JPH08197384A - Tip position correction device of rotating tool - Google Patents

Abstract

PURPOSE: To make a cut and machined surface procise by carrying out automatic correction by detecting a knife edge position including deflection of a rotating tool. CONSTITUTION: A measuring arm 15 having an X-axis sensor 16 and a Z-axis sensor 17 on a work spindle stock is provided on a stand-by position and a measuring position free to divide on a machine tool placing spindle heads 3-5 having end mills T1 -T3 and a spindle head 6 having a bar grinding stone T4 in parallel on an upper trestle 2 free to move in the X axial direction and having a spindle 12 for a work axially supported on the work spindle stock 11 free to move in the Z axial direction free to revolve and divide. Respective correction values are found by detecting a knife edge position including deflection of the end mills T1 -T3 by the X-axis sensor 16, and respective Z-axis correction values are found by the Z-axis sensor 17 in the same way and memorized, and at the time of machining, correction is carried out against a program command value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blade edge position correcting device including displacement due to runout of a rotary tool of an NC machine tool.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 9 (a), a blade position detecting device for an NC lathe is provided at the tip of a measuring arm 102 provided on a headstock 101 for swivel indexing between a measuring position and a standby position. , A touch sensor 1 that stores a plurality of touch sensors 103 that are oriented in a direction perpendicular to the spindle axis (hereinafter referred to as the X-axis direction) and in the spindle axis direction (hereinafter referred to as the Z-axis direction), and that is stored in advance.
The distance of the X-axis or Z-axis from the processing origin when the cutting edge of the cutting tool 104 abuts on 03 and outputs a touch signal, and the current value of the X-axis or Z-axis of the tool rest 105 when stopped by the touch signal. Are compared to obtain a correction value, and the machining is performed while correcting the program command value with the obtained correction value.

In the case of a rotary tool such as the end mill 106, as shown in FIG. 9B, the touch sensor 1 is used as described above.
Z from the processing origin when the tip of the rotary tool contacts 03
The axial distance was compared with the current Z-axis value of the tool rest 105 to obtain a Z-axis correction value and correction was performed.

However, it is usual not to consider the correction of the displacement of the cutting edge in the radial direction due to the runout of a rotary tool such as an end mill, and the dimension of the machined surface using the runaway tool with runout from the machining origin is highly accurate. Can't get Therefore, when machining a workpiece with high accuracy, when the rotary tool is mounted on the spindle at the machining site, the probe of a measuring instrument such as a millimeter knife fixed in an appropriate position is brought into contact with the cutting edge of the rotary tool to loosen the spindle. Measure the shake while rotating to
The present situation is that the machining is performed after the runout is adjusted to the minimum by reattaching the tool.

[0005]

The method of re-installing the rotary tool at the machining site as described in the prior art until the runout is minimized is extremely complicated and requires labor and time, which is an obstacle to labor saving. I have a problem. The present invention has been made in view of the above problems of the conventional technique, and an object thereof is, for example, high accuracy with a grindstone (rotary tool) on a surface cut by an end mill (rotary tool) with one chuck. In the case of grinding in the same manner, an object of the present invention is to provide a blade edge position correction device that can detect the blade edge position including the displacement due to the runout of the rotary tool and automatically correct it so that high-precision machining can be performed continuously with peace of mind. It is a thing.

[0006]

In order to achieve the above object, the blade edge position compensating device for a rotary tool according to the present invention is arranged in a direction perpendicular to the spindle axis of the movable table on which the work is mounted and the spindle head for the rotary tool. A correction device for a cutting edge position including a displacement due to a runout of a rotary tool of an NC machine tool that performs machining by relative axial movement with respect to an X axis and a Z axis in the spindle axis direction. An X-axis displacement sensor for detecting the radial displacement due to the runout and a Z-axis displacement sensor for detecting the axial displacement due to the runout of the cutting edge of the rotary tool tip are provided, and the radial direction detected by the X-axis displacement sensor is provided. X from the X-axis machining origin of the maximum deflection of the cutting edge on the machining side calculated from the amount of displacement
Means for obtaining an X-axis correction value by comparing the axial distance and the X-axis current value at the time of shake detection, and a maximum runout position of the cutting edge of the cutting edge obtained from the axial displacement detected by the Z-axis displacement sensor. The means for comparing the Z-axis distance from the Z-axis origin and the Z-axis current value at the time of shake detection to obtain the Z-axis correction value is provided, and the X-value obtained
A means for correcting the program command value at the time of machining is provided by the axis correction value and the Z axis correction value.

