnormality detection unit 2 determines that the actual power consumption Wr is equal to or greater than an added value (Wc + Th) obtained by adding a predetermined determination threshold Th set in advance to the scheduled power consumption Wc. In this case, the tool abnormality may be detected, and in this case, the control at the time of abnormality may be performed in any of the above-described modes.

  The input unit 3 is connected to the NC program creating unit 4 and is a device for inputting various data necessary for creating the NC program. For example, the input unit 3 includes a plurality of input switches assigned with predetermined functions, a keyboard, a mouse, and the like. . The various data includes a workpiece shape, a tool shape (number of blades, rake angle, clearance angle, torsion angle, cutting edge roundness), machining conditions, machining path, and the like. The input unit 3 outputs the received various data to the NC program creation unit 4.

  The NC program creation unit 4 is connected to the input unit 3, the simulation unit 5, and the control panel 6 of the processing machine WM, and the workpiece shape, tool shape (number of blades, rake angle, clearance angle, twist angle) from the input unit 3. , Cutting edge roundness), an apparatus for creating an NC program as an initial NC program by known conventional means based on machining conditions and machining paths. The NC program creation unit 4 outputs this initial NC program to the simulation unit 5.

  The simulation unit 5 is connected to each of the NC program creation unit 4 and the abnormality detection unit 2 and simulates (numerical calculation) the power consumption as the initial power consumption Wi based on the initial NC program created by the NC program creation unit 4. It is. And in this embodiment, the simulation part 5 calculates | requires and sets the scheduled power consumption Wc of the said fixed value previously by the simulation using the numerical model showing the said spindle motor of the process part 7. FIG.

The initial power consumption Wi of the spindle motor is obtained by the following equation (1) when the tangential force is Ft, the tool radius is r, and the rotation speed is N [rpm]. The tangential force Ft is obtained by the following equation (2) when the specific cutting resistance is Kt and the cutting sectional area of the tool is A. The specific cutting resistance Kt is a value determined according to the workpiece, and is experimentally obtained in advance from a plurality of workpiece samples. The cutting cross-sectional area A of the tool is a cross-sectional area from which the workpiece is removed (cut) by the tool when the one-blade tool makes one revolution, and is geometrical based on the tool shape, the shape of the workpiece, the machining conditions, and the machining path. Is calculated automatically.
Wi = 2π × Ft × r × N / 60/1000 (1)
Ft = Kt × A (2)
The initial power consumption Wi was created by known conventional means based on the workpiece shape, tool shape (number of blades, rake angle, clearance angle, helix angle, cutting edge roundness), machining conditions and machining path as described above. Since it was originally calculated from the NC program and generally the load applied to the tool with respect to the workpiece fluctuates depending on the machining part, it is not always a constant value but varies with time (processing progress). For this reason, in this embodiment, the simulation unit 5 outputs the initial power consumption Wi and the planned power consumption Wc to the NC program creation unit 4, and the NC program creation unit 4 further includes the initial power consumption Wi and the initial NC program. Based on the above, an NC program obtained by modifying the initial NC program so as to obtain a predetermined power consumption Wc having a predetermined constant value set in advance is created as an implementation NC program, and this implementation NC program is transmitted to the control panel 6 of the processing machine WM. Output.

  In the NC program, the coordinate value of the movement destination, the feed speed of the tool, and the rotation speed of the tool are specified for the current position. Therefore, more specifically, every time the initial power consumption Wi changes, the NC program creation unit 4 compares the initial power consumption Wi with the planned power consumption Wc, and the initial power consumption Wi is greater than the planned power consumption Wc. When the power consumption is large, the feed speed of the tool corresponding to the initial power consumption Wi is decelerated so that the initial power consumption Wi matches the planned power consumption Wc, while the initial power consumption Wi is smaller than the planned power consumption Wc. The feed speed of the tool corresponding to the initial power consumption Wi is increased so that the initial power consumption Wi matches the planned power consumption Wc. In one specific example, when the initial power consumption Wi is twice the planned power consumption Wc, the feed speed of the tool corresponding to the initial power consumption Wi so that the initial power consumption Wi matches the planned power consumption Wc. Is reduced to ½ times and the initial power consumption Wi is ½ times the planned power consumption Wc, the initial power consumption Wi is set to the initial power consumption Wi so that the initial power consumption Wi matches the planned power consumption Wc. The corresponding tool feed rate is doubled. As a result, the NC program creation unit 4 creates an NC program obtained by modifying the initial NC program as an implementation NC program so that the predetermined power consumption Wc is a predetermined constant value.

  In the present embodiment, the simulation unit 5 outputs the planned power consumption Wc to the abnormality detection unit 2.

