JPH1020911A - Tool length correcting method for numerical controller, work center position detecting method, and tool wear degree estimating method and numerical controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct a length of a tool without adding a sensor to a numerical controller by moving a tool holding shaft axially from a measurement start coordinate position and detecting the tip of the tool abutting against a collision surface plate from variation of a motor load current of a tool holding shaft, and calculating a tool length correction quantity and automatically making corrections. SOLUTION: The tool holding shaft is positioned at the measurement start position (step 18) and while the tool holding shaft is moved at a tool length measurement speed toward the collision surface plate along an X axis (step S19), the motor load current of the tool holding shaft is detected (step S20) to decide whether or not the motor load current exceeds a collision detection load current level (step S21). Then when the collision detection load current level is exceeded, the tool holding shaft is moved reversely at a fast-forward speed (step S22), the X coordinate value of the position where the tip of the tool abuts against the plane of the collision surface is read out (step S23), and the tool length correction quantity is calculated from the difference from the X-axial coordinate value of the measurement start position (step S24).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting a tool length for an automatic tool set in a numerical control device, a method for detecting a center position of a workpiece, a method for estimating a degree of tool wear, and a numerical control device.

[0002]

2. Description of the Related Art FIG. 35 shows a conventional example of a numerical controller. The numerical control device 1 includes a machining program analysis processing unit 10, a memory 20 for storing a machining program, a parameter setting unit 21, a screen display processing unit 22, an interpolation processing unit 30, a machine control signal processing unit 50, , A ladder circuit section 55 forming a sequence circuit, an axis control section 60 provided for each movable axis, and an axis movement amount input / output circuit 70.

[0003] A servo control unit 80 for each movable axis of each system is connected to the axis movement input / output circuit 70, and a servo motor 90 for each movable axis is connected to each servo control unit 80. Although not shown in FIG.
Has a pulse generator for position detection, and the servo control unit 80 has a position loop based on a position feedback signal from the pulse generator.

In the numerical controller 1, a processing program read from a tape reader or the like is stored in a memory 20. When executing the machining program, the machining program is read from the memory 20 one block at a time, and the machining program is analyzed and processed by the machining program analysis processing unit 10 to calculate the end point position and the like of each block. This end point position is processed by the interpolation processing means 31 of the interpolation processing unit 30, and the end point position is distributed to movement commands per unit time of each movable axis.

The movement command is converted into a movement command per unit time in consideration of acceleration / deceleration in accordance with an acceleration / deceleration pattern specified in advance by an acceleration / deceleration process by the axis control unit 60. It is output to the unit 80 as a servo movement command.

The servo control unit 8 receives the servo movement command.
0 gives a rotation command to a servomotor 90 attached to a machine tool (not shown).

[0007] A machine signal such as turning on / off the cutting oil is processed by a machine control signal processing unit 50 via a ladder circuit unit 55 for describing machine control, and a processing result is transmitted to an interpolation processing unit 30.

The acceleration / deceleration time constants and the like of each movable axis set by key input means (not shown) are set in a parameter setting section 2.
1 is processed and stored in the memory 20. The parameters and the like stored in this way are displayed on a display (not shown) by the screen display processing unit 22, so that the contents of the parameters and the like can be confirmed.

In order to automatically perform tool length correction, the tool T
A sensor 100 (see FIG. 36) is provided by a piezoelectric element or the like for detecting that the tip of the sensor has been abutted. The numerical controller 1 receives a signal from the sensor 100, and outputs a sensor signal input circuit 101, a sensor signal And a sensor input processing unit 102 for performing the input processing of.

The machining program analyzing unit 10 includes a tool length correction command analyzing unit 12 in addition to the machining program analyzing unit 11, and the interpolation processing unit 30 includes a correction amount calculating unit 32.
The axis control unit 60 is provided with a movement amount canceling unit 61 and a position detecting unit 62 that takes in coordinate position information from the servo control unit 80 via an axis movement amount input / output circuit 70.

Here, the tool length direction of the tool T is X
Let it be in the axial direction. Thus, the movement amount canceling means 61 and the position detecting means 62 are provided in the X-axis axis control unit 60.

In the numerical controller 1, when the machining program analyzing means 11 analyzes the tool length correction command analysis, which is one program command, the tool holding axis (X axis) starts measurement as shown in FIG. Then, the tool holding axis moves in the X-axis direction toward the sensor 100.

When the tip of the tool T mounted on the tool holding shaft collides with the sensor 100, the collision is detected.
The moving amount canceling means 6
1 immediately stops the X-axis movement and cancels the remaining X-axis movement command, and the correction amount calculating means 32
2, the tool length correction amount is calculated from the difference between the X axis coordinate value Xa at the tool length measurement point and the X axis coordinate value Xo at the measurement start position. This automatically corrects the tool length.

[0014]

In the tool length compensation in the conventional numerical controller, a dedicated sensor is used for the tool length measurement, that is, only for the tool length measurement for the tool length compensation. A sensor is required, and a special hardware configuration that configures a sensor signal input circuit and a sensor input processing unit that captures sensor signals is added to the numerical control device in addition to the normal hardware configuration for axis control. There is a problem that must be done.

In a lathe or the like, when a bar-shaped workpiece (hereinafter, sometimes referred to as a workpiece) having a circular cross section is rotated around its own central axis by a main shaft and turned with a bite tool or the like, a bite tool is used. It is necessary that the blade edge position of the work coincides with the center position of the work.However, with the conventional numerical control device, the center position of the work cannot be automatically detected without using a special measuring device. There is a problem that it cannot be automated to match the cutting edge position of the cutting tool with the center position of the work.

In the conventional numerical control device, the degree of wear of the tool cannot be detected unless a special measuring device including an image processing means is used. However, there is a problem that considerable experience is required.

The present invention has been made in view of the above-described problems, and measures the tool length without adding a special sensor, a measuring device, or a special hardware configuration to the numerical control device. It is an object of the present invention to provide a method for performing tool length correction, a method for detecting a center position of a workpiece, a method for estimating a degree of wear of a tool, and a numerical control device used for implementing these methods.

[0018]

In order to achieve the above-mentioned object, a method for correcting a tool length in a numerical control apparatus according to the present invention comprises moving a tool holding axis from a predetermined measurement start coordinate position and holding the tool holding tool. It is detected from the change in the motor load current of the tool holding shaft that the tip of the tool mounted on the shaft collides with the facing surface portion provided by the collision face plate or the workpiece, and the coordinates of the tool holding shaft at the time of the collision are detected. The tool length correction amount is calculated from the difference between the value and the coordinate value of the measurement start coordinate position, and the tool length is automatically corrected based on the tool length correction amount.

In the method of correcting a tool length in the numerical control device according to the present invention, the motor of the tool holding shaft detects that the tip of the tool mounted on the tool holding shaft has collided with the collision surface plate or the opposing surface provided by the workpiece. Detecting from the change in load current, calculating the tool length correction amount from the difference between the coordinate value of the tool holding axis at the time of the collision and the coordinate value of the measurement start coordinate position,
The tool length is automatically corrected based on the tool length correction amount.

A tool length correcting method in the numerical control device according to the next invention is such that in the above-described tool length correcting method, the tool holding axis is moved in the opposite direction at a high speed immediately after the collision is detected.

In the tool length correcting method in the numerical controller according to the present invention, the tool holding shaft moves at a high speed in the opposite direction immediately after the collision is detected, thereby preventing chipping of the tool edge.

According to a second aspect of the present invention, there is provided a tool length correcting method according to the above-described tool length correcting method, wherein the opposing surface portion is provided by a collision face plate which is axially movable in the same direction as the axial direction of the tool holding shaft. The tool holding shaft is moved by a full stroke or a predetermined stroke to sample the motor load current of the tool holding shaft, and the sampling detects a stroke region where the motor load current does not fluctuate much. The arrangement position is adjusted by axially moving the collision face plate so that the tool tip collides with the face plate, and the measurement start coordinate position is set accordingly.

In the tool length correcting method in the numerical controller according to the present invention, the tip of the tool collides with the collision face plate in a stroke region where the motor load current does not fluctuate much, and this collision detection is accurately performed.

A tool length correcting method in a numerical control device according to the present invention is the above tool length correcting method, wherein the opposed surface portion is provided from a workpiece, and the axis of the tool holding shaft is adjusted according to the material of the workpiece. This is for setting the moving speed.

In the tool length correcting method in the numerical controller according to the present invention, the axis moving speed of the tool holding shaft is set in accordance with the material of the workpiece, and the collision detection is accurately performed regardless of the material of the workpiece. Done in

A tool length correcting method in a numerical control device according to the present invention is the above-described tool length correcting method, wherein the tool holding axis is moved to the measurement start coordinate position before the tip of the tool collides with the facing surface portion. The tool holding shaft is moved at a high speed, and thereafter, the tool holding shaft is moved at a low speed so that the tool cutting edge collides with the facing surface portion.

In the tool length correction method in this numerical controller, the tool holding axis is moved at high speed to the measurement start coordinate position before the tip of the tool collides with the facing surface. As a result, fluctuations in the motor load due to the feed screw mechanism are reduced, and collision detection is accurately performed.

[0028] The tool length correcting method in the numerical control device according to the next invention is the above tool length correcting method, wherein the tool holding axis is moved for a predetermined time before the tool tip collides with the opposing surface portion. The shaft is moved to warm up the feed screw mechanism of the tool holding shaft.

In the tool length correction method in this numerical controller, the feed screw mechanism of the tool holding shaft is warmed up before the tip of the tool collides with the facing surface. As a result, motor load fluctuations caused by the feed screw mechanism are reduced, and collision detection is accurately performed.

A tool length correcting method in a numerical control device according to the present invention is the above tool length correcting method, wherein the opposed surface portion is provided by a rod-shaped workpiece having a circular cross section, and the workpiece is rotated. In this state, the tool tip is caused to collide with the outer peripheral surface of the workpiece.

In the tool length correcting method in the numerical controller according to the present invention, the collision is detected by colliding the tip of the tool with the outer peripheral surface of the workpiece while rotating the workpiece. As a result, collision detection is accurately performed.

A tool length correcting method in a numerical control device according to the present invention is the above-mentioned tool length correcting method, wherein the opposed surface portion is provided by a rod-shaped workpiece having a circular cross section, and the spindle motor rotates the workpiece. In a state where the servomotor is locked, the load current of the spindle motor is detected, and the tool edge is caused to collide with the outer peripheral surface of the workpiece at a position radially offset by a predetermined amount from the center position of the workpiece. In addition, the change of the motor load current of the tool holding shaft and the change of the motor load current of the main shaft are used to detect that the tool tip collides with the outer peripheral surface of the workpiece.

