JPH06738A - Tool exchanging method - Google Patents

Abstract

PURPOSE:To suppress the increase of a machining time owing to an exchange time. CONSTITUTION:Looking ahead of a machining program is executed at S4-S8 during a time in which a tool selection command is read during the stating of machining and each time exchange of a tool is executed. A tool code for a read tool selection command is outputted to a tool exchanging device 3 and preparation operation of exchange of a tool is started at S9. Meanwhile, a machining program is orderly executed by a CNC device 1 at S2, S3, and S11. Since preparation operation of exchange of a tool can be completed during a time in which a tool selection command is read as execution statement, there is no need to re-start the machining program after waiting for take-out of a drilling tool and its movement to a tool exchange position like a conventional method, and a machining time of the whole of one machining program can be sharply saved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling a machine tool and an improvement of a tool changing method using the tool changing device.

[0002]

2. Description of the Related Art In the field of exchanging cutting tools in so-called machining centers and exchanging drilling tools in CNC punch press machines, a tool changer is driven by a command from a controller of various machine tools or punch press machines. A method of exchanging tools for performing the automatic exchanging work is widely known. The command for driving the tool changer is composed of the tool selection command written in the machining program, and the controller that reads the tool selection command in the machining program as the execution target statement inputs the tool selection command to the tool changer. At that time, the preparatory operation on the side of the tool changer, that is, the preparatory operation of taking out the tool designated by the tool selection command from the pot or moving the tool to the tool exchanging position is started. Only when completed can the tool be replaced.

[0003]

Although the conventional technique as described above has made it possible to automate the tool exchange itself, in the case where the tool exchange is performed during the execution of machining, the control device outputs a tool selection command. From the start to the completion of the preparatory operation of the tool changer, the machining program must be executed, that is, the machining operation by the machine tool must be interrupted and the standby state must be maintained, increasing the overall machining time. Then, there was a drawback that adversely affects the running cost. In particular, recently, as the product shape has become complicated and the materials have been diversified, the tool replacement in one machining program has been frequently performed, and the increase of the processing time by the tool replacement is becoming an important issue. Therefore, an object of the present invention is to provide a tool exchanging method that suppresses an increase in machining time caused by tool exchanging and can perform a series of machining in a short time even if the tool exchanging is frequently performed.

[0004]

According to the tool exchanging method of the present invention, the machining program is pre-read by the controller until the tool selection command is read at the start of machining and every time tool exchanging is executed, and the read tool is read. After outputting the tool code of the selection command from the control device to the tool exchanging device, the machining programs are sequentially executed by the control device, and the tool code is sent when the tool exchanging device receives the tool code sent from the control device. The object is achieved by moving the tool of the code to the tool replacement position by the tool replacement device and performing the tool replacement work by the tool replacement device to which the tool selection execution command from the control device is input.

[0005]

The control device for controlling the machine tool pre-reads the machining program until the tool selection command is read at the start of machining and every time tool exchange is executed, and the tool code of the read tool selection command is read by the tool exchange device. And the machining programs are sequentially executed. The tool changer
When the tool code sent from the control device is received, the operation to move the tool of the tool code to the tool replacement position is started, and when the tool selection execution command is input from the control device, the tool replacement work is executed. To do.

A control device for controlling the machine tool pre-reads a tool selection command and outputs a tool code, so that the tool changing device performs a preparatory operation for changing the tool, that is, taking out a designated tool or moving to a tool changing position. And start
The control device drives and controls the machine tool to perform machining even while the designated tool is being taken out and moved. Moreover, at the stage when the pre-read tool selection command is subsequently read by the control device as the execution target statement and output to the tool change device as the tool selection execution command, the specified tool has already been taken out and moved, and the tool replacement Since the device can immediately execute the tool exchange when the tool selection command is input, the increase of the machining time due to the interruption of the machining for the tool exchange is suppressed to the maximum.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an outline of a CNC punch press system to which the method of the present invention is applied. This system includes a punch press machine 2 as a machine tool, a tool changing device 3, and a punch press machine 2 and a tool changing device. It is configured by the CNC device 1 which is a control device for controlling The processor 11 is a processor that controls the CNC device 1 as a whole, reads the system program stored in the ROM 12 via the bus 19, and controls the CNC device 1 as a whole according to the system program. The RAM 13 stores temporary calculation data, display data, various data input by the operator via the CRT / MDI unit 20, and the like. CMOS memory 1
4 is configured as a non-volatile memory that is backed up by a battery (not shown), and retains a stored state even when the power of the CNC device 1 is turned off. The machining program read through the interface 15 and the CRT / MDI unit 20 are stored in the memory 4. A machining program or the like input via the memory is stored. Further, various system programs for executing the edit mode processing required for creating and editing the machining program and the reproduction mode processing for automatic operation are written in the ROM 12 in advance.

