JP2001287118A - Tapping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect increase in actual cutting load acting on a tapper even during accelerating/decelerating a main spindle adapted to drive the tapper. SOLUTION: Total load torque detected when tapped during idling is preserved as data of reference load during idling by a computer. The computer calculates an actual cutting load torque by subtracting a reference load torque during idling from the total load torque detected at the time of tapping. When the actual cutting load torque exceeds an overload criterion T0, it is judged that abrasion of the tapper comes to an end of life or cutting filings are clogged to make a decelerating control at the time of cutting-in at second deceleration -α2 that is smaller than normal first deceleration -α1. After the main spindle is made a drawing control by making an accelerating/decelerating control at the second deceleration -α2 that is smaller than the normal first deceleration -α1, tapping is done repeatedly on a machining tapped hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tapping device such as a numerically controlled machine tool for performing tapping processing by synchronizing a rotation phase of a tapper and a feed speed.

[0002]

2. Description of the Related Art Conventionally, when tapping is performed by a numerically controlled machine tool such as a machining center or an NC tapping machine, the rotational phase of a main shaft that rotationally drives the tapper and the axial direction of the main shaft (hereinafter referred to as "Z axis"). The main spindle rotation motor and the main spindle feed motor are controlled such that the feed positions (1) and (2) are synchronized.

One tapping process includes a cutting step in which the tapper is fed from a tapping start position to an end position.
A drawing step of returning from the end position to the start position. Then, as shown in FIG. 3, the cutting step includes an acceleration process in which the rotation speed of the main shaft is controlled from “0” to a predetermined maximum rotation speed, a constant speed process in which the rotation speed is maintained at the maximum rotation speed, and A deceleration process in which the rotational speed is controlled to decelerate from the maximum rotational speed to “0”. The drawing process includes an acceleration process, a constant speed process, and a deceleration process, like the cutting process. Then, in each process, the spindle is controlled so that the feed position is synchronized with the rotation phase.

In the tapping process, the actual cutting load torque applied from the workpiece to the tapper during cutting may be excessive due to factors such as the life of the tapper being worn or the clogging of cutting chips. There is. In this case, the tapper may be broken or the tap hole during processing may be damaged. Therefore, a numerically controlled machine tool in which tapping is stopped without breaking the tapper even when the actual cutting load torque becomes excessive during cutting is disclosed in Japanese Patent Application Laid-Open No. 4-30910.

In this control machine tool, the detecting means detects the actual cutting load torque applied to the spindle rotating motor during tapping. Further, the monitoring means monitors whether or not the detected actual cutting load torque exceeds the allowable torque load value stored in the storage means and is overloaded. When the monitoring means determines that the actual cutting load torque is overloaded, the control means controls the spindle rotation motor and the spindle feed motor to synchronize the rotation phase of the spindle and the feed position. In this state, after stopping the rotation operation and the feed operation of the spindle, the spindle is returned to the tapping start position. Therefore, before the difference between the rotation phase command value and the actual rotation phase becomes excessive, a state where the actual cutting load torque becomes excessive is detected, and the spindle is rotated in a state where the spindle rotational phase and the feed position are synchronized. Since the rotation operation and feed operation of are stopped,
Tapping is stopped without damaging the tapper or the work.

The detecting means detects the actual cutting load torque applied to the spindle rotating motor from the value of the current supplied to the spindle rotating motor which changes according to the load. More specifically, as shown in FIG. 3, in an acceleration process and a deceleration process in a cutting process, inertia of a rotating portion such as a main shaft and a rotor of a motor is applied to a main shaft rotating motor as load torque. The load torque due to the inertia is a load torque significantly larger than the actual cutting load torque. On the other hand, the load torque applied in the constant speed process in which the rotation speed of the main shaft is maintained at the maximum rotation speed is almost only the cutting load torque applied to the tapper. Therefore, the detecting means mainly detects and detects the supply current value in the constant speed process from the time when the command value of the rotation speed of the main shaft increases and exceeds 90% to the time when the command value decelerates. The magnitude of the actual cutting load torque is determined from the supplied current value. still,
In the acceleration process and the deceleration process in the drawing process,
The load torque due to the inertia of the main shaft is applied.

[0007]

However, the actual cutting load torque applied to the tapper during machining is increased by a torque measurement using a Kistler dynamometer or the like during the deceleration process during the cutting process. That is, it is known that the maximum value is obtained near the bottom of the tapped hole. The breakage of the tapper occurs when the maximum value of the actual cutting load torque becomes excessive.

However, in the above numerically controlled machine tool,
Since the actual cutting load torque cannot be detected during acceleration / deceleration, the maximum value of the actual cutting load torque applied to the tapper cannot be detected, and it must be accurately determined that the life of the tapper has reached the end of its life. Can not.

When tapping is performed on a work made of a metal having a low hardness such as aluminum,
Since the cutting resistance is small and the cutting is easy, the machining time is shortened by increasing the spindle rotation speed and the feed speed. In this case, as shown in FIG. 10, the duration of the constant speed process in which the main shaft is controlled at the maximum rotation speed becomes extremely short, and the main shaft may be almost completely controlled only in the acceleration process and the deceleration process. .

Therefore, in tapping in such a state, it is difficult to detect the actual cutting load torque because there is almost no time during which only the cutting load torque is applied to the spindle rotary motor.

In the numerically controlled machine tool that performs such tapping processing, it is possible to accurately determine that the degree of wear of the tapper is the life based on the detected actual cutting load torque, or to prevent cutting chips from being clogged. Thus, it was impossible to determine that the overload was applied to the tapper and to take appropriate measures.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to detect a state in which an overload is applied to a tapper even during acceleration / deceleration of a spindle for driving the tapper. To provide a tapping device that can perform the tapping.

A second object of the present invention, in addition to the first object, is to detect a state in which an overload is applied to the tapper when the spindle is accelerated or decelerated, thereby preventing breakage of the tapper or damage to the work. It is to provide a tapping device that can be used.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention according to claim 1 controls the feed position of the spindle to which the tapper is fixed and the rotation phase in synchronization with each other, and also controls the rotation of the spindle. In a tapping device that detects a load applied to a motor, a total load detected at the time of tapping processing and a preset reference load, the actual cutting load applied to the tapper, or the load increase amount of the actual cutting load. The gist is that an actual cutting load detecting means for detecting is provided.

According to a second aspect of the present invention, in the first aspect of the invention, the reference load is an idle operation reference load detected when tapping is performed in the idle operation, and The gist of the present invention is that the cutting load detecting means sets a difference between the total load and the reference load during idling as the actual cutting load.

According to a third aspect of the present invention, in the first aspect of the present invention, the reference load is calculated based on at least a total inertial mass of a rotating portion including the main shaft and a rotational speed of the main shaft. It is a load, and the gist is that the actual cutting load detecting means sets a difference between the total load and the calculation reference load as the actual cutting load.

According to a fourth aspect of the present invention, in the first aspect of the invention, the reference load is a reference total load detected when tapping is actually performed by the tapper. The gist of the invention is that the cutting load detecting means sets a difference between the total load and the reference total load as the load increase amount.

