JP2001246534A - Tool life control method and tool life control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for carrying out precise and elaborate life control in consideration of a cutting condition by a work working portion and a difference of a work material. SOLUTION: A life control information memory part 10 to store a plural number of abrasion evaluation indexes and abrasion critical indexes set in accordance with progressive degrees of abrasion which are indexes to store a data concerning a plural number of tools to be used for the same working process by grouping it and to evaluate tool abrasion proceeding in each of the working processes for each of tool groups and to store an accumulated abrasion evaluation index accumulated in accordance with repetition of each of the working processes for each of the tools and a life control execution part 9 to compute the accumulated abrasion evaluation index by using abrasion evaluation indexes different for each of working portions for each of the tools to use and to judge that the tool to use reaches the limit of its life when the accumulated abrasion evaluation index reaches the abrasion critical index by comparing the computed accumulated abrasion evaluation index and the abrasion critical index with each other. It is possible to carry out precise life judgement in consideration of a point that the abrasion progressing degrees are different in each of the working portions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for managing the life of a tool used in an NC machine tool due to wear.

[0002]

2. Description of the Related Art Conventionally, a method and apparatus for managing the life of a tool due to wear described above are shown in FIGS. 5 to 8 as an example. FIG. 5 is a block diagram showing a schematic configuration and the like of a numerical control device for controlling the NC lathe, which includes a tool life management unit.

[0003] As shown in FIG.
Is a machining program storage unit 1
02, program analyzer 103, distribution command generator 10
4, a feed drive control unit 105, a spindle drive control unit 106, a tool life management unit 108, a turret drive control unit 107, and the like. In the drawing, 111 is a feed drive system of the NC machine tool, 112 is a spindle drive system, and 113 is a turret.

The machining program storage unit 102 is a functional unit for storing a machining program created in advance, and a program analysis unit 103 analyzes the machining program stored in the machining program storage unit 102 and performs a feed drive in the machining program. Feed speed, moving position, and spindle drive system 1
A command relating to the rotation of the turret 113 and the operation of the turret 113 is extracted, a command relating to the feed speed and the movement position of the feed drive system 111 is transmitted to the distribution command generation unit 104, and a command relating to the rotation of the spindle drive system 112 is transmitted to the spindle drive. Control unit 10
6 and sends a command relating to the operation of the turret 113 to the tool life management unit 108.

[0005] The spindle drive control section 106 outputs a drive current generated according to the received signal to the spindle drive system 112 and controls the operation of the spindle drive system 112. Also,
The distribution command generation unit 104 generates a movement target position (operation command signal) per unit time of the feed drive system 111 in consideration of a predetermined time constant based on the received signal, and sends this to the feed drive control unit 105. Transmit sequentially. Feed drive control unit 105
First, a speed command signal is generated by multiplying the deviation between the received moving target position and the current position signal fed back from the feed drive system 111 by a position loop gain, and then the speed command signal and the feed drive system 111 A current command signal is generated by multiplying a deviation from the current speed signal fed back by a speed loop gain, and a current loop gain is calculated by a deviation between the generated current command signal and a current driving current signal fed back from the feed driving system 111. A drive current corresponding to a drive command signal obtained by multiplication is output to the feed drive system 111, and the operation of the feed drive system 111 is controlled. FIG. 5 shows one feed drive system.
A machine tool such as a C lathe usually has a plurality of feed drive systems 111
And a distribution command generation unit 104 and a feed drive control unit 105 corresponding to the distribution command generation unit 104 are provided.

The tool life management unit 108 is set to group and store data relating to a plurality of tools that can be used in the same machining process, and to evaluate tool wear progressing in each machining process. The stored wear evaluation index is stored for each tool group, the wear limit index set for each tool group is stored, and the cumulative wear evaluation index accumulated for each processing step is stored for each tool. The life management information storage unit 110 calculates a cumulative wear evaluation index accumulated for each tool group in accordance with the repetition of each processing step, and compares the wear limit index with the calculated cumulative wear evaluation index for each tool group. When the cumulative wear evaluation index reaches the wear limit index, it is determined that the tool to be used has reached the end of its life, and the next processing will be performed in the same group as the tool to be used. Comprising a life management execution unit 109 that is configured to output a command to use the other tools.

