JP2003136332A - Threading control method and device for numerical control machine tool and numerical control machine tool incorporating the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control movement of a motor to move a tool for threading by adjusting it at an optimal adjusting value in threading work at the time of the threading work. SOLUTION: The optimal adjusting value of each of the motors to drive a spindle and a tool rest is previously found and is stored in a ROM 8 in a control unit or in an outside memory device 5 as a file for threading of a variable data at the time of the threading work by an NC machine tool. Thereafter, a variable data in a RAM 9 to use for adjustment of each of the motors by a program in practice is replaced by reading the previously stored variable data in the file for threading from the ROM 8 or the outside memory device 5 by a CPU 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread cutting control method for a numerically controlled machine tool having a tool rest on which at least one spindle and at least one thread cutting tool can be mounted, and a controller for implementing the same and a controller for the same. A numerical control machine tool.

[0002]

2. Description of the Related Art In numerically controlled machine tools such as NC lathes and NC milling machines, threading (thread cutting) is performed on the outer peripheral surface of a cylindrical workpiece (workpiece) or the inner peripheral surface of a cylindrical or perforated workpiece. When performing, as shown in FIG. 4, while the threading tool (blade) 40 is brought into contact with the rotating work material 30, Z that is parallel to the axis A is synchronized with the rotation of the work material 30. This is done by moving the tool 40 in the axial direction. However, in order to move the tool 40 in the direction along the axis A, a tool post (not shown) to which the tool 40 is attached is moved in the direction along the axis A, but it takes time to accelerate and decelerate the driving motor. In the time from the stop state of the tool 40 to the constant speed and the time from the constant speed of the tool 40 to the stop state, a portion 31b (incomplete thread portion) where the pitch of the screw 31 becomes incorrect is formed.

The occurrence of the incomplete thread portion 31b is widely recognized, and it is general to calculate the distance of the incomplete thread portion to be ensured in an actual machining program. Also, as a specification of the numerical control device, these calculation formulas are open to the public. In recent years, the cutting conditions (rotational speed,
The feed rate) has improved. Originally, also in thread cutting, it is desired to shorten the cutting time by increasing the feed rate of the tool by making the main shaft that rotates the workpiece high rotation.

However, if the feed speed of the tool is increased, it takes longer time to accelerate, and the feed speed of the tool does not follow the rotation speed of the spindle, so that the incomplete thread portion 31b shown in FIG. 4 is long. Become. Therefore, at present, it is unavoidable to reduce the rotation speed of the main shaft. Further, even if the acceleration / deceleration of the feed speed of the tool is improved, the acceleration / deceleration time cannot be made zero.

Usually, the thread cutting process is performed by repeatedly performing a cutting operation. The higher the thread, the greater the number of repetitions. Therefore, although the blade is brought into contact with the already cut screw again, it is necessary to control so that the rotation and the phase of the workpiece, that is, the rotation angle do not shift. However, the time it takes for the tool (cutting tool) to reach a constant speed from a stopped state, and the time for the tool to change from a constant speed to a stopped state, are different from the work material because the feed speed of the tool changes. Cannot be perfectly matched, and in this case, a phenomenon such as a screw thread being crushed occurs, and an incomplete thread portion is also generated.

[0006]

For the above reasons,
At the beginning of threading, as shown in FIG. 5, the portion where the pitch is incorrect (incomplete thread portion) is approached D
It must be secured as a. Taking this approach Da increases the time during which processing is not performed,
The processing time per part will also increase. Also,
Depending on the shape and length of the part to be machined and the size of the cutting chamber, it may not be possible to secure the necessary approach.

Since a material is present in the screw up part (end part), it is often impossible to secure the up distance. In this case, not only an incomplete thread portion is generated in the finished screw, but also an extra force is applied to the tool 40,
The life of the tool 40 is shortened. Conventional motor acceleration is adjusted to the limit where side effects such as overshoot do not occur, and it is not possible to simply increase the speed more than this. Further, it is difficult to set the acceleration / deceleration time to 0.

