Information analysis system and information analysis method for machine tool

Abstract

To provide an information analysis system and an information analysis method for a machine tool, which can sample a physical quantity during machining of a workpiece at a short period when an accurate waveform can be recognized, and can grasp a relationship between the position of a movable part of the machine tool and the detection value of a sensor sampled at a long period.SOLUTION: An information analysis system 1 comprises: a CPU module 51 that stores a coordinate value of a movable part of a machining sensor 2 and a detection value of a vibration sensor 60 acquired from a CNC 40 at a first sampling period; a data logger 62 that stores the detection value of the vibration sensor 60 at a second sampling period shorter than the first sampling period; and a computer 70 that performs a synchronization process for synchronizing the detection values of the vibration sensor 60 respectively stored in the CPU module 51 and the data logger 62 with each other, and an association process for associating the detection value of the vibration sensor 60 stored in the data logger 62 with the coordinate value of the movable part stored in the CPU module 51.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a machine tool information analysis system and a machine tool information analysis method. [Background technology]

[0002] Conventionally, data on physical quantities during the operation of a machine tool is recorded, and the data is used to grasp the situation before and after the occurrence of an abnormality, shorten the cycle time, or improve the machining quality. The operation status monitoring device described in Patent Document 1 includes various sensors such as a load sensor attached to the machine tool, and a storage unit provided with an index file in which data that satisfies a preset condition among data from the various sensors acquired at a predetermined sampling period is written, and alarm information indicating the occurrence of an abnormality in the machine tool is written to the index file. The waveform display device described in Patent Document 2 is configured to acquire data such as the position, speed, and torque of the drive shaft from a numerical control device that controls the drive shaft, extract and store data that satisfies a predetermined acquisition condition from the acquired data, and display the stored data as a waveform. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-4601 A [Patent Document 2] JP 2016-200894 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, when grasping the operating state of a machine tool during cutting processing using a ball end mill using a signal with a short change period, such as a vibration sensor signal, it is necessary to sample and store the sensor signal at a short sampling period. However, it is difficult to synchronize and store the sensor signal sampled at a short period with the position information of the moving part of the machine tool sampled at a long period. In addition, due to restrictions on the communication speed with the control device that controls the operation of the moving part of the machine tool, it may not be possible to obtain the position information of the moving part of the machine tool from the control device at such a short period. For example, the sampling period that can be performed by communication with a CNC (Computer Numerical Control) that controls a servo motor that operates the moving part of the machine tool is about 10 ms.

[0005] Therefore, an object of the present invention is to provide a machine tool information analysis system and a machine tool information analysis method that can sample sensor detection values ​​during machining of a workpiece at a short period so that an accurate waveform of physical quantities during machining of the workpiece can be recognized, and that can grasp the relationship between the position of the moving part of the machine tool and the sensor detection values ​​sampled at a long period. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides an information analysis system for a machine tool, comprising a first storage device that synchronously samples and stores coordinate values ​​of a moving part of the machine tool obtained from a control device that controls the operation of the machine tool and detection values ​​of a sensor that detects physical quantities when the machine tool is machining a workpiece, at a first sampling period; a second storage device that samples and stores the detection values ​​of the sensor at a second sampling period shorter than the first sampling period; and an information processing device that performs a synchronization process to synchronize the detection values ​​of the sensor stored in the first storage device with the detection values ​​of the sensor stored in the second storage device, wherein the information processing device performs an association process to associate the detection values ​​of the sensor stored in the second storage device with the coordinate values ​​of the moving part stored in the first storage device, based on information on the coordinate values ​​of the moving part and information on the detection values ​​of the sensor stored synchronously in the first storage device and the result of the synchronization process.

[0007] In addition, in order to achieve the above-mentioned object, the present invention provides an information analysis method for a machine tool, comprising the steps of: sampling, at a first sampling period, coordinate values ​​of a movable part of the machine tool obtained from a control device that controls the operation of the machine tool and detection values ​​of a sensor that detects physical quantities when a workpiece is machined by the machine tool, and storing them in a first storage device; sampling the detection values ​​of the sensor at a second sampling period shorter than the first sampling period and storing them in a second storage device; and performing a synchronization process for synchronizing the detection values ​​of the sensor stored in the first storage device with the detection values ​​of the sensor stored in the second storage device, and further comprising a step of relating the detection values ​​of the sensor stored in the second storage device with the coordinate values ​​of the movable part stored in the first storage device based on information on the coordinate values ​​of the movable part and information on the detection values ​​of the sensor stored in synchronization in the first storage device and a result of the synchronization process. Effect of the Invention

[0008] According to the machine tool information analysis system and machine tool information analysis method of the present invention, even if the communication speed of the control device is slow and the positions of the movable parts of the machine tool are stored at a long sampling period, the sensor detection values ​​can be stored at a short sampling period in which the accurate waveforms of the physical quantities during machining of the workpiece can be recognized, and the sensor detection values ​​stored at the short sampling period can be correlated with the positions of the movable parts stored at the long sampling period, thereby making it possible to clearly grasp the relationship between the physical quantities during machining of the workpiece and the positions of the movable parts of the machine tool. [Brief description of the drawings]