In the tool length correcting method in the numerical control device according to the present invention, the change in the motor load current of the tool holding shaft and the change in the motor load current of the main shaft can prevent the tool tip from colliding with the outer peripheral surface of the workpiece. To detect.

In the tool length correcting method in the numerical control device according to the next invention, the tool holding axis is moved by a predetermined amount to cut a workpiece by a tool mounted on the tool holding axis, and the tool before cutting is used. The tool length correction amount is calculated from the deviation between the actual cutting amount due to the difference between the dimension of the workpiece and the dimension of the workpiece after cutting and the command cutting amount obtained from the axis movement command value of the tool holding axis. The tool length is automatically corrected based on the tool length correction amount.

In the method of correcting a tool length in the numerical control device according to the present invention, the actual cutting amount and the axis movement command value of the tool holding axis are determined by the difference between the dimension of the workpiece before cutting and the dimension of the workpiece after cutting. The tool length correction amount is calculated from the deviation from the command cutting amount obtained from the above, and the tool length is automatically corrected based on the tool length correction amount.

A method of detecting the center position of a workpiece in a numerical control device according to the present invention detects a load current of the spindle motor in a state where a spindle motor for rotating a bar-shaped workpiece having a circular cross section is servo-locked. The axis of the tool holding shaft is moved to cause the tip of the tool mounted on the tool holding shaft to collide with the outer peripheral surface of the workpiece. Detecting the offset direction of the tool holding axis with respect to the center axis of the workpiece, moving the tool holding axis in a direction in which the offset amount is reduced, and detecting the tool holding axis based on the polarity of increase / decrease change of the spindle motor load current at the time of collision. , The center position of the workpiece is detected from the position where the polarity of the increase / decrease change of the spindle motor load current is reversed.

In the method for detecting the center position of a workpiece in the numerical control apparatus according to the present invention, the polarity of the increase or decrease of the load current of the spindle motor when the tip of the tool collides with the outer peripheral surface of the workpiece is determined. Detecting the offset direction of the tool holding axis with respect to the center axis, moving the tool holding axis in the direction in which the offset amount decreases, and detecting the offset direction of the tool holding axis from the polarity of increase / decrease change of the spindle motor load current at the time of collision. The center position of the workpiece is repeatedly detected from the position where the polarity of the increase / decrease change of the spindle motor load current is reversed.

In the method for detecting the center position of a workpiece in a numerical controller according to the next invention, a tool holding shaft is moved in a radial direction with respect to a rod-shaped workpiece having a circular cross section, and the tool is mounted on the tool holding shaft. The collision of the side surface of the tool with the outer peripheral surface of the workpiece is detected from a change in the motor load current of the tool-holding shaft, and the machining of the workpiece is performed based on the radial coordinate value of the tool-holding shaft at the time of the collision. It calculates the center position of an object.

In the method for detecting the center position of the workpiece in the numerical controller according to the present invention, the fact that the side surface of the tool collides with the outer peripheral surface of the workpiece is detected from the change in the motor load current of the tool holding shaft. The center position of the workpiece is calculated from the radial coordinate value of the tool holding shaft at the time of the collision.

A method for estimating the degree of tool wear in a numerical control device according to the present invention is characterized in that the tool holding shaft is moved axially, and that the tip of the tool mounted on the tool holding shaft collides with the workpiece. The motor load current of the retained shaft is detected, and the degree of wear of the tool is estimated from the rate of change of the motor load current at the time of the collision.

In the method for estimating the degree of wear of the tool in the numerical controller according to the present invention, the degree of wear of the tool is estimated from the rate of change of the motor load current when the tip of the tool collides with the workpiece.

According to a second aspect of the present invention, there is provided a method for estimating the degree of tool wear in the numerical control device, wherein the method for estimating the degree of tool wear based on the rate of change of the motor load current is based on the material of the workpiece. This is performed based on data indicating the correlation between the current change rate and the tool wear degree set for each.

In the method for estimating the degree of tool wear in the numerical controller according to the present invention, the motor load current is changed based on the data indicating the correlation between the current change rate set for each material of the workpiece and the degree of tool wear. Estimate the degree of tool wear from the rate.

In order to achieve the above object, a numerical control device according to the present invention comprises a tool length measurement command analyzing means for analyzing a tool length measurement command for axially moving a tool holding axis from a predetermined measurement start coordinate position. And the tip of the tool mounted on the tool holding shaft is given by the collision face plate or the workpiece in the axis movement of the tool holding shaft by the tool length measurement command from the change in the motor load current of the tool holding shaft. Collision detection means for detecting collision with the opposing surface portion, and correction amount calculation means for calculating a tool length correction amount from the difference between the coordinate value of the tool holding axis at the time of the collision and the coordinate value of the measurement start coordinate position. The tool length is automatically corrected based on the tool length correction amount calculated by the correction amount calculating means.

In the numerical controller according to the present invention, the tool length measurement command analysis means analyzes the tool length measurement command, and the collision detection means determines whether the tip of the tool has a collision face plate or a workpiece due to a change in the motor load current of the tool holding shaft. The collision amount is detected by the object and the correction amount calculation means calculates the tool length correction amount from the difference between the coordinate value of the tool holding axis and the coordinate value of the measurement start coordinate position at the time of the collision. The tool length is automatically corrected based on the tool length correction amount calculated by the correction amount calculation means.

The numerical control device according to the present invention is a numerical control device provided by a collision face plate capable of axially moving the opposed surface portion in the same direction as the axial movement direction of the tool holding shaft. Alternatively, a sampling mode command analysis means for analyzing a sampling mode command for sampling the motor load current of the tool holding axis by moving the axis by a predetermined stroke, and a motor sampled in the full stroke or the predetermined stroke of the axis movement by the sampling mode command Sampling current analysis means for detecting a stroke region where the motor load current fluctuates less than the load current, and a collision surface plate axis for performing an interpolation process for axially moving the collision surface plate so that the tool tip collides with the collision surface plate in the stroke region. Moving interpolation processing means It is intended.

In the numerical control device according to the present invention, the sampling current analysis means detects a stroke area where the motor load current does not fluctuate much, and the collision face plate axis movement interpolation processing means collides the tool tip with the collision face plate in the stroke area. Interpolation processing for axially moving the collision face plate as described above.

The numerical control device according to the present invention is the numerical control device, wherein the opposed surface portion is provided by a workpiece, wherein the measurement area feed for setting the axis moving speed of the tool holding shaft according to the material of the workpiece. It has speed setting means.

In the numerical control device according to the present invention, the measurement area feed speed setting means sets the axis moving speed of the tool holding shaft according to the material of the workpiece.

The numerical control device according to the next invention is the numerical control device according to the above-described numerical control device, wherein the high-speed feed is added to move the tool holding axis to the measurement start coordinate position at high speed before the tool tip collides with the facing surface portion. Means.

In the numerical control device according to the present invention, the high-speed feed adding means moves the tool holding axis to the measurement start coordinate position at high speed before the tip of the tool collides with the facing surface portion.

The numerical control device according to the next invention is the numerical control device according to the above-mentioned numerical control device, wherein the tool holding shaft is moved for a predetermined time before the tip of the tool collides with the facing surface portion. It has a warm-up means for warming up the feed screw mechanism of the holding shaft.

In the numerical controller according to the present invention, before the warm-up means causes the tip of the tool to collide with the facing surface portion, the tool holding shaft is moved for a predetermined time to feed the tool holding shaft. Warm up the screw mechanism.

The numerical control apparatus according to the present invention is the numerical control apparatus according to the above-mentioned numerical control apparatus, wherein the tip of the tool is formed by rotating the workpiece having a circular cross section which forms the facing surface. Is detected to collide with the outer peripheral surface of the.

In the numerical controller according to the present invention, the collision detecting means detects that the tip of the tool collides with the outer peripheral surface of the workpiece while rotating the workpiece having a circular cross section which forms the facing surface.

In the numerical control device according to the next invention, in the numerical control device described above, the collision detection means may be in a state in which a spindle motor for rotating a bar-shaped workpiece having a circular cross section formed by the facing surface portion is servo-locked. The change in the load current of the spindle motor and the change in the motor load current of the tool-holding shaft in step (1) detect that the tool tip has collided with the outer peripheral surface of the workpiece.

In the numerical controller according to the present invention, the collision detecting means detects a change in the load current of the spindle motor in a state where the spindle motor for rotating the bar-shaped workpiece having a circular cross section as the facing surface is servo-locked. A change in the motor load current of the tool holding shaft detects that the tip of the tool collides with the outer peripheral surface of the workpiece.

A numerical controller according to the next invention moves a tool holding shaft by a predetermined amount, cuts a workpiece with a tool mounted on the tool holding shaft, and measures a dimension of the workpiece before cutting. A tool length correction infeed / measurement command analyzing means for analyzing a tool length correction infeed / measurement command for measuring a tool length correction infeed / measurement command for measuring a workpiece length after cutting, Compensation amount calculation for calculating a tool length compensation amount from a deviation between an actual cutting amount due to a difference between a dimension of a workpiece and a dimension of a workpiece after cutting and a command cutting amount obtained from an axis movement command value of the tool holding axis. Means for automatically correcting the tool length based on the tool length correction amount calculated by the correction amount calculating means.

In the numerical controller according to the present invention, the infeed / measurement command analyzing means for tool length correction analyzes the infeed / measurement command for tool length correction, and the correction amount calculating means provides the dimensions of the workpiece before cutting and the cutting. A tool length correction amount is calculated from a deviation between an actual cutting amount based on a difference between a size of a workpiece to be subsequently processed and a command cutting amount obtained from an axis movement command value of a tool holding shaft. The tool length is automatically corrected based on the tool length correction amount calculated by the correction amount calculation means.

The numerical controller according to the next invention comprises a work center determination command analyzing means for analyzing a work center determination command for determining a work center, and a rod-shaped workpiece having a circular cross section being rotated by the work center determination command. Detecting the load current of the spindle motor with the spindle motor to be servo-locked, moving the tool holding shaft, and causing the tip of the tool mounted on the tool holding shaft to collide with the outer peripheral surface of the workpiece. The offset direction of the tool holding axis with respect to the center axis of the workpiece is detected from the polarity of the increase / decrease change in the load current of the spindle motor at the time of the collision, and the tool holding axis is moved in a direction in which the offset amount decreases. The detection of the offset direction of the tool holding axis is repeated from the polarity of the increase / decrease of the spindle motor load current at the time of collision, and the polarity of the increase / decrease of the spindle motor load current is reversed. The more that the position in which and a workpiece center determination means for detecting the center position of the workpiece.