The present invention has been made in order to solve the problem at the time of thread cutting in such a conventional NC machine tool, and at the time of thread cutting, a motor for moving a tool for thread cutting is optimal for thread cutting. By adjusting with the adjustment value so that operation can be controlled, the processing speed is improved, the approach at the beginning of thread cutting is shortened,
The purpose is to improve the machining accuracy even in the screw up part.

[0009]

A thread cutting control method for a numerically controlled machine tool according to the present invention is a thread cutting control method for a numerically controlled machine tool having a tool post on which at least one spindle and at least one thread cutting tool can be mounted. In order to achieve the above object, it is characterized as follows. The optimum adjustment values of the respective motors for driving the spindle and the tool rest during thread cutting by the numerically controlled machine tool are obtained in advance and saved as a file for thread cutting of variable data. When the numerically controlled machine tool performs thread cutting during execution of the machining program,
The variable data used for the adjustment of each motor in the program being executed is replaced with the variable data of the previously stored file for thread cutting.

The variable data of the file for thread cutting is a variable that shortens at least the acceleration / deceleration time of the motor for driving the tool rest or increases the responsiveness thereof as compared with the variable data used during machining other than thread cutting. It should be data. It is possible to determine whether or not the numerically controlled machine tool performs thread cutting during execution of the machining program, based on the type of command of the machining program being executed.

A control device for a numerically controlled machine tool according to the present invention has at least one spindle and at least one spindle.
A control device for a numerically controlled machine tool having a tool rest to which one screw cutting tool can be mounted, characterized in that the following means are provided to achieve the above object. That is, a storage means for storing an optimum adjustment value obtained in advance for each motor for driving the spindle and the tool post during thread cutting by the numerically controlled machine tool as a file for threading variable data, and the numerically controlled machine. When the machine determines that thread cutting is to be performed during execution of the machining program, and when the means determines that thread cutting is to be performed, the variable data of the previously stored file for thread cutting is read and executed. A means for replacing the variable data used for adjusting each of the motors with the read variable data in the program therein is provided.

In addition, the variable data of the thread cutting file stored in the storage means is at least shorter than the variable data used during machining other than thread cutting for shortening the acceleration / deceleration time of the motor for driving the tool rest, or At the same time, it is desirable to use variable data that improves responsiveness. The thread cutting determination means may be means for determining whether to perform thread cutting processing according to the type of command of the processing program being executed.

A numerically controlled machine tool according to the present invention incorporates the above-described control device so that each motor for driving the spindle and the tool rest during thread cutting can be controlled to an optimum operating state for thread cutting. .

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows a numerically controlled machine tool (hereinafter referred to as “NC machine tool”) which is an embodiment of the present invention.
2) is a block diagram mainly showing a schematic configuration on the side of a control device, and FIG. 2 is a diagram mainly showing a configuration of a main part on the side of a machine tool (for example, a lathe). An NC machine tool control device 1 shown in FIG. 1 is a numerical control device, and includes a control unit 2, an input unit 3, a display unit 4, an external storage device 5,
And a motor control unit 6. Other than that, illustration and description of the configuration of the portion not directly related to the present invention are omitted. Control unit 2 is CP
It consists of U7, ROM8, RAM9 and bus 10, and constitutes a microcomputer.

The CPU 7 is a central processing unit having various arithmetic / processing functions, and operates according to an operation program stored in the ROM 8 to control the control unit 2.
Also, the entire control device 1 is integrally controlled, and each unit of the motor control unit 6 is controlled according to the NC program stored in the RAM 9. The ROM 8 is a read-only memory, and stores in advance fixed data such as an operation program for the CPU and a variable data file (details of which will be described later) indicating adjustment values of each motor used for control during thread cutting according to the present invention. is doing. The RAM 9 is a random access memory, and temporarily stores the machining program to be executed (NC program) and variable data (details of which will be described later) used for adjusting each motor in the machining program being executed. , Is also used as a working memory of the CPU 7.