[0007]

Working is performed by, for example, the Z-axis movement positioning of the movable table on which the work is detachably attached, and by the X-axis movement positioning of the spindle head on which the spindle for detachably mounting the rotary tool is rotatably supported. In the NC machine tool, the X-axis displacement sensor and the Z-axis displacement sensor at the tip of the measuring arm provided on the moving table are indexed to the measurement position on the plane passing through the spindle axis and the Z-axis movement of the moving table is performed prior to cutting. By moving the spindle head along the X-axis, the rotary tool is positioned near the position measured by the X-axis displacement sensor. Then, the spindle head is fed at a low speed to the X-axis direction sensor side, and when the probe of the X-axis displacement sensor comes into contact with the outer peripheral surface of the rotary tool and a signal is output, the X-axis movement of the spindle head is stopped.

Next, the rotary tool is rotated at a low speed in the opposite direction of the cutting to detect the radial displacement amount due to the deflection of the cutting edge, and the reference distance from the X-axis machining origin of the X-axis displacement sensor stored in advance is detected. The X-axis distance is calculated from the X-axis machining origin at the maximum deflection of the cutting edge on the machining side, and the calculated X-axis distance is compared with the X-axis current value of the spindle head to correct the X-axis. Obtain and store the value.

Next, the rotary tool is positioned near the position measured by the Z-axis displacement sensor by the Z-axis movement of the movable table and the X-axis movement of the spindle head, and the movable table is fed at low speed to the Z-axis direction sensor side to move the Z-axis. When the contact point of the displacement sensor comes into contact with the tip surface of the rotary tool and a contact signal is output, the Z-axis movement of the movable table is stopped.

Then, similarly to the above, the rotary tool is reversely rotated to detect the axial displacement amount due to the deflection of the cutting edge, and the maximum displacement amount due to the deflection and the reference distance from the Z-axis machining origin of the Z-axis displacement sensor stored in advance. From this, the Z-axis distance is calculated from the Z-axis processing origin at the maximum runout position of the cutting edge, and the calculated Z
The Z-axis correction amount is calculated by comparing the axial distance with the Z-axis current value of the movable table and stored. Then, at the time of cutting, the stored X-axis correction value and Z-axis correction value are called to perform processing while correcting the program command value.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In the NC machine tools shown in FIGS. 1 and 2, the upper base 2 is movably positioned on the guide 1a in the X-axis direction provided on the bed 1 installed on the floor.
Four spindle heads 4, 5 and 6 from the first spindle head 3 to the fourth spindle head 6 are mounted on the upper side in parallel at substantially equal pitches with the front end faces aligned substantially.

Of the four spindle heads, the first spindle head 3 to the third spindle head 3
The three up to the spindle head 5 are for milling, and the rotary tool spindles 7 to 9 are rotatably supported, and the remaining fourth
The spindle head 6 is for grinding and a spindle 10 for a grindstone is rotatably supported. The end mill to the main shaft 7 to 9 for a rotary tool (rotary tool) T ₁ through T ₃ are detachably mounted respectively, rod-shaped grindstone in the grinding wheel spindle 10 (rotary tool) T ₄ is detachably attached.

Further, a work headstock 11 is movably mounted on a guide (not shown) provided on the left side of the bed 1 in the Z-axis direction. A work spindle 12 is supported on the work spindle stock 11 so that the work spindle 12 can be swivel-indexed.
A chuck 13 is concentrically fitted to the tip of the work spindle 12, and the work W is detachably gripped by a grip claw 13 a of the chuck 13.