In the numerical control device according to the present invention, the work center determination command analyzing means analyzes the work center determination command,
The work center is determined by the polarity of the increase or decrease in the load current of the spindle motor when the tip of the tool collides with the outer peripheral surface of the workpiece in a state where the spindle motor for rotating the workpiece is servo-locked. Detecting the offset direction of the tool-holding axis with respect to the center axis of the object, moving the tool-holding axis in a direction in which the offset amount decreases, and determining the offset direction of the tool-holding axis based on the polarity of the increase or decrease in the spindle motor load current at the time of collision And the center position of the workpiece is detected from the position where the polarity of the increase / decrease change of the spindle motor load current is reversed.

A numerical controller according to the next invention comprises a work center calculation command analyzing means for analyzing a work center calculation command for calculating a work center, and a bar-shaped workpiece having a circular cross section in response to the work center calculation command. The tool holding shaft is moved in the radial direction, and the collision of the side surface of the tool mounted on the tool holding shaft with the workpiece is detected from a change in the motor load current of the tool holding shaft. And a work center calculating means for calculating a center position of the workpiece from a radial coordinate value of the tool holding shaft.

In the numerical control device according to the present invention, the work center calculation command analyzing means analyzes the work center calculation command,
The work center calculating means moves the tool holding shaft in the radial direction with respect to the workpiece and detects that the side surface of the tool collides with the workpiece from a change in the motor load current of the tool holding shaft. The center position of the workpiece is calculated from the radial coordinate value of the tool holding shaft at the time.

A numerical control device according to the next invention is a tool wear degree estimation command analyzing means for analyzing a tool wear degree estimation command for estimating a tool wear degree, and a tool holding axis is axially moved based on the tool wear degree estimation command. Detecting that the tip of the tool mounted on the tool-holding shaft has collided with the workpiece by detecting the motor load current of the tool-holding shaft, and determining the wear rate of the tool from the rate of change of the motor load current at the time of the collision. Wear degree estimating means for estimating the degree.

In the numerical control device according to the present invention, the tool wear degree estimating command analyzing means analyzes the tool wear degree estimating command, and the wear estimating means outputs the motor load current when the tip of the tool collides with the workpiece. From the rate of change of the tool.

In the numerical controller according to the next invention, in the numerical controller described above, the wear degree estimating means indicates a correlation between a current change rate and a tool wear degree set in advance for each material of the workpiece. The tool wear degree is estimated based on the data.

In the numerical controller according to the present invention, the wear degree estimating means estimates the tool wear degree based on the data indicating the correlation between the current change rate and the tool wear degree set in advance for each material of the workpiece. I do.

[0068]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the embodiments of the present invention described below, the same components as those of the above-described conventional example are denoted by the same reference numerals as those of the above-described conventional example, and description thereof will be omitted.

(Embodiment 1) FIG. 1 shows a numerical control apparatus according to Embodiment 1 of the present invention.

The tool holding axis in the numerical control device 1 is the X axis, and the collision face plate 2 can be axially moved in the same direction as the X axis.
00 (see FIG. 2). Impact face plate 200
Is made of a metal plate or the like, and has a plane 201 orthogonal to the X axis and facing the tool T of the tool holding axis. Here, the movable axis of the collision face plate 200 is the W axis.

The numerical control device 1 allows the machining program analysis unit 10 to move the tool holding axis (X axis) by a full stroke or a predetermined stroke in addition to the machining program analysis means 11 to thereby reduce the motor load of the tool holding axis. A sampling mode command analyzing means for analyzing a sampling mode command for sampling a current; and a tool length measuring command analyzing means for analyzing a tool length measuring command for axially moving a tool holding axis from a predetermined measurement start coordinate position. ing.

The interpolation processing unit 30 includes, in addition to the interpolation processing means 31, a correction amount calculation means 32, a sampling current analysis means 33, and a collision face plate axis movement interpolation processing means 34.

The axis control unit 60 for the X axis has a moving amount canceling unit 61, a position detecting unit 62, a servo current value inputting unit 63, a current value sampling unit 64, and a collision detecting unit 65. I have.

The numerical control device 1 is provided with a servo current value input circuit 71 for inputting a load current (hereinafter, sometimes referred to as a servo current value) of the X-axis servo motor 90. The servo current value input by the circuit 71 is provided to the current value sampling means 64 and the collision detection means 65 via the servo current value input means 63 of the X-axis axis control unit 60.

The current value sampling means 64 operates by analyzing the sampling mode command by the sampling mode command analysis means 13, and stores the motor current value sampled in the X-axis movement of the tool holding axis over the entire stroke or a predetermined stroke in the memory 20. Write to.

The sampling current analysis means 33 calculates a servo current value from a servo current value (data string of the servo current value written in the memory 20) over the entire stroke or the axis movement of a predetermined stroke by the sampling mode command. A stroke region in which a change in the current value is small is detected.

The fluctuation of the servo current value here has a characteristic as illustrated in FIG. 3, and the fluctuation of the servo current value is mainly caused by a return pipe type or a deflector forming the feed screw mechanism of the tool holding shaft. This is caused by the resistance fluctuation when the ball of the ball screw nut of the formula circulates. This is caused when the feed screw starts moving (when ball circulation of the ball screw nut starts) or when the lubricating oil temperature is low and low. It will be noticeable.

The collision face plate axis movement interpolation processing means 34 performs interpolation processing for moving the collision face plate 200 in the W axis such that the tool tip collides with the collision face plate 200 in the stroke area detected by the sampling current analysis means 33.

The tool holding axis is the tool length measurement command analysis means 14
The X-axis moves from the predetermined measurement start coordinate position by the analysis of the tool length measurement command according to the above. The collision detection means 65 takes in the servo current value from the servo current value input means 63 under the X-axis movement, and It is detected from the change that the tip of the tool T has collided with the plane (opposed surface portion) 201 of the collision surface plate 200. The measurement start coordinate position is variably set to an appropriate position according to the arrangement position of the collision face plate 200.

The detection that the tip of the tool T has collided with the plane 201 of the collision face plate 200 based on the change in the servo current value indicates that the load current has exceeded the collision detection level, as shown in FIG. 4 or as shown in FIG. 4B, the detection is performed when the rate of increase of the load current exceeds a predetermined value, and the collision detection level or the like is variably set to an appropriate value from the result of sampling the load current. be able to.

The movement amount canceling means 61 detects the tip of the tool T by the collision detecting means 65 so that the tip of the tool T
1 is detected, the X-axis movement is immediately stopped to cancel the remaining X-axis movement command, and the correction amount calculating means 32 outputs the position detecting means 62 when the axis stops.
X-axis coordinate value detected by, ie, X at the tool length measurement point
The tool length correction amount is calculated from the difference between the axis coordinate value Xa and the X-axis coordinate value Xo of the measurement start position.

The interpolation processing section 30 automatically corrects the tool length based on the tool length correction amount calculated by the correction amount calculating means 32.

Next, referring to a flow chart shown in FIG. 5, a description will be given of a procedure for implementing a tool length correcting method by the numerical controller having the above-described configuration.

When the current sampling mode is designated (step S10), the collision face plate 200 is retracted (step S11), the tool holding axis is moved along the X axis over the entire stroke, and the current value sampling means 64 holds the tool. The motor load current of the shaft is sampled and registered in the memory 20 (step S12).

Next, the sampling load current of all strokes written in the memory 20 is analyzed by the sampling current analyzing means 33 to detect a stroke area where the servo current value is less varied (step S13).

Next, the collision face plate axis movement interpolation processing means 34 moves the collision face plate 200 to the W axis so that the tool tip collides with the collision face plate 200 in the stroke region where the load current fluctuation detected by the sampling current analysis means 33 is small. Perform interpolation processing to move. As a result, the collision face plate 200 is positioned at a position where the variation of the load current is small, and a range determined by a parameter based on this position is set as a tool length measurement region (step S14).

Next, the collision detection load current level is determined according to the servo current value in the stroke region where the load current variation is small (step S15), and the measurement start position is changed based on the arrangement position of the collision face plate 200 (step S15). Step S1
6).

In the tool length measurement command (step S17),
First, the tool holding axis (tool) is positioned at the measurement start position (step S18), and the tool holding axis is set to the tool length measurement speed (1).
(About 0 mm / min) to move the X-axis in a direction approaching the collision face plate 200 (step S19).

Under this axis movement, the motor load current of the tool holding axis is detected (step S20), and it is determined whether or not the motor load current has exceeded the collision detection load current level.
5 (step S21). Since this collision detection is performed in a stroke region where the fluctuation of the servo current value is small, accurate collision detection without erroneous detection is performed.

If the motor load current exceeds the collision detection load current level, the tip of the tool T
Assuming that collision has occurred, the remaining X-axis movement command is canceled by the movement amount canceling unit 61, and the tool holding axis is moved at a rapid traverse (maximum traverse) speed in the reverse direction (step S).
22), the X coordinate value Xa of the position (tool length measurement point) where the tip of the tool T collides with the plane 201 of the collision face plate 200 is read (step S23),
The tool length correction amount is calculated from the difference between the axis coordinate value Xa and the X-axis coordinate value Xo of the measurement start position (step S23).

As a result, a tool length correction amount can be obtained without requiring a special sensor or the like.

The tip of the tool T is placed on the flat surface 20 of the collision face plate 200.
In the event of collision with 1, the tool holding shaft is immediately moved in the reverse direction at the maximum feed speed, thereby avoiding chipping at the tool tip.

(Embodiment 2) FIG. 6 shows a numerical control apparatus according to Embodiment 2 of the present invention. In FIG. 6, portions corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted.

In this embodiment, a rod-shaped work W having a circular cross section (see FIG. 7) is used as the facing surface portion. As shown in FIG. 7, the work W is gripped by the collet chuck 211 and rotated around its own central axis by the main shaft 210.

The spindle 210 is a spindle motor 91 (see FIG. 6).
The spindle motor 91 is rotationally driven, and its operation is controlled by a spindle control unit 81 (see FIG. 6) capable of servo-locking. The tool holding axis in the numerical controller 1 is also the X axis in this embodiment.

The numerical control device 1 includes a machining program analyzing unit 10, a machining mode analyzing unit 11, a sampling mode command analyzing unit 13, a tool length measuring command analyzing unit 14, and a work for measuring and determining the center of the work. And a work center determination command analyzing means 15 for analyzing the center determination command.

