Biting detection device

Abstract

To detect biting more accurately.SOLUTION: A biting detection device 6 that detects biting of a tap 7 as a rotary tool that processes a workpiece 2, comprises: an acquisition section that acquires time-series waveform data of a parameter related to an operating state of a motor 8 that drives the rotary tool; an extraction section that extracts partial waveform data from the waveform data in which the parameter value falls within a predetermined range set in advance as an upper limit value and a lower limit value of the parameter value during processing by the rotary tool; a selection section that selects partial waveform data having a time width equal to or greater than a predetermined value from among the partial waveform data extracted by the extraction section; and a detection section that detects biting of the rotary tool on the basis of the selected partial waveform data.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a jamming detection device. [Background technology]

[0002] For example, a workpiece is machined using a rotary tool such as a tap. For example, Patent Document 1 describes a method for determining the lifespan of a rotary tool by calculating an increase in power consumption of a motor that drives the rotary tool. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6864394 Summary of the Invention [Problem to be solved by the invention]

[0004] However, Patent Document 1 cannot detect jamming of a rotary tool such as a tap. Furthermore, in a rotary tool such as a tap, the operating state (e.g., current) of the motor fluctuates, for example, when rotation starts or stops, and there is a possibility that such fluctuations may be erroneously detected as jamming.

[0005] In view of the above-mentioned problems, an object of the present invention is to provide a jamming detection device that can detect jamming more accurately. [Means for solving the problem]

[0006] In order to solve the above problems, the jamming detection device of the present invention is a jamming detection device that detects jamming of a rotary tool that processes a workpiece, and includes an acquisition unit that acquires time-series waveform data of parameters related to the operating state of a motor that drives the rotary tool, an extraction unit that extracts partial waveform data from the waveform data, where the parameter values ​​are within a predetermined range that is set in advance as upper and lower limit values ​​of the parameter values ​​when processing by the rotary tool, a selection unit that selects, from the partial waveform data extracted by the extraction unit, partial waveform data whose time width is equal to or greater than a predetermined value, and a detection unit that detects jamming of the rotary tool using the selected partial waveform data.

[0007] In addition, the jamming detection device further includes an extraction unit that extracts a waveform of a partial time width including the center from the waveform of the entire time width of the partial waveform data selected by the selection unit to create processed waveform data, and the detection unit detects jamming of the rotating tool using the processed waveform data.

[0008] Further, in the jamming detection device, the detection unit includes an identification unit that identifies a maximum value and an average value of the machining waveform data, a reference time that is the time at which the maximum value is reached, a first value that is a value corresponding to a time obtained by subtracting a predetermined time from the reference time, and a second value that is a value corresponding to a time obtained by adding a predetermined time to the reference time, and a judgment unit that judges whether jamming of the rotary tool has occurred in the machining waveform data, and the judgment unit includes a first judgment unit that judges whether a first difference obtained by subtracting the first value from the maximum value is equal to or greater than a predetermined value, a second judgment unit that judges whether a second difference obtained by subtracting the second value from the maximum value is equal to or greater than a predetermined value, a third judgment unit that judges whether a third difference obtained by subtracting the average value from the maximum value is equal to or greater than a predetermined value, and a fourth judgment unit that judges that jamming of the rotary tool has occurred when the first difference is equal to or greater than the predetermined value, the second difference is equal to or greater than a predetermined value, and the third difference is equal to or greater than a predetermined value.

[0009] Furthermore, in the jamming detection device, the detection unit determines that jamming of the rotary tool has occurred when at least one of the following is satisfied: a first difference obtained by subtracting the first value from the maximum value is equal to or greater than a predetermined value; a second difference obtained by subtracting the second value from the maximum value is equal to or greater than a predetermined value; and a third difference obtained by subtracting the average value from the maximum value is equal to or greater than a predetermined value, when the time when the machining waveform data reaches its maximum value is set as a reference time, a value corresponding to the time obtained by subtracting a predetermined time from the reference time is set as a first value, and a value corresponding to the time obtained by adding a predetermined time to the reference time is set as a second value.

