Cutting data analysis system

Abstract

To provide a cut processing data analysis system capable of highly precisely specifying an aerial cut section.SOLUTION: A cut processing data analysis system 1 includes an analysis unit 23 that analyses time-sequence data of a processing load. The analysis unit 23 includes a threshold designation block 24 and aerial cut determination block 25. The threshold designation block 24 divides a cut processing process into plural processing sections by regarding as a break position an initiation point of a cut feed command succeeding a fast forwarding command or an initiation point of a cut feed command that is not continuous to an immediately preceding cut feed command, and designates an aerial cut determination threshold for plural processing sections on the basis of processing load values associated with initiation points of the plural processing sections in the time-sequence data. The aerial cut determination block 25 determines as an aerial cut section a section where a processing load in the time-sequence data is lower than the aerial cut determination threshold for plural processing sections.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a cutting data analysis system. [Background technology]

[0002] Conventionally, there is known a cutting device that processes a workpiece into a desired shape according to an NC (Numerical Control) program. The NC program describes a fast-forward command and a cutting feed command, and the cutting process of the workpiece is divided into a fast-forward section according to the fast-forward command and a processing section according to the cutting feed command.

[0003] Here, the machining section includes an air-cut section in which the tool does not cut the workpiece, and the longer the air-cut section, the longer it takes to machine the workpiece.

[0004] Patent Document 1 discloses a method for identifying an air cut section by setting the start point of the air cut section to the time when a cutting feed command is output and the end point of the air cut section to the time when the load on the tool suddenly increases. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Application No. 2015 / 029218 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the method described in Patent Document 1, the end point of the air cutting section is determined to be the point when the load on the tool suddenly increases. Therefore, when a cutting process includes multiple machining sections, only the air cutting section included in the first machining section can be identified.

[0007] An object of the present disclosure is to provide a cutting data analysis system that can easily and accurately identify an air-cut section. [Means for solving the problem]

[0008] A cutting data analysis system according to an aspect of the present disclosure includes an acquisition unit and an analysis unit. The acquisition unit acquires time-series data of a machining load acting on a spindle when a cutting process is performed on a workpiece by a tool attached to the spindle according to a machining program in which a fast-forward command and a cutting feed command for the spindle of a cutting device are described. The analysis unit analyzes the time-series data. The analysis unit has a threshold setting unit and an air-cut determination unit. The threshold setting unit divides the cutting process into a plurality of machining sections using a start point of a cutting feed command following a fast-forward command or a start point of a cutting feed command that is not consecutive to the immediately preceding cutting feed command as a division position, and sets an air-cut determination threshold for each of the plurality of machining sections based on a value of the machining load corresponding to the start point of each of the plurality of machining sections in the time-series data. The air-cut determination unit determines a section in the time-series data in which the machining load is lower than the air-cut determination threshold for each of the plurality of machining sections as an air-cut section. Effect of the Invention

[0009] According to the present disclosure, it is possible to provide a cutting data analysis system capable of identifying an air cut section with high accuracy. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing functions of a cutting data analysis system according to an embodiment; [Diagram 2] 5 is a schematic diagram showing an example of time-series data of machining loads and the contents of a cutting process; FIG. [Diagram 3] 1 is a flowchart showing a cutting data analysis method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (Configuration of cutting data analysis system 1) Functions of the cutting data analysis system 1 according to this embodiment will be described with reference to the drawings. Fig. 1 is a block diagram showing the functions of the cutting data analysis system 1. Fig. 2 is a schematic diagram showing an example of time-series data of machining loads and the contents of a cutting process.

[0012] The cutting data analysis system 1 includes a cutting device 10 and a cutting data analysis device 20. The number of cutting devices 10 in the cutting data analysis system 1 is not particularly limited as long as it is one or more.

[0013] [Cutting equipment 10] The cutting device 10 includes a machine body 11 and a CNC (Computer Numerical Control) control unit 12.

[0014] The machine body 11 cuts a workpiece (a so-called workpiece) W into a desired shape. The cutting process includes drilling, milling, turning, and the like.

[0015] The machine body 11 has a table 14 , a tool 15 , and a spindle 16 .

[0016] A workpiece W is placed on the table 14. A tool 15 is used to machine the workpiece W. The tool 15 is attached to a spindle 16. The spindle 16 is driven to rotate. The tool 15 moves relative to the workpiece W placed on the table 14. The tool 15 moves relative to the workpiece W as the table 14 moves or as the spindle 16 moves.