The interpolation processing section 30 has, in addition to the interpolation processing means 31, a correction amount calculation means 32, a sampling current analysis means 33, a work center determination means 35, and a high-speed feed addition means 36.

The axis control unit 60 for the X axis includes a movement amount canceling unit 61, a position detecting unit 62, a servo current value inputting unit 63, a current value sampling unit 64, a collision detecting unit 65, a main shaft current value. And input means 66.

The tool length measurement command analysis means 14, the correction amount calculation means 32, the sampling current analysis means 33, the movement amount cancellation means 61, the position detection means 62, the servo current value input means 63, and the current value sampling means 64 This is equivalent to the case in the first embodiment.

The numerical controller 1 is provided with a spindle current value input circuit 72 for inputting a load current of the spindle motor 91 (hereinafter, sometimes referred to as a spindle current value) separately from the servo current value input circuit 71. The spindle current value input by the spindle current value input circuit 71 is given to the collision detection means 65 via the spindle current value input means 66 provided in the X-axis axis control section 60.

The collision detecting means 65 takes in the servo current value from the servo current value input means 63 while the tool holding axis is moving along the X axis, and the tip of the tool T collides with the outer peripheral surface of the work W due to the change in the servo current value. Is detected, the spindle current value is fetched from the spindle current value input means 66 while the spindle motor 91 is servo-locked, and the change in the spindle current value causes the tip of the tool T to collide with the outer peripheral surface of the workpiece W. Is detected.

The work center determining means 35 receives the load current of the spindle motor 91 in a state where the spindle motor 91 is servo-locked in accordance with the work center determination command, moves the tool holding axis in the X-axis, and mounts it on the tool holding axis. Tool T
The offset direction in the Y-axis direction of the tool holding axis with respect to the center axis of the work W is detected from the polarity of the increase / decrease change in the load current of the spindle motor 91 when the tip of the work collide with the outer peripheral surface of the work W, and the offset amount is reduced. The tool holding axis is moved in the Y-axis direction, and the detection of the offset direction of the tool holding axis is repeated based on the polarity of the increase / decrease of the load current of the spindle motor 91 at the time of collision, and the polarity of the increase / decrease of the spindle motor load current is inverted. The center position of the work W is detected from the position.

The high-speed feed adding means 36 precedes the collision of the tool tip with the workpiece W when the variation of the X-axis motor load current in the tool length measurement area is large by the sampling current analysis by the sampling current analysis means 33. To move the tool holding axis (tool) to the measurement start coordinate position at high speed. This high-speed moving speed may be about 3000 mm / min.

Next, with reference to the flow charts shown in FIGS. 8, 9 and 12, the procedure for implementing the method of detecting the center position of the workpiece and the method of correcting the center tool length by the numerical controller having the above-described configuration will be described. explain.

First, as a preparation process, a load current sampling routine shown in FIG. 8 is executed. In this routine, first, the tool holding axis (tool) is positioned at the measurement start position (step S30), and the work W is moved in the −Z axis direction (right side in FIG. 7) to retract the work W (step S31). . Next, the tool holding axis is moved along the X axis over a predetermined stroke corresponding to the tool length measurement area,
The motor load current of the tool holding axis is sampled by the current value sampling means 64 and registered in the memory 20 (step S32).

Next, the load current in the tool length measurement area written in the memory 20 is sampled by the sampling current analysis means 33.
(Step S33), and it is determined whether or not there is a load fluctuation of a predetermined level or more in the tool length measurement area (step S34). If there is a load fluctuation of a predetermined level or more in the tool length measurement area, the high-speed feed addition mode is set (step S35).

FIG. 9 shows a work center determination routine. In this routine, first, the tool holding axis (tool) is positioned at the measurement start position (step S40), and the work W
Is moved in the Z-axis direction (the left side in FIG. 7) to position the work W (step S41). The positioning position of the workpiece W is determined by the X-axis of the tool holding axis and the tool edge is
It is a position where it can collide with the outer peripheral surface of.

Next, the spindle motor 91 is set in the servo lock state by the work center determining means 35 (step S4).
2) The position of the tool T in the Y-axis direction is deviated from the tool selection position by an initial offset specified by a parameter so that a change in the current value of the spindle amplifier incorporated in the spindle control unit 81 tends to appear (step S43). ).

Next, the tool holding shaft is moved along the X axis in a direction approaching the outer peripheral surface of the work W at a tool length measuring speed (low speed feed) of about 10 mm / min (step S44).

While the shaft is moving, the load current of the spindle motor 91 is detected (step S45), and it is determined by the collision detection means 65 whether the load current has exceeded the collision detection load current level (step S46). This collision detection load current level has a plus side and a minus side as shown in FIG.

As shown in FIG. 11, when the tool T is offset to the left from the center of the work, the tool W is rotated counterclockwise by pressing the tool edge against the outer peripheral surface of the work W. The force to act acts. When the spindle motor 91 is in the servo locked state, the spindle motor 91 operates to maintain the current rotation angle position of the work W. As a result, if the forward rotation direction of the spindle motor 91 is clockwise, the collision causes the load current of the spindle motor 91 to exceed the positive side collision detection load current level.

On the other hand, if the tool T is offset to the right from the center of the work, the main motor 9
1 will exceed the negative side collision detection load current level.

If the load current of the spindle motor 91 exceeds the positive or negative collision detection load current level,
Assuming that the tip of the tool T has collided with the outer peripheral surface of the workpiece W, the remaining X-axis movement command is canceled by the movement amount canceling means 61, and the tool holding axis is rapidly traversed in the reverse direction to prevent chipping of the blade (maximum feed). It is moved at a speed (step S47).

Next, the work center determining means 35 receives a notification from the collision detecting means 2 as to whether the spindle current value has increased or decreased, and on which side of the tool holding axis from the work center (FIG. It is detected whether the offset is to the right or left (12) (step S48), and the tool holding axis is moved in the Y-axis direction in a direction in which the offset amount decreases (step S49).

Thereafter, the offset direction is detected by repeating the processing equivalent to steps S44 to S48 again (step S50), and the offset direction is detected until the polarity of the increase / decrease of the spindle current value is reversed (step S51). And the Y-axis movement of the tool holding axis in step S49 are repeated.

The fact that the polarity of the increase / decrease change of the spindle current value is reversed means that the tool holding axis has exceeded the work center due to the Y-axis movement of the tool holding axis in step S49, and the offset direction of the tool holding axis has been reversed. means. For example,
When the direction of the initial offset is on the left side, it means that the offset direction is on the right side.

If the polarity of the increase / decrease of the spindle current value is reversed (Yes at step S51), the tool holding axis is moved by a very small amount in the direction of decreasing the offset amount (step S51).
52). Thereafter, steps S44 to S4 are performed again.
8 is repeated to detect the offset direction (step S53), and until the polarity of the increase / decrease change of the spindle current value is reversed again (step S54), the offset direction is detected and the Y axis of the tool holding axis in step S53 is detected. Repeat the move.

If the polarity of the increase or decrease of the spindle current value is reversed (Yes at step S54), the work center position is determined from the average of the Y coordinate values of the two positions before and after the polarity reversal (step S55).

As a result, the center position of the work is automatically detected without the need for a special measuring device or the like, and the centering of the center position of the work with the position of the cutting edge of a cutting tool or the like can be automated.

FIG. 12 shows a tool length measurement routine. First, the tool holding axis (tool) is positioned at the measurement start position (step S60), and the tool selection axis (tool edge) is positioned at the work center measured by the work center determination means 35 (step S61).

Next, it is checked whether or not the high-speed feed addition mode is set in the load sampling routine (step S63). If the high-speed feed addition mode is set, the tool holding axis is retracted (step S64), and FIG.
As shown in (1), the tool holding axis is fed at high speed from the retreat position to the measurement start position.

The high-speed feed is such that the ball of the ball screw nut constituting the feed screw mechanism of the tool holding shaft circulates at a high speed by the high-speed feed, and a high-speed circulation of the ball is obtained by the inertial force even at a low-speed feed thereafter. This is performed in order to reduce the fluctuation of the servo current value of the tool holding shaft caused by the resistance fluctuation when the ball of the ball screw nut circulates. FIG. 14 schematically shows that high-speed feeding reduces fluctuations in load current at low-speed feeding thereafter. As shown in FIG. 15, the effect of reducing the fluctuation of the load current due to the high-speed feeding is saturated at about 3000 mm / min. Therefore, the high-speed feeding speed may be about 3000 mm / min.

When the tool holding axis reaches the measurement start position by the high-speed feed, the feed speed of the tool holding axis is switched to the tool length measurement speed, and the tool holding axis is fed at a low speed through the tool length measurement area (step S66). .

Under this axis movement, the motor load current of the tool holding axis is detected (step S67), and it is determined whether the motor load current has exceeded the collision detection load current level (step S68). Since this collision detection is performed in a state where the fluctuation of the load current is reduced, it is accurately performed without causing erroneous detection.

If the motor load current exceeds the collision detection load current level, it is determined that the tip of the tool T has collided with the outer peripheral surface of the workpiece W, and
The axis movement command is canceled, the tool holding axis is moved in the reverse direction at a rapid traverse (maximum feed) speed (step S69), and X at the position where the tip of the tool T collides with the outer peripheral surface of the workpiece W (tool length measurement point). The coordinate value Xa is read (step S7)
0), as in the first embodiment, the tool length correction amount is calculated by the correction amount calculation means 32 based on the difference between the X-axis coordinate value Xa and the X-axis coordinate value Xo at the measurement start position (step S71).

Therefore, also in this embodiment, a tool length correction amount can be obtained without requiring a special sensor or the like.

(Embodiment 3) FIG. 16 shows Embodiment 3 of a numerical controller according to the present invention. FIG.
In FIG. 6, portions corresponding to those in FIG. 6 are denoted by the same reference numerals as those in FIG. 6, and description thereof will be omitted.

This embodiment is an application of the second embodiment. The difference from the second embodiment is that a measurement area feed speed setting means 37 is provided, and the measurement area feed speed is set on an automatic board. Material (SUS, BS, Al
Etc.) to be variably set to an appropriate value.

This is because the harder the material, the higher the risk of chipping of the cutting edge of the cutting tool, and therefore the lower the feed speed. The softer the material, the smaller the change in current value at the time of collision. This is because it is preferable to increase the change in the current value at the time of collision by increasing In addition, when the material is soft, the cutting edge hardly chips even if the feed speed is increased. In this embodiment, the collision detection may be performed based on the current change rate.

The measurement area feed speed is input by an operator based on a screen display by a screen display connected to the numerical controller 1 and registered in the parameter setting section 21 by the work material setting means 23.