[0010] The jamming detection device further includes a smoothing unit that performs moving average processing on the machining waveform data, and the detection unit detects jamming of the rotary tool using the machining waveform data that has been subjected to the moving average processing. [Effects of the Invention]

[0011] According to the jamming detection device of the present invention, jamming can be detected more accurately. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing an example of the overall configuration of a processing system including a jamming detection device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing an example of various functions of the jamming detection device. [Figure 3] FIG. 10 is a diagram showing an example of time-series waveform data of a main shaft current. [Figure 4] FIG. 10 is a diagram showing an example of processed waveform data when no biting occurs. [Figure 5] FIG. 10 is a diagram showing an example of processed waveform data when jamming occurs. [Figure 6] 10 is a flowchart showing an example of the flow of a jamming detection process. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicate descriptions will be omitted where appropriate.

[0014] === Implementation form === <Overall structure> 1 is a schematic diagram showing an example of the overall configuration of a processing system 1 equipped with a jamming detection device 6 according to this embodiment. The processing system 1 performs processing on a workpiece 2. As shown in FIG. 1, the processing system 1 mainly includes a processing machine 4, a measuring instrument 5, and a jamming detection device 6.

[0015] The processing machine 4 is provided with a tap 7 as a rotary tool. The tap 7 is a type of processing tool that processes a thread into the inside of a hole in the workpiece 2. The processing machine 4 is a device that controls the rotation and feed of the tap 7. The processing machine 4 is provided with a motor 8 that rotates the tap 7 and a feed motor (not shown) that provides the feed. The motor 8 rotates the tap 7, and in synchronization with this, the feed motor rotates and provides the feed, thereby processing the workpiece 2. For example, the processing machine 4 rotates the tap 7 in the forward direction and provides the feed, thereby processing a thread into the workpiece 2. Then, the processing machine 4 rotates the tap 7 in the reverse direction and provides the feed in the opposite direction, thereby removing the tap 7 from the workpiece 2.

[0016] The measuring instrument 5 measures parameters relating to the operating state of the motor 8 and the feed motor. In this embodiment, the measuring instrument 5 measures the current in the motor 8 and the feed motor of the processing machine 4. In this embodiment, the current flowing through the motor 8 is referred to as the "spindle current." The current flowing through the feed motor is referred to as the "feed shaft current." Hereinafter, simply referring to current refers to the spindle current.

[0017] The jamming detection device 6 is an information processing device that detects jamming of the tap 7 that processes the workpiece 2. When the tap 7 processes the workpiece 2, the tap 7 may jam chips or the like. If jamming occurs (for example, frequently), the tap 7 may chip or break. For this reason, the jamming detection device 6 detects jamming of the tap 7. The jamming detection device 6 includes, for example, a control device 20, a communication device 21, a storage device 22, an operation device 23, and a display device 24. The control device 20 is mainly configured with a CPU (Central Processing Unit) 26 and a memory 27. In the control device 20, the CPU 26 executes a predetermined program stored therein to function as various functional components described below. The communication device 21 is configured with a communication interface or the like for communicating with external devices. The storage device 22 is configured with a hard disk or the like and stores various programs and information required to execute processing in the control device 20, as well as information on processing results. The operation device 23 is a device for performing operations. The display device 24 is a device that displays various information and processing results. The jamming detection device 6 may be configured with a single information processing device or multiple information processing devices. Also, FIG. 1 shows only a portion of the main hardware configuration of the jamming detection device 6, and the jamming detection device 6 may have other configurations. The jamming detection device 6 can also be configured using a CPU unit or an arithmetic unit such as a PC or PLC.

[0018] <Functional configuration> 2 is a block diagram showing an example of various functions in the jamming detection device 6. Jamming detection processing is performed by the functions of each block.

[0019] The jamming detection device 6 includes an acquisition unit 31, a cut-out unit 32, a counting unit 33, a detection unit , and a display unit .

[0020] The acquisition unit 31 acquires time-series waveform data A of parameters relating to the operating state of the motor 8. Specifically, the acquisition unit 31 acquires time-series waveform data A of the main shaft current of the motor 8.

[0021] FIG. 3 is a diagram showing an example of waveform data A of the time series of the spindle current. In FIG. 3, the vertical axis represents the current value and the horizontal axis represents time. For example, at time T1, the tap 7 starts rotating in the normal direction, causing a large spindle current to flow. Then, at time T2, the tap 7 enters an air-cut state. Then, from time T3, the tap 7 is fed to the workpiece 2 and begins to contact the workpiece 2, causing the spindle current to increase. Then, at time T4, the normal rotation of the tap 7 is decelerated to stop the rotation of the tap 7, causing the spindle current to increase. After the rotation stops, the tap 7 starts rotating in the reverse direction and is removed from the workpiece 2. In this way, waveform data A includes each state associated with machining by the tap 7.