According to a fifth aspect of the present invention, in the first aspect of the present invention, a preset value is set based on either the actual cutting load or the load increase amount. An overload determination unit that determines whether the degree of wear of the tapper is a service life or an overload determination value by using an overload determination value, and whether the spindle is accelerated or decelerated. The cutting and pulling out of the tapper is performed, and when it is determined that the degree of wear of the tapper is a life or a state in which cutting chips are clogged, the spindle is decelerated to control the spindle. And a spindle control means for stopping the cutting of the tapper while keeping the rotation phase and the feed position synchronized with each other.

According to a sixth aspect of the present invention, in the invention according to the fifth aspect, when it is determined that the cutting chips are clogged, the main spindle control means operates the main spindle with a smaller deceleration. The gist of the present invention is to stop the cutting of the tapper by deceleration control.

According to a seventh aspect of the present invention, in the fifth aspect of the invention, when it is determined that the cutting chips are clogged, the main spindle control means controls the deceleration of the main spindle to reduce the speed of the main spindle. The gist of the present invention is to stop the cutting of the tapper, perform acceleration / deceleration control of the spindle, and once pull out the tapper from the tap hole being machined, and repeat the tapping process for the tap hole.

According to an eighth aspect of the present invention, in the fifth aspect of the present invention, the spindle control means controls the spindle with a larger deceleration when it is determined that the degree of wear of the tapper is a life. The gist of the present invention is to stop the cutting of the tapper by deceleration control.

According to a ninth aspect of the present invention, in the invention according to any one of the fifth to eighth aspects, the spindle control means controls the deceleration of the spindle to stop the cutting. The gist of the present invention is to accelerate / decelerate the spindle with a smaller acceleration / deceleration to pull out the tapper.

(Operation) According to the first aspect of the present invention,
The load applied to the spindle rotating motor during tapping is detected as the total load. The total load includes an actual cutting load received by the tapper from the work, a load based on the inertia of a rotating part rotating together with the main shaft, a frictional resistance in a frictional part such as a bearing, a viscous resistance in a lubricating part such as a bearing, and the like. In addition, the reference load set to obtain the actual cutting load applied to the tapper or the increase amount of the actual cutting load is the sum of each load excluding the actual cutting load in the total load and the sum of each load excluding the actual cutting load. Will be the same. Further, when the reference load includes the actual cutting load, the difference from the total load is the increase amount of the actual cutting load. Then, the actual cutting load or the amount of increase in the actual cutting load corresponding to the feed position and the rotation phase of the main spindle is obtained as a difference between the total load at the same cutting position and the reference load during idling. Therefore, the amount of increase in the actual cutting load is detected even during acceleration / deceleration in which inertia of the main shaft or the like is applied as a load.

According to the invention described in claim 2, according to claim 1,
In addition to the operation of the invention described in the above, when the tapping is performed in the idle operation, the idle operation reference load obtained by removing only the actual cutting load from the total load is detected as the reference load. Then, the actual cutting load corresponding to the feed position and the rotation phase of the main spindle is obtained as a difference between the total load at the same cutting position and the reference load during idling. Therefore, the actual cutting load is directly detected.

According to the invention described in claim 3, according to claim 1
In addition to the effect of the invention described in at least, from the total inertial mass of the rotating part that rotates with the main shaft,
The calculated reference load obtained by removing only the actual cutting load from the total load is calculated as the reference load. Then, an actual cutting load corresponding to the feed position and the rotation phase of the spindle is obtained as a difference between the total load and the calculated reference load at the same cutting position. Therefore,
The actual cutting load is directly detected.

According to the invention described in claim 4, according to claim 1
In addition to the operation of the invention described in the above, when the tapping is performed by the tapper, the reference total load including the actual cutting load according to the degree of wear of the tapper is detected as the reference load. Then, the load increase amount of the actual cutting load corresponding to the feed position and the rotation phase of the spindle is obtained as a difference between the total load at the same cutting position and the reference total load. Therefore, the load increase amount of the actual cutting load is detected even during acceleration / deceleration in which the inertia of the main shaft or the like is applied as a load.

According to the invention described in claim 5, according to claim 1 of the present invention,
In addition to the effect of the invention described in any one of claims 4 to 4, the degree of wear of the tapper is reduced during the cutting,
Alternatively, when cutting chips are clogged, the actual cutting load applied to the tapper or the amount of increase in load from the previous actual cutting load becomes an excessive value. From the actual cutting load or the load increase amount that has become excessively large and the preset reference cutting load, it is determined that the life of the abrasion degree of the tapper has been reached or that cutting chips have been clogged. Then, the cut is stopped while the tapper is along the tap hole being cut. Therefore, during the cutting of the tapper, the degree of wear of the tapper reaches the end of its life, or when the actual cutting load applied to the tapper due to the clogged cutting chips becomes excessive, the load increase amount becomes excessive.
Cutting of the tapper is stopped in a state where the tap hole during cutting is not damaged.

According to the invention of claim 6, according to claim 5,
In addition to the effect of the invention described in the above, during cutting, if the cutting load applied to the tapper becomes excessive due to the state of cutting chips clogged, by reducing the rotation speed of the tapper more gently, Discharge of cutting chips during the deceleration process is promoted. Therefore, even if cutting chips are clogged during the cutting of the tapper, the cutting is stopped in a state where the actual cutting load applied to the tapper is suppressed.

According to the invention of claim 7, according to claim 5,
In addition to the operation of the invention described in (1), if it is determined based on the actual cutting load that the cutting chips are clogged, the tapper is once pulled out, and then tapping is repeatedly performed. Therefore, the tapping process is not stopped only by the clogging of the cutting chips, and the tapping process is repeatedly performed while discharging the cutting chips.

According to the invention described in claim 8, according to claim 5,
In addition to the operation of the invention described in the above, since the tapper determined to have a life of the wear degree at the time of the cut is controlled by the deceleration at a larger deceleration and stopped, the actual cutting load applied to the tapper during the deceleration is reduced. .

According to the ninth aspect of the present invention, in the fifth aspect,
In addition to the effects of the invention according to any one of claims 8 to 8, cutting is stopped when it is determined that the degree of wear of the tapper is life, or it is determined that cutting chips are clogged. After that, the main shaft is accelerated / decelerated at a smaller acceleration / deceleration and pulled out, so that the actual cutting load applied to the tapper at the time of drawing is reduced.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment in which the present invention is embodied in a CNC tapping machine will be described below with reference to FIGS.

As shown in FIG. 2, a CNC tapping machine 10 as a tapping device includes a processing device 11 and a control device 12. The processing apparatus 11 includes a work table 13 movable in the X-axis and Y-axis directions, a main spindle 14 fixedly disposed at a predetermined position in the X-axis and Y-axis directions, to which a tapper T is mounted, a main spindle rotation motor 15, and a main spindle feed. Motor 16,
An X-axis driving motor 17 and a Y-axis driving motor 18 are provided. Then, the processing apparatus 11 moves the work table 13 in the X-axis and Y-axis directions by the X-axis drive motor 17 and the Y-axis drive motor 18, and the work set at the position on the X-axis and Y-axis coordinates. A predetermined position of W is positioned with respect to the spindle 14. In addition, the processing device 11 performs tapping processing at a predetermined position of the positioned work W by moving the main shaft 14 on which the tapper T is mounted in the Z-axis direction.