The input unit 3 and the display unit 4 are provided on an operation panel (not shown) of this NC machine tool. The input part 3
Includes switches and buttons for selecting various functions of the NC machine tool and inputting necessary information, and an interface for inputting an NC program from an automatic programming device or a personal computer. The display unit 4 is a CRT or a liquid crystal display, and displays various information necessary for operating the NC machine tool, input information, and information such as an actual machining status. The external storage device 5 is a device that uses a large-capacity storage medium, such as a hard disk device, an FD drive device, or an MO drive device, and various processing programs (NC programs) and various conditions for each condition including the thread cutting process described above are stored in advance. It is also possible to store a file of variable data indicating the motor adjustment value.

The bus 10 connecting these is composed of a data bus, a control bus, and an address bus. The motor control unit 6, as shown by the solid line in FIG.
It has a first spindle rotation control unit 11 which is at least one spindle rotation control unit and a first tool post movement control unit 12 which is at least one tool post movement control unit, and each has a first spindle rotation drive source (spindle). The drive of the motor 21 and the first turret drive mechanism (motor) 22 is controlled. That is, the machine tool 20 controlled by the control device 1 has a tool rest on which at least one spindle (spindle) and at least one thread cutting tool can be mounted.

Further, when the machine tool 20 has a movable second spindle such as a back spindle, a second spindle rotation control section 13 for controlling the second spindle rotation drive source 23 and a second spindle drive mechanism. The second spindle movement control unit 14 for controlling the
Each is provided in the motor control unit 6 in FIG. 1 as shown by the broken line. Further, when the rotary tool can be attached to the tool rest of the machine tool 20, the rotary tool rotation control unit 15 for controlling the rotary tool rotation drive source 25 is also provided in the motor control unit 6 as indicated by a broken line. This motor control unit 6
Is also connected to the control unit 2 by the bus 10.

FIG. 2 shows an example of the simplest configuration on the machine tool 20 side together with the signal input / output relationship with the motor control section 6. The first main spindle rotation drive source 21 controlled by the first main spindle rotation control section 11 of the motor control section 6 is a main spindle motor that rotates the main spindle (spindle) 210, and a target held by a chuck 211 provided on the main spindle 210. The processing material (workpiece) 30 is rotated at high speed. A rotation detector 212 is attached to the main spindle motor 21, and a pulse signal is generated every time the main spindle 210 of the main spindle motor 21 rotates by a certain angle, and is fed back to the first main spindle rotation control unit 11. The spindle motor 21 and the chuck 21
The main shaft 210 provided with 1 is arranged in a bed (not shown).

The first tool post drive mechanism 22 includes a tool post (XZ
X-axis feed motor 22 for moving 220 held in the table mechanism in the X-axis direction (vertical direction in the figure)
1x and a feed screw 222x, and a Z-axis feed motor 221z and a feed screw 222z for moving the tool rest in the Z-axis direction (horizontal direction in the drawing). A rotation detector 223 is attached to the X-axis feed motor 221x.
x is attached, and a rotation detector 223z is attached to the Z-axis feed motor 221z.

The first tool post movement control unit 1 of the motor control unit 6
2 has an X-axis feed controller 12x and a Z-axis feed controller 12z, as shown in FIG. Then, the X-axis feed control unit 12x controls the rotation of the X-axis feed motor 221x by the output control signal, and uses a pulse signal having a frequency proportional to the rotation speed of the feed screw 222x from the rotation detector 223x as a feedback signal. input. On the other hand, Z
The axis feed control unit 12z controls the rotation of the Z axis feed motor 221z by the output control signal, and the rotation detector 223.
A pulse signal having a frequency proportional to the rotation speed of the feed screw 222z from z is input as a feedback signal.