[0022] Returning to FIG. 2, the cutout unit 32 performs a processing process on the waveform data A acquired by the acquisition unit 31. The cutout unit 32 cuts out, from the waveform data A, the waveform during machining of the workpiece 2 by the tap 7 as machined waveform data C. "During machining" means the state in which the tap 7 is currently machining the workpiece 2. In other words, the state in which the tap 7 is currently machining the workpiece 2 is "during machining." The cutout unit 32 discards from the waveform data A waveforms corresponding to operations (non-machining operations) that are not actually performing machining on the workpiece 2, such as the operation of moving the tap 7 to a predetermined position or standby operations between machining operations, and cuts out the waveform during machining as machined waveform data C.

[0023] Specifically, the cutout unit 32 includes an extraction unit 41, a selection unit 42, an excerpt unit 43, and a correction unit 44.

[0024] The extraction unit 41 extracts partial waveform data B, in which the value of the spindle current falls within a predetermined range R1, from the entire waveform represented by the waveform data A. The predetermined range R1 is a range set in advance as the upper and lower limits of the value of the spindle current (parameter) during machining by the tap 7. The predetermined range R1 is set in advance as the range of the value of the spindle current when the tap 7 is machining the workpiece 2. FIG. 3 shows an example of the predetermined range R1. When processing the waveform data A shown in FIG. 3, the extraction unit 41 extracts each piece of partial waveform data B, in which the value of the spindle current falls within the predetermined range R1. In the example of FIG. 3, the extraction unit 41 extracts partial waveform data B1, partial waveform data B2, partial waveform data B3, partial waveform data B4, and partial waveform data B5 as the partial waveform data B.

[0025] Returning to FIG. 2, the selection unit 42 selects the partial waveform data B extracted by the extraction unit 41. Specifically, the selection unit 42 selects, from among the multiple partial waveform data B, partial waveform data B whose time width is equal to or greater than a predetermined value R2. The predetermined value R2 is set in advance based on the machining time of the workpiece 2 by the tap 7. The selection unit 42 may also select partial waveform data B whose time width is equal to or greater than the predetermined value R2 but equal to or less than a predetermined value (upper limit of the time width) greater than the predetermined value R2. For example, in FIG. 3, the time width (ΔT) of partial waveform data B3 is equal to or greater than the predetermined value R2, while the time widths of the other partial waveform data B1, partial waveform data B2, partial waveform data B4, and partial waveform data B5 are less than the predetermined value R2. Therefore, in the example of FIG. 3, the selection unit 42 selects partial waveform data B3. As a result, the operating waveform during machining is identified as partial waveform data B3.

[0026] Returning to FIG. 2 , the excerpting unit 43 excerpts the partial waveform data B3 selected by the selecting unit 42. Specifically, the excerpting unit 43 excerpts a waveform of a partial time width from the waveform of the entire time width of the partial waveform data B3. As shown in FIG. 3 , when the entire time width of the partial waveform data B3 is set to 100%, the excerpting unit 43 truncates both ends of the entire time width by 20%. That is, the excerpting unit 43 truncates each end of the partial waveform data B3 by 20% of the entire time width. The time widths of both ends to be truncated are set based on the entire time width of the partial waveform data B3. As a result, a waveform of 60% of the time width including the center of the entire time width of the partial waveform data B3 is excerpted as the net forward-rotation machining portion. The net forward-rotation machining portion is the waveform of the spindle current during machining of the workpiece 2 by the tap 7 rotating in the forward direction. Note that the 20% to be truncated is just an example, and the specific percentage is not limited to the above. Alternatively, the time widths to be truncated may be set separately on the start and end sides of the partial waveform data B3. In this way, the extracting unit 43 extracts a waveform of a partial time width including the center from the waveform of the entire time width of the partial waveform data B3, and sets it as processed waveform data C.

[0027] 2, the correction unit 44 performs correction on the processed waveform data C. Specifically, the correction unit 44 includes an identification unit 46 and a difference unit 47. Note that the correction process by the correction unit 44 may be omitted.