The processing device 11 is provided with an X-axis coordinate detector 19 for detecting the position of the work table 13 on the X-axis coordinate positioned with respect to the main shaft 14, and similarly, the position of the work table 13 on the Y-axis coordinate. -Axis coordinate detector 2 for detecting
0 is provided. Further, a rotation phase detector 21 for detecting a rotation phase of the main shaft 14 around the Z axis and a Z-axis coordinate detector 22 for detecting a feed position of the main shaft 14 on the Z-axis coordinates are provided. Then, the processing device 11 sequentially detects the position on the X and Y coordinate axes of the work table 13 positioned with respect to the main shaft 14, and feeds the main shaft 14 on the Z-axis coordinate and around the Z-axis. The rotation phase is sequentially detected.

The control device 12 includes a computer 23, a drive device 24, a load detection device 25, and the like. In the present embodiment, the computer 23 is an overload determination unit and a spindle control unit, and the computer 23 and the load detection device 25 constitute an actual cutting load detection unit.

The driving device 24 includes a main shaft driving device 26, a main shaft feed driving device 27, an X-axis driving device 28 and a Y-axis driving device 29. The spindle drive device 26 controls the drive of the spindle rotation motor 15. The spindle feed drive device 27 controls the drive of the spindle feed motor 16. Also, the X-axis driving device 2
8 controls the driving of the X-axis driving motor 17 and the Y-axis driving device 29 controls the driving of the Y-axis driving motor 18.

The computer 23 includes a central processing unit 30
The storage device includes a storage device 31, an input device 32, a display device 33, an input / output device 34, and the like. The storage device 31 includes a spindle rotation motor 15, a spindle feed motor 16, an X-axis drive motor 17
And a control program for controlling the driving of the Y-axis driving motor 18 via the respective driving devices 26 to 29. In addition, the storage device 31 stores a work program in which a plurality of tapping processing positions set for each workpiece W and a tapping processing condition of each tapping processing are set. Tapping conditions include X,
Tapping position on Y axis coordinate, tap end position and tapping start position on Z axis coordinate, rotation phase of spindle 14 at tapping start position, screw pitch amount of tapper T, maximum spindle rotation speed, tap size, etc. are set. Have been.

The central processing unit 30 operates in accordance with the control program stored in the storage device 31 according to the X, Y axis driving device 2.
The drive of the X-axis drive motor 17 and the Y-axis drive motor 18 is controlled via 8 and 29 to control the work W to position a predetermined tapping position on the X and Y axis coordinates with respect to the main shaft 14. At this time, the central processing unit 30 performs feedback control by software servo based on the detection results of the X-axis coordinate detector 19 and the Y-axis coordinate detector 20 according to the control program.

In accordance with the control program, the central processing unit 30 controls the spindle rotation motor 15 and the spindle feed motor 16 via the spindle drive unit 26 and the spindle feed drive unit 27 at predetermined positions on the X-axis and Y-axis coordinates. And the rotation phase / rotational speed control and the feed position / feed speed control are performed such that tapping processing including a cutting step and a drawing step is performed under the tapping processing conditions set in the work program. That is, the central processing unit 30 synchronizes the rotation phase with the feed amount based on the rotation phase at the tapping start position specified by the tapping processing conditions of the work program, the screw pitch amount of the tapper T, and the maximum spindle rotation speed. It performs rotation phase / rotation speed control and feed position / feed speed control.

In accordance with the control program, the central processing unit 30 changes the spindle rotation speed and the feed speed during the cutting control for sending the tapper T from the tapping start position to the tapping end position, and changes the spindle rotation speed from "0" to the tapping speed. After increasing at a preset rotational acceleration until the maximum spindle speed specified by the processing conditions is reached, the rotational speed is reduced from the maximum spindle speed to “0” at the same magnitude of rotational acceleration. still,
The tapping start position or the rotational acceleration is set so that the acceleration process at the time of the cut ends before the tapper T enters the cut state, or the tapper T enters the cut state during acceleration. Similarly, according to the control program, the central processing unit 30 sets the spindle speed from “0” to the maximum spindle speed during the pull-out control for returning the tapper T from the tapping end position to the tapping start position. After increasing with acceleration, "0" from the maximum spindle speed
Until the same magnitude of rotational acceleration. At this time,
The central processing unit 30 controls the rotation phase detector 21 and the Z
The feedback control by software servo is performed based on each detection result of the axis coordinate detector 22.

The central processing unit 30 controls the acceleration control at the time of cutting the main shaft 14 by setting a first rotational acceleration (hereinafter, referred to as a first acceleration) α1 and a second rotational acceleration (hereinafter, referred to as a first acceleration). 2), and the same deceleration control is performed, and the same deceleration control is performed for a preset first rotation deceleration (hereinafter, referred to as a first deceleration) -α1, and a second rotation deceleration ( Hereinafter, it is referred to as a second deceleration.)-Α2
And a third rotation deceleration (hereinafter, referred to as a third deceleration).
Performs any of -α3. The first acceleration α1 and the first deceleration -α1 are set for normal use and have the same magnitude, and the second acceleration α2 and the second deceleration -α2 are It is used when the actual cutting load to be applied becomes excessive, has the same magnitude, and is set to a value (absolute value) smaller than the first acceleration α1 and the first deceleration -α1. I have. Further, the third deceleration -α3 is set to a value (absolute value) larger than the first deceleration -α1.

The load detecting device 25 detects a drive current value of the main shaft rotating motor 15 whose magnitude changes in accordance with the rotational load torque received by the main shaft rotating motor 15 when the main shaft 14 is rotationally driven. And outputs it to the computer 23. Note that the rotational load torque received by the spindle rotating motor 15 during tapping processing includes the actual cutting load torque due to the cutting load received by the tapper T from the work W, and the rotating part (tapper T that rotates together with the spindle 14 during acceleration and deceleration of the spindle 14). ,
The total load torque mainly includes load torque based on inertia of a chuck, a rotating shaft, a rotor of a spindle rotating motor, and the like, frictional resistance in a frictional portion such as a bearing, and viscous resistance in a lubricating portion such as a bearing.

(Detection of Actual Cutting Load) Central Processing Unit 30
Detects the total load torque applied to the spindle rotation motor 15 sequentially from the drive current value detected by the load detection device 25 according to the control program. FIG. 3 is a graph showing the time characteristics of the total load torque and the spindle speed in one tapping process. Note that the characteristics shown in this graph are for the case where the tapper T is set to enter the cutting state after the completion of the acceleration process of the spindle 14 at the time of cutting.

As shown in the graph of FIG. 3, the total load torque detected during the acceleration process at the time of cutting does not include the actual cutting load torque. It does not include the load torque based on the inertia of the rotating part. Further, the total load torque detected in the deceleration process at the time of cutting is obtained by synthesizing the actual cutting load torque and the load torque based on the inertia of the rotating part. In addition, the total load torque detected in the acceleration process at the time of drawing is a combination of the load torque based on the inertia of the rotating part and the resistance load torque due to clogging of cutting chips, etc. The load torque does not include the load torque based on the inertia of the rotating part including the main shaft 14. Further, the total load torque detected in the deceleration process at the time of pulling out includes the load torque based on the inertia of the rotating part.

