JPH09300177A - Tool cutting edge tip detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the reduction in cutting edge tip position detection accuracy due to elastic deformation of a support member which supports a detection sensor which detects the contact with a tool cutting edge tip and perform cutting edge tip position compensation of a grip means which grips a workpiece by taking thermal deformation. into consideration. SOLUTION: A tool cutting edge tip detection device 40 is provided with a dummy workpiece 2 which has the same shape as a workpiece and can be mounted and dismounted on a chuck 3. A detection part main body is attached to the other face 2b of the dummy workpiece 2. Detection sensors 30, 32 are mounted in the detection part main body and are supported on the detection part main body so that they are positioned in parallel in the Z direction and Y direction, respectively. The detection sensors 30, 32 consist of touch sensors which detect the contact when they come into contact with a cutting edge tip 7a of a tool 7 and output a detection signal, and the outputted detection signal is given to a numerical controller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool cutting edge detecting device used for a machine tool having a cutting edge position correcting function for correcting a cutting edge position of a tool for machining a workpiece held by a gripping means, and more particularly to an NC lathe and the like. The present invention relates to a tool edge detection device suitable for.

[0002]

2. Description of the Related Art Conventionally, an NC lathe having a cutting edge position correcting function for correcting the cutting edge position of a tool for machining a workpiece held by a chuck detects the cutting edge position of the tool and corrects the cutting edge position based on this detection signal. There is something to do.

An NC lathe having this blade edge position correcting function will be described with reference to FIG. 2A and 2B are diagrams showing a main part of an NC lathe in which a conventional tool edge detecting device is mounted, FIG. 2A is a front view thereof, and FIG. 2B is a plan view thereof.

In the conventional NC lathe, as shown in FIG.
The tool blade edge detection device 50 is used to execute the blade edge position correction function.

The tool edge detecting device 50 is provided with an arm 21.
The arm 21 is attached to a position near a spindle (headstock) 4 that rotates the chuck 3 around a spindle centerline 31 in the Z direction (main axis direction). Specifically, one end of the arm 21 is rotatably supported by a support portion 4a provided near the spindle 4 in the Y direction, and the detection portion main body 20 is attached to the other end. The detection unit main body 20 is provided with a plurality of detection sensors 30 and 32 that detect the contact when the blade tip 7a of the tool 7 comes into contact and output a detection signal. When the blade edge position is detected, the detection sensors 30 and 32 respectively detect the Z direction,
The detection unit body 20 is supported so as to be positioned parallel to the X-direction axis, and detects the Z-direction and X-direction positions of the cutting edge 7a, respectively.

In this NC lathe, when the workpiece W is turned, the arm 21 is rotated around one end thereof to retract the detector main body 20 to the outside of the region to be processed.
The detection unit main body 20 should not interfere with processing,
The detector body 20 is protected from chips and the like.

When the position of the cutting edge is to be corrected by exchanging the tool 7, etc., the arm 21 is rotated about one end thereof,
The detector main body 20 is held at a position between the work W and the tool 7. Next, the holder base 9 for holding the tool holder 8 of the tool 7 is once moved to, for example, the initial position X0 in the X direction by the movable table 10 which is movable in the X and Z directions, and then again from the initial position X0 in the X direction. To detection sensor 32
Will be moved to. Simultaneously with the start of the movement from the initial position X0, the movement amount of the holder base 9 in the X direction is counted, and the coordinate position of the blade edge 7a of the tool 7 in the X direction is calculated by counting the movement amount.

When the cutting edge 7a of the tool 7 comes into contact with the detection sensor 32 of the detection unit main body 20 located at the predetermined position while the holder base 9 is moving, a detection signal is output from the detection sensor 32 and the detection signal is output. Holder base 9 at the same time
Movement is stopped.

At the same time when the movement of the holder base 9 is stopped, the holder base 9 moves from the initial position X0 to the stop position Xs.
The coordinate position Xt of the blade edge 7a of the tool 7 in the X direction is calculated based on the movement amount (Xst-X0) up to t. The calculated coordinate position Xt is compared with the reference coordinate position Xr, and the difference δx (= Xt−Xr) is calculated. Since the coordinate position of the cutting edge 7a of the tool 7 deviates from the reference coordinate position by the calculated difference δx, the coordinate position of the cutting edge 7a of the tool 7 is corrected with respect to the reference coordinate position according to the difference δx.

Next, in the position correction in the Z direction, the position is moved to the initial position Z0 in the Z direction, and the initial position Z0 is again moved in the Z direction toward the detection sensor 32. This initial position Z
Simultaneously with the start of movement from 0, the amount of movement of the holder base 9 in the Z direction is counted, and the coordinate position of the cutting edge 7a of the tool 7 in the Z direction is calculated by counting the amount of movement.

When the cutting edge 7a of the tool 7 comes into contact with the detection sensor 30 of the detection unit main body 20 at the predetermined position while the holder base 9 is moving, a detection signal is output from the detection sensor 30 and the detection signal is output. Holder base 9 at the same time
Movement is stopped.