The interface 15 is an interface for an external device connectable to the CNC device 1, and is connected with an external device 18 such as a paper tape reader, a paper tape puncher, and an external storage device. Processing programs are read from the paper tape reader and external storage device, and
The machining program edited in the CNC device 1 can be output to a paper tape puncher or an external storage device. P
MC (Programmable Machine Controller) 16
Is a sequence program built in the CNC device 1 that converts a command code from the processor 11 into a signal required by the tool changing device 3 and outputs the signal from the I / O unit 17 to the tool changing device 3. 2 and limit switches of the tool changer 3 and signals of various switches of the operation panel provided on the main body of the punch press machine 2,
Perform necessary processing and pass it to the processor 11.

The CRT / MDI unit 20 is a manual data input device equipped with a display, a keyboard, etc.
The interface 21 receives data from the keyboard of the CRT / MDI unit 20 and transfers it to the processor 11. The interface 22 is connected to the manual pulse generator 23 and receives pulses from the manual pulse generator 23.
The manual pulse generator 23 is mounted on the operation panel of the punch press machine 2 and is used for precisely positioning the movable part of the punch press machine 2 by controlling each axis by the distribution pulse based on the manual operation.

The axis control circuits 30 to 32 receive the movement command of each axis from the processor 11 and output the command of each axis to the servo amplifiers 40 to 42. In response to this command, the servo amplifiers 40 to 42 drive the servo motors 50 to 52 of the respective axes of the punch press machine 2. The servo motor 50,
Reference numeral 51 is for feeding the die plate in the X-axis and Y-axis directions, and the servo motor 52 is for changing the rotational position of the chuck holding the drilling tool. Servo motor 50 for each axis
52 has a built-in pulse coder for position detection,
The position signal from this pulse coder is fed back as a pulse train. In some cases, a linear scale is used as the position detector. In addition, this pulse train is F
A speed signal can be generated by converting / V (frequency / speed). In FIG. 1, the description of the flywheel for driving the punching tool of the punch press machine 2 and the electric motor or the like (which may be a hydraulic circuit) as a drive source thereof is omitted.

In the vicinity of the tool exchanging device 3, there is provided a pot in which a large number of various punching tools having different shapes and materials are stocked, and the tool exchanging function of the tool exchanging device 3 causes the chuck of the punch press machine 2 to move. Collect the punching tool and store it in a pot, select a designated punching tool from the pot and move it to the tool change position, and further attach the tool moved to the tool change position to the chuck of the punch press machine 2. You can do it. Such a function is, for example, after taking out the specified drilling tool from the pot and moving it to the tool exchange position, after confirming that the drilling tool has been recovered from the chuck of the punch press machine 2, the function is moved to the tool exchange position. It is realized by the cooperative operation of the first robot arm that attaches a certain punching tool to the chuck and the second robot arm that collects the punching tool from the chuck of the punch press machine 2 and stores it in the pot.

2 and 3 are flowcharts showing the outline of the system program executed by the processor 11 (hereinafter referred to as CPU) of the CNC device 1 in the process of the automatic operation mode. Hereinafter, the two robot arms will operate cooperatively. The tool exchanging method of the embodiment will be described by taking the tool exchanging device 3 for exchanging tools as an example. It should be noted that the processing program to be reproduced is already stored in the CMOS memory 14.