Further, a bracket 14 is fixed to the front end surface 11a of the work headstock 11 and the bracket 14 has an L-shape.
A character-shaped measuring arm 15 is rotatably supported, and the measuring arm 15 is rotatably positionable by an actuator 18 between an upper standby position a and a measuring position b on a plane passing through the spindle axis. Then, an X-axis displacement sensor 16 (hereinafter simply referred to as an X-axis sensor) that detects a radial displacement amount due to runout of the outer circumference of the rotary tool at the tip of the measurement arm 15.
And a Z-axis displacement sensor 17 (hereinafter simply referred to as a Z-axis sensor) that detects the amount of axial displacement due to the shake of the tip.

As the X-axis sensor 16 and the Z-axis sensor 17, it is possible to use an ultra-small contact type displacement sensor such as AT type manufactured by KEYENCE. This is a displacement sensor that uses an amorphous magnetic alloy as the core and is lighter and more compact than the conventional differential transformer system.It is centered on the zero point, which is the reference in proportion to the amount of movement of the stylus that can move in the axial direction. And outputs ± voltage.

FIG. 3 is a block diagram showing the control system of the NC device 19 relating to the blade edge position correcting device for a rotary tool of the present invention. The program storage unit 21 is a unit that stores a measurement program and a machining program sent from the input unit 20. The program analysis unit 22 is a unit that analyzes the contents of the program and sorts the signals to the required places. Function generator 23
Is the part that generates the functions required for each axis control.

The spindle motor control unit 24 is for the work spindle 1
A part that controls the rotation of the spindle motor 25 that drives the motor 2. X
The axis motor control unit 26 controls the X-axis motor 2 that drives the upper base 2.
The part that controls the rotation of 7. The X-axis position detector 28 is a detector that is rotated by the X-axis motor 27 and detects the current value of the upper table 2 in the X-axis direction. The Z-axis motor control unit 29 is a part that controls the rotation of the Z-axis motor 30 that drives the work headstock 11. The Z-axis position detector 31 is a detector that is rotated by the Z-axis motor 30 and detects the current value of the work headstock 11 in the Z-axis direction.

The X-axis sensor output detector 32 is arranged at the measurement position b.
A part for converting the ± voltage centered around zero output by the contact point 16a of the X-axis sensor positioned at the contact point with the object to be measured (rotary tool) to a digital numerical value and outputting it. In the X-axis sensor reference distance storage unit 33, the probe 16a of the X-axis sensor 16 positioned at the measurement position b is pressed into contact with the object to be measured, and the X-axis sensor output detection unit 32 displays a reference value of zero. This is a part for storing the reference distance A (FIG. 4) from the sensor position to the processing origin when output.

The X-axis correction value calculation unit 34 uses, for example, the end mill T ₁ detected by the X-axis sensor 16 as shown in FIG.
From the maximum displacement C in the radial direction due to the runout of the outer circumference and the reference distance A of the X-axis sensor, the distance B from the maximum runout position of the cutting edge of the end mill T ₁ to the X-axis machining origin is found, and the found distance B
And an X-axis current value of the upper table 2 detected by the X-axis position detector 28 are compared to obtain an X-axis correction value D ₁ (FIG. 7).

A calculation example of the X-axis correction value calculation unit 34 described above is as follows.
This is a case where the correction value of the end mill T ₁ of the first headstock 3 is obtained, and the end mill T ₂ of the second headstock 4 or the third headstock 5 is used.
To obtain the respective correction values for the end mill T ₃ of
At the obtained distance B, the pitch P ₁ between the first spindle head 3 and the second spindle head 4 or the pitch P between the first spindle head 3 and the third spindle head 4
_The correction value D ₂ or D ₃ is obtained by comparing the numerical value obtained by adding ₂ (FIG. 7) and the X-axis current value.

Further, the portion for obtaining the correction value of the grindstone T ₄ of the fourth spindle head 6 is almost the same, but in this case, since the dressing is performed on the machine before the measurement, it is not necessary to detect the shake, The distance B is the distance from the X-axis machining origin to the stationary outer peripheral surface of the grindstone. The X-axis correction value storage unit 35 is a unit that stores the obtained X-axis correction values.