In accordance with the control program, the central processing unit 30 calculates the total load torque detected in accordance with the rotational phase and the feed position during the tapping operation designated by the input operation on the input device 32, and outputs the rotational phase and the feed torque. It is stored as reference load torque data corresponding to the position. Further, the central processing unit 30 determines the same rotational position and feed rate of the stored total load torque data from the value of the total load torque detected corresponding to the rotational phase and the feed position at each tapping according to the control program. The value obtained by subtracting the value of the reference load torque at the position is obtained as the amount of increase in the actual cutting load torque at the feed position and the same rotational phase applied to the tapper T during cutting.

That is, the data of the reference load torque corresponding to the rotation phase and the feed position includes the actual cutting load torque by the cutting load received from the work W according to the degree of wear of the tapper T at that time, and the acceleration and deceleration of the spindle 14. It is composed of a load torque based on the inertia of a rotating part that sometimes rotates with the main shaft 14, a frictional resistance in a frictional part such as a bearing, a viscous resistance in a circulating part such as a bearing, and the like. Further, the total load torque detected at each subsequent tapping operation is increased by an increase in the actual cutting load torque due to the progress of the degree of wear of the tapper T. Accordingly, the central processing unit 30 subtracts the reference load torque from the total load torque detected during each tapping process, thereby obtaining the load torque increase of the actual cutting load torque corresponding to the progress of the degree of wear of the tapper T at that time. To detect.

When the reference load torque is the idling reference load torque detected during the idling operation in which tapping is not actually performed, the idling reference load torque is calculated as shown in FIG. The actual cutting load torque is composed of a load torque based on the inertia of a rotating portion that rotates together with the main shaft 14 during acceleration and deceleration of the main shaft 14, a frictional resistance in a frictional portion such as a bearing, and a viscous resistance in a circulating portion such as a bearing. It is not included. Therefore, the central processing unit 3
In the case of 0, the actual cutting load torque itself corresponding to the degree of wear of the tapper T at that time is detected as shown in FIG. 5 by subtracting the reference load torque during idle operation from the total load torque. Note that the actual cutting load torque obtained by subtracting the reference load torque from the total load torque matches well with the measured value of the cutting load torque actually applied to the tapper T at the time of tapping by measuring with a Kistler dynamometer or the like.

The actual cutting load torque detected at the time of tapping processing has a substantially constant magnitude during cutting when the spindle 14 is controlled at a constant speed, and during cutting when the spindle 14 is controlled to decelerate. Shows a characteristic that as the spindle speed decreases, it gradually increases. Therefore, the actual cutting load torque usually has a maximum value just before the tapping end position. Further, the actual cutting load torque shows a characteristic that increases sharply when cutting chips are clogged.

(Tapping) Next, the central processing unit 3
The procedure of the tapping process performed by the “0” will be described with reference to the flowchart of FIG. That is, before performing the tapping process, the X-axis and the Y-axis specified in the tapping process conditions are set.
A predetermined position of the workpiece W on the axis coordinates is positioned with respect to the spindle 14, and the spindle 14 is positioned at the tapping start position.
Are arranged at a predetermined rotation phase. It is also assumed that the reference load torque during idling is stored as the reference load torque.

The CPU 30 first controls the spindle rotating motor 15 in step 10 as tapping processing control.
In addition, the drive of the spindle feed motor 16 is controlled to cut the spindle 14 in a state where the rotation phase and the feed position are synchronized. At this time, the central processing unit 30 performs control so as to accelerate and decelerate the rotation speed of the main shaft 14 at the first first acceleration α1 and the first deceleration −α1. The first acceleration α1 and the first deceleration -α1 are values set together with the maximum spindle speed for the workpiece W and the tapper T to be tapped, and are, for example, received by the tapper T whose degree of wear is short. The actual cutting load torque is a value that falls within the allowable range of the tapper T, and is a value as large as possible.

More specifically, at the time of cutting of the tapper T, as the rotational acceleration and the rotational deceleration are greater and the degree of wear of the tapper T is greater, the cutting chips are more difficult to be discharged and stay in the tapped holes during machining. . As a result, the actual cutting load torque applied to the tapper T excessively increases due to the clogging of the stagnant cutting chips. Therefore, in a state where cutting chips are not clogged and the degree of wear of the tapper T is not the life,
By performing the acceleration / deceleration control with the first acceleration α1 and the first deceleration −α1, the cutting and the drawing are completed in a short time.

During the cutting control of the spindle 14, the central processing unit 30 sequentially calculates the actual cutting load torque obtained by subtracting the idling reference load torque from the sequentially detected total cutting load torque in step 11. Then, in step 12, the central processing unit 30 determines whether or not the calculated actual cutting load torque is greater than a preset overload determination value T0. The overload judgment value T0 is the first
When the main shaft 14 is subjected to acceleration / deceleration control at the acceleration α1, the actual cutting load torque received by the tapper T is a value set in advance to determine that the torque is the size of the upper limit region of the allowable range.

When the actual cutting load torque is equal to or less than the overload determination value T0 in step 12, the degree of wear of the tapper T is not the service life, and the cutting chips are clogged and the tapper T has an allowable range. In step 13, the cutting control is performed up to the tapping end position, assuming that the cutting load in the upper limit region is not applied.

After performing the cutting control to the tapping end position while the actual cutting load is equal to or less than the overload judgment value T0, the central processing unit 30 proceeds to steps 14 and 15 to perform the first acceleration α1 and the first reduction. The main shaft 14 is accelerated / decelerated at the speed -α1, and the pull-out control is performed from the tapping end position to the tapping start position.

On the other hand, the central processing unit 30 executes step 12
When the actual cutting load torque exceeds the overload determination value T0, the wear of the tapper T has reached the end of its life, or the cutting load has clogged with the cutting debris in the upper limit range of the allowable range. It is determined that either torque has been applied. In this case, in step 16, the central processing unit 30 determines whether or not the actual cutting load torque has exceeded the overload determination value T0 in the previous tapping operation.

If the actual cutting load has not exceeded the overload judgment value T0 in the previous tapping operation in step 16, the central processing unit 30 increments the count value C in step 17 and then proceeds to step 18
Then, the spindle 14 is controlled to decelerate at the second deceleration -α2, and is stopped while keeping the rotation phase and the feed position synchronized. The second deceleration-[alpha] 2 is the second deceleration even when the actual cutting load torque received by the tapper T when decelerating at the first deceleration-[alpha] 1 exceeds the allowable range of the tapper T. The actual cutting load torque is set to be within an allowable range when decelerating at −α2.

In step 18, the central processing unit 30
6, when the spindle 14 is controlled at the maximum spindle speed, as shown in FIG. 6, performs the deceleration control at the second deceleration -α2 based on the rotation speed and the feed speed.
Is a deceleration state by the first deceleration -α1, the deceleration control is performed by switching the first deceleration -α1 to the second deceleration -α2, as shown in FIG. Thus, when the central processing unit 30 determines that the actual cutting load exceeds the overload determination value T0 due to the clogging of the cutting chips, the central processing unit 30 performs the deceleration control with the second deceleration -α2. Then, the actual cutting load torque applied to the tapper T during cutting is prevented from further increasing.