[0017] The type of tool 15 (hereinafter, abbreviated as "tool type") is appropriately selected depending on the processing content to be performed on the workpiece W. Therefore, a plurality of types of tools 15 are usually used in the cutting processing device 10. Examples of tool types include, but are not limited to, milling cutters, end mills, drills, reamers, taps, boring cutters, and the like.

[0018] The CNC control unit 12 controls the CNC control unit 12 in accordance with an NC (Numerical Control) program to execute a cutting process on the workpiece W using the tool 15. The NC program is an example of a machining program according to the present disclosure.

[0019] The NC program describes rapid-forward commands (q1, q2, q3, q4...) and cutting feed commands (p1, p2, p3, p4...). The rapid-forward commands are commands for moving the tool 15 toward and away from the workpiece W at a predetermined rapid-forward speed. The cutting feed commands are commands for cutting the workpiece W with the tool 15 at a predetermined cutting feed speed.

[0020] The cutting process of the workpiece W is divided into a fast-forward section in accordance with a fast-forward command and a cutting section in accordance with a cutting feed command, as shown in Fig. 2. The cutting section includes an air-cut section in which the tool 15 rotates idly without cutting the workpiece W.

[0021] When the machining of the workpiece W is completed, the CNC control unit 12 generates machining data for the workpiece W. The machining data includes an NC program in which a fast-forward command and a cutting feed command are described, and time-series data of the machining load acting on the spindle 16. The machining load acting on the spindle 16 is acquired by, for example, a torque sensor attached to the spindle 16.

[0022] The CNC control unit 12 transmits the generated machining data to a cutting data analysis device 20 .

[0023] [Cutting data analysis device 20] The cutting data analysis device 20 can communicate with the cutting device 10 via a network. The functions of the cutting data analysis device 20 can be achieved by a server. The server may be a cloud server.

[0024] The cutting data analysis device 20 includes an acquisition unit 21, a storage unit 22, and an analysis unit 23.

[0025] The acquisition unit 21 acquires machining data (time-series data of an NC program and machining load) from the cutting device 10. The acquisition unit 21 stores the acquired machining data in the storage unit 22. The acquisition unit 21 stores the newly acquired machining data in the storage unit 22 every time the acquisition unit 21 acquires machining data.

[0026] The analysis unit 23 analyzes the time series data of the machining load included in the machining data by referring to the machining data in the storage unit 22. The analysis unit 23 has a threshold setting unit 24, an air cut determination unit 25, an evaluation value calculation unit 26, a previous process evaluation unit 27, and a workpiece evaluation unit 28.

[0027] The threshold setting unit 24 divides the cutting process into a machining section and a fast-forward section by referring to the machining data in the storage unit 22. Specifically, the threshold setting unit 24 divides the cutting process into a plurality of machining sections by using as a dividing position the start point of a cutting feed command following a fast-forward command or the start point of a cutting feed command that is not consecutive with the immediately preceding cutting feed command. A cutting feed command that is not consecutive with the immediately preceding cutting feed command means that at least one of the cutting feed speed and the target coordinate point is different from that of the immediately preceding cutting feed command.

[0028] In the example shown in FIG. 2, the cutting process is divided into first to fourth machining sections. The first machining section is a section starting from a start point S1 of a cutting feed command p1 following a fast-forward command q1. The second machining section is a section starting from a start point S2 of a cutting feed command p2 following a fast-forward command q2. The third machining section is a section starting from a start point S3 of a cutting feed command p3 (≠ p2) that is not continuous with the immediately preceding cutting feed command p2. The fourth machining section is a section starting from a start point S4 of a cutting feed command p4 following a fast-forward command q3. Note that in FIG. 2, each machining section is terminated at the end point of each cutting feed command.

[0029] The threshold setting unit 24 sets an air cut judgment threshold for each machining section based on the value of the machining load corresponding to the start point of each of the multiple machining sections in the time series data. In the example shown in Fig. 2, a first air cut judgment threshold TH1 is set for the first machining section based on the value of the machining load corresponding to the start point S1 of the first machining section, and similarly, second to fourth air cut judgment thresholds TH2 to TH4 are set for the second to fourth machining sections, respectively.

[0030] The air-cut judgment threshold is set to a value that makes it possible to determine whether or not the tool 15 is rotating idly without cutting the workpiece W. For example, the air-cut judgment threshold can be set to a value slightly (e.g., a few percent of the maximum machining load in each machining section) larger than the machining load value corresponding to the start point. The machining load corresponding to the start point is the machining load at the start point or the average machining load for a predetermined time (e.g., 2 to 3 seconds) from the start point.