[0009] [Figure 1] 1 is a block diagram showing an example of the configuration of an information analysis system according to a first embodiment of the present invention together with a schematic configuration of a machining center. [Diagram 2] 1A is an external perspective view showing an example of a processing section for cutting a workpiece, and FIG. 1B is an explanatory view showing an example of a processing zone for the workpiece. [Diagram 3] 13 is a flowchart showing a specific example of processing performed by the computer 70 on the data logger 62. [Figure 4] 1 is a graph showing, on a common time axis, vibration intensity indicated by detection values ​​of a vibration sensor stored in a first sampling period and coordinates of a movable part of a machining center. [Diagram 5] 5 is a graph showing a partially enlarged view of the vibration intensity in the graph of FIG. 4. [Figure 6] 6 is a graph showing the vibration intensity indicated by the detection values ​​of the vibration sensor stored in the data logger in a second sampling period, on a time axis different from that of the graph in FIG. 5. [Figure 7] FIG. 2 is an explanatory diagram showing in table form the contents stored in a CPU module of a PLC and a data logger. [Figure 8] FIG. 11 is an explanatory diagram showing, in table form, an example of the results of an association process that associates each of the coordinate values ​​of the X-axis, Y-axis, and Z-axis stored in the CPU module with the detection values ​​of the vibration sensor stored in the data logger. [Figure 9] FIG. 11 is an explanatory diagram showing an example of a display of the results of a correlation process performed by a computer on a display screen. [Figure 10] 10(a) is a graph showing stored changes in the position of the table in the X-axis direction during machining of a workpiece in a second embodiment of the present invention, and (b) is a graph showing changes in the position of the table in the X-axis direction by a simulation of the operation of an NC program. [Figure 11] 13A is a graph showing a change in the position of the table in the X-axis direction stored during machining of a workpiece in the second embodiment of the present invention, and FIG. 13B is a graph showing the simulation results after a simulation result synchronization process is performed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [First embodiment] A first embodiment of the present invention will be described with reference to Figures 1 to 9. Note that the embodiment described below is shown as a preferred specific example for carrying out the present invention, and while there are some parts that specifically exemplify various technical matters that are technically preferable, the technical scope of the present invention is not limited to this specific embodiment.

[0011] Fig. 1 is a block diagram showing an example of the configuration of an information analysis system 1 according to a first embodiment of the present invention, together with a schematic configuration of a machining center 2 that processes a workpiece 6. Fig. 2 is an external perspective view showing an example of a processing unit 3 that cuts the workpiece 6 in the machining center 2. The machining center 2 is a type of machine tool, and is an analysis target whose operation is analyzed by the information analysis system 1.

[0012] 2(a), the processing unit 3 has a bed 31 serving as a base, a column 32 fixed to the bed 31, a spindle 33 on which a tool 300 is attached, a spindle head 34 on which the spindle 33 is rotatably attached, a saddle 35 slidably installed on the upper part of the bed 31, and a table 36 slidably installed on the upper part of the saddle 35. Also, as shown in FIG. 1, the processing unit 3 has a first servo motor 37 for moving the table 36 in the X-axis direction (left-right direction) relative to the saddle 35, a second servo motor 38 for moving the saddle 35 in the Y-axis direction (front-back direction) relative to the bed 31, and a third servo motor 39 for moving the spindle head 34 in the Z-axis direction (up-down direction) relative to the column 32.

[0013] The machining unit 3 moves the table 36, the saddle 35, and the spindle head 34 in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively, while rotating the tool 300, to machine the workpiece 6 fixed on the table 36. The tool 300 is, for example, a ball end mill.

[0014] The first to third servo motors 37, 38, 39 rotate at rotational speeds according to drive currents supplied from the first to third servo amplifiers 41, 42, 43, respectively, and rotate the ball screws 371, 381, 391, respectively. The table 36, the saddle 35, and the spindle head 34 move in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively, by the rotation of the ball screws 371, 381, 391. The first to third servo amplifiers 41, 42, 43 receive movement commands from the CNC 40 and control the first to third servo motors 37, 38, 39, respectively. The CNC 40 is a control device that controls the operation of the machining center 2.

[0015] The CNC 40 stores an NC program created by a user, and sends movement commands to the first to third servo amplifiers 41, 42, and 43 in accordance with the NC program. The CNC 40 stores a plurality of NC programs identified by program numbers. The NC programs are operation programs for controlling the operation of the machining center 2. The NC programs stored in the CNC 40 include a main NC program prepared for each workpiece 6, and a sub NC program prepared for each machining zone of the workpiece 6. A sub NC program is used because it is necessary to make cuts in one direction several times in a certain machining zone. The main NC program is an NC program for machining one workpiece, and the use of the sub NC program is described at various points, and the sub NC program is executed based on this description.

[0016] FIG. 2(b) shows an example of the machining zones of the workpiece 6. In this example, the workpiece 6 is a block-shaped metal lump, and the workpiece 6 is cut by the machining center 2 to become a die used for injection molding. The first machining zone 6a, which corresponds to the periphery of the workpiece 6, is an abutting portion that is abutted during die matching, and the second machining zone 6b is a portion where a molded product is formed by injection molding. The third to sixth machining zones 6c to 6f between the first machining zone 6a and the second machining zone 6b are portions where, for example, water channels for cooling water are formed. The first to sixth machining zones 6a to 6f are machined by sub-NC programs to which different program numbers are assigned.

