JP2020086642A - Numerical value control apparatus - Google Patents

Abstract

To provide a numerical value control apparatus which pre-reads a processing program even if a workpiece is being subjected to cutting and feeding processes under a constant peripheral speed control by a default condition, and which automatically controls, on the basis of the pre-reading result, whether or not to perform the constant peripheral speed control, thereby suppressing power consumption without a decrease in the process precision of the processed workpiece.SOLUTION: A numerical value control apparatus 100 includes: a program pre-reading unit 111 which pre-reads a processing program; a determining unit 112 which calculates, on the basis of the pre-reading result by the program pre-reading unit 111, any one of at least the positional change amount of a reference axis, the change amount of a peripheral speed, or the change amount of the rotating speed of a main shaft during cutting and feeding processes, and determines, on the basis of such a change amount, whether or not to perform constant peripheral speed control; and an action control unit 113 which controls, on the basis of the determination result by the determining unit 112, the presence or absence of a constant peripheral speed control function.SELECTED DRAWING: Figure 5

Description

The present invention relates to a numerical control device.

Conventionally, in the turning process on a lathe, control is performed to keep the peripheral speed constant. More specifically, when a work piece is mounted on a spindle in a lathe for machining, and when the work piece continues to rotate at a constant speed, the tool moves toward the center of the work piece, Since the peripheral speed of the contacting portion with becomes slow, there arises a problem that the cutting accuracy of the workpiece is lowered and the life of the tool is shortened. Conversely, as the tool moves in the outer peripheral direction of the workpiece, the peripheral speed of the contact portion of the workpiece with the tool becomes faster, so that the cutting edge of the tool is chipped or the life of the tool becomes shorter. Therefore, in general, constant peripheral speed control is performed to keep the peripheral speed constant so that the relative speed between the tool and the contact part of the workpiece becomes constant, preventing a decrease in the cutting accuracy of the workpiece and increasing the tool life. I'm stretching.

For this reason, every time the reference axis position of the tool changes, the spindle on which the workpiece is mounted accelerates/decelerates, and when the tool frequently moves the reference axis position, power consumption increases. There was a problem that the spindle motor overheated.

In this regard, Japanese Patent Application Laid-Open No. 2004-242242 discloses that when a workpiece is processed under constant peripheral speed control, when a fast-forward command in a direction in which the tool retracts from the workpiece or a direction in which the tool moves in parallel is received, the spindle rotation is changed. When the cutting feed command or the fast feed command in the direction in which the tool approaches the work is received after the fast feed, the next machining start position or the fast feed in the approaching direction is fixed. NC lathe that can reduce the deterioration of machining accuracy due to power consumption of the spindle motor and heat generation of the spindle bearing by specifying the coordinate value of the X position of the tool edge at the end position of the tool and returning to constant peripheral speed control Is disclosed.

Japanese Patent No. 6317923

However, the technique described in Patent Document 1 is a technique for suppressing power consumption by reducing the frequency of changing the spindle speed during fast-forwarding, and the spindle speed during cutting-feeding is not considered at all.

If the X position changes frequently during cutting feed, power consumption may increase due to acceleration/deceleration of the spindle, or the spindle may overheat.

FIG. 8 is a graph showing an example of a machining path (thick solid line) in the upper stage, and a lower part in the graph showing an example of changes in the spindle speed (thick solid line) when cutting the machining route. Note that, in FIG. 8, for convenience of description in the subsequent stage, the position change amount of the crest portion or the groove portion (hereinafter collectively referred to as “mountain groove area”) during cutting feed is cut by “a”. The position change amount at the escape portion at the end of feeding (hereinafter, also referred to as "relief area") is "b", and the entire continuous cutting feed (hereinafter, also referred to as "cutting area") The width between the maximum value and the minimum value of the X position of is indicated by "c". In addition, the arrow indicated by the dotted line in FIG. 8 indicates the moving path of the cutting tool during the rapid feed.