Then, the tool (tool) 40 attached to the tool rest 220 is moved to the X position by the first tool rest drive mechanism 22.
The workpiece 30 held in the chuck 211 of the main shaft 210 and rotated is moved while being moved in the axial direction and the Z-axis direction. In this example, only one tool 40 is attached to the tool rest 220, but generally, a turret type tool rest is used, and a large number of tools are radially arranged around the tool rest, for example, various kinds of outer diameter cutting tools and inner diameter cutting tools. Cutting tool, thread cutting tool,
A cutting tool for cutting off and a drill, which is a rotary tool, are attached so that any one of them can be selected and used. Also in this embodiment, it is assumed that the turret type tool post can be used to automatically change the tool during the execution of the machining program.

Next, a thread cutting control method according to the present invention by the control device 1 in this NC machine tool will be described. First, an outline of a thread cutting control method for an NC machine tool according to the present invention will be described in itemized form. 1) At the time of thread cutting, the acceleration / deceleration time of the turret moving motor is set to be short. 2) During thread cutting, it is set so that it can be synchronized with the rotation of the workpiece even during the acceleration / deceleration of the turret moving motor. 3) At the time of thread cutting, at least the setting data of 1) above is used, so that the variable data for adjustment can be used interchangeably with the variable data for adjustment. 4) For that purpose, separate variable data (parameters) dedicated to thread cutting are provided.

If the motor is adjusted specifically for the cutting condition of thread cutting and the set value is used during thread cutting, it is possible to improve the current incomplete thread portion. However, performing all the processing with this setting causes adverse effects such as vibration and heat generation. The reason is,
This is because in order to react promptly to a change in speed (increase the response), a control is performed such that a high current is always supplied even in an idle state.

Next, N described with reference to FIGS.
An example of implementing the thread cutting control method according to the present invention on a C machine tool will be specifically described. First of all, the thread cutting by this NC machine tool is performed by the tool rest 22 shown in FIG.
It is assumed that a thread cutting tool (blade) is selected as the tool 40 of 0 and thread cutting is performed on the outer peripheral surface of the work material 30 rotated by the spindle 210. At the time of the thread cutting, the spindle motor 21 that rotates the spindle 210, the optimum adjustment values of the X-axis feed motor 221x and the Z-axis feed motor 221z that drive the tool rest 220 in the X-axis direction and the Z-axis direction are calculated or measured. Each adjusted value is stored as a variable data file, for example, file SA-7 and file TA-7 with file names, and stored in the ROM 8 in the control unit 2 shown in FIG. 1 or the external storage device 5. Let me save it.

The RAM in the control unit 2
In FIG. 9, there is only one area (variable data area) that is used by the CPU 7 during execution of the machining program and that stores adjustment data that directly affects the operation of each motor.
Usually, like the conventional NC machine tool controller,
The standard adjustment data (variable data) determined by giving priority to the processing condition and the use condition is stored. Table 1 shows an example of the standard variable data. For example, the file SA-0 and the file TA-0 are given file names so that the data can be written back again after being rewritten. It is stored in the storage device 5 and saved. Table 2 shows an example of the variable data of the file SA-7 and the file TA-7 for thread cutting. In these tables, the first axis of the spindle is the spindle motor 21, the first axis of the tool rest is the X-axis feed motor 221x,
The second axis is each data for the Z-axis feed motor 221z.

[0027]

[Table 1]

[0028]

[Table 2]

Here, the variable data is as follows. ○ Maximum speed (rapid feed speed): The maximum value of the speed when the motor is rotated to move the axis, the unit is mm / sec ○ Acceleration / deceleration time (time constant): For acceleration from the stopped state to the maximum speed It is a time required and its unit is msec (millisecond) Responsiveness (gain): an increase amount of a response force to a reaction force and a follow-up force at the start of rotation of the motor, which is a relative proportional value. Correction (lost motion correction, etc.): A function that compensates for the tendency found under special conditions, and is a relative proportional value.