[0017] Furthermore, the CNC 40 can acquire the X-axis coordinate which is the position of the machine reference point of the table 36 in the X-axis direction, the Y-axis coordinate which is the position of the machine reference point of the saddle 35 in the Y-axis direction, and the Z-axis coordinate which is the position of the machine reference point of the spindle head 34 in the Z-axis direction, based on the detection results of rotational position detectors (encoders) provided on the first to third servo motors 37, 38, and 39, respectively. The table 36, saddle 35, and spindle head 34 are movable parts of the machining center 2 whose positions in the movement direction are controlled by the CNC 40, and the X-axis coordinate of the table 36, the Y-axis coordinate of the saddle 35, and the Z-axis coordinate of the spindle head 34 are coordinate values ​​of the movable parts in the machining center 2.

[0018] A vibration sensor 60 is attached to the table 36 to detect the intensity of vibration, which is one of the physical quantities during machining of the workpiece 6. The vibration sensor 60 is omnidirectional or directional, and outputs an analog signal having a magnitude corresponding to the intensity of vibration as a detection signal. The number of vibration sensors 60 is not limited to one, and multiple vibration sensors 60 may be attached to the machining center 2 or the workpiece 6. In addition, a cutting load sensor 62 that detects a cutting load during machining by the tool 300 and an acoustic sensor 63 that detects the volume of sound during machining of the workpiece 6 are attached to the machining center 2. The cutting load detected by the cutting load sensor 62 and the volume of sound detected by the acoustic sensor 63 are physical quantities during machining of the workpiece 6. The following description will focus on a case where information analysis is performed using the detection result of the vibration sensor 60, but information analysis can also be performed by the cutting load sensor 62 and the acoustic sensor 63 using a similar system configuration and method.

[0019] The CNC 40 is connected to a PLC (Programmable Logic Controller) 5, and performs control in response to signals from the PLC 5. The PLC 5 has a base 50, and a CPU module 51, an analog input module 52, an input module 53, an output module 54, and a communication module 55, which are attached to the base 50. The CPU module 51 can send and receive data to and from the analog input module 52, the input module 53, the output module 54, and the communication module 55 via a data bus provided in the base 50.

[0020] The CPU module 51 has a function of executing a sequence program created by a user, and a function of storing data in a storage unit 510. The storage unit 510 is configured by, for example, a non-volatile semiconductor memory.

[0021] An amplified signal obtained by amplifying the detection signal of the vibration sensor 60 by the sensor amplifier 61 is input to the analog input module 52. This amplified signal is an analog signal obtained by amplifying the detection signal of the vibration sensor 60 by a predetermined amplification factor. Hereinafter, the amplified signal output by the sensor amplifier 61 is referred to as a vibration sensor amplified signal. The analog input module 52 converts the input vibration sensor amplified signal into a digital value. The CPU module 51 acquires the digital value converted by the analog input module 52 and stores it in the memory unit 510 as the detection value of the vibration sensor 60.

[0022] The input module 53 has a plurality of input terminals to which binary signals of ON or OFF are input. Each input terminal is connected to switches 21 such as proximity switches, limit switches, or push button switches provided in each part of the machining center 2. The output module 54 has a plurality of output terminals, each of which is connected to output devices 22 such as relays and lamps provided in each part of the machining center 2, an ATC (Automatic Tool Changer) 23, etc.

[0023] The communication module 55 performs bidirectional communication with the CNC 40. The CNC 40 executes an NC program in response to a signal sent from the PLC 5 by the communication module 55. The PLC 5 acquires the X-axis coordinate of the table 36, the Y-axis coordinate of the saddle 35, and the Z-axis coordinate of the spindle head 34 through communication with the CNC 40. The data of these coordinate values ​​acquired by the PLC 5 is stored in the memory unit 510 of the CPU module 51. The CPU module 51 functions as a first storage device in the present invention. The communication module 55 and the memory unit 510 may be provided in a newly installed personal computer separate from the PLC 5. The newly installed personal computer acquires the X-axis coordinate of the table 36, the Y-axis coordinate of the saddle 35, and the Z-axis coordinate of the spindle head 34 through communication with the CNC 40 via the communication module 55. The data of these acquired coordinate values ​​is stored in the memory unit 510 of the newly installed personal computer.

[0024] (Information Analysis System Configuration) The information analysis system 1 is composed of a vibration sensor 60, a sensor amplifier 61, a CPU module 51 of a PLC 5, a data logger 62 as a second storage device that stores the detection value of the vibration sensor 60, a computer 70 as an information processing device, and a display 71 and an input device 72 connected to the computer 70. The input device 72 is, for example, a pointing device such as a mouse, or a keyboard.

[0025] The CPU module 51 simultaneously samples the detection value of the vibration sensor 60 obtained from the analog input module 52 and the coordinate value data obtained from the CNC 40 at a predetermined sampling period, and stores the samples in the storage unit 510. This sampling period is, for example, 10 ms, and can be set by a sequence program. Hereinafter, the period at which the CPU module 51 samples the detection value and coordinate value data of the vibration sensor 60 is referred to as a first sampling period. This sampling process and storage process are executed, for example, according to a sequence program.

[0026] The data logger 62 has a larger storage capacity than the storage unit 510 of the CPU module 51, samples the vibration sensor amplified signal output by the sensor amplifier 61 at a second sampling period of 1 μs, which is shorter than the first sampling period, converts it into a digital value as the detection value of the vibration sensor 60, and logs it. Here, logging means recording in a certain format in a chronological order. The second sampling period is, for example, 1 / 10 to 1 / 10,000 of the first sampling period, and the data logger 62 itself can set the sampling period using an app. When the data logger 62 receives a command to acquire data, it records the NC program number and records the detection value of the vibration sensor 60 in a chronological order at the set sampling period.