Next, a tool length measurement routine in this embodiment is shown in FIG. The difference between the tool length measurement routine according to this embodiment and the case according to the second embodiment is, as apparent from comparison with FIG. 12, that the material of the work is first read out (step S59) and that the step S66 is performed. The only difference is that the measurement area feed speed is set in accordance with the material and the tool holding shaft is fed at a low speed, and the other points are the same as those in the second embodiment.

In this embodiment, accurate collision detection is performed irrespective of the material of the work, and accurate tool length correction is performed.

(Embodiment 4) FIG. 18 shows a numerical control apparatus according to Embodiment 3 of the present invention. FIG.
In FIG. 8, portions corresponding to those in FIG. 6 are denoted by the same reference numerals as those in FIG. 6, and description thereof will be omitted.

This embodiment is a modification of the second embodiment, in which a warm-up means 38 is provided in place of the high-speed feeding means 36. Warm-up means 38
Prior to causing the tool tip to collide with the workpiece W, the tool holding shaft is moved for a predetermined time to warm up the feed screw mechanism of the tool holding shaft.

In this embodiment, a load sampling warm-up routine as shown in FIG. 19 is executed prior to the tool length measurement. In this routine,
First, the work W is moved in the −Z-axis direction (right side in FIG. 7) to retract the work W (Step S80), and the tool holding axis (tool) is positioned at the measurement start position (Step S).
81).

Next, the tool holding shaft is moved along the X-axis over a predetermined stroke corresponding to the tool length measurement area, and the motor load current of the tool holding shaft is sampled by the current value sampling means 64. Register (step S82).

Next, the load current in the tool length measurement area written in the memory 20 is sampled by the sampling current analysis means 33.
(Step S83), and it is determined whether or not there is a load fluctuation of a predetermined level or more in the tool length measurement area (step S84). If there is a load fluctuation exceeding a predetermined level in the tool length measurement area, the warm-up means 38
The tool is reciprocated repeatedly at a rapid traverse speed from the measurement start position to a position just before the stroke end in the direction in which the tool holding shaft moves away from the workpiece W (step S).
85). As a result, the ball screw generates heat, and the frictional resistance between the ball and the pipe or the diffuser decreases,
The load fluctuation gradually disappears.

Thereafter, the above-described processing is repeated until the load fluctuation of a predetermined level or more is reduced in the tool length measurement area, and when the load fluctuation disappears, the tool length measurement is started.

In the tool length measurement, only the low-speed feed is performed from the measurement start position, the collision is detected by the same means as in the second embodiment, and the correction amount calculating means 32 calculates the tool length correction amount.

Also in this embodiment, since the collision detection is performed in a state where the fluctuation of the load current is reduced, the collision detection is accurately performed without causing the erroneous detection, and the tool length correction is also accurately performed.

(Embodiment 5) FIG. 20 shows a numerical controller according to Embodiment 3 of the present invention. Note that FIG.
6, the same reference numerals as in FIG. 6 denote parts corresponding to those in FIG. 6, and a description thereof will be omitted.

In this embodiment, the collision detecting means 65
Is that the tip of the workpiece W is changed by a change in the load current of the spindle motor 91 in a state where the spindle motor 91 for rotating the rod-shaped workpiece W having a circular cross section is servo-locked and a change in the motor load current of the tool holding axis. It is detected that the outer peripheral surface has collided.

The tool edge is positioned at a position shifted by about several μm from the center of the work in the Y-axis direction so that the spindle current value changes when a rotational force is applied to the work W at the time of the collision. Not on line. For this reason, it is necessary to correct the coordinate value at the tool length measurement point for calculating the correction amount to a value corresponding to the work center line.

For this purpose, the interpolation processing section 30 is provided with collision position calculation means 39.

As shown in FIGS. 21A and 21B, when the offset amount in the Y-axis direction of the collision position of the tool edge from the center of the work in the Y-axis direction is R, and the radius of the work W is R, the coordinate values are as follows. The correction amount B is calculated by the following equation. That is, B = R−√ (R ² −A ² ).

FIG. 22 shows a tool length measurement routine in this embodiment. In this routine, first, the tool holding axis (tool) is positioned at the measurement start position (step S90), and the work W is positioned in the Z-axis direction (step S91). Then, the tool selection axis (tool edge) is positioned at a predetermined offset amount at the work center measured by the work center determination means 35 (step 9).
2).

Next, the tool holding axis is fed at a low speed through the tool length measurement area (step S93).

Under this axis movement, the motor load current of the tool holding axis (tool feed axis) and the load current of the spindle motor 91 are detected (step S94), and the motor load current of the tool feed axis is set to the collision detection load current level. (Step S9)
5) It is determined whether the current value of the spindle motor 91 has changed (step S96).

If the AND condition is satisfied that the motor load current of the tool feed shaft has exceeded the collision detection load current level and that the current value of the spindle motor 91 has changed, the tool T
Is determined to have collided with the outer peripheral surface of the workpiece W, the remaining X-axis movement command is canceled by the movement amount canceling unit 61, and the tool holding axis is moved at a rapid traverse speed in the reverse direction (step S97). Reads the X-coordinate value Xb of the position (tool length measurement point) where it collides with the outer peripheral surface of the workpiece W (step S98), and calculates the coordinate value correction amount B by the collision position calculation means 39 (step S99).

Then, the X-axis coordinate value Xb + the coordinate value correction amount B is taken as the X-axis coordinate value Xb + the coordinate value correction amount B by the correction amount calculation means 32, and the X-axis coordinate value Xb + the coordinate value correction amount B is calculated. The tool length correction amount is calculated based on the difference from the coordinate value Xo (step S100).

In this embodiment, as shown in FIG. 23, the motor load current of the tool feed shaft exceeds the collision detection load current level on the way due to the load fluctuation e caused by the feed operation by the feed screw mechanism. However, at this time, there is no change in the current value of the spindle motor 91, so that erroneous collision detection is not performed.

(Sixth Embodiment) FIG. 24 shows a sixth embodiment of the numerical controller according to the present invention. Note that FIG.
In FIG. 4, portions corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof is omitted.

In this embodiment, the interpolation processing section 30 is provided with the spindle rotation command means 40. The spindle rotation command means 40 determines the spindle motor 91 by a tool length measurement command according to parameters, machining program commands and the like. Control to rotate with the number of rotations is performed.

Therefore, in the tool length measuring process similar to the tool length measuring process in the first embodiment, as shown in FIG. 25, the tool blade tip collides with the outer peripheral surface of the rotating work W. Become. When the tool edge collides with the outer peripheral surface of the workpiece W, the tangential force acts on the tool T because the workpiece W is rotating, and the motor load current of the tool feed shaft rapidly increases with a relatively large increase rate. I do.

As a result, the load current level for detecting the collision of the motor load current can be set higher than when the tool edge collides with the stopped surface portion, and even if there is a load variation due to the feed operation by the feed screw mechanism. Thus, erroneous collision detection is not performed.

(Seventh Embodiment) FIG. 26 shows a seventh embodiment of the numerical controller according to the present invention. Note that FIG.
In FIG. 6, portions corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and description thereof will be omitted.

In this embodiment, in addition to the ordinary machining program analysis means 11, the machining program analysis processing section 10 includes a work center calculation command analysis means 16 for analyzing a work center calculation command for calculating a work center, and a tool Tool length compensation notch for analyzing length compensation notch / measurement command
And a measurement command analysis means 17.

The interpolation processing section 30 has a work center calculating means 4
1 is provided. The work center calculation means 41 moves the tool holding shaft in the radial direction (Y-axis direction) with respect to the rod-shaped work W having a circular cross section in response to the work center calculation command, and the side surface of the tool T mounted on the tool holding shaft. Is detected from the change in the motor load current of the tool-holding shaft, and the center position of the work W is calculated from the radial coordinate value of the tool-holding shaft at the time of the collision. The radial coordinate value (Y-axis coordinate value) of the tool holding axis can be obtained from the position detecting means of the Y-axis axis control unit 60.

The work center calculation by the work center calculation means 41 is specifically performed by causing the side surface of the tool T to collide with the work W from the left side as shown in FIG. Then, the side of the tool T is made to collide with the work W from the right side to obtain the Y-axis coordinate value Yb at this time, and the work W is calculated by the following formula in consideration of the known tool width dimension t of the tool T. Is calculated in the Y-axis direction.
That is, Wc = {(Yb-t-Ya) / 2} + Ya = (Ya + Yb-t) / 2.

When the radius r of the work W is known, the center coordinate value Wc of the work W in the Y-axis direction can be calculated by the following equation using only one side measurement. That is, Wc = Ya + (r / 2).

The interpolation processing unit 30 is provided with a spindle rotation command means 40.
The rotation of the spindle motor 91 is commanded by the tool length correction infeed / measurement command, and the tool holding axis is moved by a predetermined amount X
Interpolation processing is performed for cutting the workpiece W, which is rotating by rotating the axis, with the tool T mounted on the tool holding axis.

The correction amount calculating means 32 calculates the workpiece W before cutting.
The actual cutting amount is calculated from the difference between the radius of the workpiece W and the radius of the workpiece W before cutting, and the tool length correction amount is calculated from the deviation between the actual cutting amount and the command cutting amount obtained from the axis movement command value of the tool holding shaft. . Actually, there is an initial setting value of the tool length correction amount. If this initial setting value is Co, the actual cutting amount is Cr, and the command cutting amount is Ct (see FIG. 28),
The tool length correction amount C is calculated by the following equation. That is, C = Co + (Cr-Ct).

Next, with reference to the flow charts shown in FIGS. 29 and 30, a description will be given of the procedure for executing the method of detecting the center position of the workpiece and the method of correcting the tool length by the numerical controller having the above-described configuration.

FIG. 29 shows a work center calculation routine. In this routine, first, the tool (tool T) is positioned on the left side of the work W (step S110), and the tool is positioned with the tool holding axis at a Y-axis position about 2 to 3 mm before the contact between the tool holder and the work W. (Step S111).

Next, the tool holding axis is set to the tool length measurement speed (1
The workpiece W is moved in the Y-axis direction (approximately 0 mm / min) (step S112), and the servo current value (motor load current) of the tool holding axis is detected under this axis movement (step S113). The collision detection means 65 determines whether or not the value has exceeded the collision detection load current level (step S114). The change in current at the time of the collision is larger than when the tool edge collides with the workpiece W, and there is no bite. Therefore, the error in the collision detection position is extremely small, and accurate collision detection is performed. .