CPU that started processing in automatic operation mode
First, the values of the execution position storage index R0 and the prefetch start position storage index R1 are both initialized to "0" to reset the prefetch prohibition flag F0 (step S1), and the value of the execution position storage index R0 is set to "1". After the increment (step S2), the statement with the sequence number R0 is read from the machining program of the CMOS memory 14 based on the value "1" of the index R0, and is temporarily stored in the RAM 13 as an execution target statement (step S3). Then
The CPU determines whether or not the prefetch prohibition flag F0 is set (step S4). In this case, since the prefetch prohibition flag F0 is reset in the process of step S1, the determination result of step S4 is false. Become. Therefore, the CPU increments the value of the prefetch start position storage index R1 by "1" (step S5), and the index R1
The statement with the sequence number R1 is prefetched from the machining program of the CMOS memory 14 based on the value "1" of the above, and this statement is temporarily stored in the RAM 13 as a prefetch statement (step S6). Then
The CPU determines whether or not a tool selection command (T code) is attached to the statement prefetched in the process of step S6 (step S7). If the tool selection command is not attached, this statement is further added. Is determined to indicate the program end (step S8). If it does not indicate the program end, the CPU moves to the processing of step S5 again, and the prefetch start position is continued until the statement with the tool selection command or the statement indicating the program end is prefetched. The value of the storage index R1 is sequentially incremented, and the processing from step S5 to step S8 (hereinafter referred to as the prefetch processing) is repeatedly executed.

Then, when the statement to which the tool selection command is added is pre-read while the pre-reading process is repeatedly executed, that is, when the determination result of step S7 is true, it is stored in the CMOS memory 14. This means that the machining program that is included includes at least one tool change work, and the prefetch start position storage index R1 stores the sequence number of the statement regarding the next tool change work. Further, if the statement with the tool selection command is not read even if prefetching is performed to the end of the machining program, that is, if the determination result in step S8 is true, it is stored in the CMOS memory 14. This means that the machining program is a machining program that does not require tool replacement work, and the prefetch start position storage index R1 stores the sequence number "n" of the last statement in the machining program.

Therefore, first, the flow of processing when the machining program stored in the CMOS memory 14 includes a tool changing operation will be described with reference to the machining program of FIG. The G code statement shown in FIG. 4 is for a normal machining operation regarding the feed of each axis and the chuck rotation position in the punch press machine 2, and the T code is a tool selection for tool change. It is a command and is always modified by a tool code indicating a new selection target.

Therefore, in the example of the machining program of FIG.
First, the statement with the sequence number R0 = “1” is temporarily stored in the RAM 13 as the statement to be executed, and further, the prefetch process is repeatedly executed and the value of the prefetch start position storage index R1 is incremented to “3”, The statement of the sequence number "3" having the tool selection command is read as the prefetch statement, the determination result of step S7 becomes true, and the CPU shifts to the processing of step S9.

The CPU that has proceeded to step S9 outputs the value of the tool code written in the look-ahead statement of sequence number R1 = "3", that is, the value of the tool code A in the example of FIG. 4, to the PMC16. After the signal is converted into a necessary signal by the tool changing device 3, the signal is further output to the tool changing device 3 via the I / O unit 17 (above, step S
9). Then, the tool changer 3 that has received the tool code A
Drives the first robot arm to take out the drilling tool having the tool code A from the pot, and starts the movement of the first robot arm with the tool exchange position as the final target position.

The CPU which has output the value of the tool code to the tool changer 3 immediately sets the prefetch prohibition flag F0 (step S10), and the sequence number R0 = "1".
The execution target statement of sequence number R0 = "1" is executed after the punch press machine 2 is caused to perform a normal machining operation related to the feed of each axis, the rotational position of the chuck, etc. (step S11). It is determined whether or not the tool selection command has been given, that is, whether or not the tool replacement work has been performed in the current processing cycle (step S12). If the tool exchange work is performed in the current processing cycle, the CPU shifts to the processing of step S13 and resets the prefetch prohibition flag F0.
In the example of FIG. 4, since the tool selection command is not attached to the execution target statement of sequence number R0 = “1”, the determination result of step S12 is false, and the CPU executes step S12.
The process of No. 13 is unexecuted, and the process proceeds to the process of step S14 to determine whether or not the execution target statement of sequence number R0 = "1" indicates the program end. As above, refer to the processing cycle 1 in FIG.