[0027] The computer 70 performs a synchronization process to synchronize the detection values ​​of the vibration sensor 60 stored in the CPU module 51 with the detection values ​​of the vibration sensor 60 stored in the data logger 62, and an association process to associate the detection values ​​of the vibration sensor 60 stored in the data logger 62 with the coordinate values ​​stored in the CPU module 51 based on the results of this synchronization process.

[0028] The computer 70 can acquire information on the program number of the sub NC program being executed by the CNC 40, for example, via the PLC 5, and when the acquired program number matches a preset program number, outputs a command signal to the data logger 62 to start sampling. Upon receiving this start command, the data logger 62 starts sampling the vibration sensor amplified signal output by the sensor amplifier 61. The program number of the sub NC program to be analyzed is preset in the computer 70 by the input device 72. The computer 70 may acquire information on the program number of the sub NC program being executed directly from the CNC 40. Also, the command to start sampling to the data logger 62 may be manually issued by a user such as an operator.

[0029] FIG. 3 is a flow chart showing a specific example of the process that the computer 70 performs on the data logger 62. Here, a case will be described where the data logger 62 performs logging when the CNC 40 is executing the sub NC program with program number 2. The computer 70 acquires information on the program number of the sub NC program being executed by the CNC 40 (step S11), and judges whether the acquired program number is 2 or not (step S12). If the acquired program number is 2 (S12: Yes), the computer 70 transmits the program number to the data logger 62 and instructs it to start logging (step S13). Upon receiving this instruction, the data logger 62 records the program number and starts logging (step S21). Thereafter, the computer 70 judges whether the execution of the sub NC program with program number 2 has ended (step S14), and if it is judged that the execution has ended (S14: Yes), it instructs the data logger 62 to stop logging (step S15). Upon receiving this instruction, the data logger 62 stops logging (step S22).

[0030] The computer 70 acquires the information stored in the CPU module 51 and the information stored in the data logger 62, for example, by communication. If the storage unit 510 of the CPU module 51 is a storage medium such as a memory card that is detachable from the CPU module 51, the computer 70 may acquire information on the storage medium by inserting the storage medium into a connector of the computer 70. Similarly, for information stored in the data logger 62, the computer 70 may acquire information on the storage medium by inserting a storage medium that is detachable from the body of the data logger 62 into a connector of the computer 70. Next, specific examples of the synchronization process and the association process performed by the computer 70 will be described with reference to FIGS. 3 to 8.

[0031] Fig. 4 is a graph showing vibration intensity indicated by detection values ​​of the vibration sensor 60 stored in the CPU module 51 in a first sampling period during execution of one NC program, the X-axis coordinate of the table 36, the Y-axis coordinate of the saddle 35, and the Z-axis coordinate of the spindle head 34, with a common time axis as the horizontal axis. Fig. 5 is a graph showing the vibration intensity before and after time T1 in the graph of Fig. 4, enlarged by extending the time axis. Fig. 6 is a graph showing the vibration intensity indicated by detection values ​​of the vibration sensor 60 stored in the data logger 62 in a second sampling period, with a different time axis from that of the graph of Fig. 4. Fig. 6 is a graph enlarged by extending the time axis compared to Fig. 4.

[0032] Time T1 shown in Fig. 4 is the start time of cutting by the tool 300, and time T2 is the end time of cutting. In the time periods other than from time T1 to T2, the tool 300 moves relative to the workpiece 6 in an idle cutting state where no cutting is performed. The dashed line in the Z-axis coordinate graph in Fig. 4 indicates that from time T1 to T2, the height of the workpiece 6 was higher than the height of the bottom end of the ball end mill shown by the solid line, and indicates that the dashed portion was cut.

[0033] As shown in FIG. 6, the vibration intensity generated during machining of the workpiece 6 changes periodically with a period P. The period P is a time expressed as t / n, where n is the number of teeth of the tool 300, which is a ball end mill, and t is the time required for the tool 300 to rotate once. For example, when the rotation speed of the tool 300 is 5000 rpm and the number of teeth is 4, the period P is 60 / 5000 / 4 (s) = 3 (ms). As is clear from the graphs of FIG. 5 and FIG. 6, the first sampling period is 10 ms, which is not sufficient to accurately represent the waveform of the vibration generated during machining of the workpiece 6, and the information stored in the CPU module 51 cannot capture the maximum value of the vibration intensity in one period P or the periodic change of the vibration intensity. For this reason, in order to accurately represent the waveform of the vibration generated during machining of the workpiece 6, it is necessary to use data on the vibration intensity sampled at a second sampling period shorter than the first sampling period.

[0034] Therefore, in this embodiment, a synchronization process is performed to synchronize the detection value of the vibration sensor 60 stored in the CPU module 51 with the detection value of the vibration sensor 60 stored in the data logger 62, and a correlation process is performed to correlate the detection value of the vibration sensor 60 stored in the data logger 62 with each of the coordinate values ​​of the X-axis, Y-axis, and Z-axis stored in the CPU module 51. In this process, the coordinate values ​​sampled in the first sampling period are correlated with the vibration intensity data sampled in the second sampling period via the vibration intensity data sampled in the first sampling period. This correlation is possible because the CPU module 51 of the PLC 5 synchronously stores the vibration intensity data and the coordinate value data.