[0028] The identification unit 46 identifies air-cut waveform data D corresponding to the machining waveform data C. Air-cut refers to a state in which the tap 7 is rotating without touching any other member before contacting the workpiece 2. The identification unit 46 identifies the start point P1 of partial waveform data B3 in the waveform data A, before extracting the machining waveform data C. The identification unit 46 then determines, as the target period H2, a fixed period immediately before a predetermined period H1 of a predetermined time width immediately before the start point P1. The time width of the target period H2 is set in advance. That is, the identification unit 46 determines, as the air-cut waveform data D, the portion of the waveform data A in the target period H2 that is the predetermined period H1 before the start point P1.

[0029] Returning to FIG. 2, the difference unit 47 corrects the machining waveform data C using the identified air-cut waveform data D. Specifically, the difference unit 47 calculates the average value of the spindle current of the waveform indicated by the air-cut waveform data D. Then, the difference unit 47 calculates the difference between the waveform of the machining waveform data C and the average value. Specifically, the difference unit 47 subtracts the average value from the machining waveform data C. This results in a state in which the base portion has been removed from the waveform of the machining waveform data C. In other words, the corrected machining waveform data C becomes the net spindle current during machining.

[0030] FIG. 4 is a diagram showing an example of corrected machining waveform data C corresponding to the waveform data A in FIG. 3. Note that the ranges of the horizontal and vertical axes in FIG. 4 only show the range of the machining waveform data C in FIG. 3 (the same applies to FIG. 5 described later). FIGS. 3 and 4 show an example of data when no cutting occurs when the workpiece 2 is machined with the tap 7. Here, FIG. 5 shows an example of machining waveform data C corrected as in FIG. 3, where cutting occurs when the workpiece 2 is machined with the tap 7. As shown by part E in FIG. 5, when cutting occurs, the spindle current temporarily increases. Note that even if cutting occurs and the spindle current temporarily increases in FIG. 5, the current does not increase as much as it does immediately after time T1 (when rotation starts) or immediately after time T4 (when rotation stops) in FIG. 3. For example, when cutting does not occur, the extraction unit 32 outputs machining waveform data C as shown in FIG. 4, and when cutting occurs, outputs machining waveform data C as shown in FIG. 5.

[0031] The counting unit 33 counts the number of machining operations, which is the number of times the workpiece 2 has been machined by the tap 7. For example, the counting unit 33 counts each time the cutting unit 32 cuts out the machining waveform data C (or partial waveform data B3), which is the net forward machining location. In other words, the count value becomes the machining number by the tap 7. Note that the counting by the counting unit 33 is not limited to the above timing as long as the number of machining operations can be counted. Furthermore, the count value of the counting unit 33 is reset to the initial value, for example, when the tap 7 is replaced.

[0032] The detection unit 34 detects whether the tap 7 is caught on the basis of the selected partial waveform data B. Specifically, the detection unit 34 detects whether the tap 7 is caught on the basis of the processed waveform data C.

[0033] The detection unit 34 includes a specification unit 51, a recording unit 52, and a determination unit 53.

[0034] The specifying unit 51 specifies various information (features) in the processed waveform data C. Specifically, the specifying unit 51 specifies the maximum value MAX, the average value AVG, and the first value W1 and second value W2 that are shifted from the maximum value MAX by a predetermined time Wmax in the processed waveform data C.

[0035] 5, the specifying unit 51 specifies a maximum value MAX for the processed waveform data C. The specifying unit 51 also specifies the time at which the processed waveform data C reaches the maximum value MAX as the reference time ARGMAX. The specifying unit 51 then specifies an average value AVG for the processed waveform data C.

[0036] The specifying unit 51 also specifies a value of the machining waveform data C (spindle current) corresponding to a time obtained by subtracting a predetermined time Wmax from the specified reference time ARGMAX, and sets the value as a first value W1. The specifying unit 51 also specifies a value of the machining waveform data C (spindle current) corresponding to a time obtained by adding a predetermined time Wmax to the specified reference time ARGMAX, and sets the value as a second value W2. The predetermined time Wmax is a preset threshold. The predetermined time Wmax is set in advance as the maximum value of the duration of a temporary increase in the spindle current when jamming occurs (maximum duration of jamming). In other words, the predetermined time Wmax is set based on the duration of a temporary increase in the spindle current expected when jamming occurs. The predetermined time Wmax is set in advance through testing or the like. In this embodiment, the same predetermined time Wmax is used for the first value W1 and the second value W2, but different predetermined times may be set for each value.