  Such an input unit 3, NC program creation unit 4, simulation unit 5 and abnormality detection unit 2 are, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk. A drive, a display device, a keyboard, a mouse, an interface, and a CPU, RAM, ROM, HDD, a display device, a bus that connects the keyboard, mouse, and interface to each other. Is possible. The keyboard and interface are an example of the input unit 3, and each of the NC program creation unit 4, the simulation unit 5, and the abnormality detection unit 2 is functionally configured in the CPU by executing a program.

  Next, the operation of this embodiment will be described. FIG. 2 is a flowchart illustrating an operation related to detection of tool abnormality in the tool abnormality detection device of the embodiment.

  When the processing is started, in the processing machine WM, the control panel 6 controls the processing unit 7 according to the execution NC program and processes the workpiece with the tool.

  In detecting the tool abnormality during the machining of the workpiece, the tool abnormality detection device D is firstly operated by the abnormality detection unit 2 from the power measurement unit 1 to the measured machining unit 7. The actual power consumption Wr of the spindle motor is acquired (S1).

  Next, in the abnormality detection unit 2, the actual power consumption Wr acquired from the power measurement unit 1 in the process S1 is equal to or greater than a first addition value (Wc + Th1) obtained by adding the first determination threshold value Th1 to the scheduled power consumption Wc. It is determined whether or not. As a result of this determination, when the actual power consumption Wr is not greater than or equal to the first addition value (Wc + Th1) (that is, when the actual power consumption Wr is less than the first addition value (Wc + Th1)) (No) Next, the abnormality detection unit 2 executes the process S11. On the other hand, as a result of the determination, when the actual power consumption Wr is equal to or greater than the first addition value (Wc + Th1) (Yes), the abnormality detection unit 2 next executes a process S3.

  In process S11, the abnormality detection unit 2 determines whether or not the machining of the workpiece is finished. For example, the control panel 6 notifies the abnormality detection unit 2 when the machining of the workpiece is completed, or determines whether or not the actual power consumption Wr of the spindle motor is zero. Can be executed. As a result of this determination, when the machining of the workpiece has been completed (Yes), the abnormality detection unit 2 terminates the present process, whereas, as a result of the determination, the machining of the workpiece has not been completed. In (No), the abnormality detection unit 2 returns the process to the process S1. Thereby, the presence or absence of tool abnormality is repeatedly determined during machining of the workpiece.

  In the process S3, the abnormality detection unit 2 determines that the actual power consumption Wr acquired from the power measurement unit 1 in the process S1 is equal to or greater than a second addition value (Wc + Th2) obtained by adding the second determination threshold Th2 to the scheduled power consumption Wc. It is determined whether or not. As a result of this determination, when the actual power consumption Wr is not greater than or equal to the second addition value (Wc + Th2) (that is, when the actual power consumption Wr is less than the second addition value (Wc + Th2)) (No) Then, the abnormality detection unit 2 determines that there is a wear tool abnormality (S4), and then executes processing S6. On the other hand, as a result of the determination, if the actual power consumption Wr is equal to or greater than the second added value (Wc + Th2) (Yes), the abnormality detection unit 2 determines that the tool is defective (S5), and then Then, process S6 is executed.

  In this process S6, the tool abnormality detection device D controls the movement of the tool in the processing unit 7 of the processing machine WM to the movement at the time of abnormality by the abnormality detection unit 2, and ends the present process. More specifically, in the present embodiment, the abnormality detection unit 2 sends the first control signal for relatively rotating the tool and the workpiece at the rotation speed at the time of the abnormality to the control panel 6 of the processing machine WM. To terminate the process. Upon receiving this, the control panel 6 interrupts the NC program being executed, and controls the spindle motor of the machining unit 7 so that the tool and the workpiece are rotated relatively at the rotational speed at the time of the abnormality. To do.

  When the present process is terminated, the abnormality detection unit 2 may terminate the present process after outputting a tool abnormality detection result to a display device such as a liquid crystal display device. Here, when the process S4 is executed, a wear tool abnormality is displayed on the display device, and when the process S5 is executed, a defective tool abnormality is displayed on the display device. The

  FIG. 3 is a diagram illustrating a change in power consumption over time as an example. 3A shows a case where there is no tool abnormality, FIGS. 3B and 3C show a case where a tool abnormality occurs, and FIG. 3B shows a case where the abnormal speed control function executed in the case of a tool abnormality is turned off. FIG. 3C shows a case where the abnormal speed control function executed when the tool is abnormal is turned on. Each horizontal axis in FIGS. 3A to 3C is time, and each vertical axis is power consumption.

  In this example, a machining center is used as the processing machine WM, the workpiece is S45C, the tool is a φ20 mm tip type end mill (3 blades), cutting conditions are cutting speed 300 m / min, feed 0.3 mm. / Blade, shaft cut 2 mm, diameter cut ae 5 mm, machining time 30 minutes.