The Z-axis sensor output detector 36 is arranged at the measurement position b.
A portion for converting the ± voltage centered on the reference zero point output by the contact point of the Z-axis sensor 17 positioned at the point of contact with the object to be measured and converting it into a digital numerical value. The Z-axis sensor reference storage unit 37 stores the Z position from the sensor position when the probe of the Z-axis sensor 17 is pressed into contact with the object to be measured and the reference zero value is output from the Z-axis sensor output detection unit 36. This is a part for storing the reference distance E (FIG. 4) to the axis machining origin.

As shown in FIG. 4, the Z-axis correction value calculation unit 38 is positioned at the measurement position b and detected by the Z-axis sensor 17 and the maximum displacement amount G in the axial direction due to the shake of the tips of the end mills T _{1 to} T _{3 is} detected. The distance F from the maximum deflection of the cutting edge to the Z-axis machining origin is calculated from the reference distance E of the Z-axis sensor, and the distance F and the Z-axis current value of the work spindle head 11 detected by the Z-axis position detector 31 are calculated. Comparing the Z-axis correction values H _{1 to} H ₃
This is a part for obtaining (FIG. 7).

Further, when obtaining the correction value H ₄ of the grindstone T ₄ , it is not necessary to detect the shake like the above, so the distance F
Is the distance from the Z-axis machining origin to the stationary end face of the grindstone. The Z-axis correction value storage unit 39 is a unit that stores each of the calculated correction values. The pitch between the spindle head is NC device 19 in the case of absolute value scheme the first spindle head 3 between the third main spindle distance and P _2, a first spindle head 3 and the fourth spindle head distance P ₃ Although it is more convenient, when the NC device is an incremental type, P ₂ ′ is between the second spindle head 4 and the third spindle head 5, and P ₃ ′ is between the third spindle head 5 and the fourth spindle head 6. Is more convenient (Fig. 7).

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. In step S1, the measurement arm 15
Is positioned at the measurement position b, and the end mill T ₁ of the first spindle head 3 is moved to the measurement position XSn (XS ₁ ) by the X-axis sensor 16 by the Z-axis movement of the work headstock 11 and the X-axis movement of the upper base 2.
Position near. In step S2, upper table 2
Is moved toward the minus side in the X-axis direction at low speed, and in step S3, the tracing stylus 16a of the X-axis sensor 16 is moved to the end mill T.
_{1 It} is confirmed whether the X-axis sensor comes into contact with the outer peripheral portion and a signal is output. If NO, the process returns to step S2 and the upper table 2 is moved along the X-axis until a contact signal is output.

If YES, then step S4
In, the X-axis movement of the upper table 2 is immediately stopped, and it is confirmed in step S5 whether N = 3 or less. In this case, since N = 1, the determination result is YES, and in step S6, the spindle 7 (end mill T ₁ ) is reversely rotated at a low speed in the reverse direction during cutting (FIG. 5).

In step S7, the tracing stylus 16a axially moves following the irregularities of the outer peripheral surface by the reverse rotation of the end mill T ₁ , and as shown in the graph of FIG. appear. This peak point is the end mill T
Includes the deflection of _one radial, the maximum value from the zero point when the end mill T ₁ is to more one rotation (deflection maximum value) is detected.

Next, in step S8, the distance B from the X-axis machining origin at the maximum deflection position of the cutting edge is calculated from the sum of the maximum deflection C and the X-axis sensor reference distance A stored in advance, and the calculated distance B is obtained. The correction value D ₁ (FIG. 7) is obtained by comparing with the X-axis current value and stored.

Next, in step S9, the end mill T ₁ of the first spindle head 3 is moved to the measuring position ZSn by the Z-axis sensor 17 by the Z-axis movement of the work headstock 11 and the X-axis movement of the upper base 2.
(ZS ₁ ), the work headstock 11 is moved to the negative side in the Z-axis direction at a low speed in step S10, and the probe of the Z-axis sensor 17 contacts the tip of the end mill T ₁ in step S11. Then, it is confirmed whether a signal is output. If NO, the process returns to step S9 and the headstock 11 is moved in the Z-axis until a contact signal is output.

If YES, step S1
In 2, the Z-axis movement of the work headstock 11 is stopped, and in step S13, it is confirmed again whether N = 3 or less,
Here too, the answer is YES, and in step S14, the spindle 7 (end mill T ₁ ) is reversely rotated at low speed.