In the NC machining program, a tool group number is instructed instead of a tool number, and when the tool group number is extracted by the program analysis unit 103, non-life tools belonging to this group are managed by tool life management. The tool data selected by the unit 108 is transmitted from the tool life management unit 108 to the turret drive control unit 107.
The turret 113 is driven by the turret drive control unit 107, and the tool is indexed to a machining position.

Specifically, the life management information storage unit 110 stores the life management information shown in FIGS. 6 and 7. The data table shown in FIG. 6 is a data table related to a tool group, and includes a group number, a turret number of a tool belonging to each group, a tool selection number as an index number assigned to each turret number in the group, and It comprises a current tool selection number indicating a tool currently selected in the tool group, and a management counter set as data corresponding to the cumulative wear evaluation index for each tool. The data table shown in FIG. 7 is a data table related to tool life management. For each of the tool groups, a management type as data corresponding to the wear evaluation index such as the number of cuts and a cutting time, and a wear limit index are included. And corresponding setting values.

The life management execution unit 109 executes the processing shown in FIG. 8 to perform tool life management. That is, a tool life management start command (for example, a command specified by an M code in an NC machining program) is received from the program analysis unit 103 to start processing, and further, a command relating to a tool group is transmitted from the program analysis unit 103. After the reception (Step S101), the current tool selection number for the tool group (the tool number currently selected for the tool group) stored in the life management information storage unit 110 is read (Step S102).

Next, it is confirmed whether or not the current tool selection number is 0, and if it is not 0, the process proceeds to the next step S104.
If so, the process is terminated after displaying an alarm or the like (step S103). Note that the current tool selection number means the tool selection number of the non-life tool that is currently selected as the tool to be used for machining among the tools belonging to the group, and all the tools in the group have the same life. Is reached, it is set to 0.

In step S104, a turret indexing command (tool indexing command) corresponding to the tool selection number is output to the turret drive control unit 107, and the turret 113 is controlled.
Is driven to index the tool corresponding to the tool selection number to the machining position. Thereafter, the NC processing program is sequentially executed to perform the processing, and then, when an update command of the management counter is extracted by the program analysis unit 103 (step S105), the processing of updating the management counter shown in FIG. 6 is performed. Execute (Step S106). That is, for the tool group in which the management type is the number of cuts shown in FIG. 7, a process of adding 1 to the current management counter is performed. Perform the addition process. The machining time may be calculated from the machining program or may be the actual cutting feed time.

Next, it is determined whether or not the updated management counter has exceeded the set value shown in FIG. 7 (step S1).
07), if the management counter is less than the set value, a command to end the tool life management from the program analysis unit 103 (for example, a command specified by an M code that is paired with the tool life management start command in the NC machining program) ) Is received (step S109). If no end command has been received, the processing from step S101 is repeated, and if an end command has been received, this processing ends.

On the other hand, if it is determined in step S107 that the management counter has exceeded the set value, the tool selection number is updated (step S108). That is, the next tool selection number whose management counter shown in FIG. 6 is less than the set value is searched, and the tool selection number is set as a tool to be used for the next machining. In other words, the current tool selection number shown in FIG. 6 is replaced with the retrieved tool selection number. When all the tools in the tool group have reached the end of their life, the tool selection number is set to 0 as described above. Then, after performing such processing, the process proceeds to next step S109, and the above processing is executed. That is, when the end command of the tool life management has not been received, the updated non-life tool is determined and machining is performed by the tool.

Thus, according to the numerical controller 101, a plurality of tools that can be used in the same machining step are grouped and registered, and the tool wear progressing in each machining step is evaluated. A management type, which is a wear evaluation index, is set for each tool group, and a management counter, which is a cumulative wear evaluation index, which is accumulated in accordance with the repetition of each of the machining steps, is calculated for each of the tools. The set value which is the set wear limit index is compared with the control counter, and when the control counter reaches the set value, it is determined that the tool to be used has reached the end of its life, and the next processing is performed in the same group as the tool to be used. If you use a tool that has exceeded its wear limit, the tool may be damaged or the work may be defective. That the it is possible to prevent an effect is obtained that it is possible to perform an unattended operation for a long period of time.

[0015]

By the way, in general machining, even if machining using the same tool,
The cutting conditions (cutting speed, feed rate, and cutting depth) differ depending on the processing part of the work, and the degree of wear of the tool usually greatly varies depending on the cutting conditions and the material of the work.