If the servo current value of the tool holding axis exceeds the collision detection load current level, it is determined that the tip of the tool T has collided with the outer peripheral surface of the work W, the remaining Y-axis movement commands are canceled, and the tool holding axis is reversed. The tool T is moved at a rapid traverse (maximum traverse) speed in the direction (step S115), and the Y coordinate value Ya at the position where the side surface of the tool T collides with the outer peripheral surface of the workpiece W is read out.
This is written in the memory 20 (step S116).

Next, it is checked whether both collision positions on the right and left sides of the work have been read out, and if both collision positions have not been read out yet, the tool T is moved to the work W
In order to detect the collision position on the right side of the work, steps S111 to S116 are executed again.

As a result, the Y coordinate value Ya of the collision position on the left side of the workpiece W and the Y coordinate value Yb of the collision position on the right side of the workpiece W are obtained. The center coordinate value Wc of the work W in the Y-axis direction is calculated (Step S119).

As a result, the center position of the work is automatically detected without requiring a special measuring device or the like, and the centering of the center position of the work with the position of the cutting edge of a cutting tool or the like can be automated.

FIG. 30 shows a tool length measurement routine. First, the spindle motor 91 is driven to rotate by the blade command of the spindle rotation command means 40, and the work W is rotated at a predetermined turning speed by the spindle rotation (step S120).

Next, the tool is positioned at the work center calculated by the above-described work center calculation routine (step S).
121), the tool holding axis is moved in the X-axis by the reference tool length correction (the X-axis movement command (cutting command) in which the initial tool length correction has been performed), and the workpiece W is cut by the tool T of the tool holding axis (step S122). .

When the cutting is completed, the rotation of the spindle is stopped (step S123), the tool T is positioned on the left side of the work W (step S124), and about 2 to 3 mm before the contact between the tool holder and the work W. The tool is positioned with the tool holding axis at the Y-axis position (step S12).
5).

Next, the tool holding axis is moved in the Y-axis direction in the direction approaching the workpiece W at the tool length measurement speed (step S).
126), the servo current value of the tool holding axis is detected during this axis movement (step S127), and it is determined by the collision detection means 65 whether the servo current value has exceeded the collision detection load current level (step S128). . Since the current change at the time of the collision is also large as compared with the case where the tool edge collides with the workpiece W, the error of the collision detection position is very small, and there is no bite, so that accurate collision detection is performed. Become.

If the servo current value of the tool holding axis exceeds the collision detection load current level, it is determined that the tip of the tool T has collided with the outer peripheral surface of the work W, the remaining Y-axis movement commands are canceled, and the tool holding axis is reversed. The tool T is moved in the direction at a rapid traverse (maximum traverse) speed (step S129), and the Y coordinate value Ya 'of the position where the side surface of the tool T collides with the outer peripheral surface of the work W is read and written to the memory 20 (step S13).
0).

Next, the correction amount calculating means 34 calculates the actual cutting amount Cr from the Y coordinate value Ya before cutting and the Y coordinate value Ya 'after cutting obtained in the work center calculating routine, and calculates the actual cutting amount Cr from the cutting instruction. The tool length correction amount C is obtained from the above-described formula using the command cut amount Ct and the initial set value Co.
Is calculated.

Therefore, also in this embodiment, a tool length correction amount can be obtained without requiring a special sensor or the like.

(Eighth Embodiment) FIG. 31 shows an eighth embodiment of the numerical controller according to the present invention. Note that FIG.
In FIG. 1, portions corresponding to those in FIG. 26 are denoted by the same reference numerals as those in FIG. 26, and description thereof will be omitted.

In this embodiment, the machining program analysis processing section 10 is provided with a tool wear degree estimation command analyzing means 18 for analyzing a tool wear degree estimation command for estimating the tool wear degree.

The interpolation processing section 30 includes a wear degree estimating means 42.
Is provided. The wear degree estimating means 42 moves the tool holding axis along the X axis based on the tool wear degree estimation command, and detects the motor load current of the tool holding axis when the tip of the tool T mounted on the tool holding axis collides with the workpiece. Then, the degree of wear of the tool T is estimated from the magnitude of the change rate of the motor load current at the time of the collision. This estimation is performed based on the data which shows the correlation between the current change rate set for each material of the workpiece and the degree of tool wear in the form of a table or an approximate curve and is registered in the memory 20 in advance. Can be done.

The estimation of the degree of tool wear is based on the assumption that as the tool wear progresses, the sharpness decreases and the bite when the tool edge collides with the work is reduced.
Is performed based on the fact that the rate of change (slope) of the motor load current at the time of collision increases. The gradient of the motor load current at the time of collision increases as the degree of wear increases.

Next, a tool wear degree estimation routine will be described with reference to FIG. First, the tool holding axis (tool) is positioned at the measurement start position (step S140), and the tool selection axis (tool edge) is positioned at the work center calculated by the work center calculation means 41 (step S141).

Next, the tool holding axis is fed at a low speed through the tool length measurement area at the tool length measurement speed (step S1).
42).

Under this axis movement, the motor load current of the tool holding axis is detected (step S143), and it is determined whether or not the motor load current has exceeded the collision detection load current level (step S144).

If the motor load current exceeds the collision detection load current level, it is determined that the tip of the tool T has collided with the outer peripheral surface of the workpiece W, and
The axis movement command is canceled, and the tool holding axis moves in the reverse direction at a rapid traverse (maximum traverse) speed (step S145),
The change rate (gradient) of the motor load current at this time is detected (step S146). Next, the degree of wear of the tool T is estimated based on the gradient of the motor load current (step S14).
7).

As a result, the degree of wear of the tool can be detected without using a special measuring device including an image processing means and the like, so that it is possible to easily grasp the timing of tool replacement.

[0186]

As can be understood from the above description, according to the tool length correcting method in the numerical controller according to the present invention, the tip of the tool mounted on the tool holding shaft is provided by the collision face plate or the workpiece. Collision with the opposing surface is detected from the change in the motor load current of the tool holding shaft,
Since the tool length correction amount is calculated from the difference between the coordinate value of the tool holding axis at the time of the collision and the coordinate value of the measurement start coordinate position and the tool length is automatically corrected, the tool length correction is a special sensor, measuring device, This can be easily performed without adding a special hardware configuration to the numerical controller.

According to the tool length correcting method in the numerical controller according to the next invention, since the tool holding axis moves in the opposite direction at a high speed immediately after the collision is detected, chipping of the tool edge is prevented.

According to the tool length correcting method in the numerical controller according to the next invention, the tool tip collides with the collision face plate in the stroke region where the motor load current does not fluctuate.
The collision detection is accurately performed, and the calculation of the tool length correction amount and the automatic correction of the tool length are properly performed.

According to the tool length correcting method in the numerical controller according to the next invention, the axis moving speed of the tool holding shaft is set according to the material of the workpiece, and the collision is performed irrespective of the material of the workpiece. Since the detection is accurately performed, the calculation of the tool length correction amount and the automatic correction of the tool length are properly performed regardless of the material of the workpiece.

According to the tool length correction method in this numerical controller, the tool holding axis is moved to the measurement start coordinate position at a high speed before the tip of the tool collides with the facing surface. Motor load fluctuation is reduced, collision detection is performed accurately, and calculation of the tool length correction amount and automatic correction of the tool length are properly performed.

According to the tool length correcting method in this numerical controller, the feed screw mechanism of the tool holding shaft is warmed up before the tip of the tool collides with the facing surface, so that the motor load by the feed screw mechanism is increased. Fluctuations are reduced, collision detection is performed accurately, and calculation of the tool length correction amount and automatic correction of the tool length are properly performed.

According to the tool length correcting method in the numerical controller according to the next invention, the tip of the tool collides with the outer peripheral surface of the workpiece while the workpiece is being rotated, so that the collision detection is accurately performed. As a result, the calculation of the tool length correction amount and the automatic correction of the tool length are properly performed.

According to the tool length correcting method in the numerical controller according to the next invention, the tip of the tool collides with the outer peripheral surface of the workpiece due to the change in the motor load current of the tool holding shaft and the change in the motor load current of the spindle. Therefore, the collision detection is accurately performed regardless of the motor load fluctuation caused by the feed screw mechanism, and the tool length correction amount is calculated and the tool length is automatically corrected.

According to the tool length correcting method in the numerical controller according to the next invention, the actual cutting depth due to the difference between the dimension of the workpiece before cutting and the dimension of the workpiece after cutting and the axis of the tool holding axis are determined. The tool length correction amount is calculated from the deviation from the command cutting amount obtained from the movement command value, and the tool length is automatically corrected based on the tool length correction amount. Therefore, the tool length correction requires special sensors, measuring devices, and special hardware. This can be easily performed without adding a hardware configuration to the numerical controller.

According to the method for detecting the center position of the workpiece in the numerical control apparatus according to the next invention, the polarity of the increase or decrease in the load current of the spindle motor when the tip of the tool collides with the outer peripheral surface of the workpiece is determined. Detect the offset direction of the tool holding axis with respect to the center axis of the workpiece, move the tool holding axis in the direction to reduce the offset amount, and determine the offset direction of the tool holding axis based on the polarity of the increase and decrease of the spindle motor load current at the time of collision. Detection is repeated, and the center position of the workpiece is detected from the position where the polarity of the increase / decrease change of the spindle motor load current is reversed, so the center position detection of the workpiece is a special sensor, measuring device, special hardware configuration Can be easily performed without adding to the numerical controller.

According to the workpiece center position detecting method in the numerical controller according to the next invention, the fact that the side surface of the tool collides with the outer peripheral surface of the workpiece is detected from the change in the motor load current of the tool holding shaft. Since the center position of the workpiece is calculated from the radial coordinate value of the tool holding axis at the time of the collision, the center position of the workpiece is numerically controlled by a special sensor, measuring device, or special hardware configuration. This can be easily performed without adding to the device.

In the method for estimating the degree of tool wear in the numerical controller according to the next invention, the degree of wear of the tool is estimated from the rate of change of the motor load current when the tip of the tool collides with the workpiece. The degree of wear of the tool can be detected without requiring a special measuring device including the above.

According to the method for estimating the degree of tool wear in the numerical controller according to the next invention, the motor load is determined based on the data indicating the correlation between the current change rate set for each material of the workpiece and the degree of tool wear. Since the degree of tool wear is estimated from the current change rate, the degree of tool wear is accurately detected.