[0037] In this way, the identification unit 51 identifies the maximum value MAX, the average value AVG, the first value W1, and the second value W2 corresponding to the processed waveform data C. Note that, although the above example illustrates a case where each piece of information is identified using the processed waveform data C of Fig. 5 as an example, the same identification process is also performed on the processed waveform data C of Fig. 4.

[0038] The recording unit 52 associates each piece of information identified by the identification unit 51 with the count value and records them in the storage device 22. That is, each processing (processing number) by the tap 7 and each piece of information corresponding to the processed waveform data C of that processing are associated with each other and recorded as history information of processing by the tap 7.

[0039] The determination unit 53 determines whether or not jamming has occurred in the tap 7 based on the information identified by the identification unit 51. Specifically, the determination unit 53 includes a first determination unit 55, a second determination unit 56, a third determination unit 57, and a fourth determination unit 58.

[0040] The determination unit 53 uses a predetermined value Hmin. The predetermined value Hmin is a preset threshold value. The predetermined value Hmin is set in advance as the minimum value of the temporary increase in the spindle current (minimum height of the jamming) when jamming occurs and the spindle current temporarily increases. In other words, the predetermined value Hmin is set based on the expected amount of temporary increase in the spindle current when jamming occurs. The predetermined value Hmin is set in advance through testing or the like.

[0041] The first determination unit 55 makes a determination regarding the rising height of the spindle current. The determination process in the first determination unit 55 is referred to as the first determination process. Specifically, the first determination unit 55 determines whether or not a first difference obtained by subtracting a first value W1 from the maximum value MAX is equal to or greater than a predetermined value Hmin. That is, the first determination unit 55 determines whether or not the relational expression MAX-W1≧Hmin is satisfied. If the first difference obtained by subtracting the first value W1 from the maximum value MAX is equal to or greater than the predetermined value Hmin, the first determination unit 55 determines a positive determination as the first determination result for the corresponding processed waveform data C.

[0042] The second determination unit 56 makes a determination regarding the falling edge height of the spindle current. The determination process in the second determination unit 56 is referred to as the second determination process. Specifically, the second determination unit 56 determines whether or not a second difference obtained by subtracting the second value W2 from the maximum value MAX is equal to or greater than a predetermined value Hmin. That is, the second determination unit 56 determines whether or not the relational expression MAX-W2≧Hmin is satisfied. If the second difference obtained by subtracting the second value W2 from the maximum value MAX is equal to or greater than the predetermined value Hmin, the second determination unit 56 determines a positive determination as the second determination result for the corresponding processed waveform data C.

[0043] The third determination unit 57 makes a determination regarding the increase amount of the spindle current. The determination process in the third determination unit 57 is referred to as the third determination process. Specifically, the third determination unit 57 determines whether or not a third difference obtained by subtracting the average value AVG from the maximum value MAX is equal to or greater than a predetermined value Hmin. In other words, the third determination unit 57 determines whether or not the relational expression MAX-AVG≧Hmin is satisfied. If the third difference obtained by subtracting the average value AVG from the maximum value MAX is equal to or greater than the predetermined value Hmin, the third determination unit 57 determines the third determination result of the corresponding processed waveform data C as positive.

[0044] In this embodiment, the first determination unit 55, the second determination unit 56, and the third determination unit 57 use the same predetermined value Hmin, but different predetermined values ​​may be set for each unit.

[0045] The fourth determination unit 58 determines whether or not jamming has occurred at the tap 7 based on the determination results of the first determination unit 55, the second determination unit 56, and the third determination unit 57. Specifically, the fourth determination unit 58 determines that jamming has occurred at the tap 7 when the determination results of the first determination unit 55, the second determination unit 56, and the third determination unit 57 are all positive. That is, the fourth determination unit 58 determines that jamming has occurred at the tap 7 when the first difference is equal to or greater than a predetermined value Hmin, the second difference is equal to or greater than a predetermined value Hmin, and the third difference is equal to or greater than a predetermined value Hmin. For example, when the determination process is performed in response to the processed waveform data C in FIG. 5, all of the determination results are positive, and it is determined that jamming has occurred.

[0046] If any one of the judgment results of the first judgment unit 55, the second judgment unit 56, and the third judgment unit 57 is not a positive judgment, the fourth judgment unit 58 judges that no jamming has occurred in the tap 7. For example, when the judgment process is performed in accordance with the processed waveform data C in Fig. 4, the judgment result is not a positive judgment, and it is determined that no jamming has occurred.