Even if the X position changes during cutting feed, the peripheral speed is kept constant so that when the X position coordinate value increases, the spindle speed decreases and when the X position coordinate value decreases. Spindle speed increases. As a result, as shown in FIG. 8, if the X position changes frequently during cutting feed, it is necessary to frequently accelerate and decelerate the spindle, which increases power consumption and may overheat the spindle. The nature is enhanced.

Therefore, if the torque of the spindle motor is limited in order to suppress the possibility of power consumption and overheating, the responsiveness of the spindle is reduced, which causes problems such as an increase in cycle time and a reduction in machining accuracy.

The present invention, even when performing the cutting feed machining of the work under constant peripheral speed control by default, pre-reads the machining program, and based on the result of the pre-read, performs constant peripheral speed control, An object of the present invention is to provide a numerical control device that can suppress power consumption without automatically reducing the machining accuracy of a workpiece by automatically controlling whether or not to perform.

(1) A numerical control device according to the present invention (for example, a “numerical control device 100” described later) is a numerical control device having a peripheral speed constant control function for controlling the spindle speed so that the peripheral speed becomes constant. Based on the result of the pre-reading by the program pre-reading unit (for example, "Program pre-reading unit 111" described later) and the program pre-reading unit, the position change amount of at least the reference axis during cutting feed. , A change amount of the peripheral speed or a change amount of the rotational speed of the main spindle, and based on the change amount, a determination unit that determines whether or not to perform constant peripheral speed control (for example, as described below “Determination unit 112”), and an operation control unit (for example, “Actuation control unit 113” described later) that controls whether or not the peripheral speed constant control function is activated based on the determination result of the determination unit.

(2) In the numerical controller according to (1), the determination unit calculates a position change amount of the reference axis in the entire cutting feed, and compares the position change amount with a preset cutting threshold value. On the basis of the above, it may be determined whether or not the constant peripheral speed control is performed.

(3) In the numerical control device described in (1) or (2), the determination unit calculates the position change amount of the reference axis during the escape operation at the cutting feed final part, and calculates the position change amount as the position change amount. Alternatively, it may be determined whether or not the constant peripheral speed control is performed based on the result of comparison with a preset escape threshold.

(4) In the numerical control device described in (1) to (3), the determination unit controls the reference axis at a position where the reference axis changes from the current position and then returns to the current position during cutting feed. The position change amount may be calculated, and it may be determined whether the peripheral speed constant control is performed or not based on the comparison result between the position change amount and a preset groove groove threshold value.

(5) In the numerical controller according to (4), at least one of the cutting threshold value, the clearance threshold value, and the crest groove threshold value may be set in the machining program.

(6) In the numerical control device described in (1) to (5), the determination unit reads from the beginning of a machining path after the entire machining program is pre-read by the program pre-reading unit at the start of cutting. The range in which the constant peripheral speed control function is operated and the range in which the constant peripheral speed control function is stopped may be determined based on the position change to the end.

(7) In the numerical control device according to (1) to (5), the determination unit may change the position of the machining path from the position of the reference axis at the sampling time at predetermined sampling times, The range in which the constant peripheral speed control function is operated and the range in which the constant peripheral speed control function is stopped may be determined.

(8) In the numerical control device according to (1) to (5), the determination unit determines, for each block of the machining program being executed, a position of a machining path from a position of the reference axis corresponding to the block. The range in which the constant peripheral speed control function is operated and the range in which the constant peripheral speed control function is stopped may be determined based on the change.

According to the present invention, even when the cutting feed is machined under the constant peripheral speed control by default, the machining program is pre-read and the constant peripheral speed control is performed based on the result of the pre-read. By automatically controlling whether or not to perform the work, it is possible to suppress the power consumption without deteriorating the machining accuracy of the workpiece.