According to the numerical controller according to the next invention,
The change in the motor load current of the tool holding shaft detects that the tip of the tool mounted on the tool holding shaft has collided with the opposing surface provided by the collision face plate or the workpiece, and the coordinates of the tool holding shaft at the time of this collision The tool length correction amount is calculated from the difference between the value and the coordinate value of the measurement start coordinate position, and the tool length is automatically corrected. Therefore, the tool length correction requires special sensors, measuring devices, and special hardware configurations using numerical control devices Can be easily performed without adding the

According to the numerical control device of the next invention,
Since the tool tip collides with the collision face plate in the stroke area where the motor load current is small, the collision detection is accurately performed, the tool length correction amount is calculated, and the tool length is automatically corrected.

According to the numerical controller according to the next invention,
The axis moving speed of the tool holding shaft is set according to the material of the workpiece, and the collision detection is accurately performed regardless of the material of the workpiece, so that the tool length is independent of the material of the workpiece. The calculation of the correction amount and the automatic correction of the tool length are properly performed.

According to the numerical control device of the next invention,
Since the tool holding axis is moved at high speed to the measurement start coordinate position, fluctuations in motor load due to the feed screw mechanism are reduced, collision detection is performed accurately, tool length correction amount calculation, tool length correction Automatic correction is performed properly.

According to the numerical controller according to the next invention,
Since the feed screw mechanism of the tool holding shaft is warmed up, fluctuations in motor load due to the feed screw mechanism are reduced,
Collision detection is accurately performed, and the calculation of the tool length correction amount and the automatic correction of the tool length are properly performed.

According to the numerical control device of the next invention,
Since the tool tip collides with the outer peripheral surface of the workpiece while the workpiece is being rotated, the collision detection is performed accurately, the tool length correction amount is calculated, and the tool length is automatically corrected. Become.

According to the numerical controller according to the next invention,
The change of the motor load current of the tool holding shaft and the change of the motor load current of the spindle detect that the tool tip has collided with the outer peripheral surface of the workpiece. Is accurately performed, and the calculation of the tool length correction amount and the automatic correction of the tool length are properly performed.

The numerical control device according to the next invention provides a command obtained from an actual cutting amount based on a difference between a dimension of a workpiece before cutting and a dimension of a workpiece after cutting and an axis movement command value of a tool holding axis. Calculate the tool length correction amount from the deviation from the cutting amount,
Since the tool length is automatically corrected by this tool length correction amount,
Tool length correction can be easily performed without adding a special sensor, measuring device, or special hardware configuration to the numerical control device.

According to the numerical control device of the next invention,
Detects the offset direction of the tool holding axis with respect to the center axis of the workpiece from the polarity of the increase / decrease change in the load current of the spindle motor when the tip of the tool collides with the outer peripheral surface of the workpiece, in the direction in which the offset amount decreases The tool holding shaft is moved to repeat the detection of the offset direction of the tool holding shaft from the polarity of the increase / decrease of the spindle motor load current at the time of collision, and the center of the workpiece is shifted from the position where the polarity of the increase / decrease of the spindle motor load current is reversed. Since the position is detected, the detection of the center position of the workpiece can be easily performed without adding a special sensor, a measuring device, or a special hardware configuration to the numerical controller.

According to the numerical controller according to the next invention,
Detects that the side of the tool collides with the outer peripheral surface of the workpiece from the change in the motor load current of the tool holding shaft, and calculates the center position of the workpiece from the radial coordinate value of the tool holding shaft at the time of this collision Therefore, the center position of the workpiece can be easily detected without adding a special sensor, a measuring device, or a special hardware configuration to the numerical control device.

According to the numerical controller according to the next invention,
Since the degree of wear of the tool is estimated from the rate of change of the motor load current when the tip of the tool collides with the workpiece, the degree of wear of the tool can be detected without the need for a special measuring device including image processing means.

According to the numerical controller according to the next invention,
Since the tool wear degree is estimated from the motor load current change rate based on data indicating the correlation between the current change rate and the tool wear degree set for each material of the workpiece, the tool wear degree can be accurately detected. Done in

[Brief description of the drawings]

FIG. 1 is a first embodiment of a numerical control device according to the present invention;
FIG.

FIG. 2 is an explanatory diagram showing a tool length measurement procedure according to the first embodiment.

FIG. 3 is a graph showing fluctuation characteristics of a motor load current of a tool holding shaft.

FIGS. 4A and 4B are graphs of load current characteristics showing a collision detection procedure according to the first embodiment.

FIG. 5 is a flowchart illustrating a tool length correction routine according to the first embodiment.

FIG. 6 is a second embodiment of the numerical controller according to the present invention;
FIG.

FIG. 7 is an explanatory view showing a machine tool applied in a second embodiment.

FIG. 8 is a flowchart showing a load sampling routine according to the second embodiment.

FIG. 9 is a flowchart illustrating a work center determination routine according to the second embodiment.

FIG. 10 is a graph of load current characteristics showing a collision detection procedure according to the second embodiment.

FIG. 11 is an explanatory diagram showing a work center determination procedure according to the second embodiment.

FIG. 12 is a flowchart illustrating a tool length measurement routine according to the second embodiment.

FIG. 13 is an explanatory diagram showing a tool length measurement procedure according to the second embodiment.

FIG. 14 is a graph of load current characteristics showing a tool length measurement procedure according to the second embodiment.

FIG. 15 is a graph showing a relationship between a feed speed and a load change.

FIG. 16 is a block diagram showing a numerical control device according to a third embodiment of the present invention.

FIG. 17 is a flowchart illustrating a tool length measurement routine according to the third embodiment.

FIG. 18 is a block diagram showing a numerical control device according to a fourth embodiment of the present invention.

FIG. 19 is a diagram illustrating load sampling and
9 is a flowchart illustrating a warm-up routine.

FIG. 20 is a block diagram showing a numerical control device according to a fifth embodiment of the present invention.

FIGS. 21 (a) and 21 (b) are explanatory diagrams showing a tool length measuring procedure according to the fifth embodiment.

FIG. 22 is a flowchart illustrating a tool length measurement routine according to the fifth embodiment.

FIG. 23 is a graph of load current characteristics showing a collision detection procedure according to the fifth embodiment.

FIG. 24 is a block diagram showing a sixth embodiment of the numerical controller according to the present invention;

FIG. 25 is an explanatory diagram showing a collision detection procedure according to the sixth embodiment.

FIG. 26 is a block diagram showing a numerical control apparatus according to a seventh embodiment of the present invention.

FIG. 27 is an explanatory diagram showing a work center calculation procedure according to the seventh embodiment.

FIG. 28 is an explanatory diagram showing a procedure for calculating a tool length correction amount according to the seventh embodiment.

FIG. 29 is a flowchart illustrating a work center calculation routine according to the seventh embodiment.

FIG. 30 is a flowchart illustrating a tool length measurement routine according to the seventh embodiment.

FIG. 31 is a block diagram showing Embodiment 8 of a numerical controller according to the present invention.

FIG. 32 is a graph of load current characteristics showing a collision detection procedure according to the eighth embodiment.

FIG. 33 is a graph showing the relationship between the degree of wear of the tool and the slope of the load current.

FIG. 34 is a flowchart showing a wear degree estimation routine in the eighth embodiment.

FIG. 35 is a block diagram showing a conventional numerical control device.

FIG. 36 is an explanatory view showing a conventional tool length measurement procedure.

[Explanation of symbols]

1 Numerical control unit, 10 Machining program analysis processing unit,
11 Machining program analysis processing means, 13 Sampling mode command analysis means, 14 Tool length measurement command analysis means, 15 Work center determination command analysis means, 16 Work center calculation command analysis means, 17 Tool length correction cut /
Measurement command analysis means, 18 Tool wear degree estimation command analysis means 18, 20 memory, 21 parameter setting unit, 2
2 screen display processing unit, 23 work material setting means, 30
Interpolation processing unit, 31 interpolation processing means, 32 correction amount calculation means, 33 sampling current analysis means, 34 collision face plate axis movement interpolation processing means, 35 work center determination means, 3
6 high-speed feed addition means, 37 measurement area feed speed setting means, 38 warm-up means, 39 collision position calculation means, 40 spindle rotation command means, 41 work center calculation means, 42 wear degree estimation means, 50 machine control signal processing section, 55 ladder circuit section, 60 axis control section, 61 movement amount canceling means, 62 position detecting means, 63 servo current value input means, 64 current value sampling means, 65
Collision detection means, 66 spindle current value input means, 70 axis movement amount output circuit, 71 servo current value input circuit, 72 spindle current value input circuit, 80 servo control section, 81 spindle control section, 90 servo motor, 91 spindle motor, 200
Collision face plate, 210 spindle, 211 collet chuck

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[Procedure amendment]

[Submission date] April 2, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0077

[Correction method] Change

[Correction contents]

The fluctuation of the servo current value here has a characteristic as illustrated in FIG. 3, and the fluctuation of the servo current value is mainly caused by a return pipe type or a deflector forming the feed screw mechanism of the tool holding shaft. are those balls of formula of the ball screw nut due to the resistance change at the time of circulation, which, Jun Namerayu temperature becomes more pronounced at low low temperature.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0122

[Correction method] Change

[Correction contents]

The high-speed feed is such that the ball of the ball screw nut constituting the feed screw mechanism of the tool holding shaft circulates at a high speed by the high-speed feed, and a high-speed circulation of the ball is obtained by the inertial force even at a low-speed feed thereafter. This is performed in order to reduce the fluctuation of the servo current value of the tool holding shaft caused by the resistance fluctuation when the ball of the ball screw nut circulates. Figure 14 variation of the load current in the subsequent slow feed is schematically shown to reduce the high feed. As shown in FIG. 15, the effect of reducing the fluctuation of the load current due to the high-speed feeding is saturated at about 3000 mm / min. Therefore, the high-speed feeding speed may be about 3000 mm / min.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0143

[Correction method] Change

[Correction contents]

In order to change the spindle current value when a rotational force is applied to the work W at the time of collision, the tool cutting edge is positioned at a position shifted from the center of the work by about several μm to about several nm in the Y-axis direction. The position is not on the work center line. For this reason, it is necessary to correct the coordinate value at the tool length measurement point for calculating the correction amount to a value corresponding to the work center line.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0162

[Correction method] Change

[Correction contents]

The correction amount calculating means 32 calculates the workpiece W before cutting.
The actual cutting amount is calculated from the difference between the radius of the workpiece W and the radius of the workpiece W after cutting, and the tool length correction amount is calculated from the deviation between the actual cutting amount and the command cutting amount obtained from the axis movement command value of the tool holding shaft. . Actually, there is an initial setting value of the tool length correction amount. If this initial setting value is Co, the actual cutting amount is Cr, and the command cutting amount is Ct (see FIG. 28),
The tool length correction amount C is calculated by the following equation. That is, C = Co + (Cr-Ct).