[0047] In this way, the fourth determination unit 58 determines whether or not jamming has occurred by combining the determination results related to the rising edge height of the spindle current, the falling edge height of the spindle current, and the increase amount of the spindle current. The recording unit 52 records each determination result.

[0048] The display unit 35 controls the display device 24 to display information. Specifically, the display unit 35 causes the display device 24 to display various information processed by the jamming detection device 6, for example. In particular, the display unit 35 displays jamming detection results. Specifically, the display unit 35 displays the processing number and the jamming detection results for the processing corresponding to the processing number. By checking the display, the user can recognize whether jamming has occurred during processing by the tap 7.

[0049] <Processing flow> 6 is a flowchart showing an example of the flow of the jamming detection process according to this embodiment. Each of the following steps is started when the user gives an instruction to start the process. Note that the order and content of each of the following steps can be changed as appropriate.

[0050] (Step SP10) The counting section 33 initializes the count value indicating the number of processing operations, that is, the count value becomes 0. Then, the process proceeds to step SP11.

[0051] (Step SP11) The acquisition unit 31 acquires time-series waveform data A of the main shaft current of the tap 7. Then, the process proceeds to step SP12.

[0052] (Step SP12) The cutout unit 32 cuts out the processed waveform data C from the waveform data A and corrects it using the air-cut waveform data D. Then, the process proceeds to step SP13.

[0053] (Step SP13) The counting unit 33 counts the number of processes and sets the count value. Specifically, the counting unit 33 adds 1 to the number of processes (counts up) and sets the count value. Then, the process proceeds to step SP14.

[0054] (Step SP14) The specifying unit 51 specifies the maximum value MAX, the average value AVG, the first value W1, and the second value W2 corresponding to the processed waveform data C. Then, the process proceeds to step SP15.

[0055] (Step SP15) The first determination unit 55 determines whether a first difference obtained by subtracting the first value W1 from the maximum value MAX is equal to or greater than a predetermined value Hmin, and sets the determination result as a first determination result. Then, the process proceeds to step SP16.

[0056] (Step SP16) The second determination unit 56 determines whether a second difference obtained by subtracting the second value W2 from the maximum value MAX is equal to or greater than a predetermined value Hmin, and sets the determination result as a second determination result. Then, the process proceeds to step SP17.

[0057] (Step SP17) The third determination unit 57 determines whether a third difference obtained by subtracting the average value AVG from the maximum value MAX is equal to or greater than a predetermined value Hmin, and sets the determination result as a third determination result. Then, the process proceeds to step SP18.

[0058] (Step SP18) The fourth determination unit 58 determines whether the first, second, and third determination results are all positive. If the first, second, and third determination results are all positive, the process proceeds to step SP19. If any one of the first, second, and third determination results is not positive, the process proceeds to step SP20.

[0059] (Step SP19) The fourth judging unit 58 judges that jamming has occurred in the tap 7. Then, the process proceeds to step SP21.

[0060] (Step SP20) The fourth judging section 58 judges that no jamming has occurred in the tap 7. Then, the process proceeds to step SP21.

[0061] (Step SP21) The display unit 35 displays the jamming detection result, and the process then proceeds to step SP22.

[0062] (Step SP22) The counting unit 33 determines whether or not there is a next processing. Whether or not there is a next processing can be set by the user, for example. Also, for example, the user who has checked the display may be able to select whether to continue or end. If there is a next processing, the process returns to step SP11 and repeats. If there is no next processing, the process ends.

[0063] By executing the process as described above, it is detected whether or not biting has occurred during each machining of the workpiece 2 by the tap 7, and the user is notified of this. Therefore, the user can recognize whether or not biting has occurred during machining.

[0064] <Action and effect>

[0065] As described above, in this embodiment, the jamming detection device 6 is a jamming detection device 6 that detects jamming of a rotary tool that processes a workpiece 2, and includes an acquisition unit 31 that acquires time-series waveform data A of parameters related to the operating state of the motor 8 that drives the rotary tool, an extraction unit 41 that extracts, from the waveform data A, partial waveform data B whose parameter values ​​are within a predetermined range that is set in advance as upper and lower limit values ​​of the parameter values ​​during machining by the rotary tool, a selection unit 42 that selects, from the partial waveform data B extracted by the extraction unit 41, partial waveform data B3 whose time width is equal to or greater than a predetermined value, and a detection unit 34 that detects jamming of the rotary tool using the selected partial waveform data B3. This configuration makes it possible to detect the engagement of the tap 7 while suppressing the influence of current fluctuations when the rotation of the tap 7 starts or stops. In other words, it becomes possible to detect engagement more accurately. In other words, work crossing is suppressed.