However, the above-described conventional numerical controller 1
According to No. 01, as the tool wear evaluation index, the number of cuts and the cutting time in which the difference in the cutting conditions and the material of the workpiece according to the workpiece processing portion is not taken into account is used, that is, in the processing in which the cutting conditions and the material of the workpiece are different. Even though there is no weighting based on the difference in the number of times of cutting and the cutting time, the difference in the cutting conditions and the difference in the material of the workpiece cannot be accurately reflected in the evaluation of the tool wear. Detailed life management could not be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a tool life management method capable of performing accurate and detailed life management in consideration of differences in cutting conditions and work materials depending on a work processing portion. And a tool life management device.

[0018]

Means for Solving the Problems and Effects Thereof The invention described in claim 1 of the present invention for solving the above-mentioned problems has the following features.
C An invention according to a method for managing the life of a tool used in a machine tool, wherein a plurality of tools that can be used in the same machining process are grouped and registered, and the tool progresses by performing each machining process. A wear evaluation index for evaluating wear is set for each of the tool groups, and a cumulative wear evaluation index that is accumulated according to the repetition of each of the machining steps is calculated for each of the used tools, and is set in advance for each of the used tools. The wear limit index and the cumulative wear evaluation index are compared, and when the cumulative wear evaluation index reaches the wear limit index, it is determined that the used tool has reached the end of its life, and the same group as the used tool from the next machining is determined. In the tool life management method in which other tools are used, a plurality of wear evaluation indices set according to the degree of progress of wear are added to the wear evaluation index set for each of the tool groups. Was used, the calculated cumulative wear evaluation index using different the wear evaluation index by the machining site,
The tool life is determined using the calculated cumulative wear evaluation index.

According to this method, a plurality of tools that can be used in the same machining step are grouped and registered,
A wear evaluation index for evaluating tool wear progressing by performing each processing step is set for each of the tool groups, and a cumulative wear evaluation index that is accumulated in accordance with the repetition of each of the processing steps is calculated for each of the tools. For each of the tool groups, a preset wear limit index and the cumulative wear evaluation index are compared, and when the cumulative wear evaluation index reaches the wear limit index, it is determined that the tool to be used has reached the end of its life, Since another tool in the same group as the tool to be used is used from the next machining, the use of a tool that has exceeded the wear limit may cause the tool to be damaged or the workpiece to be defective. This can be prevented, and unmanned operation can be performed for a long time.

Further, according to this method, a plurality of wear evaluation indices set according to the degree of progress of wear are used for the wear evaluation indices set for each of the tool groups, and a plurality of wear evaluation indices are set according to a machining portion, that is, cutting conditions. If the work material is different depending on the machined part, the cumulative wear evaluation index is calculated using the wear evaluation index corresponding to this and the tool life is determined using the calculated cumulative wear evaluation index. Even when machining with the same tool, if the cutting conditions and the material of the workpiece are different depending on the machining area, the degree of progress of the tool wear is different depending on the machining area. When machining with the same tool,
The cumulative wear evaluation index is calculated using the wear evaluation index corresponding to each processing part, and the tool life is determined using the calculated cumulative wear evaluation index. Can be accurately reflected in the evaluation of tool wear, and as a result, accurate and detailed life management can be performed.

The above-mentioned method invention can be suitably implemented by the apparatus invention described in claim 2.
That is, the invention described in claim 2 is an invention relating to an apparatus for managing the life of a tool used in an NC machine tool,
Data relating to a plurality of tools that can be used in the same machining process is grouped and stored, and a wear evaluation index set for evaluating tool wear progressing by performing each machining process is stored for each tool group. And a life management information storage unit storing a wear limit index set for each tool group, and storing a cumulative wear evaluation index accumulated for each tool in accordance with the repetition of each processing step,
The cumulative wear evaluation index is calculated for each tool used, and the calculated cumulative wear evaluation index is compared with the wear limit index.When the cumulative wear evaluation index reaches the wear limit index, the tool reaches the end of its life. And a life management execution unit configured to output a command to use another tool in the same group as the tool to be used from the next machining. The management information storage unit is configured to store a plurality of wear evaluation indices set for each of the tool groups in accordance with the degree of progress of wear, and the life management execution unit is configured to perform the wear management depending on a machining part. The present invention is characterized in that the cumulative wear evaluation index is calculated using an evaluation index, and the tool life is determined using the calculated cumulative wear evaluation index.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram illustrating a schematic configuration and the like of a numerical control device for controlling an NC lathe according to the present embodiment, the numerical control device including a tool life management unit. As shown in this figure, the numerical controller 1 of the present example is the same as the conventional numerical controller 1 shown in FIG.
The configuration differs from that of the first embodiment in that a tool life management unit 8 having a different function is provided. Therefore, the same components as those of the numerical control device 101 are denoted by the same reference numerals, and a detailed description thereof will be omitted.