[0035] The synchronization process is a process for synchronizing the detection value of the vibration sensor 60 stored in the CPU module 51 with the detection value of the vibration sensor 60 stored in the data logger 62 by matching the sampling time when the detection value of the vibration sensor 60 stored in the CPU module 51 has changed beyond a predetermined value with the sampling time when the detection value of the vibration sensor 60 stored in the data logger 62 has changed beyond a predetermined value. Note that this process includes a time error due to the difference between the first sampling period and the second sampling period.

[0036] FIG. 7 is an explanatory diagram showing in table form memory contents 51a of X-axis coordinates, Y-axis coordinates, Z-axis coordinates, and vibration intensity stored in memory unit 510 of CPU module 51, and memory contents 62a of vibration intensity stored in data logger 62. In FIG. 7, memory contents 51a, 62a in some cells are shown as numerical values, and numerical values ​​are not shown in the other cells. The unit of vibration intensity is Ggal (10 -2 m / s 2 ) The data number indicates the cumulative number of samplings from the start of sampling. The CPU module 51 and the data logger 62 record these data together with the program number.

[0037] The predetermined value used in the synchronization process is desirably set to about half the average of multiple maximum values ​​of vibrations occurring during machining so that the detection values ​​of the vibration sensor 60 stored in the CPU module 51 and the data logger 62 do not frequently exceed or fall below the predetermined value. Here, the maximum value is the maximum value of vibration intensity within a time period equivalent to the above-mentioned period P. For example, if the average value of the maximum values ​​of vibrations occurring during machining is 2 Ggal, the predetermined value used in the synchronization process is set to 1 Ggal. In the graphs of Figures 5 and 6, this predetermined value is indicated as S0.

[0038] 5 and 6, the time when the machining center 2 starts machining and the detection value of the vibration sensor 60 stored in the CPU module 51 changes beyond the predetermined value S0 is designated as T 01 The time when the detection value of the vibration sensor 60 stored in the data logger 62 changes beyond the predetermined value S0 is represented by T 02 As shown by arrow A in the graph of Fig. 5, since the sampling period of the first sampling period is rough (details are described in paragraph 0033), the values ​​sampled over sampling periods 1 to 3 may fall below the predetermined value S0 even during cutting of the workpiece 6, and this time period may be mistaken for dry cutting. However, since the values ​​sampled over sampling periods 2 to 4 exceed the predetermined value S0, and the movement speeds of the table 36, saddle 35, and spindle head 34 are sufficiently low compared to the rate of change in vibration intensity, it is determined that such a time error does not pose a problem.

[0039] 7, in the memory contents 51a of the CPU module 51, the vibration intensity exceeds a predetermined value (1 Ggal) at the next sampling time (data No. 10101) of data No. 10100, and in the memory contents 62a of the data logger 62, the vibration intensity exceeds the predetermined value at the next sampling time (data No. 2021022) of data No. 2021021. Therefore, the sampling time of the sampled value of data No. 10101 in the memory contents 51a of the CPU module 51 and the sampling time of the sampled value of data No. 2021022 in the memory contents 62a of the data logger 62 are regarded as the same sampling time, and the detection value of the vibration sensor 60 stored in the CPU module 51 and the detection value of the vibration sensor 60 stored in the data logger 62 are associated with each other.

[0040] The correlation process is a process of correlating the detection value of the vibration sensor 60 stored in the data logger 62 with the coordinate value of the moving part stored in the CPU module 51, based on information on the coordinate values ​​of the moving part (the X-axis coordinate of the table 36, the Y-axis coordinate of the saddle 35, and the Z-axis coordinate of the spindle head 34) stored in synchronization in the CPU module 51 and information on the detection value of the vibration sensor 60, and the result of the synchronization process.

[0041] 8 is an explanatory diagram showing, in the form of a table, an example of the results of a correlation process that correlates each of the coordinate values ​​of the X-axis, Y-axis, and Z-axis stored in the CPU module 51 with the detection values ​​of the vibration sensor 60 stored in the data logger 62. In this process, common X-axis coordinates, Y-axis coordinates, and Z-axis coordinates are used for each data number in the memory contents 62a of the data logger 62 for a number of times according to the ratio of the first sampling period to the second sampling period, that is, for the first sampling period, with respect to the sampling period considered to be the same. Specifically, when the first sampling period is 10000 times the second sampling period, the X-axis coordinate, the Y-axis coordinate, and the Z-axis coordinate of data No. 10100 in the memory contents 51a of the CPU module 51 are repeatedly used for data No. 2011022 to 2021021 in the memory contents 62a of the data logger 62, and the X-axis coordinate, the Y-axis coordinate, and the Z-axis coordinate of data No. 10101 in the memory contents 51a of the CPU module 51 are repeatedly used for data No. 2021022 to 2031021 in the memory contents 62a of the data logger 62. This reuse is repeatedly performed for each first sampling period, with the sampling times considered to be the same as the boundary.

[0042] The predetermined value S0 may be a value that is automatically set by the processing of the computer 70, or may be a value that an operator of the computer 70 sets in the computer 70 using the input device 72. As for the cutting load sensor 62 and the acoustic sensor 63, it is desirable to set the predetermined value when performing the synchronization processing to about half the average value of multiple maximum values ​​of the detection values ​​during machining.