Thereafter, the central processing unit 30 executes step 1
9 and 20, the second acceleration α, as shown in FIGS.
Control the acceleration and deceleration of the spindle 14 with the second and second deceleration -α2,
The main shaft 14 is controlled to be pulled from the stopped position on the Z-axis coordinates to the tapping start position. Then, the central processing unit 30
Performs tapping again at the same position on the X-axis and Y-axis coordinates. The central processing unit 30 converts the tapper T stopped during the cut into the second acceleration α2 and the second deceleration −α2.
, The actual cutting load torque applied to the tapper T during drawing is prevented from further increasing.

Accordingly, when the central processing unit 30 determines that the overload due to the clogging of the cutting chips has been applied to the tapper T based on the detected actual cutting load torque, the tapping process is interrupted halfway and the spindle 14 is once tapped. After returning to the start position, tapping is performed again.

On the other hand, the central processing unit 30 executes step 16
If the actual cutting load torque has exceeded the overload determination value T0 in the previous tapping operation, it is determined in step 21 whether or not the count value C exceeds a preset life determination value CL. Life judgment value CL
The reason for the fact that the actual cutting load torque exceeded the overload determination value T0 during the tapping process this time is not due to an increase in the cutting load due to clogging of the cutting chips, but due to the life of the wear of the tapper T. It is set to judge.

When the count value C is equal to or less than the life determination value CL in step 21, the central processing unit 30 determines that the degree of wear of the tapper T is not the life, and proceeds to step 17. Then, in the same manner as described above, the cutting process is interrupted, and tapping is performed again on the same portion of the work W.

Therefore, the central processing unit 30 determines that the overload applied to the tapper T is not due to the fact that the degree of wear of the tapper T has reached the end of its life. Assuming that there is, the tapping process is interrupted, the spindle 14 is returned to the tapping start position, and then the tapping process is performed again.

The central processing unit 30 executes step 21
If the count value C exceeds the life determination value CL, it is determined that the degree of wear of the tapper T is the life.
In 2, the main shaft 14 is controlled to decelerate at the third deceleration -α3,
Stopping while keeping the rotation phase and the feed position synchronized.
In step 22, the central processing unit 30
Is the constant speed control state, as shown in FIG. 8, the third deceleration -α
When the deceleration control is performed in step S3, and the control state of the spindle 14 is the deceleration state by the first deceleration -α1, FIG.
, The first deceleration-α1 is changed to the third deceleration-α
Switch to 3 to perform deceleration control.

If the wear of the tapper T reaches the end of its life during cutting, if the cutting is continued as it is, the actual cutting load torque may be further increased and the tapper T may be broken. The central processing unit 30 controls the main shaft 14 to decelerate at a third deceleration -α3 greater than the first deceleration -α1 and stops the main shaft 14 so that the incision is terminated early. Is not added.

Thereafter, the central processing unit 30 executes step 2
At 3 and 24, as shown in FIGS.
Control the acceleration and deceleration of the spindle 14 with the second and second deceleration -α2,
Spindle 14 from the stopped position on the Z axis to the tapping position
Is controlled. Then, the central processing unit 30 controls the display device 33 in step 25 to display that the wear state of the tapper T has reached the end of its life.

Therefore, when the central processing unit 30 determines that an overload due to the life of the wear of the tapper T has been applied based on the detected actual cutting load torque,
After the tapping process is stopped halfway and the spindle 14 is controlled to be pulled out, the tapping process is terminated as it is.

Next, the operation of the CNC tapping machine configured as described above will be described. When creating and storing reference load value data, tapping is performed in idle operation, and the total load data detected at that time is
An input operation on the input device 32 causes the computer 23 to store the reference load.

In the tapping process, the central processing unit 30 subtracts the idle operation reference load torque at the same position from the total load torque sequentially detected corresponding to the rotation position and the feed position during the cutting control of the tapper T. The actual cutting load torque is sequentially calculated. Accordingly, the actual cutting load torque is detected even during acceleration / deceleration in which the inertia of the main shaft 14 or the like is applied as a load. In addition, the maximum value of the actual cutting load torque which is maximum during the deceleration process of the main shaft 14 at the time of cutting is detected.

When the actual cutting load torque detected during the cutting control exceeds a preset overload determination value T0, the central processing unit 30 temporarily increases the actual cutting load torque due to clogging of cutting chips. Is in a state of
It is determined that the life of the tapper T has reached the end of its life. Then, the spindle 14 is decelerated and stopped in a state where the rotation phase and the feed position are kept synchronized, and the cutting control is stopped. Therefore, when the cutting chips are clogged and the actual cutting load torque temporarily increases during the cutting control, or when the tapper T
When the degree of wear reaches the end of the life, the cutting of the tapper T is stopped in a state where the tap hole during the cutting is not damaged.

When the actual cutting load torque detected during the cutting control exceeds a preset overload determination value T0, the central processing unit 30 sets the actual cutting load torque to an overload when cutting in each tapping operation. When the number of times exceeding the determination value T0 is equal to or less than the predetermined life determination value CL, it is once determined that the cutting chips are clogged during each tapping process and the actual cutting load torque is temporarily increased. Then, the spindle 14 stopped before the tapping end position is moved to the second acceleration α2
Then, acceleration / deceleration control is performed at the second deceleration -α2, and pull-out control is performed from the stop position to the tapping start position. Therefore,
When the cutting chips are clogged and the actual cutting load torque temporarily increases during the cutting control, the actual cutting load torque applied to the tapper T at the time of drawing is suppressed.

Further, when the number of times the actual cutting load torque exceeds the overload judgment value T0 at the time of cutting is equal to or less than the life judgment value CL, the central processing unit 30 stops the spindle 14 just before the tapping end position. Then, the spindle 14 which has been pulled out to the tapping start position is subjected to acceleration / deceleration control again at the first acceleration α1 and the first deceleration −α1, and the cutting control is performed from the tapping start position to the tapping end position.
Therefore, at the time of the cut control, the tapping process is not stopped only by the clogging of the cutting chips, and the tapping process at the same position is automatically and repeatedly performed.

When the actual cutting load torque detected at the time of cutting control exceeds the preset overload judgment value T0, the actual cutting load torque changes to the overload judgment value T0 at the time of cutting for each tapping operation. Exceeded count is life judgment value C
If it exceeds L, the central processing unit 30 determines that the wear state of the tapper T is the life. Then, the main shaft 14 is moved to the first
At the third deceleration -α3 larger than the deceleration -α1 of the above. Therefore, when it is determined that the life of the tapper T at the time of cutting is the life, the actual cutting load torque applied to the tapper T during deceleration is reduced.

Further, at the time of cutting for each tapping process,
When the number of times the actual cutting load torque exceeds the overload determination value T0 exceeds the life determination value CL, the spindle 14 stopped by the deceleration control is applied with the second acceleration α2 and the second deceleration -α2. After deceleration control and pull-out control to the tapping start position, tapping processing is stopped. Accordingly, when the degree of wear of the tapper T reaches the end of its life at the time of the cut control, the actual cutting load torque applied so that the tapper T is not broken at the time of drawing is suppressed.

According to the present embodiment described in detail above, the following effects can be obtained. (1) The actual cutting applied to the tapper T from the total load torque detected at the time of tapping processing and the reference load torque set for obtaining the load torque increase in the total load torque of the actual cutting load torque applied to the tapper T. Load torque was determined.