It is a graph which shows the example of the processing route of the 1st pattern in the embodiment of the present invention. 6 is a flowchart showing a first operation corresponding to the machining path of the first pattern by the numerical controller according to the embodiment of the present invention. It is a graph which shows the example of the processing route of the 2nd pattern in the embodiment of the present invention. 7 is a flowchart showing a first operation corresponding to the machining path of the second pattern by the numerical controller according to the embodiment of the present invention. It is a graph which shows the example of the processing route of the 3rd pattern in the embodiment of the present invention. It is a flow chart which shows the 1st operation corresponding to the processing course of the 3rd pattern by the numerical control device concerning the embodiment of the present invention. It is the whole block diagram of the numerical control system which relates to the execution form of this invention. It is a functional block diagram of a numerical control device concerning an embodiment of the present invention. It is a graph which shows the example of control of the spindle speed by the numerical control device which concerns on embodiment of this invention. It is a flow chart which shows operation of a numerical control device concerning an embodiment of the present invention. It is a flow chart which shows operation of a numerical control device concerning an embodiment of the present invention. It is a flow chart which shows operation of a numerical control device concerning an embodiment of the present invention. It is a graph which shows the example of a processing path and the change of the spindle speed for cutting the processing path in the prior art.

Embodiments of the present invention will be described below with reference to FIGS. 1A to 8.
[1. Summary of Invention]
The numerical controller according to the embodiment of the present invention pre-reads a machining program during cutting feed during constant peripheral speed control, and confirms the amount of movement of the X position of the cutting edge of the cutting tool. In the machining path, the numerical control device turns off the constant peripheral speed control function and changes the spindle speed at a position where it is determined that the peripheral speed is not affected because the movement amount of the X position is smaller than the threshold value. Try not to.

The numerical controller switches on/off the constant peripheral speed control function based on the amount of change in the coordinate value (diameter value) of the X position according to one of the following three patterns.

[1.1 First pattern]
The first pattern is a pattern for switching on/off the peripheral speed constant control function based on the amount of change in the coordinate value of the X position in the mountain groove region during cutting feed (hereinafter also referred to as “position change amount”). Is. FIG. 1A shows a specific example of the amount of change in the mountain portion and groove portion during cutting feed. In the example shown in FIG. 1A, the height of both the mountain portion and the groove portion is “a”. When the magnitude of "a" is equal to or smaller than the first threshold value, the numerical control device turns off the constant peripheral speed control function in the mountain groove region and does not change the spindle speed. In the present specification, the first threshold is also referred to as “mountain threshold”.

FIG. 1B is a flowchart showing an operation in the first pattern of the numerical control device.
In step S11, when the operation to be executed is cutting feed (S11: YES), the process proceeds to step S12. If the operation to be executed is not cutting feed (S11: NO), the process ends.

In step S12, the numerical controller reads ahead the next block until the cutting feed is completed.

In step S13, when the X position of the cutting tool moves from the current position in the prefetched block and then returns to the current position (S13: YES), the process proceeds to step S14. If different from this (S13: NO), the process ends.

In step S14, the numerical controller calculates the change amount of the coordinate value of the X position.
If the amount of change in the coordinate value of the X position is equal to or smaller than the first threshold value in step S15 (S15: YES), the process proceeds to step S16. If the amount of change in the coordinate value of the X position exceeds the first threshold value (S15: NO), the process ends.

In step S16, the numerical control device turns off the peripheral speed constant control function at a position where the X position has moved from the current position and then returned to the current position.

[1.2 Second pattern]
The second pattern is a pattern for switching on/off the peripheral speed constant control function based on the amount of change in the X position in the relief area of the cutting feed. FIG. 2A shows a specific example of the amount of change in the escape area during cutting feed. In the example shown in FIG. 2A, the height of the escape area is “b”. When the magnitude of "b" is equal to or smaller than the second threshold value, the numerical control device does not change the spindle speed in the relief area. In the present specification, the second threshold is also referred to as “escape threshold”.

FIG. 2B is a flowchart showing an operation in the second pattern of the numerical control device.
In step S21, when the prefetched block is the last block of the cutting feed (S21: YES), the process proceeds to step S22. When the prefetched block is not the last block of the cutting feed (S21: NO), the process ends.