[0031] Then, in step S15, Z-axis sensor 1 to follow the unevenness of the distal end surface at the reverse rotation of the end mill T ₁
The probe of No. 7 moves in the axial direction, and a peak point appears every time the cutting edge comes to the front surface. This peak point includes the displacement in the axial direction due to the shake of the end mill T ₁ , and the maximum value (runout maximum value) G from the zero point of the peak point is detected.

Next, at step S16, the distance F from the Z-axis machining origin of the maximum deflection of the cutting edge is obtained from the sum of the maximum deflection G and the reference distance E of the Z-axis sensor stored in advance.
The calculated distance F is compared with the Z-axis current value to calculate and store the correction value H ₁ (FIG. 7). Next, in step S17, it is confirmed whether N = 4. In this case, N = 1, so NO.
Then, in step S18, n + 1 is performed and N =
It becomes 2 and the process returns to step S1.

Continuing, X of the end mill T ₂ of the second spindle head 4
Second step S1 to S8 of obtaining and storing the axis correction value
And the second operation of obtaining and storing the Z-axis correction value in steps S9 to S16. In this way, the correction value of the end mill T ₂ of the second spindle head 4 is calculated and stored, and the operation of N = 2 ends, and at step S18 N
= 3.

Then, in the third operation of steps S1 to S17, the X-axis and Z-axis correction values of the end mill T ₃ of the third spindle head 5 are calculated and stored, and the operation of N = 3 ends, and step S18 N = 4 in the fourth step S
1, the grinding wheel T ₄ of the fourth spindle head 6 is attached to the X-axis sensor 16
Position near the predetermined measurement position XS ₄ by.

Then, in step S2, the upper base 2 is moved to the X position.
It moves to the minus side in the axial direction at a low speed, and in step S3, it is confirmed whether or not the contact point 16a of the X-axis sensor 16 has contacted the outer circumference of the grindstone, and if NO, the process returns to step S2,
If YES, the X-axis movement of the upper table 2 is stopped in step S4.

Next, in step S5, it is confirmed whether N = 3 or less. In this case, N = 4, and thus NO, and in step S8, the value from the zero point of the X-axis sensor 16 at the time of contact and the reference of the X-axis sensor. The distance B from the X-axis machining origin to the outer peripheral surface of the grindstone T ₄ is calculated from the sum of the distance A, and the calculated distance B is compared with the X-axis current value of the upper table 2 to obtain the X-axis correction value D ₄
(FIG. 7) is obtained and stored.

Next, in step S9, the grindstone T ₄ of the fourth spindle head 6 is positioned near the measurement position ZS ₄ measured by the Z-axis sensor 17, and in step S10 the work spindle stock 11 is moved to the minus side in the Z-axis direction at low speed. After moving, it is confirmed in step S11 whether or not the Z-axis sensor 17 is contacted. If NO, the process returns to step S10. If YES, in step S12, the Z of the work headstock 11 is moved.
The axis movement is stopped, and in step S13, it is confirmed whether N = 3 or less. In this case, N = 4, so NO is reached, and the process jumps to step S16, and the Z-axis sensor 17 at the time of contact detection.
Z from the sum of the value from the zero point of Z and the reference distance E of the Z-axis sensor
The distance F from the axis machining origin to the tip surface of the grindstone T ₄ is obtained, and the obtained distance F is compared with the Z-axis current value of the work headstock 11 to calculate a Z-axis correction value, which is stored. Then, in step S17, it is confirmed whether N = 4, and the result is YES, and the process ends.

However, the X-axis correction values D _{2 to} D ₄ calculated in the second to fourth steps S8 are based on the arrangement from the first spindle head 3 which is a reference to the distance B from the X-axis machining origin to the cutting edge. It is obtained from the difference between the value obtained by adding the X-axis dimensions P _{2 to} P ₃ and the X-axis current value of the upper table 2 (FIG. 7).