[0066] Furthermore, the jamming detection device 6 according to this embodiment further includes an extraction unit 43 that extracts a waveform of a partial time width including the center from the waveform of the entire time width of the partial waveform data B3 selected by the selection unit 42, and sets the extracted waveform as machining waveform data C. The detection unit 34 detects jamming of the rotary tool using the machining waveform data C. According to this configuration, it is possible to more accurately detect jamming by extracting the partial waveform data B3 to obtain the machining waveform data C. It is more preferable that the detection unit 34 detects jamming of the rotary tool using the machining waveform data C from which the extracted portion 43 has been extracted and corrected by the correction unit 44.

[0067] In the jamming detection device 6 according to this embodiment, the detection unit 34 includes an identification unit 51 that identifies the maximum value MAX of the machining waveform data C, the average value AVG, a reference time that is the time at which the maximum value MAX is reached, a first value W1 that is a value corresponding to the time obtained by subtracting a predetermined time Wmax from the reference time, and a second value W2 that is a value corresponding to the time obtained by adding the predetermined time Wmax to the reference time, and a determination unit 53 that determines whether jamming of the rotary tool has occurred in the machining waveform data C. The determination unit 53 subtracts the first value W1 from the maximum value MAX. a first judgment unit 55 that judges whether the first difference obtained by subtracting the second value W2 from the maximum value MAX is greater than or equal to a predetermined value Hmin; a second judgment unit 56 that judges whether the second difference obtained by subtracting the second value W2 from the maximum value MAX is greater than or equal to the predetermined value Hmin; a third judgment unit 57 that judges whether the third difference obtained by subtracting the average value AVG from the maximum value MAX is greater than or equal to the predetermined value Hmin; and a fourth judgment unit 58 that judges that jamming of the rotary tool has occurred when the first difference is greater than or equal to the predetermined value Hmin, the second difference is greater than or equal to the predetermined value Hmin, and the third difference is greater than or equal to the predetermined value Hmin. According to this configuration, it is possible to effectively suppress false detection of jamming by determining that jamming has occurred when all three judgment processes of the first judgment unit 55, the second judgment unit 56, and the third judgment unit 57 result in a positive judgment.

[0068] <Modification> The present invention is not limited to the above-described embodiments. In other words, designs that are produced by those skilled in the art with appropriate design modifications to the above-described specific examples are also included within the scope of the present invention as long as they include the features of the present invention. Furthermore, the elements of the above-described embodiments and the following modifications can be combined to the extent technically possible, and such combinations are also included within the scope of the present invention as long as they include the features of the present invention.

[0069] For example, in the above embodiment, the case where the tap 7 is used as the rotary tool has been described as an example, but the rotary tool is not limited to the tap 7 as long as it has a similar characteristic (for example, a tool that rotates during processing). For example, a drill or the like may be used as the rotary tool.

[0070] Furthermore, in the above embodiment, the current flowing through the motor 8 is used as the parameter relating to the operating state of the motor 8, but the parameter is not limited to the above as long as it indicates the operating state of the motor 8. For example, the parameter relating to the operating state of the motor 8 may be the torque (main shaft torque) of the motor 8.

[0071] Furthermore, in the above embodiment, the detection unit 34 performs the process of detecting jamming using the corrected processed waveform data C, but the process may be performed using the processed waveform data C before correction by the correction unit 44, or the process may be performed using the processed waveform data C (partial waveform data B3) before extraction by the extraction unit 43.

[0072] In the above embodiment, the fourth determination unit 58 determines that jamming has occurred when all of the first determination process, the second determination process, and the third determination process are affirmative. However, the fourth determination unit 58 may determine that jamming has occurred when at least one of the processes is affirmative. That is, in the jamming detection device 6, the detection unit 34 determines that jamming has occurred when at least one of the following conditions is satisfied: a first difference obtained by subtracting the first value W1 from the maximum value MAX is equal to or greater than a predetermined value Hmin (first determination process); a second difference obtained by subtracting the second value W2 from the maximum value MAX is equal to or greater than a predetermined value Hmin (second determination process); or a third difference obtained by subtracting the average value AVG from the maximum value MAX is equal to or greater than a predetermined value Hmin (third determination process). According to this configuration, if at least one of the three determination processes is satisfied, it is determined that jamming of the rotary tool has occurred, thereby making it possible to detect jamming of the tap 7.