[0043] Here, since the CPU module 51 and the data logger 62 have different sampling periods, even if the sampling time of the vibration sensor 60 stored in the CPU module 51 and the sampling time of the vibration sensor 60 stored in the data logger 62 are made to correspond to each other by synchronization processing, the two sampling times cannot be made to strictly coincide with each other. As described in paragraphs 0035 and 0038, a time error is included. However, since the moving speed of the table 36, the saddle 35, and the spindle head 34 is sufficiently slow compared to the speed of change in vibration intensity, a difference of, for example, about 10 ms between the two sampling times is permissible when analyzing the operation of the machining center 2.

[0044] Since the CPU module 51 and the data logger 62 each perform sampling at a fixed period and store the detection values ​​of the vibration sensor 60, if the detection value of the vibration sensor 60 at the point in time when cutting is started from idle cutting can be found, it becomes possible to match the sampling times of the vibration sensor 60 stored in the CPU module 51 over the entire sampling time with the sampling times of the vibration sensor 60 stored in the data logger 62. Furthermore, since the coordinate values ​​of the movable part and the detection values ​​of the vibration sensor 60 are stored synchronously in the CPU module 51, it is possible to correlate the detection values ​​of the vibration sensor 60 stored in the data logger 62 with the coordinate values ​​of the movable part stored in the CPU module 51.

[0045] FIG. 9 is a diagram showing an example of a graph that is drawn based on the table format of FIG. 8 and displayed on the screen of the display 71 after making this correlation. FIG. 9 shows the vibration intensity before and after time T1 based on the information stored in the data logger 62, the X-axis coordinate of the table 36, the Y-axis coordinate of the saddle 35, and the Z-axis coordinate of the spindle head 34 displayed on the display 71. The solid line in the graph of the Z-axis coordinate represents the height of the bottom end of the tool 300 (ball end mill), and the dashed line in the graph of the Z-axis represents the height of the workpiece 6, and the tool 300 cuts into the workpiece 6 by the difference between the height of the end mill and the height of the workpiece 6. In FIG. 9, the graphs of the X-axis coordinate and the Y-axis coordinate corresponding to the actual output value of the vibration sensor 60 are shown by two-dot chain lines for comparison. The deviation between the solid line and the two-dot chain line in the graphs of the X-axis coordinate and the Y-axis coordinate in FIG. 9 is the time difference that can occur due to the difference between the first sampling period and the second sampling period, as described above, or the time difference that results when the values ​​sampled over the first through third sampling periods fall below the predetermined value S0 and this time period is mistakenly recognized as being in idle cutting even though cutting is actually occurring.

[0046] This screen display allows the operator of the computer 70 and the programmer creating the NC program to clearly understand what type of vibration was occurring when the machining unit 3 of the machining center 2 was machining which part of the workpiece 6. As a result, when large vibration occurs, for example, improvements can be made to reduce the vibration by slowing down the relative movement speed between the tool 300 and the workpiece 6 when machining the part where the large vibration occurred, or by reducing the amount of cut. Also, when machining defects such as chatter occur, it becomes possible to improve the NC program so that the machining defects do not recur.

[0047] Note that the computer 70 may output the correlation results not only by displaying them on the display 71, but also by issuing a print command to a printer, or by generating an image file.

[0048] (Information analysis method) The configuration and processing contents of the information analysis system 1 have been described above, and from this description, the information analysis method in the first embodiment can be understood. This information analysis method analyzes information during operation of the machining center 2 by the following steps 1 to 4. Step 1: The coordinate values ​​of the movable parts of the machining center 2 obtained from the CNC 40 that controls the operation of the machining center 2 and the detection values ​​of the vibration sensor 60 when the machining center 2 is machining the workpiece 6 are sampled at a first sampling period and stored in the CPU module 51 of the PLC 5. Step 2: The detection value of the vibration sensor 60 is sampled at a second sampling period that is shorter than the first sampling period, and stored in the data logger 62. Step 3: A process is performed to synchronize the detection value of the vibration sensor 60 stored in the CPU module 51 with the detection value of the vibration sensor 60 stored in the data logger 62. Step 4: Based on the result of the synchronization process in step 3, a correlation process is performed to correlate the detection value of the vibration sensor 60 stored in the data logger 62 with the coordinate value of the movable part stored in the CPU module 51. It should be noted that steps 1 and 2 are executed in parallel at the same time, and steps 3 and 4 are executed after steps 1 and 2.

[0049] (Effects of the First Embodiment) According to the first embodiment described above, even if the communication speed between the CPU module 51 and the CNC 40 is slow and the machining position is stored in the CPU module 51 at a long sampling period (first sampling period), the detection value of the vibration sensor 60 can be stored in the data logger 62 at a short sampling period (second sampling period) in which the vibration waveform during machining of the workpiece 6 can be recognized. The vibration intensity and machining position during machining of the workpiece 6 are synchronously stored in the CPU module 51, and later, by synchronization processing, the computer 70 matches the sampling time of the detection value of the vibration sensor 60 stored in the CPU module 51 with the sampling time of the detection value of the vibration sensor 60 stored in the data logger 62, and correlates the detection value of the vibration sensor 60 stored in the data logger 62 with the coordinate values ​​of the moving part stored in the CPU module 51, thereby making it possible to clearly grasp the relationship between the vibration intensity and the machining position during machining of the workpiece 6.