In the series of operations of this embodiment, the X-axis direction and the Z-axis direction are sequentially measured for each spindle head, but the Z-axis direction is measured after the measurement of each spindle head in the X-axis direction is completed. May be measured. Further, in the present embodiment, an example of an NC machine tool having a plurality of spindle heads has been described, but it goes without saying that a single spindle head is also applicable.

[0040]

Since the present invention is configured as described above, it has the following effects. Since the tool position is automatically corrected by detecting the tool edge position including the radial and axial runout of the rotating tool, for example, deterioration of machining accuracy due to runout of the end mill and dimensional error, and tool replacement There are no machining problems due to dimensional errors or mounting errors, and the preparation time can be shortened by eliminating the need to measure the tool condition with a measuring instrument in advance.

Further, for example, in the case where the surface machined by the end mill is ground by holding the work once, the cutting edge position of the grindstone which changes depending on the dressing is automatically detected simultaneously with the detection of the blade tip position including the runout of the end mill. If the correction is carried out, the machined surface of the end mill is accurate, and the machined surface is accurate regardless of the dimensional change due to the dressing of the grindstone. Therefore, continuous processing can be smoothly and highly accurately performed.

[Brief description of drawings]

FIG. 1 is a top view of an NC machine tool having a rotary tool blade position correcting device according to an embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a block diagram showing a control system of a blade edge position correcting device for a rotary tool.

FIG. 4 is an explanatory diagram showing a relationship between detection of shake of a rotary tool by a sensor and a distance from a processing origin.

5 is a cross-sectional view taken along the line EE of FIG.

FIG. 6 is a graph showing the deflection of the cutting edge.

FIG. 7 (a) is an X of a plurality of spindle head end mills and a grindstone.
FIG. 6B is an explanatory diagram of measurement of the blade edge position by the axis sensor, and FIG. 8B is an explanatory diagram of blade edge position measurement by the Z axis sensor of the plurality of spindle head end mills and the grindstone.

FIG. 8 is a flowchart for explaining the operation of the embodiment of the present invention.

FIG. 9A is a top view showing a state in which a cutting edge position of a cutting tool is detected in an NC lathe according to a conventional technique, and FIG.
It is a figure which shows the state of the tip position detection of the end mill in a C lathe.

[Explanation of symbols]

1 Bed 2 Upper Platform 3 1st Spindle Head 4 2nd Spindle Head 5 3rd Spindle Head 6 4th Spindle Head 7,8,9 Spindle Tool Spindle 10 Grindstone Spindle 11 Work Spindle Base 12 Work Spindle 13 Chuck 15 Measuring Arm 16 X-axis displacement sensor 17 Z-axis displacement sensor 28 X-axis position detector 31 Z-axis position detector 32 X-axis sensor output detector 33 X-axis sensor reference distance storage unit 34 X-axis correction value calculation unit 36 Z-axis sensor output detection Part 37 Z-axis sensor reference distance storage unit 38 Z-axis correction value calculation unit T ₁ , T ₂ , T ₃ End mill (rotary tool) T ₄ grindstone (rotary tool) W work

Claims (1)

[Claims] 1. An NC machine tool that performs machining by relative axial movement of an X-axis in a direction perpendicular to a spindle axis of a movable table on which a work is attached and a spindle head for a rotary tool and a Z-axis in a spindle axis direction. A correction device for a cutting edge position including a displacement due to a runout of a rotary tool, wherein an X-axis displacement sensor for detecting a radial displacement amount due to a runout of a cutting edge around the rotary tool and a runout of a tip end of the rotary tool on the moving base. An X-axis distance from the X-axis machining origin of the maximum deflection of the cutting edge on the machining side, which is provided with a Z-axis displacement sensor that detects the amount of axial displacement, and is determined from the amount of radial displacement detected by the X-axis displacement sensor. And a current X-axis value at the time of shake detection to obtain an X-axis correction value, and a Z-axis of the maximum run-out position of the cutting edge of the machining side obtained from the amount of axial displacement detected by the Z-axis displacement sensor. Z-axis distance from the origin and Z-axis current when shake is detected A cutting edge position of a rotary tool, which is provided with a means for comparing a current value with a Z-axis correction value, and means for correcting a program command value at the time of machining based on the obtained X-axis correction value and Z-axis correction value. Correction device.