[0073] Furthermore, although the determination unit 53 has been described as including the first determination unit 55, the second determination unit 56, and the third determination unit 57 as an example, it may have at least one of the first determination unit 55, the second determination unit 56, and the third determination unit 57. That is, at least one of the first determination process, the second determination process, and the third determination process may be performed, and if the performed determination process results in a positive determination (if multiple determination processes are performed, all of them result in a positive determination), the fourth determination unit 58 may determine whether or not jamming has occurred.

[0074] Furthermore, in the above embodiment, the case where the jamming detection process is performed on the processed waveform data C as shown in, for example, FIGS. 4 and 5 has been exemplified, but the detection process may be performed after the processed waveform data C has been smoothed. In this case, the jamming detection device 6 further includes a smoothing unit, which performs moving average processing on the processed waveform data C (which may be partial waveform data B3). The moving average may be, for example, a five-term moving average, and the number of terms is not limited. The detection unit 34 then detects jamming using the processed waveform data C that has been subjected to the moving average process. By performing the moving average in this manner, erroneous jamming detection due to the influence of noise, etc. is suppressed. [Explanation of symbols]

[0075] 2: Work 6: Biting detection device 7: Tap (rotary tool) 8: Motor 31: Acquisition part 34: Detection unit 41:Extraction part 42: Selection Department A: Waveform data B: Partial waveform data R1: Predetermined range R2: Predetermined value

Claims

1. A jamming detection device that detects jamming of a rotary tool that processes a workpiece, an acquisition unit that acquires time-series waveform data of parameters related to an operating state of a motor that drives the rotary tool; an extracting unit that extracts partial waveform data from the waveform data, the parameter values ​​of which fall within a predetermined range that is set in advance as upper and lower limit values ​​of the parameter values ​​during machining by the rotary tool; a selection unit that selects, from the partial waveform data extracted by the extraction unit, partial waveform data whose time width is equal to or greater than a predetermined value; a detection unit that detects jamming of the rotary tool based on the selected partial waveform data; A bite detection device comprising:

2. an extracting unit that extracts a waveform of a partial time width including a center from the waveform of the entire time width of the partial waveform data selected by the selecting unit, and generates processed waveform data; Further provided with The detection unit detects jamming of the rotary tool based on the machining waveform data. The jamming detection device according to claim 1 .

3. The detection unit an identifying unit that identifies a maximum value and an average value of the processed waveform data, a reference time that is the time at which the maximum value is reached, a first value that is a value corresponding to a time obtained by subtracting a predetermined time from the reference time, and a second value that is a value corresponding to a time obtained by adding the predetermined time to the reference time; a determination unit that determines whether or not biting of the rotary tool has occurred in the machining waveform data; Equipped with The determination unit a first determination unit that determines whether a first difference obtained by subtracting the first value from the maximum value is equal to or greater than a predetermined value; a second determination unit that determines whether a second difference obtained by subtracting the second value from the maximum value is equal to or greater than a predetermined value; a third determination unit that determines whether a third difference obtained by subtracting the average value from the maximum value is equal to or greater than a predetermined value; a fourth determination unit that determines that jamming of the rotary tool has occurred when the first difference is equal to or greater than a predetermined value, the second difference is equal to or greater than a predetermined value, and the third difference is equal to or greater than a predetermined value; Equipped with The jamming detection device according to claim 2 .

4. The detection unit When the time when the processed waveform data reaches a maximum value is set as a reference time, a value corresponding to a time obtained by subtracting a predetermined time from the reference time is set as a first value, and a value corresponding to a time obtained by adding the predetermined time to the reference time is set as a second value, When at least one of the following conditions is satisfied: a first difference obtained by subtracting the first value from the maximum value is equal to or greater than a predetermined value; a second difference obtained by subtracting the second value from the maximum value is equal to or greater than a predetermined value; and a third difference obtained by subtracting the average value from the maximum value is equal to or greater than a predetermined value, it is determined that jamming of the rotary tool has occurred. The jamming detection device according to claim 2 .

5. a smoothing unit that performs a moving average process on the processed waveform data; Further provided with The detection unit detects jamming of the rotary tool based on the machining waveform data that has been subjected to the moving average processing. The jamming detection device according to any one of claims 2 to 4.

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