Accordingly, the actual cutting load torque can be detected even during acceleration / deceleration in which the inertia of the main shaft 14 or the like is applied as load torque, and it is possible to detect a state where an overload is applied to the tapper T during acceleration / deceleration. it can.

(2) It is possible to detect the actual cutting load torque during deceleration at the time of cutting when the actual cutting load torque applied to the main shaft 14 becomes the maximum, so that the maximum value of the actual cutting load torque can be detected. Therefore, it is possible to accurately determine that the life of the tapper T is the life or the cutting chips are clogged.

Further, even in a high-speed tapping process in which the drive time of the main shaft 14 at a constant rotation speed and a feed speed is extremely short, the actual cutting load torque applied to the tapper T can be detected.

(3) The actual cutting load torque, instead of the load torque increase amount, is directly obtained from the idle operation reference load torque and the total load torque detected when tapping is performed in the idle operation. Accordingly, since the actual cutting load torque is determined, the life of the tool T is determined by the degree of wear.
Alternatively, it is possible to easily determine a state in which cutting chips are clogged.

(4) From the overload judgment value T0 set in advance for the detected actual cutting load torque, the computer 23 determines from the overload judgment value T0 that the cutting chips are clogged and that the degree of wear of the tapper T is the life. to decide. Then, the spindle 14 is decelerated, and the cutting control is stopped while the rotation phase of the spindle 14 and the feed position are synchronized.

Therefore, when the actual wear load torque applied to the tapper T due to the life of the wear of the tapper T during the cutting or the fact that the cutting chips are clogged becomes excessive, the actual force applied to the tapper T is increased. The cutting is stopped in a state where the cutting load torque is suppressed. As a result, it is possible to prevent breakage of the tapper T or damage to the tap hole when the degree of wear of the tapper T reaches the end of its life or the cutting chips are clogged during cutting.

(5) The computer 23 determines that cutting chips are clogged at the time of cutting based on the actual cutting load torque, and decelerates at the second deceleration -α2 smaller than the first deceleration -α1. Control was performed to stop the machine, and the cutting was stopped.

Therefore, when cutting chips are clogged during cutting, cutting is stopped in a state in which clogging of cutting chips is eased. The tapped hole can be prevented from being damaged.

(6) Even when the deceleration control at the time of cutting is in progress, if the detected actual cutting load torque exceeds the overload judgment value T0, the computer 23 sets a value lower than the normal first deceleration -α1. Spindle 14 with small second deceleration-α2
Was controlled to decelerate.

Therefore, in the deceleration process at the time of cutting at which the actual cutting load torque is maximized, the cutting is stopped so that the cutting chips are hardly clogged, so that the tapper T is broken due to the clogging of the cutting chips at the time of cutting and the tap hole is damaged. Can be more reliably prevented.

(7) The computer 23 confirms that the cutting chips are clogged and the actual cutting load torque is excessive.
Has determined based on the actual cutting load torque, and repeatedly performs tapping processing on the tap hole for which tapping processing has been stopped.

Therefore, the tapping process is not stopped but the tapping process is repeatedly performed only when the cutting chips are clogged. Therefore, even if the cutting chips are once clogged at the time of cutting, the tap hole is automatically and securely formed without breaking the tapper T. It can be processed and formed.

(8) If it is determined that the life of the tapper T at the time of cutting is longer than the third life,
The spindle 14 is decelerated and stopped at the deceleration -α3. Therefore, even if the degree of wear of the tapper T reaches the end of its life during cutting, the cutting is stopped in a state where the actual cutting load torque applied to the tapper T is reduced. Of the tap hole and damage to the tapped hole can be prevented.

(9) After stopping the cutting based on the actual cutting load torque, the computer 23 controls the acceleration / deceleration of the spindle 14 with the second acceleration α2 and the second deceleration -α2 smaller than usual, and controls the tapper T. Was pulled out.

Therefore, the actual cutting load applied to the tapper T at the time of pulling out is reduced after the cutting is stopped after the degree of wear of the tapper T reaches the end of its life or cutting chips are clogged and the tapper T is removed. The tapper T can be pulled out without causing breakage and damage to the tap hole.

(10) When the actual cutting load torque exceeds the overload judgment value T0, it is determined that cutting chips are clogged, the cutting control is stopped, and the tapper T is arranged outside the tap hole. After the main shaft 14 is controlled to be pulled out, the tapping process is repeatedly performed on the tap hole during the tapping process. When the number of times that the actual cutting load torque continuously exceeds the overload determination value T0 for each tapping operation on the same tap hole exceeds a preset life determination value CL, it is once again determined that the degree of wear of the tapper T is the life. Judge,
The cutting control of the spindle 14 was stopped, and the tapping process was stopped after the spindle 14 was pulled out.

Therefore, when cutting chips are clogged, tapping of the tap hole during machining can be automatically continued without causing breakage of the tapper T and damage to the tap hole. When the life reaches the level of wear, the tapper T can be pulled out from the tap hole being processed to complete the tapping process.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG.
Note that the present embodiment is different from the first embodiment only in that the control content of the tapping processing in the first embodiment is changed. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Only the control contents of the tapping process will be described in detail.

The procedure of the tapping process performed by the central processing unit 30 will be described with reference to the flowchart of FIG.
In the present embodiment, the main shaft 1 is used as the reference load torque.
The calculated reference load torque value obtained from the inertial mass of the entire rotating unit that rotates together with the rotational speed 4 and the rotational speed of the main shaft 14 is stored in advance.

In step 30, the central processing unit 30 cuts the spindle 14 in a state where the spindle rotation motor 15 and the spindle feed motor 16 are drive-controlled to synchronize the rotation phase and the feed position. Control.
At this time, the central processing unit 30 controls the acceleration and deceleration of the main shaft 14 with the first acceleration α1 and the first deceleration −α1.

In step 31, the central processing unit 30 sequentially calculates the actual cutting load torque obtained by subtracting the calculated reference load torque from the sequentially detected total cutting load torque during the cutting control of the main shaft 14. Then, the central processing unit 30
Determines in step 32 whether the calculated actual cutting load torque exceeds a preset overload determination value T0. In the present embodiment, the overload determination value T0 is set to a value that can determine whether or not the degree of wear of the tapper T is life based on the actual cutting load torque applied to the tapper T at the time of cutting.

When the actual cutting load torque is equal to or less than the overload determination value T0 in step 32, the central processing unit 30 determines that the degree of wear of the tapper T is not the life, and in step 33, controls the cutting control to the tapping end position. Do until.

After performing the cutting control to the tapping end position while the actual cutting load torque is equal to or less than the overload determination value T0, the central processing unit 30 proceeds to steps 34 and 35.
The main shaft 14 is subjected to acceleration / deceleration control at the first acceleration α1 and the first deceleration −α1, and pull-out control is performed from the tapping end position to the tapping start position.

On the other hand, the central processing unit 30 executes step 32
When the actual cutting load torque exceeds the overload determination value T0, it is determined that the degree of wear of the tapper T has progressed to its life,
In step 36, deceleration control is performed with the third acceleration -α3, and the spindle 14 is stopped while the rotation phase and the feed position are kept synchronized.