Compared with the standard variable data shown in Table 1, the variable data for thread cutting shown in Table 2 significantly shortens the acceleration / deceleration time of each motor for driving the turret, and has a significantly high responsiveness. is doing. At the time of thread cutting, the CPU 7 shown in FIG.
RA is read from the ROM 8 or the external storage device 5.
Replace (rewrite) the variable data in M9. There are a plurality of methods for exchanging variable data, and the method of exchanging variable data is selected on the screen of the display unit 4.

FIG. 3 shows an example of the selection screen of the variable data replacement method on the display unit 4. In this example, any one of [Auto], [Program command], and [Operation] can be selected from the screen. Here, "automatic" is a method of automatically exchanging variable data according to a command of a machining program or a state of a motor. The "program command" is a method of giving a command for instructing replacement of variable data in the machining program.

The "operation" is a method of instructing replacement of variable data when operating a machine. According to the selected replacement method, the adjustment data (variable data) of the threading or standard file is selected and the variable data stored in the RAM 9 is replaced while determining whether or not the thread cutting is performed. Variable data for processing conditions other than thread cutting, usage conditions, or combinations thereof is also saved with a file name, and the variable data stored in the RAM 9 is replaced when necessary by reading the variable data. May be.

Further, the Z-axis feed motor 2 of the tool rest 220
Even during the acceleration / deceleration of 21z, in order to synchronize with the rotation of the material 30 to be processed, from the start of the Z-axis feed motor 221z until the feed speed of the tool 40 in the Z-axis direction becomes constant, the spindle motor 21 is driven. Lower the rotation and move the Z-axis feed motor 2
It is said that control is performed so as to increase the rotational speed in synchronization with 21z.

[Example of Variable Data Swap by Machining Program] Here, a specific example of a method for exchanging variable data by a machining program when “program command” is selected on the selection screen shown in FIG. 3 will be described. In this example,
It is assumed that the tool post 220 shown in FIG. 2 is a turret type tool post and a thread cutting tool is attached to the T04 position thereof.

Machining program (NC program) M3 S1 = 5000 T0400 M107 X13.0 G92 X11.5 Z-80 F0.7 X11.1 X10.96 X10.96 G0 X 13.0

During execution of this machining program, T0400, which is the T code of the tool instruction, is stored in the CPU 7 in FIG.
When it is read in, the turret type tool post is rotated to select the thread cutting tool, and the M code for the next auxiliary command is M
When 107 is read, file SA-7 and file TA
The variable data for thread cutting of -7 is read from the ROM 8 and the variable data stored in the RAM 9 is replaced. In this example, the last numerical value "7" of M107 of the M code indicates the numerical value of the file name, and the CPU 7 thereby discriminates the thread cutting processing of the file SA-7 and the file TA-7 shown in Table 2. Then, the variable data of each file is read from the ROM 8 and the variable data of the RAM 9 is replaced. Therefore, during the turning process started thereafter, each motor is adjusted based on the variable data of "Turning 2 (medium speed)" shown in Table 3.

When this turning process is completed and a tool other than the thread cutting tool is selected by the T code of the next tool command, the CPU 7 sends the file SA-0 by the M code of the next auxiliary command.
And the variable data of the standard file of file TA-0
The variable data read from M8 and stored in the RAM 9 are replaced (restored to the original data). In this example, the M code of the auxiliary instruction in the machining program is used to determine the thread cutting operation and read out and replace the variable data of the file.
Since it is possible to determine that the thread cutting process is performed also by the code, the CPU 7 may replace the variable data of the RAM 9 by this T code.

According to this thread cutting control method, the thread cutting approach Da shown in FIG. 5 can be shortened to improve the work efficiency of thread cutting. Further, the length of the incomplete threaded portion 31b according to the conventional threading process shown in FIG. 4 varies depending on the rotation speed of the spindle, but when the threading process is performed with the spindle rotation speed of 5000 rpm, 7 to 8 is obtained.
It was on the pitch. By implementing the thread cutting control method of the present invention, the incomplete thread portion can be reduced to a few pitches.