In step S22, the numerical controller calculates the change amount of the coordinate value of the X position.
When the amount of change in the coordinate value of the X position is equal to or smaller than the second threshold value in step S23 (S23: YES), the process proceeds to step S24. If the amount of change in the coordinate value of the X position exceeds the second threshold value (S24: NO), the process ends.

In step S24, the numerical control device turns off the peripheral speed constant control function in the escape area.

[1.3 Third pattern]
The third pattern is a pattern for switching on/off the constant peripheral speed control function based on the amount of change in the coordinate value of the X position in the entire continuous cutting region. FIG. 3A shows a specific example of the amount of change in the coordinate value of the X position in the entire continuous cutting region. In the example shown in FIG. 3A, the width (change amount) from the minimum value to the maximum value of the coordinate value of the X position in the entire continuous cutting area is “c”. When the magnitude of "c" is equal to or smaller than the third threshold value, the numerical control device does not change the spindle speed in the entire continuous cutting area. In the present specification, the third threshold value is also referred to as “cutting threshold value”.

FIG. 3B is a flowchart showing an operation in the third pattern of the numerical control device.
In step S31, when the operation to be executed is cutting feed (S31: YES), the process proceeds to step S32. If the operation to be executed is not cutting feed (S31: NO), the process ends.

In step S32, the numerical control device prefetches all blocks until the cutting feed is completed.

In step S33, the numerical control device calculates the amount of change from the maximum value to the minimum value of the coordinate value of the X position in the continuous cutting area.

When the amount of change in the X position is equal to or smaller than the third threshold value in step S34 (S34: YES), the process proceeds to step S35. If the amount of change in the X position exceeds the third threshold value (S34: NO), the process ends.

In step S35, the numerical control device turns off the constant peripheral speed control function for the entire continuous cutting region.

The above-mentioned first to third thresholds may be set in advance by the MTB or the like in the numerical controller. Further, the above-mentioned first to third thresholds may be set by the user in the numerical control device when the machining program is executed. Further, the above-mentioned first to third thresholds may be set in the machining program.
Further, it is preferable that the first to third thresholds are set to different values according to the required surface processing quality during rough processing, finish processing, or the like.

[2 embodiments]
[2-1 Structure of the Invention]
FIG. 4 is an overall configuration diagram of the numerical control system 10 according to the embodiment of the present invention. The numerical control system 10 includes a numerical control device 100 and a machine tool 200. The numerical control device 100 and the machine tool 200 are connected in a one-to-one set so that they can communicate with each other. Although not shown in FIG. 4, the numerical control device 100 and the machine tool 200 may be connected via a network. Here, the network is realized by a network such as a LAN (Local Area Network) installed in the factory.

The numerical control device 100 is a device for controlling the machine tool 200 to cause the machine tool 200 to perform predetermined machining. The specific configuration and function of the numerical control device 100 will be described later.

The machine tool 200 is a device that performs predetermined machining such as cutting under the control of the numerical controller 100. The machine tool 200 includes a motor that is driven to machine a workpiece, a spindle and a feed shaft that are attached to the motor, jigs and tools that correspond to these axes, and the like. Then, the machine tool 200 drives the motor based on the operation command output from the numerical control device 100 to perform predetermined machining. Here, the content of the predetermined machining includes at least cutting, but in addition to cutting, other processing such as grinding, polishing, rolling, or forging may be performed.

FIG. 5 is a functional block diagram of the numerical control device 100. The numerical controller 100 includes a control unit 110 and a storage unit 120, and the control unit 110 includes a program prefetch unit 111, a determination unit 112, and an operation control unit 113.

The control unit 110 has a CPU, a ROM, a RAM, a CMOS memory, and the like, and these are known to those skilled in the art and configured to be able to communicate with each other via a bus.

The CPU is a processor that controls the numerical control device 100 as a whole. The CPU reads the system program and the application program stored in the ROM via the bus and controls the entire numerical control device 100 in accordance with the system program and the application program, thereby controlling the control unit 110 as shown in FIG. It is configured to realize the functions of the program prefetching unit 111, the determination unit 112, and the operation control unit 113. Various data such as temporary calculation data and display data are stored in the RAM. The CMOS memory is backed up by a battery (not shown), and is configured as a non-volatile memory that retains its storage state even when the numerical control device 100 is powered off.