At the same time when the movement of the holder base 9 is stopped, the holder base 9 moves from the initial position Z0 to the stop position Zs.
The coordinate position Zt of the blade edge 7a of the tool 7 in the Z direction is calculated based on the movement amount (Zst-Z0) up to t. The calculated coordinate position Zt is compared with the reference coordinate position Zr, and the difference δz (= Zt−Zr) is calculated. Since the coordinate position of the cutting edge 7a of the tool 7 deviates from the reference coordinate position by the calculated difference δz, the coordinate position of the cutting edge 7a of the tool 7 is corrected with respect to the reference coordinate position according to the difference δz.

After correcting the positions of δx and δz, the detection unit main body 20 is retracted to the outside of the region to be processed by the rotational movement of the arm 21, that is, the obstacles that interfere with the process are removed from the region to be processed, A space is ensured in which turning of W can be stably performed.

[0014]

In the above-described conventional tool edge detecting device 50, when the workpiece W is turned, the arm 21 is rotated around one end thereof to retract the detector main body 20 out of the region to be processed. This prevents the detection unit main body 20 from interfering with processing and protects the detection unit main body 20 from chips and the like.
Is set to be long.

However, since the length of the arm 21 is set to be long, the main body 20 of the detection unit by the arm 21 is
Since the supporting rigidity for the arm 21 becomes smaller and the amount of thermal deformation of the arm 21 becomes larger, when the arm 21 is rotated around one end thereof to hold the detector main body 20 at a position between the work W and the tool 7. Due to the deformation of the arm 21, the holding position of the detection unit main body 20 (detection sensors 30 and 32) is not constant, and the detection accuracy of the position of the cutting edge 7a of the tool 7 is reduced. Further, the support portion 4a supporting one end of the arm 21 is provided in the vicinity of the spindle 4, but the arm 21 is not directly affected by the thermal deformation of the spindle 4 itself, and the position of the cutting edge 7a of the tool 7 is corrected. Cannot be performed in consideration of thermal deformation of the spindle 4 itself (for example, the spindle 4 expands and contracts in the Z direction due to thermal influence).

As described above, the conventional tool edge detecting device 50
In the above, the elastic deformation of the arm 21 forming the support member for supporting the detection sensors 30 and 32 lowers the detection accuracy of the tool edge position, and the tool edge position correction is performed in consideration of the thermal deformation of the spindle 4 including the chuck. There is a problem that it can not be done.

The present invention has been made in view of the above problems, and eliminates the deterioration of the cutting edge position detection accuracy due to the elastic deformation of the support member that supports the detection sensor for detecting the contact with the cutting edge of the tool. In addition, thermal deformation of the gripping means for gripping the workpiece (for example, thermal deformation of the spindle 4 in the Z direction causes the relative position in the Z direction between the workpiece W gripped by the chuck 3 and the tool edge detection device 50). It is an object of the present invention to provide a tool blade edge detection device capable of performing blade edge position correction in consideration of the change (the Z direction distance between the work W and the tool blade edge 7a changes).

[0018]

To achieve the above object, the invention according to claim 1 provides a machine tool having a blade edge position correcting function for correcting a blade edge position of a tool for machining a workpiece held by a gripping means. In the tool edge detecting device used, a dummy work similar to the workpiece and attachable to and detachable from the gripping means, and attached to the dummy work, and when the blade edge of the tool comes into contact with the contact portion, the contact is detected. And a detection sensor that outputs a detection signal used for the blade edge position correction function.

In the structure of the tool edge detecting device according to the first aspect of the present invention, a dummy work similar to a workpiece and attachable to and detachable from the gripping means, and attached to the dummy work, when the blade edge of the tool comes into contact with the contact portion, Since it is provided with a detection sensor that detects the contact and outputs a detection signal used for the blade edge position correcting function, when performing the blade edge position correction along with the tool replacement, by holding the dummy work by the gripping means, The detection sensor attached to the dummy work will be attached to the gripping means under the same conditions as the attachment conditions of the gripping means to the workpiece, and if the cutting edge position is detected in this state, the tool cutting edge in consideration of thermal deformation of the gripping means. Position correction can be performed. That is, the work W gripped by the chuck 3 and the dummy work are made of the same material,
By being composed of similar or identical shapes,
Since both of them expand and contract under the influence of heat, the dummy work is always located at the actual machining position of the work W. This is because the thermal effect of the detection sensor attached to the dummy work is negligible. Therefore, as in the prior art, even if the relative displacement of the work W and the tool edge position detecting device 50 due to the thermal effect in the Z direction occurs,
This relative displacement is canceled in the present invention, and the tool edge 7
The position of the tool edge 7a can be corrected between a and the work W.

Further, since the dummy work forming the support member for supporting the detection sensor can be easily constructed so as to reduce mechanical and thermal elastic deformation, the dummy work is caused by the elastic deformation of the support member. It is possible to eliminate the deterioration of the tool edge position detection accuracy.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a main part of an NC lathe in which an embodiment of a tool edge detecting device according to the present invention is mounted. FIG. 1 (a) is a front view thereof, and FIG. 1 (b) is shown. Is a plan view thereof.