[0050] [Second embodiment] Next, a second embodiment of the present invention will be described. In the second embodiment, the information analysis system 1 is configured similarly to the first embodiment, but the computer 70 performs a simulation result synchronization process to synchronize the coordinate values ​​of the movable part stored in the CPU module 51 with the coordinate values ​​of the movable part resulting from a simulation of the operation of the movable part when the NC program stored in the CNC 40 is executed, in addition to the synchronization process and correlation process similar to the first embodiment. That is, the information analysis method according to the second embodiment has, in addition to steps 1 to 4 described in the first embodiment, step 5 to synchronize the coordinate values ​​of the movable part stored in the CPU module 51 with the coordinate values ​​of the movable part resulting from a simulation of the operation of the movable part when the NC program is executed. In this simulation, a movement trajectory showing the time-dependent change in the coordinate values ​​of the movable part can be created based on the position and speed of the movable part included in the command code (G code) described in the NC program using an application.

[0051] Fig. 10(a) is a graph showing an example of the change over time in the actual position in the X-axis direction of table 36 stored in CPU module 51 during machining of workpiece 6. Fig. 10(b) is a graph showing an example of the change over time in the position in the X-axis direction of table 36 obtained by simulating the operation of an NC program. The time axis is the same for both graphs.

[0052] As shown in Figs. 10(a) and (b), the moving speed of the movable parts such as the table 36 differs between the simulation result and the actual machining center 2 due to, for example, the inertia of the movable parts of the machining center 2 and the workpiece 6. When the application cannot properly decode the command code (G code) described in the NC program, an incorrect simulation result is displayed. For this reason, in this embodiment, a simulation result synchronization process is performed using the computer 70. This process is performed by a time axis length adjustment process in which the time axis of the coordinate values ​​of the movable parts in the simulation result is extended or shortened, or the time axis of the coordinate values ​​of the movable parts in the actual machine result is extended or shortened, to match the length of the time axis of the coordinate values ​​of the movable parts in the simulation result with the length of the time axis of the coordinate values ​​of the movable parts in the actual machine result, and a coordinate value synchronization process in which the coordinate values ​​of the movable parts in the simulation result are synchronized with the coordinate values ​​of the movable parts stored in the CPU module 51. Note that if these processes are performed for the coordinates of the X axis, the processing results can also be expanded to the Y axis and Z axis.

[0053] Here, an example of the specific processing contents of the time axis length adjustment process will be described with reference to Figures 10(a) and (b). In this example, a reference value for the coordinate value of the X axis is determined, and the time interval at which the coordinate value stored in the CPU module 51 changes beyond the reference value is matched with the time interval at which the coordinate value of the movable part in the simulation result changes beyond the reference value. Note that the reference value may be a value set in the computer 70 by an operator of the computer 70 using the input device 72 so as to facilitate the simulation result synchronization process, or may be a value automatically set by the processing of the computer 70 itself.

[0054] In the graph of FIG. 10(a), the first to fourth intersection points P 11 ~P 14 , and the first to fourth intersection points P 11 ~P 14 The first to third time intervals T 11 ~T 13 In the graph of FIG. 10(b), the first to fourth intersection points P 21 ~P 24 , and the first to fourth intersection points P 21 ~P 24 The first to third time intervals T 21 ~T 23 The reference value S1 in the graph of Fig. 10(a) and the reference value S1 in the graph of Fig. 10(b) are the same value.

[0055] In the time axis length adjustment process, the first to third time widths T 21 ~T 23 10(a) is stored in the CPU module 51. 11 ~T 13 More specifically, the first intersection point P 21 and the second intersection point P 22 In the section between the first time interval T 11 The first time span T 21 The quotient obtained by dividing by is used as an adjustment coefficient, and the adjustment coefficient is applied to the simulation result to obtain the first time span T 21 The first time span T 11 The second intersection point P 22 and the third intersection point P 23 and the third intersection point P 23 and the fourth intersection point P 24 The same process is carried out for the section between.

[0056] The coordinate value synchronization process can be performed, for example, in the same manner as the synchronization process in the first embodiment, based on the time when the coordinate value changes beyond a predetermined value. For example, the intersection point P 11 Intersection point P at time 21 The operator of the computer 70 can also perform the coordinate value synchronization process by moving the graph of the simulation results on the screen of the display 71 along the time axis and visually aligning both graphs to align the times.

[0057] The magnitude of vibration generated during machining may also be simulated. The vibration magnitude simulation can be performed based on the tool diameter, tool length, cutting depth, and spindle speed of a tool (e.g., a ball end mill), the hardness of the workpiece, and the position and moving speed of the tool relative to the workpiece specified in the NC program. In the simulation result synchronization process, the time axis is also extended or shortened for the vibration magnitude. Then, the simulation of the vibration magnitude is compared with the actually generated vibration intensity, and if vibration greater than that expected by the simulation occurs in the actual machine, the movement of the moving parts is observed in the simulation to verify the cause.

[0058] 11(a) is a graph showing the change over time in the actual position of the table 36 in the X-axis direction stored in the CPU module 51 during machining of the workpiece 6, similar to FIG. 10(a), and FIG. 11(b) is a graph showing the simulation result after the simulation result synchronization process has been performed. By performing the simulation result synchronization process in this manner, it is possible to make the coordinate values ​​of the movable part in the simulation result correspond to the detection value of the vibration sensor 60 stored in the data logger 62. Specifically, for example, instead of the graphs of the X-axis coordinate of the table 36, the Y-axis coordinate of the saddle 35, and the Z-axis coordinate of the spindle head 34 in the display example shown in FIG. 9, it is also possible to display on the display 71 the graphs of the X-axis coordinate of the table 36, the Y-axis coordinate of the saddle 35, and the Z-axis coordinate of the spindle head 34 in the simulation result after the simulation result synchronization process has been performed.