In the example of FIG. 4, since the determination result of step S14 is also false, the CPU moves to the process of step S2 again and increments the value of the execution position storage index R0 by "1" to obtain the value of the index R0. CMOS memory 1 based on "2"
The statement with the sequence number R0 is read from the machining program of No. 4 and RA is executed as the statement to be executed.
It is temporarily stored in M13 (step S3). Then CP
U determines whether or not the prefetching prohibition flag F0 is set (step S4). In this case, since the prefetching prohibition flag F0 has been set in the processing of step S10 of the previous processing cycle, the determination of step S4 is made. When the result becomes true, the pre-reading process of steps S5 to S8, the process related to the output of the tool code of step S9, and the process of step S10 are not executed, and the CPU executes step S1.
The processing shifts to 1. Then, the CPU executes the statement to be executed with the sequence number R0 = “2” to cause the punch press machine 2 to perform a normal machining operation relating to the feed of each axis, the rotational position of the chuck, etc. (step S1
1), whether or not the execution target statement of sequence number R0 = "2" is the one to which the tool selection command is attached,
That is, it is determined whether or not the tool replacement work has been performed in the current processing cycle (step S12). In the example of FIG. 4, since the tool selection command is not attached to the execution target statement of the sequence number R0 = “2”, the determination result of step S12 is false, and the CPU deactivates the processing of step S13 and sets the prefetch prohibition flag F0. While the set state is maintained, the process proceeds to step S14 and the sequence number R
It is determined whether or not the execution target statement of 0 = “2” indicates the program end. In this case, the determination result of step S14 is also false, and therefore the CPU shifts to the processing of step S2 again. Become. As above, refer to the processing cycle 2 in FIG.

As a result of the non-execution of the process of step S13 in the previous processing cycle, the set state of the readahead prohibition flag F0 is maintained as it is in the current processing cycle. The statement with the sequence number R0 is read from the machining program of the CMOS memory 14 based on the value "3" of the execution position storage index R0 that is incremented in the same manner as in step S5 to step S8 and the step S9.
Related to output of tool code of step S10
Is executed and the execution target statement of sequence number R0 = "3" is executed in the process of step S11. In the example of FIG.
Since the tool selection command is attached to the execution target statement of = “3”, the CPU outputs the tool selection command written in this statement to the tool changer 3 via the PMC 16 and the I / O unit 17 ( Above, step S11). Then, the tool exchanging device 3 that has received the tool selection command drives the second robot arm to start the operation of collecting the punching tool that has been used so far from the chuck of the punch press machine 2 and storing it in the pot. When it is confirmed that the punching tool is recovered from the chuck of the punch press machine 2, the first robot arm in the tool exchange position is immediately driven to attach the punching tool of the tool code A to the chuck of the punch press machine 2. . The command for taking out the drilling tool of the tool code A and moving it to the tool changing position has already been output to the tool changing device 3 in the processing cycle two cycles before, and at this stage, the tool taking out and the movement to the tool changing position are performed. Since it has already been completed, the tool changer 3 can immediately attach the drilling tool of the tool code A in the tool change position to the chuck of the punch press machine 2.

Then, the CPU which has output the tool selection command to the tool changer 3 determines whether or not the execution target statement of the sequence number R0 = "3" has the tool selection command, that is, the current processing cycle. It is determined whether or not the tool replacement work has been performed (step S12).
In this example, since the tool selection command is attached to the execution target statement of sequence number R0 = “3”, step S
The determination result of 12 is true. Therefore, the CPU that has confirmed the execution of the tool change operation resets the prefetch prohibition flag F0 (step S13) and determines whether or not the execution target statement of sequence number R0 = "3" indicates the program end. In this case, step S14
Since the determination result of is false, the CPU again returns to step S2.
The processing will shift to. As above, refer to the processing cycle 3 in FIG.

CPU that has moved to the processing of step S2
First, after incrementing the value of the execution position storage index R0 by “1”, the CMOS is calculated based on the value “4” of the index R0.
The statement with the sequence number R0 is read from the processing program in the memory 14 and temporarily stored in the RAM 13 as an execution target statement (step S3). Next, the CPU determines whether or not the prefetch prohibition flag F0 is set (step S4). In this case, since the prefetch prohibition flag F0 has been reset in the process of step S13 in the previous processing cycle, S4
The determination result of is false. Therefore, the CPU increments the value of the prefetch start position storage index R1 by "1" (step S5) and prefetches the statement of the sequence number R1 from the machining program of the CMOS memory 14 based on the value "4" of the index R1. Hereinafter, the prefetching process is repeatedly executed to detect the statement to which the tool selection command is added. In the example of FIG. 4, since the tool selection command is added to the statement with the sequence number “7”, the determination result of step S7 becomes true when the value of the prefetch start position storage index R1 is incremented to “7”. .