The program pre-reading unit 111 pre-reads the machining program block by block and analyzes the machining route of the work prior to actual cutting by executing the machining program.

The determination unit 112 calculates the position change amount of the reference axis in the machining path analyzed by the program prefetch unit 111, and based on the calculated position change amount, any of the above-described first pattern to third pattern. According to the above, it is determined whether or not the constant peripheral speed control is performed.

Further, in the present embodiment, the determination unit 112, at the start of cutting, after the entire program is pre-read by the program pre-reading unit 111, based on the position change from the beginning to the end of the machining path, the peripheral speed constant. Determine the range in which the control function is turned on/off. Here, the “range” may be, for example, a block range in a machining program, a range of a machining path, or a range of a cutting region.

The operation control unit 113 executes the cutting process by controlling the presence or absence of the operation of the constant peripheral speed control function during the actual cutting process based on the determination result of the determination unit 112.

The storage unit 120 stores the machining program prefetched by the program prefetching unit 111. Further, the storage unit 120 stores the determination result of the determination unit 112, that is, the range in which the peripheral speed constant control function during cutting feed is switched on/off.

When the numerical control device 100 controls the machine tool 200 to cut the machining path in the upper stage of FIG. 8, as an example, the position change amount a of the mountain portion and the groove portion during cutting feed is smaller than the first threshold value. It is assumed that the position change amount b of the relief portion of the cutting feed is smaller than the second threshold value and the position change amount c of the entire continuous cutting feed is larger than the third threshold value.

In this case, the determination unit 112 turns on the peripheral speed constant control function with the default value for the entire continuous cutting region, but the peripheral speed is constant in the mountain groove region during cutting feed and the escape region of cutting feed. The control function is turned off. The operation control unit 113 controls the presence or absence of the operation of the constant peripheral speed control function based on the determination result of the determination unit 112, and further controls the spindle speed.

FIG. 6 is a graph showing a temporal change (solid line portion) of the spindle speed controlled by the operation control unit 113. The dotted line portion in FIG. 6 shows the change over time in the spindle speed according to the conventional technique shown in the lower graph of FIG.

As can be seen by comparing the solid line portion and the dotted line portion in FIG. 6, the spindle speed does not change at the portions corresponding to the mountain groove region during cutting feed and the relief region of cutting feed. This minimizes the change in the spindle speed and reduces the frequency of spindle acceleration/deceleration, thus suppressing power consumption.

[2-2 Operation of Invention]
7A to 7C are flowcharts showing the operation of the numerical control device 100 according to the present embodiment. The operations shown in FIGS. 7A to 7C are based on the assumption that the constant peripheral speed control function is on.

In step S51, the program prefetch unit 111 prefetches the entire block from the start to the end of the cutting feed of the machining program.

In step S52, when the change amount of the maximum value to the minimum value of the coordinate value of the X position in the entire continuous cutting area is equal to or less than the third threshold value (S52: YES), the process proceeds to step S53. .. When the amount of change from the maximum value to the minimum value of the coordinate value of the X position in the entire cutting region exceeds the above-mentioned third threshold value (S52: NO), the process proceeds to step S54.

In step S53, the determination unit 112 turns off the peripheral speed constant control function for the entire cutting region. Then, a process transfers to step S63.

In step S54, if the amount of change in the coordinate value of the X position in the escape area is equal to or less than the second threshold value (S54: YES), the process proceeds to step S55. When the amount of change in the coordinate value of the X position in the escape area exceeds the second threshold value (S54: NO), the process proceeds to step S56.

In step S55, the determination unit 112 turns off the peripheral speed constant control function in the escape area.

In step S56, the determination unit 112 searches for a set of blocks corresponding to the mountain groove region. Here, FIG. 7C shows the sub-steps that comprise step S56.