The tool life management unit 8 of this embodiment comprises a life management execution unit 9 and a life management information storage unit 10, and as described above, differs from the tool life management unit 108 in the numerical control device 101 exemplified as the conventional example. Its function is different. Hereinafter, the life management execution unit 9 and the life management information storage unit 10 will be described in detail.

The life management information storage unit 10 specifically stores the life management information shown in FIGS. 2 and 3. The data table shown in FIG. 2 is a data table relating to a tool group. It comprises a current tool selection number indicating a tool currently selected in the tool group, and a management counter set as data corresponding to the cumulative wear evaluation index for each tool. The management counter indicates the cumulative wear rate (%). The data table shown in FIG. 3 is a data table relating to tool life management. A plurality of wear rates are set as the wear evaluation index for each tool group, and a set number is set as an index number of the wear rate. It is composed of The wear rate means the rate of tool wear progressing in one machining, and the cumulative wear rate is 100%.
Is an index at which the wear limit, that is, the life can be determined.

Further, the life management execution unit 9 executes the processing shown in FIG. 4 to perform tool life management. That is, a tool life management start command (for example, a command specified by the M code in the NC machining program) is received from the program analysis unit 103 to start the process, and further, a command (for the tool group) from the program analysis unit 103 relating to the tool group is received. After receiving the command number for the tool group to be used in the NC machining program) and the setting number for the wear rate (commanded in the NC machining program) (step S1,
Step S2), the wear rate corresponding to the set number stored in the life management information storage unit 10 is read (Step S3). In the NC machining program, a tool group number is instructed instead of a tool number, and a set number is instructed for each machining region. Therefore, even if the tools used are the same, if the wear rate of the tool differs depending on the processing part, a different setting number is commanded for each processing part.

Next, the current tool selection number for the tool group stored in the life management information storage unit 10 (the currently selected tool number for the tool group)
Is read (step S4), it is confirmed whether or not the current tool selection number is 0. If not, the next step S6
If the value is 0, an alarm is displayed and the process is terminated (step S5). Note that the current tool selection number means the tool selection number of the non-life tool that is currently selected as the tool to be used for machining among the tools belonging to the group, and all the tools in the group have the same life. Is reached, it is set to 0.

In step S6, a turret number indexing command (tool indexing command) corresponding to the tool selection number is output to the turret drive control unit 107, and the turret 113 is driven to activate the tool corresponding to the tool selection number. To the machining position. Thereafter, while the NC machining program is sequentially executed to perform machining, a process of updating the management counter shown in FIG. 2 is executed (step S7). That is, a process of adding the wear rate to the management counter of the selected tool selection number is performed.

Next, it is determined whether or not the updated management counter has reached 100 or more (step S8). If the management counter does not reach 100, the program analysis unit 103 issues a tool life management termination command (for example, It is determined whether or not the NC machining program has received the command specified by the M code that is paired with the tool life management start command) (step S10). Is repeated, and when an end instruction is received, the process is terminated.

On the other hand, if it is determined in step S8 that the management counter has reached 100 or more, the tool selection number is updated (step S9). That is, FIG.
Is searched for the next tool selection number whose management counter is less than 100, and the tool selection number is set as a tool to be used for the next machining. In other words, the current tool selection number shown in FIG. 2 is replaced with the retrieved tool selection number. When all the tools in the tool group have reached the end of their life, the tool selection number is set to 0 as described above. After performing such processing, the process proceeds to the next step S10, and the above processing is executed. That is, when the end command of the tool life management has not been received, the updated non-life tool is determined and machining is performed by the tool.

Thus, according to the numerical controller 1,
A plurality of tools that can be used for the same machining process are grouped and registered, and a wear ratio, which is a wear evaluation index for evaluating tool wear progressing by performing each machining process, is set for each of the tool groups, A cumulative wear rate (management counter), which is a cumulative wear evaluation index accumulated in accordance with the repetition of each processing step, is calculated for each of the tools, and for each of the tool groups, a preset wear limit index (100 in this example). ) Is compared with the cumulative wear rate (management counter), and when the cumulative wear rate (management counter) reaches 100, it is determined that the tool to be used has reached the end of its life, and the same group as the tool to be used from the next machining. Since other tools are used, the tool may be damaged by using a tool whose wear limit has been exceeded, or the work may become defective. That the it is possible to prevent an effect is obtained that it is possible to perform an unattended operation for a long period of time.