[0059] In the simulation results, it is possible to refer to which part of the NC program was being executed at each time, so it is possible to know which part of the NC program the CNC 40 was executing when, for example, there was a large change in the vibration intensity detected by the vibration sensor 60. As a result, according to this embodiment, it is possible to improve or correct the NC program more efficiently than in the first embodiment.

[0060] (Additional Note) The present invention has been described above based on the first and second embodiments, but these embodiments do not limit the invention according to the claims. It should be noted that not all of the combinations of features described in the embodiments are essential to the means for solving the problems of the invention. The present invention can be modified as appropriate by omitting some configurations or adding or replacing configurations within the scope of the gist of the invention. Furthermore, the present invention can be modified as follows, for example.

[0061] In the above embodiment, the case where the detection signal of the vibration sensor 60 is amplified by the sensor amplifier 61 has been described, but depending on the magnitude of the detection signal of the vibration sensor 60, it is not necessary to use the sensor amplifier 61. Also, in the example described with reference to Fig. 5 and Fig. 6 in the first embodiment, the case where the synchronization process is performed based on the time when the coordinate value exceeds the predetermined value S0 has been described, but this is not limiting, and the synchronization process may be performed based on the time when the coordinate value falls below the predetermined value S0. [Explanation of symbols]

[0062] 1...Information analysis system 2...Machining center (machine tool) 6...Workpiece 34...Spindle head (movable part) 35...Saddle (movable part) 36...Table (movable part) 40... CNC (control device) 51... CPU module (first storage device) 60... Vibration sensor 62... Data logger (second storage device) 70...Computer (information processing device)

Claims

1. a first storage device which samples and stores coordinate values ​​of a movable part of a machine tool obtained from a control device which controls an operation of the machine tool and detection values ​​of a sensor which detects a physical quantity when a workpiece is machined by the machine tool, in a first sampling period in synchronization with the coordinate values; a second storage device that samples and stores the detection value of the sensor at a second sampling period that is shorter than the first sampling period; an information processing device that performs a synchronization process to synchronize the detection value of the sensor stored in the first storage device with the detection value of the sensor stored in the second storage device; the information processing device performs an association process for associating the detection value of the sensor stored in the second storage device with the coordinate value of the movable part stored in the first storage device, based on information on the coordinate value of the movable part and information on the detection value of the sensor synchronously stored in the first storage device, and a result of the synchronization process; Machine tool information analysis system.

2. the synchronization process is a process for synchronizing the detection value of the sensor stored in the first storage device with the detection value of the sensor stored in the second storage device by matching a sampling time when the detection value of the sensor stored in the first storage device has changed beyond a predetermined value with a sampling time when the detection value of the sensor stored in the second storage device has changed beyond the predetermined value; 2. The machine tool information analysis system according to claim 1.

3. the correlation process is such that, with respect to the combined sampling time as a boundary, the coordinate values ​​of the movable part in the first sampling period are repeatedly used as the coordinate values ​​of the movable part in the second sampling period for the first sampling period, and this reuse is repeated for each first sampling period.

3. The machine tool information analysis system according to claim 2.

4. the control device stores and executes an operation program for controlling an operation of the machine tool, the information processing device performs a simulation result synchronization process in addition to the synchronization process and the association process; the simulation result synchronization process includes a process of matching a length of a time axis of the coordinate values ​​of the movable part stored in the first storage device with a length of a time axis of the coordinate values ​​of the movable part in the simulation result, The matching process is performed by extending or shortening the length of the time axis of the coordinate values ​​of the movable part stored in the first storage device, or by extending or shortening the length of the time axis of the coordinate values ​​of the movable part in the simulation result.

3. The machine tool information analysis system according to claim 1 or 2.

5. the simulation result synchronization process includes a process of time-synchronizing an intersection of coordinate values ​​and time of the movable part stored in the first storage device with an intersection of coordinate values ​​and time of the movable part as a result of simulating the operation of the movable part when the operation program is executed, 5. The machine tool information analysis system according to claim 4.

6. a step of sampling coordinate values ​​of a movable part of the machine tool obtained from a control device that controls an operation of the machine tool and detection values ​​of a sensor that detects physical quantities when a workpiece is machined by the machine tool at a first sampling period and storing the samples in a first storage device; sampling the detection value of the sensor at a second sampling period shorter than the first sampling period and storing the sampled value in a second storage device; performing a synchronization process for synchronizing the detection value of the sensor stored in the first storage device with the detection value of the sensor stored in the second storage device; The method further includes a step of correlating the detection value of the sensor stored in the second storage device with the coordinate value of the movable part stored in the first storage device based on information on the coordinate value of the movable part and information on the detection value of the sensor synchronously stored in the first storage device and a result of the synchronization process. A method for analyzing information on a machine tool comprising the steps of:

7. In the step of performing the synchronization process, a sampling time when the detection value of the sensor stored in the first storage device changes beyond a predetermined value is matched with a sampling time when the detection value of the sensor stored in the second storage device changes beyond the predetermined value, thereby synchronizing the detection value of the sensor stored in the first storage device with the detection value of the sensor stored in the second storage device. The method for analyzing information about a machine tool according to claim 6.

8. The method further includes a step of synchronizing the coordinate values ​​of the movable part stored in the first storage device with the coordinate values ​​of the movable part obtained by simulating the operation of the movable part during execution of the operation program stored in the control device.

8. The method for analyzing information on a machine tool according to claim 6 or 7.

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