Then, the central processing unit 30 executes step 3
At 7 and 38, the second acceleration α2 and the second deceleration −α
In step 2, the main shaft 14 is subjected to acceleration / deceleration control, and the main shaft 14 is pulled out from the stopped position on the Z-axis coordinate to the tapping start position. Then, the central processing unit 30 controls the display device 33 in step 39 to display that the life of the tapper T has reached the end of its life.

Therefore, when the central processing unit 30 determines that the load torque due to the life of the wear of the tapper T is applied based on the detected actual cutting load torque, the tapping process is stopped and the spindle 14 is pulled out. After the control, the tapping process is terminated.

The operation of the CNC tapping machine configured as described above will be described. The data of the calculated reference load torque is stored in a computer in advance. The central processing unit 30 obtains the actual cutting load torque from the detected total load torque and the calculated reference load torque during the cutting control.
When the actual cutting load torque calculated sequentially exceeds the overload determination value T0, the central processing unit 30 determines that the wear of the tapper T has reached the end of its life. Then, the spindle 14 is decelerated and stopped at the third acceleration -α3, and the cut control is stopped. Therefore, at the time of cutting, when the degree of wear of the tapper T reaches the end of its life, the cutting is stopped in a state where the load torque applied to the tapper T is suppressed.

According to the CNC tapping machine of the present embodiment described in detail above, the effects described in (1), (2), (8), and (9) in the first embodiment are described below. Can be obtained.

(11) A calculation reference load torque not including the actual cutting load torque is calculated from at least the inertial mass of the rotating part including the main shaft 14 and the rotation speed of the main shaft 14. Then, the actual cutting load torque is directly obtained from the calculated reference load torque and the total load torque detected sequentially.
Therefore, since the actual cutting load torque is directly determined, it can be easily determined that the degree of wear of the tapper T is the life or that the cutting chips are clogged.

(12) The computer 23 determines whether or not the degree of wear of the tapper T is a service life from an overload determination value T0 preset for the detected actual cutting load torque. Then, when the life is over, the spindle 14 is decelerated at the third deceleration -α3, and the cutting control is stopped while keeping the rotation phase and the feed position synchronized. Therefore, when the degree of wear of the tapper T reaches the end of its life during the cutting of the tapper T, the cutting is stopped in a state where the actual cutting load torque applied to the tapper T is suppressed. As a result, even if the degree of wear of the tapper T during the cutting reaches its life,
The tapping process can be stopped without breaking the tapper T or damaging the tap hole.

Hereinafter, embodiments other than the above-described embodiment embodying the present invention will be listed as other examples. In the first embodiment, the idling reference load torque is
Only the machining process including the deceleration process in the cutting process may be set, and the computer 23 may detect the actual cutting load torque in this machining process. Even in this case, the actual cutting load torque applied to the tapper during the deceleration process of the cutting process in which the actual cutting load torque is maximized can be detected, and therefore, it is accurately determined whether the degree of wear of the tapper T is the life. be able to.

Similarly, in the second embodiment, the calculated reference load torque is set only in the machining process including the deceleration process in the cutting process, and the actual cutting load torque in this machining process is detected. Good. In this case, the same effect is obtained.

Instead of using the reference load torque during idle operation or the calculated reference load torque as the reference load, it has the same specifications (tap size, screw pitch amount, etc.) as the tapper T used to detect the actual cutting load torque. The total load torque detected when tapping is actually performed using the tapper T may be used as a reference load (reference total load) torque. Then, the reference total load torque is subtracted from the total load torque detected when detecting the actual cutting load torque, and the load torque increase amount of the actual cutting load torque is obtained. That is, the increase amount of the load torque is an increase amount of the actual cutting load torque corresponding to the difference in the degree of wear of the tapper T. From the amount of increase in the load torque, the tapper T
It may be determined whether or not the degree of wear is the life, or whether or not the cutting waste is clogged.

In the first and second embodiments, the acceleration and deceleration of the main shaft 14 are performed at constant acceleration (α1) and deceleration (−α1). However, the present invention is not limited to this. For example, acceleration and deceleration may be performed at acceleration and deceleration that increase or decrease linearly or quadratically. In this case, the average acceleration or the average deceleration in the acceleration process or the deceleration process may be made smaller or larger. That is, during cutting, when it is determined that the degree of wear of the tapper T is the life, or when it is determined that the cutting chips are clogged, the deceleration process is performed at a smaller average deceleration, and at the time of reverse pulling after stopping, The acceleration and deceleration processes are performed with a larger average acceleration and average deceleration. As a result, when the actual cutting load torque applied to the tapper T during cutting becomes excessive, the increase in the actual cutting load torque applied to the tapper T is reduced to stop, and the tapping T is also applied to the tapper T at the time of reverse drawing after the stop. The actual cutting load torque can be reduced.

A tapping machine in which the work table is fixed so as not to move in the X-axis and Y-axis directions and the main shaft 14 is controlled to be positioned in the X-axis, Y-axis and Z-axis directions, and the work table is in the X-axis and Y-axis directions. And a tapping machine whose position is controlled in the Z-axis direction.

The present invention is not limited to a CNC tapping machine that is a soft-wired NC, but may be implemented on a hard-wired NC machine. The present invention is not limited to a tapping machine that is a single-purpose NC machine, but may be implemented on a tapping machine such as an NC machining center (combined NC machine) having a synchronous tapping function.

Hereinafter, in addition to the inventions described in the claims, the technical ideas grasped from the above-described embodiment or each of the examples will be described together with their effects. (1) In the invention as set forth in claim 1, the reference load is set only in a machining process including a deceleration process in a cutting process, and the actual cutting load detecting means includes an actual cutting load or a load increase amount in the machining process. Is detected. Even with such a configuration, it is possible to detect the actual cutting load applied to the tapper in the deceleration process of the cutting process in which the actual cutting load is maximized.

(2) In the invention according to claim 6,
The spindle control means, when it is determined that cutting chips are clogged, even during the deceleration control of the spindle, the spindle at a deceleration smaller than a preset deceleration. Is decelerated. According to such a configuration, even in the deceleration process at the time of cutting at which the actual cutting load is maximized, the cutting can be stopped in a state where the cutting load applied to the tapper when the cutting chips are clogged is suppressed, The breakage of the tapper and the damage of the tap hole can be more reliably prevented.

(3) In the invention according to claim 5,
When the actual cutting load exceeds the overload determination value, the overload detection means determines that the cutting chips are clogged, and the spindle control means determines that the cutting chips are clogged. When it is determined, the cutting control of the spindle is stopped, and after the spindle is pulled out until the tapper is arranged outside the tap hole, the tapping process is repeatedly performed on the tap hole during the tapping process. When the number of times that the cutting waste is continuously determined to be in the clogged state exceeds the preset number (lifetime determination value CL), the cutting control of the spindle is stopped, and the spindle is pulled out. After that, the tapping process is stopped.
According to such a configuration, when cutting chips are clogged,
Tapping processing can be automatically performed on the tap hole during processing without causing breakage of the tapper or damage to the tap hole, and when the degree of wear of the tapper reaches the end of its life during cutting, the The tapping process can be terminated by pulling out the tapper from the tape.