The CPU that has proceeded from step S7 to step S9 has the value of the tool code written in the look-ahead statement of sequence number R1 = "7", that is,
In the example of FIG. 4, the value of the tool code B is output to the PMC 16 and converted into a necessary signal by the tool changer 3, and then the I / O
Output to the tool changing device 3 via the O unit 17. Then, the tool exchanging device 3 that has received the tool code B drives the first robot arm to take out the drilling tool of the tool code B from the pot, and starts the movement of the first robot arm with the tool exchanging position as the final target position. Let

The CPU which has output the value of the tool code to the tool changer 3 immediately sets the prefetch prohibition flag F0 (step S10), and the sequence number R0 = "4".
The execution target statement of sequence number R0 = "4" is executed after the punch press machine 2 is caused to perform a normal machining operation related to the feed of each axis, the rotational position of the chuck, etc. (step S11). It is determined whether or not the tool selection command has been given, that is, whether or not the tool replacement work has been performed in the current processing cycle (step S12). In the example of FIG. 4, the sequence number R0 =
Since the tool selection command is not attached to the execution target statement of "4", the determination result of step S12 is false,
The CPU does not execute the process of step S13 and moves to the process of step S14, and the sequence number R0 = "4".
It is determined whether or not the statement to be executed of indicates the program end. As above, refer to the processing cycle 4 in FIG.

In the example of FIG. 4, since the determination result of step S14 is also false, the CPU again shifts to the processing of step S2 and increments the value of the execution position storage index R0 by "1" to obtain the value of the index R0. CMOS memory 1 based on "5"
The statement with the sequence number R0 is read from the machining program of No. 4 and RA is executed as the statement to be executed.
It is temporarily stored in M13 (step S3). Then CP
U determines whether or not the prefetching prohibition flag F0 is set (step S4). In this case, since the prefetching prohibition flag F0 has been set in the processing of step S10 of the previous processing cycle, the determination of step S4 is made. When the result becomes true, the pre-reading process of steps S5 to S8, the process related to the output of the tool code of step S9, and the process of step S10 are not executed, and the CPU executes step S1.
The processing shifts to 1. Then, the CPU executes the statement to be executed with the sequence number R0 = “5” to cause the punch press machine 2 to perform a normal machining operation relating to the feed of each axis, the rotational position of the chuck, etc. (step S1
1), whether or not the execution target statement of the sequence number R0 = “5” has been given a tool selection command,
That is, it is determined whether or not the tool replacement work has been performed in the current processing cycle (step S12). In the example of FIG. 4, since the tool selection command is not attached to the execution target statement of sequence number R0 = “5”, the determination result of step S12 is false, and the CPU does not execute the processing of step S13 and proceeds to the processing of step S14. Then, it is determined whether or not the execution target statement having the sequence number R0 = “5” indicates the program end. As above, refer to the processing cycle 5 in FIG.

In the example of FIG. 4, since the determination result of step S14 is also false, the CPU moves to the process of step S2 again and increments the value of the execution position storage index R0 by "1" to obtain the value of the index R0. The following processing is executed based on "6", but in this case as well, the prefetch prohibition flag F0 is the same as above.
Is set, the determination result of step S4 becomes true, the prefetching process of steps S5 to S8, the process related to the output of the tool code of step S9, and the process of step S10 are not executed, and the CPU executes step S1.
Punch press machine 2 by executing the statement to be executed with sequence number R0 = "6"
To perform a normal machining operation regarding the feed of each axis, the rotation position of the chuck, and the like, and then perform steps S12 and S14.
After executing the determination process of No., the process again moves to step S2. As above, refer to the processing cycle 6 in FIG.