  When no tool abnormality has occurred, as shown in FIG. 3A, the actual power consumption Wr measured by the power measuring unit 1 by the NC program substantially matches the planned power consumption (analysis) Wc. Therefore, when a defect is given to the end mill of the tool, as shown in FIG. 3B, the actual power consumption Wr measured by the power measuring unit 1 at the time of giving the defect is larger than the planned power consumption (analysis) Wc. A peak occurs. By detecting this peak using the determination threshold Th (the first and second determination thresholds Th1 and Th2 in the above description), the tool abnormality can be detected by the power consumption of the spindle motor in the machining unit 7. On the other hand, when such a tool abnormality is detected, the control panel 6 that has received the first control signal from the abnormality detection unit 2 controls the spindle motor at the rotation speed at the time of abnormality, as shown in FIG. 3C. The end mill of the tool continues to rotate without biting into S45C of the workpiece.

  As described above, the tool abnormality detection device D and the tool abnormality detection method implemented in the tool abnormality detection tool detect the tool abnormality with the power consumption, so that the tool abnormality is detected even if the voltage and current are controlled by the inverter. it can. In the tool abnormality detection device D and the tool abnormality detection method, the planned power consumption Wc is preset at a constant value. Therefore, in order to detect a tool abnormality, load fluctuations due to the machining site in the workpiece, tool abnormality, There is no need to separate the load fluctuation due to Therefore, the tool abnormality detection device D and the tool abnormality detection method can detect a tool abnormality more appropriately.

  In the tool abnormality detection device D and the tool abnormality detection method, the planned power consumption Wc is obtained in advance by simulation, so that the planned power consumption Wc can be appropriately set.

  Since the tool abnormality detection device D and the tool abnormality detection method detect the tool abnormality using the first and second determination threshold values Th1 and Th2, the tool wear and the tool chipping (for example, blade spillage) are detected. it can.

  In the processing machine WM, if the movement of the tool is stopped during processing, the tool may bite into the workpiece, and if the tool bites into the workpiece, labor (man-hours) is required to cope with it. Take it. In the tool abnormality detection device D and the tool abnormality detection method, when an abnormality of the tool is detected, a first control signal for relatively rotating the tool and the workpiece at a rotation speed at the time of abnormality is transmitted to the processing machine WM. Since the tool can be rotated without stopping the movement of the tool, the possibility that the tool bites into the workpiece can be reduced.

  In the above-described embodiment, the processing machine WMD that performs the cutting process rotates the tool with respect to the work, but the work machine WMD may rotate the work with respect to the tool. For example, such a processing machine WM for cutting includes a lathe using a cutting tool as the tool.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

D Tool abnormality detection device WM Processing machine 1 Power measurement unit 2 Abnormality detection unit 3 Input unit 4 NC program creation unit 5 Simulation unit 6 Control panel 7 Processing unit

Claims (6)

A tool abnormality detection device that detects an abnormality of the tool in a processing machine that processes the workpiece by relatively rotating a tool and a workpiece processed by the tool with a motor,
A power measuring unit for measuring the power consumption of the motor as actual power consumption;
An abnormality detection unit that detects an abnormality of the tool by comparing a predetermined predetermined scheduled power consumption set in advance with an actual power consumption measured by the power measurement unit;
Tool abnormality detection device. The scheduled power consumption is obtained in advance by a simulation using a mathematical model representing the motor.
The tool abnormality detection device according to claim 1. Abnormalities of the tool include wear of the tool and chipping of the tool,
The abnormality detection unit is configured such that the actual power consumption is equal to or greater than a first addition value obtained by adding a predetermined first determination threshold value that is set in advance to the scheduled power consumption, and the actual power consumption is the planned power consumption. When the power consumption is less than a second addition value obtained by adding a predetermined second determination threshold value that is set in advance larger than the first determination threshold value, wear of the tool is detected, and the actual power consumption is When the added value is 2 or more, the tool is detected to be missing.
The tool abnormality detection device according to claim 1 or 2. When the abnormality of the tool is detected, the abnormality detection unit further sends a first control signal for rotating the tool and the workpiece relative to each other at a rotation speed set in advance to the processing machine. Output,
The tool abnormality detection device according to any one of claims 1 to 3. The processing machine further processes the workpiece by relatively moving the tool and the workpiece,
When the abnormality of the tool is detected, the abnormality detection unit further sends a second control signal for relatively moving the tool and the workpiece at a preset movement speed at the time of abnormality to the processing machine. Output,
The tool abnormality detection apparatus of any one of Claim 1 thru | or 4. A tool abnormality detection method for detecting abnormality of the tool in a processing machine that processes the workpiece by relatively rotating a tool and a workpiece processed by the tool by a motor,
A power measurement step of measuring the power consumption of the motor as actual power consumption;
An abnormality detection step of detecting an abnormality of the tool by comparing a predetermined predetermined scheduled power consumption set in advance with the actual power consumption measured in the power measurement step;
Tool abnormality detection method.

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