In the controller of the numerically controlled machine tool according to the present invention, the ROM 8 or the external storage device 5 shown in FIG. 1 has the previously determined optimum values for the respective motors for driving the spindle and the tool rest during thread cutting by the NC machine tool. It is a storage means that saves various adjustment values as a file for threading variable data. In addition, the CPU 7
C When the machine tool determines that thread cutting is to be performed while the machine tool is executing the machining program, and when the means determines that thread cutting is to be performed, the variable data of the previously stored file for thread cutting is stored. It serves as a function of replacing the variable data read out and used in the adjustment of each motor in the running program with the read variable data.

[0040]

As described above, according to the present invention, at the time of thread cutting in a numerically controlled machine tool, each motor that drives each axis is optimally adjusted for thread cutting, and the adjustment value is set. Since the operation can be controlled originally, the processing speed can be improved. Moreover, the approach at the beginning of thread cutting can be shortened, and the machining accuracy can be improved even at the part where the thread is cut up. It can also suppress the generation of vibration and heat and extend the life of the tool (cutting tool).

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration mainly on a control device side of a numerically controlled machine tool according to an embodiment of the present invention.

FIG. 2 is also a diagram mainly showing a main part configuration of the machine tool side.

FIG. 3 is a diagram showing an example of a selection screen of a variable data replacement method on the display unit 4 in FIG.

FIG. 4 is a diagram used for explaining that an incomplete thread portion is generated by thread cutting with a conventional NC machine tool.

FIG. 5 is a diagram for explaining an approach to prevent an incomplete thread portion from occurring.

[Explanation of symbols]

1: Control device 2: Control unit 3: Input section 4: Display section 5: External storage device 6: Motor control unit 7: CPU 8: ROM 9: RAM 10: Bus 11: First spindle rotation controller 12: 1st turret movement control section 20: Machine tool 21: 1st spindle rotation drive source (spindle motor) 22: First turret drive mechanism 30: Work material 40: Tool (tool for thread cutting) 210: Spindle 220: Turret 221x: X-axis feed motor 221z: Z-axis feed motor

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[Procedure amendment]

[Submission date] November 12, 2001 (2001.11.
12)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art In numerically controlled machine tools such as NC lathes and NC milling machines, threading (thread cutting) is performed on the outer peripheral surface of a cylindrical workpiece (workpiece) or the inner peripheral surface of a cylindrical or perforated workpiece. When performing, as shown in FIG. 4, while making the threading tool (blade) 40 in contact with the rotating workpiece 30, the Z parallel to the axis A is synchronized with the rotation of the workpiece 30. This is done by moving the tool 40 in the axial direction. However, in order to move in a direction along the tool 40 in the axial A, but is moved in a direction along the tool rest (not shown) attached to the tool 40 to the axis A, since it takes time to acceleration and deceleration of the drive motor, During the time from the stop state of the tool 40 to the constant speed and the time from the constant speed of the tool 40 to the stop state, a portion (incomplete thread portion) 31b in which the pitch of the screw 31 becomes incorrect is formed.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

The "operation" is a method of instructing replacement of variable data when operating a machine. According to the selected replacement method, the adjustment data (variable data) of the threading or standard file is selected and the variable data stored in the RAM 9 is replaced while determining whether or not the thread cutting is performed. Variable data for machining conditions other than thread cutting, usage conditions, or combinations thereof are also saved with a file name, and the variable data stored in the RAM 9 can be replaced by reading the variable data as needed. Good.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

Further, the Z-axis feed motor 2 of the tool rest 220
Even during the acceleration / deceleration of 21z, in order to synchronize with the rotation of the material 30 to be processed, from the start of the Z-axis feed motor 221z until the feed speed of the tool 40 in the Z-axis direction becomes constant, the spindle motor 21 is driven. Lower the rotation and move the Z-axis feed motor 2
When 21z and is synchronized by controlling so as to increase the rotational speed still good.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

During execution of this machining program, T0400, which is the T code of the tool instruction, is stored in the CPU 7 in FIG.
When it is read in, the turret type tool post is rotated to select the thread cutting tool, and the M code for the next auxiliary command is M
When 107 is read, file SA-7 and file TA
The variable data for thread cutting of -7 is read from the ROM 8 and the variable data stored in the RAM 9 is replaced. In this example, the last number of the M107 M-code "7" indicates the value of the file name, CPU 7 is to determine the result threading file SA-7 and file TA-7 thereto, each The variable data of the file is read from the ROM 8 and the variable data of the RAM 9 is replaced. Therefore, during the turning process started thereafter, each motor is adjusted based on the variable data of “thread cutting” shown in Table 2 .