Then, the CPU that has incremented the value of the execution position storage index R0 by "1" in the process of step S2,
The following processing is executed based on the value "7" of the index R0. In this case as well, since the read-ahead prohibition flag F0 is set similarly to the above, the determination result of step S4 becomes true, and steps S5 to S8 are performed. The prefetching process of step S9, the process of outputting the tool code in step S9, and the process of step S10 are not executed, and the CPU executes step S11.
In the example of FIG. 4, a tool selection command is attached to the execution target statement of sequence number R0 = “7”, in which the execution target statement of sequence number R0 = “7” is executed. Therefore, the CPU sends the tool selection command written in this statement to the PMC.
Tool changer 3 via 16 and I / O unit 17
To the output (above, step S11). Then, the tool exchanging device 3 that has received the tool selection command drives the second robot arm to perform an operation of collecting the punching tool of the tool code A that has been used so far from the chuck of the punch press machine 2 and storing it in the pot. When the punching tool 2 is started and it is confirmed that the punching tool is recovered from the chuck of the punching press machine 2, the first robot arm in the tool changing position is immediately driven to move the punching tool of the tool code B to the punching press machine 2 Attach it to the chuck. The command for taking out the drilling tool of the tool code B and moving it to the tool changing position has already been output to the tool changing device 3 in the processing cycle three cycles before, and at this stage, the tool taking out and the movement to the tool changing position are performed. Since it has already been completed, the tool changing device 3 can immediately attach the drilling tool of the tool code B in the tool changing position to the chuck of the punch press machine 2.

Then, the CPU that has output the tool selection command to the tool changer 3 determines whether or not the execution target statement having the sequence number R0 = "7" has the tool selection command, that is, the current processing cycle. It is determined whether or not the tool replacement work has been performed (step S12).
In this example, since the tool selection command is attached to the execution target statement of sequence number R0 = "7", step S
The determination result of 12 is true. Therefore, the CPU that confirms the execution of the tool exchange work resets the prefetch prohibition flag F0 (step S13), and determines whether or not the statement to be executed with the sequence number R0 = "7" indicates the program end. In this case, step S14
Since the determination result of is false, the CPU again returns to step S2.
The processing will shift to. As above, refer to the processing cycle 7 in FIG.

CPU that has moved to the processing of step S2
First, after incrementing the value of the execution position storage index R0 by "1", the CMOS is calculated based on the value "8" of the index R0.
The statement with the sequence number R0 is read from the processing program in the memory 14 and temporarily stored in the RAM 13 as an execution target statement (step S3). Next, the CPU determines whether or not the prefetch prohibition flag F0 is set (step S4). In this case, since the prefetch prohibition flag F0 has been reset in the process of step S13 in the previous processing cycle, S4
The determination result of is false. Therefore, the CPU increments the value of the prefetch start position storage index R1 by "1" (step S5), and prefetches the statement of the sequence number R1 from the machining program of the CMOS memory 14 based on the value "8" of the index R1. In the following, the prefetch process is repeatedly executed to detect the statement to which the tool selection command is added. In the example of FIG. 4, the sequence number "7" is set.
Since there is no statement to which the tool selection command is attached thereafter, the determination result of step S8 is obtained when the prefetching up to the program end is completed, that is, when the value of the prefetching start position storage index R1 reaches “n”. Be true. Therefore, the CPU shifts to the process of step S10 and sets the prefetch prohibition flag F0 to prohibit the prefetch process of steps S5 to S8 from being executed in the subsequent process, and the sequence number R0 = “8”. After executing the statement to be executed of "" to cause the punch press machine 2 to perform a normal machining operation regarding the feed of each axis, the rotation position of the chuck, and the like (step S11), the sequence number R0 =
It is determined whether or not the execution target statement of "8" has been given a tool selection command, that is, whether or not the tool replacement work has been performed in the current processing cycle (step S1).
2). In the example of FIG. 4, since the tool selection command is not attached to the execution target statement of sequence number R0 = “8”, the determination result of step S12 is false, and the CPU deactivates the processing of step S13 and the prefetch prohibition flag F0.
While maintaining the set state of step S14, the process proceeds to step S14, and it is determined whether or not the execution target statement of sequence number R0 = "8" indicates the program end. In this case, the determination result of step S14 is also obtained. Since it is false, the CPU shifts to the process of step S2 again. As above, refer to the processing cycle 8 in FIG.