Further, even if machining is performed with the same tool, if the cutting conditions and the material of the workpiece are different depending on the machining portion, the degree of progress of the tool wear is different. , Set a plurality of wear ratios (wear evaluation index) according to the degree of progress of wear,
When the machining conditions, that is, the cutting conditions and the material of the workpiece are different depending on the machining area, the cumulative wear rate (management counter) is calculated using the wear rate according to the machining area, and the calculated cumulative wear rate (management counter) is calculated. Is used to determine the tool life, so that differences in cutting conditions and differences in work materials can be accurately reflected in the evaluation of tool wear, and accurate and detailed life management can be performed.

In this example, an example in which only the wear rate is used as the wear evaluation index is shown. However, even when the number of times of cutting and the cutting time are used together as the wear evaluation index, it is within the scope of the object of the present invention. If so, it doesn't hurt.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration and the like of a numerical control device for controlling an NC lathe according to an embodiment of the present invention, which is provided with a tool life management unit.

FIG. 2 is a data table showing data stored in a life management information storage unit according to the embodiment.

FIG. 3 is a data table showing data stored in a life management information storage unit according to the embodiment.

FIG. 4 is a flowchart showing a processing procedure in a life management execution unit according to the embodiment.

FIG. 5 is a block diagram showing a schematic configuration and the like of a numerical control device for controlling an NC lathe according to a conventional example, which is provided with a tool life management unit.

FIG. 6 is a data table showing data stored in a life management information storage unit according to a conventional example.

FIG. 7 is a data table showing data stored in a life management information storage unit according to a conventional example.

FIG. 8 is a flowchart showing a processing procedure in a life management execution unit according to a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Numerical control device 8 Tool life management unit 9 Life management execution unit 10 Life management information storage unit 102 Processing program storage unit 103 Program analysis unit 104 Distribution command generation unit 105 Feed drive control unit 106 Spindle drive control unit 107 Turret drive control unit 111 Feed drive system 112 Spindle drive system 113 Turret

Claims (2)

[Claims] 1. A method for managing the life of a tool used in an NC machine tool, wherein a plurality of tools that can be used in the same machining process are grouped and registered, and the progress is made by executing each machining process. A wear evaluation index for evaluating tool wear to be set is set for each of the tool groups, and a cumulative wear evaluation index that is accumulated in accordance with the repetition of each of the machining steps is calculated for each of the used tools. The set wear limit index and the cumulative wear evaluation index are compared, and when the cumulative wear evaluation index reaches the wear limit index, it is determined that the tool to be used has reached the end of its life, and the next processing is performed with the use tool. In a tool life management method in which another tool in the same group is used, a wear evaluation index set for each tool group includes a plurality of wears set in accordance with the degree of progress of wear. A tool that calculates the cumulative wear evaluation index by using the wear evaluation index that varies depending on a processing portion using an evaluation index, and determines the tool life by using the calculated cumulative wear evaluation index. Life management method. 2. An apparatus for managing the life of a tool used in an NC machine tool, wherein data relating to a plurality of tools which can be used in the same machining process is grouped and stored, and each machining process is executed. The wear evaluation index set for evaluating the tool wear progressing according to is stored for each of the tool groups, the wear limit index set for each tool group is stored, and the cumulative total is set in accordance with the repetition of each processing step. The life management information storage unit storing the calculated cumulative wear evaluation index for each tool, and calculating the cumulative wear evaluation index for each tool used, and comparing the calculated cumulative wear evaluation index with the wear limit index. When the cumulative wear evaluation index reaches the wear limit index, it is determined that the tool to be used has reached the end of its life, and an instruction is made to use another tool in the same group as the tool to be used from the next processing. And a life management execution unit configured to output a plurality of wears set for each of the tool groups in accordance with a progress degree of wear. While storing the evaluation index, the life management execution unit calculates the cumulative wear evaluation index using the wear evaluation index that varies depending on the processing part, and uses the calculated cumulative wear evaluation index to calculate the cumulative wear evaluation index. A tool life management device configured to determine a tool life.