In step S56a, when the X position of the cutting tool moves from the current position and then returns to the current position in the prefetched block (S56a: YES), the process proceeds to step S56b. In other cases (S56a: NO), the process proceeds to step S56a (return).

In step S56b, the determination unit 112 recognizes a region in which the X position of the cutting tool has moved from the current position and then returned to the current position in the pre-read block as a mountain groove region. This search for the mountain groove region is repeated until the last block. Then, the process returns to step S56 (return).

In step S56, the determination unit 112 repeats the loop including steps S56a and S56b over the entire cutting area. As a result, it is assumed that the determination unit 112 recognizes N mountain groove regions.

In step S57, the determination unit 112 sets i=1 as the initial value of the parameter i.

In step S58, if the amount of change in the coordinate value of the X position in the "mountain groove region i" that is the i-th mountain groove region is equal to or less than the first threshold value (S58: YES), the process is step S59. Move to. When the change amount of the coordinate value of the X position exceeds the first threshold value (S58: NO), the process proceeds to step S60.

In step S59, the determination unit 112 turns off the peripheral speed constant control function in the mountain groove region i.

In step S60, the determination unit 112 increments the parameter i (adds 1).

If the parameter i exceeds N in step S61 (S61: YES), the process proceeds to step S62. If the parameter i is N or less (S61: NO), the process proceeds to step S58.

In step S62, the operation control unit 113 executes the cutting process by controlling the presence or absence of the operation of the peripheral speed constant control function during the actual cutting feed based on the determination result of the determination unit 112.

[2-3 Effects of the embodiment]
The numerical control device 100 according to the present embodiment calculates the position change amount of the reference axis during the cutting feed based on the result of the prefetch of the machining program, and performs the constant peripheral speed control based on the calculated amount. The determination unit 112 determines whether or not there is, and the operation control unit 113 that controls whether or not the peripheral speed constant control function is activated based on the determination result of the determination unit 112.

As a result, the power consumption can be suppressed without reducing the machining accuracy of the workpiece even when the workpiece is machined under the constant peripheral speed control for the spindle speed during cutting feed. ..

In the above description, the case where the reference axis is the X axis has been described as an example, but the present invention is not limited to this, and any axis can be used as the reference axis.

[3 Modifications]
[3-1 Modification 1]
In the embodiment described above, at the start of cutting, after the entire program is pre-read by the program pre-reading unit 111, the determining unit 112 sets the peripheral speed constant based on the position change from the beginning to the end of the machining path. Although the range in which the control function is operated and the range in which the constant peripheral speed control function is stopped are determined, the present invention is not limited to this.

For example, the determination unit 112, for each predetermined sampling time, based on the position change from the position of the reference axis at the sampling time to the end of the machining path, the range in which the constant peripheral speed control function is activated and the constant peripheral speed. You may determine the range which stops operation of a control function.

In this case, the determination unit 112 performs the determination according to the first pattern and the second pattern described above at every predetermined sampling time, and performs the determination according to the third pattern at the start of cutting. More specifically, the determinations shown in FIGS. 1B and 2B are performed at every predetermined sampling time, and the determinations shown in FIG. 3B are performed at the start of cutting. However, the determination process of FIGS. 1B and 2B is not executed while the constant peripheral speed control function is turned off by any of FIGS. 1B, 2B, and 3B.

[3-2 Modification 2]
Further, the determination unit 112 determines, for each block of the machining program being executed, a range in which the constant peripheral speed control function is operated based on the position change from the position of the reference axis corresponding to the block to the end of the machining path. The range in which the operation of the constant peripheral speed control function is stopped may be determined.

Also in this case, similarly to the modified example 1, the determination unit 112 performs the determination according to the first pattern and the second pattern described above for each block, and the determination according to the third pattern is performed by the cutting process. Run at start

[3-3 Modification 3]
In the above embodiment, the determination unit 112 calculates the position change amount of the reference axis (for example, the X axis) based on the result of the prefetch by the program prefetch unit 111, and the peripheral speed based on the calculated position change amount. Although it is determined whether the constant control is performed or not performed, the present invention is not limited to this.