In the example shown in FIG. 4, since there is no statement to which the tool selection command is given after the sequence number "7", once the value of the execution position storage index R0 becomes "8" or more, the execution target is executed. The prefetch prohibition flag F0 will not be reset again no matter how far the statement is executed. Therefore, hereinafter, the CPU repeatedly executes only the processes of steps S2 to S4 and steps S11, S12, and S14, and the sequence number R0 = “9” to “n” in the process of step S11.
Execute each statement that is not related to tool change of
Finally, when the value of the execution position storage index R0 becomes "n" and the execution of all the machining programs is confirmed in the determination processing in step S14, the processing in the reproduction mode ends. As above, refer to the processing cycles 9 to n in FIG.

As described above, in the tool exchanging method of the present embodiment, the pre-reading process of steps S5 to S8 is executed at the start of machining and every time the tool exchanging is executed to select the next punching tool. By outputting the tool code of the tool code to the tool changing device 3, the picking tool to be selected and the movement to the tool changing position are started by the tool changing device 3, and the tool is taken out and moved to the tool changing position. The machining program is executed by the CNC device 1 even while the tool selection command is being read, and the tool change command is output immediately when the tool selection command is read as the statement to be executed. There is no need to restart the machining program after waiting for the drilling tool to be removed from the machine and moving to the tool change position. The processing time of and it is possible to save a lot.

When the statement with the tool selection command is not read even if prefetching is performed to the end of the machining program in the prefetching process at the time of machining start, that is, the prefetch start position storage index in the first processing cycle. R1
Is "n" and the result of the determination in step S8 is true, it is confirmed that the machining program stored in the CMOS memory 14 is a machining program that does not require tool replacement work. , The prefetch prohibition flag F in the processing of step S10 in the first processing cycle.
This state is maintained until 0 is set and the execution of all machining programs is confirmed thereafter. In this case, the CPU prohibits the useless prefetching process and executes step S
2 to step S4 and step S11, step S1
2, Only the processing of step S14 is repeatedly executed, and the same machining control as the conventional one is performed. This also applies to the case where the last tool exchange work is executed in the example of the machining program as shown in FIG. 4, and as a result of the prefetch prohibition flag F0 being set in the next processing cycle, the subsequent processing cycle. Then all useless prefetching is prohibited.

As a special example, in the case where the tool selection command is attached to the statement of sequence number "1", after the tool code is output in the process of step S9, the process of step S11 in the same process cycle is performed. Although the tool exchanging work is performed in the process, the exchanging operation in this case is similar to the conventional one, and is performed after waiting for the drilling tool designated by the tool code to move to the tool exchanging position.

[0034]

According to the tool changing method of the present invention, the control device for controlling a machine tool pre-reads a tool selection command and outputs a tool code to cause the tool changing device to start a preparatory operation for tool change, While the specified tool is being taken out and moved, the machine tool is controlled by the control device to execute machining.Therefore, as in the conventional case, the tool selection command is output and then the drilling tool is taken out and the tool is replaced. Since it is not necessary to restart the machining program after waiting for the movement to the position, it is possible to greatly save the machining time of the entire one machining program which requires the tool replacement work.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a CNC punch press system to which a method of the present invention is applied.

FIG. 2 is a flowchart showing an outline of a tool changing process in the embodiment.

FIG. 3 is a continuation of the flowchart showing the outline of the tool changing process.

FIG. 4 is a diagram conceptually showing an example of a machining program including a tool changing operation.

FIG. 5 shows each processing cycle of tool exchange processing, execution position storage index R0, prefetch start position storage index R1 (final value), presence / absence of tool code output, sequence number of statement to be executed, and set state of prefetch prohibition flag F0. FIG. 5 is a diagram showing the relationship of [1] corresponding to the example of FIG. 4.

[Explanation of symbols]

1 CNC device (control device for controlling machine tool) 2 Punch press machine (machine tool) 3 Tool changer 11 Processor (CPU) 14 CMOS memory 16 PMC (programmable machine controller) 17 I / O unit

Claims (1)

[Claims] 1. In a tool changing method in which a tool changing device is driven by a tool selection command from a control device for controlling a machine tool based on a machining program to perform automatic tool changing work, the machining start and the tool change are executed. Each time, the control device pre-reads the machining program until the tool selection command is read, outputs the tool code of the read tool selection command to the tool changing device, and then sequentially executes the machining program, When the tool changer receives the tool code sent from the control device, it moves the tool of the tool code to the tool change position, and when a tool selection execution command is input from the control device, the tool change operation is performed. How to change the tool.