[0031] The air cut determination unit 25 determines, in the time series data, a section in which the machining load is lower than the air cut determination threshold of each machining section as an air cut section. In the example shown in Fig. 2, the air cut sections are present at the beginning of the first machining section, the beginning of the third machining section, and the beginning and middle of the fourth machining section.

[0032] As described above, by setting an air cut judgment threshold for each machining section whose dividing position is the start point of a cutting feed command following a fast forward command, or the start point of a cutting feed command that is not consecutive to the immediately preceding cutting feed command, all air cut sections can be identified easily and accurately even when a cutting machining process includes multiple machining sections.

[0033] The evaluation value calculation unit 26 calculates an air-cut evaluation value indicating the amount (number) of air-cut sections included in the cutting process. As the air-cut evaluation value, at least one of the time of each air-cut section included in the cutting process, the total time of the air-cut sections included in the cutting process, the ratio of the time of each air-cut section to the total time of the cutting process, and the ratio of the total time of the air-cut sections to the total time of the cutting process can be used.

[0034] The evaluation value calculation unit 26 stores the calculated air cut evaluation value in the storage unit 22.

[0035] The pre-process evaluation unit 27 evaluates the machining accuracy of the workpiece W in a process prior to the cutting process based on the air-cut evaluation value. The pre-process is a process carried out prior to the cutting process, and is a process for forming (e.g., forging) the workpiece W.

[0036] For example, when the ratio of the total time of the air-cut section to the total time of the cutting process is used as the air-cut evaluation value, the pre-process evaluation unit 27 evaluates the air-cut evaluation value as "good" when it is less than a predetermined value (for example, 10%), and evaluates the air-cut evaluation value as "poor" when it is equal to or greater than the predetermined value. This makes it possible to easily determine whether or not the machining accuracy in the pre-process needs to be improved.

[0037] Furthermore, when multiple air cut evaluation values ​​for one NC program are stored in the storage unit 22, the pre-process evaluation unit 27 calculates an index (for example, a standard deviation) indicating the variation of the multiple air cut evaluation values. Based on the index indicating the variation, it is possible to easily determine whether or not the variation in machining accuracy in the pre-process needs to be improved.

[0038] The workpiece evaluation unit 28 evaluates the dimensional accuracy of the workpiece W based on the air-cut evaluation value. For example, when the ratio of the total time of the air-cut section to the total time of the cutting process is used as the air-cut evaluation value, the workpiece evaluation unit 28 evaluates the air-cut evaluation value as "good" when it is less than a predetermined value (e.g., 10%), and evaluates the air-cut evaluation value as "poor" when it is equal to or greater than the predetermined value. This makes it possible to easily determine whether or not the dimensional accuracy in the previous process needs to be improved.

[0039] Furthermore, when multiple air cut evaluation values ​​for one NC program are stored in the storage unit 22, the workpiece evaluation unit 28 calculates an index (for example, a standard deviation) indicating the variation of the multiple air cut evaluation values. Based on the calculated index indicating the variation, it is possible to easily determine whether or not the variation in dimensional accuracy in the previous process needs to be improved.

[0040] (Method of analyzing cutting data) The cutting data analysis method in the cutting data analysis system 1 will be described with reference to the drawings. Fig. 3 is a flowchart showing the cutting data analysis method.

[0041] In step S1 , the acquisition unit 21 acquires machining data from the cutting device 10 .

[0042] In step S2, the threshold setting unit 24 divides the cutting process into a plurality of machining sections by referring to the machining data (time-series data of the NC program and machining load). At this time, the threshold setting unit 24 sets the start point of a cutting feed command following a fast-forward command or the start point of a cutting feed command that is not consecutive to the immediately preceding cutting feed command as a division position.

[0043] In step S3, the threshold setting unit 24 sets an air cut determination threshold for each of the multiple machining sections based on the value of the machining load corresponding to the start point of each of the multiple machining sections in the time-series data.

[0044] In step S4, the air cut determination unit 25 determines, based on the air cut determination threshold, a section in which the machining load is lower than the air cut determination threshold of each machining section in the time-series data, as an air cut section.

[0045] In step S5, the evaluation value calculation unit 26 calculates an air-cut evaluation value indicating the amount of the air-cut section included in the cutting process.

[0046] In step S6, the pre-process evaluation unit 27 and the workpiece evaluation unit 28 evaluate the machining accuracy and dimensional accuracy of the workpiece W in the process prior to the cutting process based on the air-cut evaluation value.

[0047] (Modification of the embodiment) The present disclosure is not limited to the above-described embodiments, and various modifications and alterations are possible without departing from the scope of the present disclosure.

