JP7637647B2 - Cutting data analysis system - Google Patents

Description

This disclosure relates to a cutting processing data analysis system.

Conventionally, cutting processing devices are known that process a workpiece into a desired shape according to an NC (Numerical Control) program. The NC program contains fast-forward commands and cutting feed commands, 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.

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.

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.

International Application No. 2015/029218

However, in the method described in Patent Document 1, the end point of the air cut section is determined to be the point when the load on the tool suddenly increases, so if there are multiple machining sections in the cutting process, only the air cut section included in the first machining section can be identified.

The purpose of this disclosure is to provide a cutting data analysis system that can easily and accurately identify air cut sections.

The cutting data analysis system according to one aspect of the present disclosure includes an acquisition unit and an analysis unit. The acquisition unit acquires time series data of the machining load acting on the spindle when the cutting process is performed on the 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 the 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 multiple machining sections using 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, and 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. The air cut determination unit determines, as an air cut section, a section in the time series data in which the machining load is lower than the air cut determination threshold for each of the multiple machining sections.

This disclosure provides a cutting data analysis system that can accurately identify air cut sections.

1 is a block diagram showing functions of a cutting data analysis system according to an embodiment; 5 is a schematic diagram showing an example of time-series data of machining loads and the contents of a cutting process; FIG. 1 is a flowchart showing a cutting data analysis method.

(Configuration of cutting data analysis system 1)
The functions of the cutting data analysis system 1 according to the present 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.

The cutting data analysis system 1 includes a cutting device 10 and a cutting data analysis device 20. There is no particular limit to the number of cutting devices 10 in the cutting data analysis system 1, and it may be one or more.

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

The machine body 11 cuts the workpiece W into a desired shape. Cutting includes drilling, milling, turning, etc.

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

A workpiece W is placed on the table 14. A tool 15 is used to process 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 by the movement of the table 14 or the movement of the spindle 16.

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

The CNC control unit 12 executes a cutting process on the workpiece W using the tool 15 by controlling the CNC control unit 12 according to an NC (Numerical Control) program. The NC program is an example of a machining program according to the present disclosure.

The NC program contains fast-forward commands (q1, q2, q3, q4...) and cutting feed commands (p1, p2, p3, p4...). The fast-forward command is a command for moving the tool 15 toward and away from the workpiece W at a predetermined fast-forward speed. The cutting feed command is a command for cutting the workpiece W with the tool 15 at a predetermined cutting feed speed.

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

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 fast-forward commands and cutting feed commands are written, and time-series data of the machining load acting on the spindle 16. The machining load acting on the spindle 16 is acquired, for example, by a torque sensor attached to the spindle 16.

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

[Cutting data analysis device 20]
The cutting data analysis device 20 is capable of communicating 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.

The cutting processing data analysis device 20 has an acquisition unit 21, a memory unit 22, and an analysis unit 23.

The acquisition unit 21 acquires machining data (NC program and time series data of machining load) from the cutting device 10. The acquisition unit 21 stores the acquired machining data in the storage unit 22. Every time the acquisition unit 21 acquires machining data, it stores the newly acquired machining data in the storage unit 22.

The analysis unit 23 refers to the processing data in the memory unit 22 and analyzes the time series data of the processing load included in the processing data. 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.

The threshold setting unit 24 refers to the machining data in the memory unit 22 and divides the cutting process into a machining section and a fast-forward section. Specifically, the threshold setting unit 24 divides the cutting process into a plurality of machining sections, using as a dividing point 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.

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

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.

The air cut judgment threshold is set to a value that makes it possible to determine whether 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 greater than the machining load value corresponding to the start point (e.g., a few percent of the maximum machining load in each machining section). 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 period (e.g., 2 to 3 seconds) from the start point.

The air cut determination unit 25 determines, in the time series data, a section in which the processing load is lower than the air cut determination threshold for each processing section as an air cut section. In the example shown in FIG. 2, air cut sections exist at the beginning of the first processing section, the beginning of the third processing section, and the beginning and middle of the fourth processing section.

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 easily and accurately identified even when the cutting process includes multiple machining sections.

The evaluation value calculation unit 26 calculates an air cut evaluation value that indicates the amount (number) of air cut sections included in the cutting process. As the air cut evaluation value, at least one of the following can be used: 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.

The evaluation value calculation unit 26 stores the calculated air cut evaluation value in the memory unit 22.

The pre-process evaluation unit 27 evaluates the machining accuracy of the workpiece W in the process prior to the cutting process based on the air cut evaluation value. The pre-process is a process that is carried out prior to the cutting process and is used to form (e.g., forge) the workpiece W.

When the pre-process evaluation unit 27 uses, for example, the ratio of the total time of the air cut section to the total time of the cutting process as the air cut evaluation value, it 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 easy to determine whether or not the machining accuracy in the pre-process needs to be improved.

In addition, when multiple air cut evaluation values for one NC program are stored in the memory unit 22, the pre-process evaluation unit 27 calculates an index (e.g., 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.

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 easy to determine whether or not the dimensional accuracy in the previous process needs to be improved.

In addition, when multiple air cut evaluation values for one NC program are stored in the memory unit 22, the workpiece evaluation unit 28 calculates an index (e.g., 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 dimensional accuracy variation in the previous process needs to be improved.

(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.

In step S1, the acquisition unit 21 acquires processing data from the cutting device 10.

In step S2, the threshold setting unit 24 divides the cutting process into a plurality of processing sections by referring to the processing data (NC program and time series data of processing 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 with the immediately preceding cutting feed command, as the division position.

In step S3, the threshold setting unit 24 sets an air cut judgment threshold for each processing section based on the processing load value corresponding to the start point of each of the multiple processing sections in the time series data.

In step S4, the air cut determination unit 25 determines, based on the air cut determination threshold, the sections in the time series data where the processing load is lower than the air cut determination threshold for each processing section as air cut sections.

In step S5, the evaluation value calculation unit 26 calculates an air cut evaluation value that indicates the amount of air cut sections included in the cutting process.

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 preceding the cutting process based on the air cut evaluation value.

(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.

(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.

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 memory unit 22. The analysis unit 23 refers to the memory unit 22 and analyzes the time series data of machining load for each NC program to identify air cut sections for each of the multiple types of NC programs. The analysis unit 23 calculates an air cut evaluation value for each NC program.

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 workpieces W machined during a specified evaluation period and the air cut evaluation value.

Specifically, the priority setting unit sets a higher improvement priority the more workpieces W are machined and the higher the air cut evaluation value. This makes it easy to determine the order of improvement when it is unclear which NC program should be improved first among multiple types of NC programs.

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

(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.

(Variation 3)
In the above embodiment, the cutting data analysis device 20 temporarily stores the machining data acquired from the cutting device 10 and then analyzes the data, but the cutting data analysis device 20 may analyze the machining data while acquiring the data from the cutting device 10. In this case, a series of analyses including identification of the machining section start point, 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.

REFERENCE SIGNS LIST 1 Cutting data analysis system 10 Cutting device 11 Machine body 12 CNC control unit 14 Table 15 Tool 16 Spindle 20 Cutting data analysis device 21 Acquisition unit 22 Storage unit 23 Analysis unit 24 Threshold setting unit 25 Air cut determination unit 26 Evaluation value calculation unit 27 Previous process evaluation unit 28 Workpiece evaluation unit

Claims (6)

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. 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.
2. The cutting data analysis system according to claim 1. 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 . The analysis unit has a workpiece evaluation unit that evaluates the dimensional accuracy of the workpiece in a process prior to the cutting process based on the air cut evaluation value.
The cutting data analysis system according to claim 2 . 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. 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 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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