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

When this thread cutting process is completed and a tool other than the thread cutting tool is selected by the T code of the next tool command, the CPU 7 sends the file S by the M code of the next auxiliary command.
The variable data of the standard file of A-0 and the file TA-0 is read from the ROM 8 and the variable data stored in the RAM 9 is replaced (restored to the original data). In this example, the M code of the auxiliary command in the machining program is used to determine the thread cutting process and read out and replace the variable data in the file, but the T code of the tool command can also be used to perform the thread cutting process. Since it can be discriminated, the CPU 7 causes the RAM 9 to
The variable data may be exchanged.

Claims (9)

[Claims] 1. A thread cutting control method for a numerically controlled machine tool having a tool rest capable of mounting at least one spindle and at least one thread cutting tool, wherein the spindle and the tool rest are driven during thread cutting by the numerically controlled machine tool. Determine the optimum adjustment value for each motor in advance, save it as a file for thread cutting of variable data, and when the numerically controlled machine tool performs thread cutting during execution of the machining program, A thread cutting control method for a numerically controlled machine tool, characterized in that the variable data used for adjusting each of the motors is replaced with the variable data stored in the thread cutting file. 2. The variable data of the thread cutting file is variable data that shortens at least the acceleration / deceleration time of the motor for driving the tool rest, as compared with the variable data used during machining other than thread cutting. The thread cutting control method for a numerically controlled machine tool according to claim 1. 3. The variable data of the file for thread cutting is variable data which shortens at least the acceleration / deceleration time of the motor for driving the tool rest and enhances the responsiveness, as compared with the variable data used for machining other than thread cutting. The thread cutting control method according to claim 1, wherein 4. The numerical control machine tool according to claim 1, wherein the numerical control machine tool determines whether or not to perform thread cutting while the machining program is being executed, according to the command type of the machining program being executed. 2. A thread cutting control method for a numerically controlled machine tool according to claim 1. 5. A controller for a numerically controlled machine tool having a tool rest capable of mounting at least one spindle and at least one thread cutting tool, wherein the spindle and the tool rest are driven during thread cutting by the numerically controlled machine tool. Storage means for saving the optimum adjustment value obtained in advance for each motor as a file for thread cutting of variable data, and thread cutting discrimination for judging whether or not the numerically controlled machine tool performs thread cutting during execution of a machining program. Means, and when the means determines that thread cutting is to be performed, the variable data of the previously stored file for thread cutting is read out, and the variable data used for adjusting each motor in the program being executed is read out. A control device for a numerically controlled machine tool, characterized in that means for exchanging data is provided. 6. A variable for reducing the acceleration / deceleration time of at least a motor for driving the tool rest, as compared with variable data used in machining other than thread cutting, wherein variable data of the thread cutting file stored in the storage means The control device for a numerically controlled machine tool according to claim 5, wherein the control device is data. 7. The variable data of the thread cutting file stored in the storage means shortens at least the acceleration / deceleration time of the motor for driving the tool rest, as compared with the variable data used for machining other than thread cutting. The control device for a numerically controlled machine tool according to claim 5, wherein the control data is variable data for enhancing responsiveness. 8. The thread cutting discrimination means is means for discriminating whether or not to perform thread cutting according to a command type of a machining program being executed, according to any one of claims 5 to 7. Numerically controlled machine tool control device. 9. A numerically controlled machine tool having the control device according to claim 5 incorporated therein.