[0048] (Variation 1) In the above embodiment, the cutting device 10 executes the cutting process on the workpiece W according to one NC program, but it may execute the cutting process according to a plurality of types of NC programs.

[0049] In this case, the acquisition unit 21 acquires machining data (including time series data of machining load) for each NC program from the cutting device 10 and stores it in the storage unit 22. The analysis unit 23 identifies an air cut section for each of the multiple types of NC programs by analyzing the time series data of the machining load for each NC program with reference to the storage unit 22. The analysis unit 23 calculates an air cut evaluation value for each NC program.

[0050] The analysis unit 23 preferably has a priority setting unit that sets an improvement priority for each NC program. The priority setting unit sets an improvement priority for each machining program based on the number of machined workpieces W in a predetermined evaluation period and the air cut evaluation value.

[0051] Specifically, the priority setting unit sets a higher improvement priority as the number of times the workpieces W are machined increases and as the air cut evaluation value increases. This makes it possible to easily determine the order of improvement when it is unclear which NC program should be improved first among multiple types of NC programs.

[0052] In the above explanation, multiple types of NC programs are used in one cutting processing device 10, but similar processing can be performed even if different NC programs are used in multiple cutting processing devices 10 connected to the cutting processing data analysis device 20.

[0053] (Variation 2) In the above embodiment, the functions of the cutting data analysis device 20 can be achieved by a server, but this is not limited to the above. At least a part of the functions of the cutting data analysis device 20 can be achieved by a terminal device. The terminal device may be attached to the cutting device 10.

[0054] (Variation 3) In the above embodiment, the cutting data analysis device 20 analyzes the machining data acquired from the cutting device 10 after temporarily storing the data, but the cutting data may be analyzed while acquiring the data from the cutting device 10. In this case, a series of analyses including identification of the start point of the machining section, setting of the air cut judgment threshold, and identification of the air cut section are executed in real time together with acquisition of the machining data. [Explanation of symbols]

[0055] 1 Cutting processing data analysis system 10 Cutting equipment 11 Machine body 12 CNC control unit 14 Tables 15 Tools 16 spindle 20 Cutting data analysis device 21 Acquisition Department 22 Memory section 23 Analysis Department 24 Threshold setting section 25 Air cut judgment section 26 Evaluation value calculation unit 27 Front-end Process Evaluation Department 28 Workpiece evaluation department

Claims

1. an acquisition unit that acquires time-series data of a processing load acting on a spindle when a cutting process is performed on a workpiece by a tool attached to the spindle in accordance with a processing program in which a fast-forward command and a cutting feed command for the spindle of a cutting device are described; An analysis unit that analyzes the time series data; Equipped with The analysis unit is a threshold setting unit which divides the cutting process into a plurality of machining sections by using a start point of the cutting feed command following the fast-forward command or a start point of the cutting feed command that is not consecutive to the immediately preceding cutting feed command as a dividing position, and sets an air cut judgment threshold for each of the plurality of machining sections based on the value of the machining load corresponding to the start point of each of the plurality of machining sections in the time-series data; an air-cut determination unit that determines, in the time-series data, a section in which the machining load is lower than the air-cut determination threshold for each of the plurality of machining sections as an air-cut section; having Cutting processing data analysis system.

2. The analysis unit has an evaluation value calculation unit that calculates at least one of the following as an air cut evaluation value: an individual time of the air cut section included in the cutting process, a total time of the air cut section included in the cutting process, a ratio of an individual time of the air cut section to a total time of the cutting process, and a ratio of a total time of the air cut section to a total time of the cutting process. The cutting data analysis system according to claim 1 .

3. The analysis unit has a pre-process evaluation unit that evaluates a machining accuracy of the workpiece in a pre-process of the cutting process based on the air cut evaluation value. The cutting data analysis system according to claim 2 .

4. The analysis unit has a workpiece evaluation unit that evaluates the dimensional accuracy of the workpiece in a process preceding the cutting process based on the air cut evaluation value. The cutting data analysis system according to claim 2 .

5. The acquisition unit acquires the time series data when the cutting process is performed in accordance with a plurality of types of the machining programs, The analysis unit analyzes a plurality of the time series data. The cutting data analysis system according to any one of claims 1 to 4.

6. The acquisition unit acquires the time series data when the cutting process is performed according to a plurality of types of the machining programs, The analysis unit analyzes a plurality of the time series data, The analysis unit has a priority setting unit that sets an improvement priority for each of the plurality of types of machining programs based on the number of processed objects of the workpieces in a predetermined evaluation period and the air cut evaluation value. The cutting data analysis system according to claim 2 .

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