For example, the determination unit 112 calculates the change amount of the peripheral speed based on the result of the pre-reading by the program pre-reading unit 111, and determines whether to perform the constant peripheral speed control based on the calculated change amount. You may.

[3-4 Modification 4]
Further, the determination unit 112 calculates the amount of change in the rotational speed of the spindle based on the result of the pre-reading by the program pre-reading unit 111, and whether the peripheral speed constant control is performed or not based on the calculated change amount. May be determined.

Each component included in the numerical control device 100 and the numerical control system 10 described above can be realized by hardware, software, or a combination thereof. Further, the numerical control method performed by the cooperation of each of the components included in the numerical control device 100 and the numerical control system 10 described above can also be realized by hardware, software, or a combination thereof. Here, “realized by software” means realized by the computer reading and executing the program.

The program can be stored using various types of non-transitory computer readable media and can be supplied to the computer. Non-transitory computer readable media include various types of tangible storage media. Examples of the non-transitory computer-readable medium include a magnetic recording medium (for example, flexible disk, magnetic tape, hard disk drive), magneto-optical recording medium (for example, magneto-optical disk), CD-ROM (Read Only Memory), CD- R, CD-R/W, and semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)) are included. In addition, the program may be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. The transitory computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

10 Numerical Control System 100 Numerical Control Unit 110 Control Unit 111 Program Lookahead Unit 112 Judgment Unit 113 Operation Control Unit 120 Storage Unit 200 Machine Tool

Claims (8)

A numerical controller having a constant peripheral speed control function for controlling the spindle speed so that the peripheral speed is constant,
A program pre-reading section that pre-reads the machining program,
Based on the result of the pre-reading by the program pre-reading unit, during cutting feed, at least, the position change amount of the reference axis, the peripheral speed change amount, or the spindle rotational speed change amount is calculated, the change amount Based on, the determination unit for determining whether to perform the constant peripheral speed control, or not,
Based on the determination result of the determination unit, an operation control unit for controlling the presence or absence of the operation of the constant peripheral speed control function,
Numerical control device equipped with. The determination unit calculates the position change amount of the reference axis in the entire cutting feed, and based on the result of comparison between the position change amount and a preset cutting threshold value, the peripheral speed constant control is performed or not performed. The numerical control device according to claim 1, which determines whether or not it is. The determination unit calculates the position change amount of the reference axis at the time of the escape operation at the cutting feed final part, and based on the result of comparison between the position change amount and a preset escape threshold, the peripheral speed constant control is performed. The numerical control device according to claim 1, which determines whether or not to perform. During the cutting feed, the determination unit calculates a position change amount of the reference axis at a position where the reference axis changes from the current position and then returns to the current position, and the position change amount and a preset groove groove. The numerical controller according to any one of claims 1 to 3, which determines whether or not to perform constant peripheral speed control based on a comparison result with a threshold value. The numerical control device according to claim 1, wherein at least one of the cutting threshold value, the relief threshold value, and the crest groove threshold value is set in the machining program. The determination unit is a range in which the constant peripheral speed control function is operated based on the position change from the beginning to the end of the machining path after the entire machining program is pre-read by the program pre-reading unit at the start of cutting. The numerical controller according to any one of claims 1 to 5, which determines whether or not the operation of the constant peripheral speed control function is stopped. The determination unit, for each predetermined sampling time, from the position of the reference axis at the sampling time, based on the position change of the machining path, the range for operating the constant peripheral speed control function, and the operation of the constant peripheral speed control function. The numerical controller according to any one of claims 1 to 5, which determines a range to stop the. The determination unit, for each block of the machining program being executed, a range in which the constant peripheral velocity control function is operated based on a change in the position of the machining path from the position of the reference axis corresponding to the block, and the peripheral speed. The numerical controller according to any one of claims 1 to 5, which determines a range in which the operation of the constant control function is stopped.

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