(4) In the invention according to claim 8,
The spindle control means, when it is determined that the degree of wear of the tapper is the life, even during the deceleration control of the spindle, the spindle with a deceleration larger than a preset deceleration. Is decelerated. According to such a configuration, even in the deceleration process at the time of cutting at which the actual cutting load is maximized, the cutting is stopped in a state where the actual cutting load applied to the tapper is reduced when the life of the tapper reaches the end of its life. Accordingly, breakage of the tapper at the time of cutting and damage to the tap hole can be more reliably prevented.

[0115]

As described in detail above, according to the first to ninth aspects of the present invention, the amount of increase in the actual cutting load applied to the tapper even during acceleration / deceleration of the spindle for driving the tapper is detected. be able to.

In addition, according to the second and third aspects of the present invention, since the actual cutting load is directly obtained, it is possible to easily determine the degree of wear of the tapper and the state of clogging of the cutting chips.

In addition, according to the invention of claim 4, it is possible to detect the increase in the actual cutting load without performing the idle operation or the load calculation. In addition, according to the invention of claim 5, when the actual cutting load applied to the tapper during cutting becomes excessive, tapping can be stopped without causing breakage of the tapper or damage to the tap hole. .

In addition, according to the invention as set forth in claim 6, even if cutting chips are clogged during cutting, breakage of the tapper or damage to the tap hole can be reliably prevented. In addition, according to the invention of claim 7, when cutting chips are clogged during cutting, tapping to the tap hole being processed can be automatically continued without causing breakage of the tapper or damage to the tap hole. it can.

In addition, according to the invention as set forth in claim 8, when the degree of wear of the tapper reaches the end of its life during cutting, the tapper can be cut from the tap hole being processed without causing breakage of the tapper or damage to the tap hole. Can be pulled out.

In addition, according to the ninth aspect of the present invention, when the degree of wear of the tapper reaches the end of its life during cutting and when cutting chips are clogged, the tapper is not broken and the tap hole is not damaged. And the tapping process can be stopped.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a control procedure of tapping processing according to a first embodiment.

FIG. 2 is a schematic configuration diagram of a CNC tapping machine.

FIG. 3 is a graph showing the time characteristics of the total load torque and the spindle speed during tapping.

FIG. 4 is a graph showing time characteristics of a reference load torque and a spindle speed during idling.

FIG. 5 is a graph showing time characteristics of actual cutting load torque and spindle speed.

FIG. 6 is a graph showing a control state of a spindle rotation speed and a time characteristic of an actual cutting load torque when cutting is stopped.

FIG. 7 is a graph showing a control state of a spindle rotation speed and a time characteristic of an actual cutting load torque when cutting is stopped.

FIG. 8 is a graph showing a control state of a spindle rotation speed and a time characteristic of an actual cutting load torque when cutting is stopped.

FIG. 9 is a graph showing a control state of a spindle rotation speed and a time characteristic of an actual cutting load torque when cutting is stopped.

FIG. 10 is a graph showing time characteristics of actual cutting load torque and spindle speed during conventional tapping processing.

FIG. 11 is a flowchart showing a control procedure at the time of tapping processing according to the second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... CNC tapping machine as a tapping device, 14 ... Spindle, 15 ... Spindle rotation motor, 23 ... Computer as overload determination means and spindle control means constituting actual cutting load detection means, 25 ... Actual cutting load detection means T: Tapper, T0: Overload determination value, α1: first rotational acceleration, −α1: first rotational deceleration, α2: second rotational acceleration, −α2: second Rotational deceleration, -α3 ... third rotational deceleration.

 ──────────────────────────────────────────────────続 き Continuation of the front page (71) Applicant 000205454 Osaka Kiko Co., Ltd. 3-21-9 Toyosaki, Kita-ku, Osaka-shi, Osaka (71) Applicant 000006013 Mitsubishi Electric Corporation 2-2-2 Marunouchi, Chiyoda-ku, Tokyo No. (71) Applicant 000114787 Yamazaki Mazak Co., Ltd. 1st boarding, Oguchi-machi, Oguchi-cho, Niwa-gun, Aichi Prefecture (72) Inventor Yoshiaki Kakino 256-5 Iwakura Hanazonocho, Sakyo-ku, Kyoto-shi, Kyoto (72) Inventor Makoto Fujishima Nara 106 Mori Seiki Seisakusho Co., Ltd. (72) Inventor Hisashi Otsubo 1160 Hamanaka Oaza, Satosho-gun, Okayama Prefecture Yasuda Industry Co., Ltd. (72) Inventor Hideo Nakagawa Kita Itami-shi, Hyogo 8-10 Itami, Osaka Kiko Co., Ltd. (72) Inventor Torao Takeshita 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric (72) Inventor Yoshinori Yamaoka, Yamaguchi Mazak Co., Ltd.

Claims (9)

[Claims] 1. A tapping device for controlling a feed position of a spindle to which a tapper is fixed and a rotation phase in synchronization with each other, and detecting a load applied to a spindle rotation motor. A tapping device comprising: an actual cutting load detecting unit that detects an actual cutting load applied to the tapper or a load increase amount of the actual cutting load from a preset reference load. 2. The method according to claim 1, wherein the reference load is an idle operation reference load detected when tapping is performed in the idle operation, and the actual cutting load detection unit includes the total load and the idle operation reference load. 2. The difference between the actual cutting load and the actual cutting load.
3. The tapping device according to claim 1. 3. The reference load is a calculated reference load obtained from at least a total inertial mass of a rotating part including the main shaft and a rotation speed of the main shaft, and the actual cutting load detecting means includes:
The tapping device according to claim 1, wherein a difference between the total load and the calculation reference load is set as the actual cutting load. 4. The reference load is a reference total load detected when tapping is actually performed by the tapper, and the actual cutting load detection unit is configured to determine a difference between the total load and the reference total load. The tapping device according to claim 1, wherein a difference is defined as the load increase amount. 5. A method for determining whether or not the degree of wear of the tapper is a life, by using a preset overload determination value based on one of the actual cutting load and the load increase amount, or Overload determining means for determining whether or not is in a clogged state, acceleration and deceleration control of the spindle, cutting and pulling out of the tapper, the wear degree of the tapper is life, or When it is determined that cutting chips are clogged, spindle control means for decelerating the spindle and stopping cutting of the tapper while keeping the rotation phase of the spindle and the feed position synchronized. The tapping device according to any one of claims 1 to 4, comprising: 6. The spindle control means according to claim 5, wherein, when it is determined that cutting chips are clogged, the spindle is decelerated at a smaller deceleration to stop cutting of the tapper. Tapping equipment. 7. When the spindle control means determines that the cutting chips are clogged, the spindle control means decelerates the spindle to stop cutting the tapper, and accelerates / decelerates the spindle to control the spindle. 6. The tapping device according to claim 5, wherein after tapping the tapper from the tap hole being processed, tapping processing is repeatedly performed on the tap hole. 8. The spindle control device according to claim 5, wherein when it is determined that the wear of the tapper is a life, the spindle control means controls the spindle to decelerate at a larger deceleration to stop the cutting of the tapper. Tapping equipment. 9. The spindle control device according to claim 5, wherein said spindle control means controls said spindle to decelerate at a smaller acceleration / deceleration after said deceleration control to stop said cutting, and pulls out said tapper. The tapping device according to claim 1.