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0165

[Correction method] Change

[Correction contents]

Next, the tool holding axis is set to the tool length measurement speed (1
The workpiece W is moved in the Y-axis direction (approximately 0 mm / min) (step S112), and the servo current value (motor load current) of the tool holding axis is detected under this axis movement (step S113). The collision detection means 65 determines whether or not the value has exceeded the collision detection load current level (step S114). The change in current at the time of the collision is larger than when the tool edge collides with the workpiece W, and there is no bite, so that the error of the collision detection position becomes very small, and accurate collision detection is performed. . Ma
Also, since the tool edge does not collide, the tipping
There is no arrangement.

[Procedure amendment 6]

[Document name to be amended] Drawing

[Correction target item name] Fig. 7

[Correction method] Change

[Correction contents]

FIG. 7

Claims (25)

[Claims] 1. A tool holding axis is axially moved from a predetermined measurement start coordinate position, and it is determined that the tip of a tool mounted on the tool holding axis has collided with an opposing surface provided by a collision face plate or a workpiece. A tool length correction amount is detected from a change in the motor load current of the tool holding axis, and a tool length correction amount is calculated from a difference between the coordinate value of the tool holding axis at the time of the collision and the coordinate value of the measurement start coordinate position. A tool length correction method in a numerical control device, wherein the tool length is automatically corrected by the method. 2. The method according to claim 1, wherein the tool holding shaft is moved in the opposite direction at a high speed immediately after the collision is detected. 3. The tool holding shaft is provided by providing the opposed surface portion with a collision face plate which is axially movable in the same direction as the axial movement direction of the tool holding shaft, and moving the tool holding shaft by a full stroke or a predetermined stroke. The motor load current is sampled, a stroke area where the variation of the motor load current is small is detected by this sampling, and the collision face plate is moved axially so that the tool tip collides with the collision face plate in this stroke area, and the arrangement position is changed. The method according to claim 1, wherein the adjustment is performed, and the measurement start coordinate position is set according to the adjustment. 4. The tool according to claim 1, wherein the opposed surface portion is provided from a workpiece, and an axis moving speed of the tool holding shaft is set according to a material of the workpiece. Length correction method. 5. The tool holding shaft is moved at a high speed to the measurement start coordinate position before the tool tip collides with the facing surface portion, and thereafter, the tool holding shaft is axially moved at a low speed to move the tool cutting edge. 2. The tool length correcting method according to claim 1, wherein the collision is performed with the facing surface portion. 6. The tool holding shaft is moved for a predetermined time before the tool tip collides with the facing surface portion, and the feed screw mechanism of the tool holding shaft is warmed up. The tool length correction method in the numerical controller according to claim 1, wherein 7. The method according to claim 7, wherein the opposed surface portion is provided by a rod-shaped workpiece having a circular cross section, and a tool tip collides with an outer peripheral surface of the workpiece while rotating the workpiece. Item 2. A tool length correction method in the numerical control device according to Item 1. 8. The load current of the spindle motor is detected in a state where the opposed surface portion is provided by a rod-shaped workpiece having a circular cross section and the spindle motor for rotating the workpiece is servo-locked.
The tool cutting edge is caused to collide with the outer peripheral surface of the workpiece at a position radially offset by a predetermined amount from the center position of the workpiece, so that a change in the motor load current of the tool holding shaft and the 2. The method according to claim 1, wherein a change in the motor load current is used to detect that the tip of the tool collides with the outer peripheral surface of the workpiece. 9. A tool holding shaft is moved by a predetermined amount to cut a workpiece with a tool mounted on the tool holding shaft, and the dimensions of the workpiece before cutting and the size of the workpiece after cutting are cut. Calculating a tool length correction amount from a deviation between the actual cutting amount due to the difference between the dimension and the command cutting amount obtained from the axis movement command value of the tool holding axis, and automatically correcting the tool length by the tool length correction amount. A tool length correction method in a numerical controller characterized by the following. 10. A spindle motor for rotating a bar-shaped workpiece having a circular cross section is servo-locked, a load current of the spindle motor is detected, and a tool holding shaft is axially moved to be mounted on the tool holding shaft. The tip of the tool is collided with the outer peripheral surface of the workpiece, and the offset direction of the tool holding axis with respect to the center axis of the workpiece is detected from the polarity of the increase or decrease in the load current of the spindle motor at the time of the collision. Then, the tool holding axis is moved in the direction in which the offset amount decreases, and the detection of the offset direction of the tool holding axis is repeated from the polarity of the increase / decrease change of the spindle motor load current at the time of the collision. A method of detecting a center position of a workpiece in a numerical control device, wherein the center position of the workpiece is detected from a position where the polarity is reversed. 11. A tool holding shaft is moved in a radial direction with respect to a rod-shaped workpiece having a circular cross section, and a side surface of a tool mounted on the tool holding shaft collides with an outer peripheral surface of the workpiece. That is, the center position of the workpiece in the numerical controller that detects the change in the motor load current of the tool holding axis and calculates the center position of the workpiece from the radial coordinate value of the tool holding axis at the time of the collision. Detection method. 12. A tool holding shaft is axially moved, and when a tip of a tool mounted on the tool holding shaft collides with a workpiece, a motor load current of the tool holding shaft is detected. A method for estimating the degree of wear of the tool in the numerical controller, wherein the degree of wear of the tool is estimated from the rate of change of the motor load current. 13. The estimation of the degree of tool wear based on the rate of change of the motor load current is performed based on data indicating the correlation between the current change rate and the degree of tool wear set in advance for each material of the workpiece. The method for estimating a degree of tool wear in the numerical control device according to claim 12. 14. A tool length measurement command analyzing means for analyzing a tool length measurement command for axially moving the tool holding axis from a predetermined measurement start coordinate position, and the tool length measurement based on a change in motor load current of the tool holding axis. Collision detection means for detecting that the tip of a tool mounted on the tool holding shaft has collided with an opposing surface provided by a collision face plate or a workpiece in the axis movement of the tool holding shaft according to a command; Correction amount calculating means for calculating a tool length correction amount from the difference between the coordinate value of the tool holding axis and the coordinate value of the measurement start coordinate position, and the tool is calculated based on the tool length correction amount calculated by the correction amount calculating means. Numerical control device characterized by automatically correcting the length. 15. A numerical control device provided by a collision face plate capable of axially moving the opposed surface portion in the same direction as the axial movement direction of the tool holding shaft, wherein the tool holding shaft is axially moved by a full stroke or a predetermined stroke. A sampling mode command analyzing means for analyzing a sampling mode command for sampling the motor load current of the tool holding shaft; and a motor load current variation based on the motor load current sampled in the full-stroke or predetermined stroke axis movement by the sampling mode command. Sampling current analysis means for detecting a stroke area having a small amount of collision, and collision face plate axis movement interpolation processing means for performing interpolation processing for axially moving the collision face plate so that a tool tip collides with the collision face plate in the stroke area. Claims characterized by the following Numerical controller according to 4. 16. A numerical control device provided with the facing surface portion from a workpiece, comprising a measurement area feed speed setting means for setting an axis moving speed of the tool holding shaft according to a material of the workpiece. The numerical control device according to claim 14, wherein: 17. The apparatus according to claim 14, further comprising a high-speed feeding means for moving the tool holding shaft to the measurement start coordinate position at a high speed prior to causing the tip of the tool to collide with the facing surface portion. Numerical control device as described. 18. A warm-up means for warming up the feed screw mechanism of the tool holding shaft by moving the tool holding shaft for a predetermined time before the tip of the tool collides with the facing surface portion. The numerical control device according to claim 14, comprising: 19. The collision detecting means detects that a tool tip collides with an outer peripheral surface of the workpiece in a state where the workpiece having a circular cross section forming the opposed surface portion is rotated. Item 15. The numerical control device according to item 14. 20. The collision detecting means according to claim 1, wherein said spindle motor for rotating a bar-shaped workpiece having a circular cross section formed by said opposing surface portion is servo-locked with respect to a change in load current of said spindle motor and said tool holding shaft. 15. The numerical controller according to claim 14, wherein a change in the motor load current is used to detect that the tip of the tool collides with the outer peripheral surface of the workpiece. 21. A tool holding shaft is moved by a predetermined amount to cut a workpiece by a tool mounted on the tool holding shaft, and the dimensions of the workpiece before cutting and the size of the workpiece after cutting are cut. A tool length correction infeed / measurement command analyzing means for analyzing the tool length correction infeed / measurement command for measuring the dimensions and the tool length correction infeed / measurement command, Correction amount calculating means for calculating a tool length correction amount from a deviation between an actual depth of cut due to a difference with a dimension of a workpiece and a command depth of cut obtained from an axis movement command value of the tool holding axis; A numerical control device for automatically correcting a tool length based on a tool length correction amount calculated by an amount calculating means. 22. A work center determination command analyzing means for analyzing a work center determination command for determining a work center, and a main shaft motor for rotating a rod-shaped workpiece having a circular cross section by the work center determination command is servo-locked. In this state, the load current of the spindle motor is detected, the tool holding shaft is axially moved, and the tip of a tool mounted on the tool holding shaft collides against the outer peripheral surface of the workpiece. The direction of the offset of the tool holding axis with respect to the center axis of the workpiece is detected from the polarity of the increase / decrease change of the load current. The detection of the offset direction of the tool-holding axis is repeated from the polarity of the increase / decrease change of the tool spindle. Numerical controller, characterized in that it comprises a workpiece center determination means for detecting the position. 23. A work center calculation command analyzing means for analyzing a work center calculation command for calculating a work center, wherein the tool holding shaft is radially moved with respect to a rod-shaped workpiece having a circular cross section by the work center calculation command. Moving, detecting that the side surface of the tool mounted on the tool holding shaft collides with the workpiece from a change in the motor load current of the tool holding shaft, and detecting the radial direction of the tool holding shaft at the time of the collision. And a work center calculating means for calculating a center position of the workpiece from the coordinate values of (a) and (b). 24. A tool wear degree estimation command analyzing means for analyzing a tool wear degree estimation command for estimating a tool wear degree, and a tool holding axis is axially moved based on the tool wear degree estimation command, and mounted on the tool holding axis. Wear degree estimating means for detecting that the tip of the tool collides with the workpiece by detecting the motor load current of the tool holding shaft and estimating the degree of wear of the tool from the rate of change of the motor load current at the time of the collision. And a numerical controller characterized by having: 25. The wear degree estimating means estimates a tool wear degree based on data indicating a correlation between a current change rate and a tool wear degree set in advance for each material of a workpiece. The numerical control device according to claim 24.