As shown in FIG. 1, the NC lathe has a spindle (spindle head) 4 for rotating a chuck 3 around a spindle center line 31 in the Z direction (spindle direction), and a tool equipped with a tool 7. A moving base 10 having a holder base 9 for holding the holder 8 and capable of movement control in each of the X and Z directions.
And a numerical controller (not shown) for performing a blade edge position correction function for correcting the blade edge 7a position of the tool 7 for processing the workpiece (not shown) held by the chuck 3, and the blade edge position correction A tool blade edge detection device 40 is used for.

The tool edge detector 40 is a dummy work 2 which can be attached to and detached from a chuck 3 having the same shape as the work.
Is provided. One surface 2a of the dummy work 2 facing the chuck 3 is formed as a reference surface, and the dummy work 2 is gripped by the chuck claws 5 of the chuck 3 while the one surface 2a of the dummy work 2 is abutted against the body 6. .

The detection unit body 1 is attached to the other surface 2b of the dummy work 2 which faces the chuck 3.
Detection sensors 30 and 32 are attached to the detection unit body 1, and the detection sensors 30 and 32 are supported by the detection unit body 1 so as to be positioned parallel to the X-direction and Z-direction axes, respectively. The detection sensors 30 and 32 have a contact surface (not shown) capable of contacting the blade edge 7a of the tool 7 from each of the X and Z directions, and when the blade edge 7a of the tool 7 comes into contact with the contact surface. It consists of a touch sensor composed of a high-precision micro-limit switch differential transformer, a piezoelectric element, etc., which detects and outputs a detection signal. The detection signal output from the detection sensor 30 or the detection sensor 32 is transmitted to the numerical controller by a wireless method. The detection signals output from the detection sensors 30 and 32 may be transmitted to the numerical controller by a wired method.

In this NC lathe, when the cutting edge position correction in the XZ plane is performed due to the replacement of the tool 7 or the like,
First, the dummy work 2 is gripped by the chuck claws 5 of the chuck 3 with the facing surface 2a thereof being abutted against the body 6
Positioning of the holder base 9 in the Z direction is performed by moving the moving base 10 in the Z direction so that the blade edge 7a of the tool 7 and the detection sensor 30 come into contact with each other to correct the blade edge position in the Z direction (of the detection sensor 32). Move to a position separated in the X direction on the center line). It is assumed that the cutting edge 7a of the tool 7 is properly positioned in the height direction (Y direction) by a core height adjusting device (not shown) provided in the holder base 9. The dummy work 2 is attached to and detached from the chuck 3 by a work loading device (not shown).

After the holder base 9 is positioned in the Z direction, the holder base 9 is moved in the X direction so that the holder base 9 moves in the X direction such that the cutting edge 7a of the tool 7 and the detection sensor 30 are separated from each other, for example, the initial position. After being moved to X0,
The initial position X0 is moved again in the X direction toward the detection sensor 32. At the same time when the movement from the initial position X0 is started, the numerical control device starts counting the movement amount of the movement amount holder base 9 of the movement table 10 in the X direction, that is, the movement amount of the movement table 10 in the X direction. The coordinate position of the blade edge 7a of the tool 7 in the X direction is sequentially calculated based on the moved amount.

While the holder base 9 is moving, the cutting edge 7 of the tool 7 is attached to the detection sensor 32 of the detection unit main body 1 located at the predetermined position.
When a comes into contact, a detection signal is output from the detection sensor 32, and the numerical control device inputs the detection signal and simultaneously stops the movement of the holder base 9, that is, the movement of the movable table 10.

At the same time when the movement of the holder base 9 is stopped, the holder base 9 is stopped from the initial position X0 to the stop position Xs.
The coordinate position Xt of the blade edge 7a of the tool 7 in the X direction is calculated based on the movement amount (Xst-X0) up to t. The calculated coordinate position Xt is compared with the reference coordinate position Xr, and the difference δx (= Xt−Xr) is calculated. Since the coordinate position of the cutting edge 7a of the tool 7 is deviated from the reference coordinate position by the calculated difference δx, the coordinate position of the cutting edge 7a of the tool 7 is corrected with respect to the reference coordinate position Xr according to the difference δx, and the correction is performed. The coordinate position of the cutting edge 7a of the tool 7 thus obtained is stored in the memory of the numerical controller as a true coordinate position.

Similarly, with respect to the positioning in the Z direction, after the holder base 9 is positioned in the X direction, the moving base 10 is moved in the Z direction (moved to a position separated in the Z direction on the center line of the detection sensor 30). Thus, the holder base 9 is moved to a position in the Z direction at which the cutting edge 7a of the tool 7 and the detection sensor 32 are separated from each other, for example, an initial position Z0, and then moved from the initial position Z0 toward the detection sensor 30 again in the Z direction. To be done. At the same time when the movement from the initial position Z0 is started, the numerical controller starts counting the movement amount of the movement amount holder base 9 of the movement table 10 in the X direction, that is, the movement amount of the movement table 10 in the Z direction. The coordinate position of the blade edge 7a of the tool 7 in the Z direction is sequentially calculated based on the moved amount.

While the holder base 9 is moving, the cutting edge 7 of the tool 7 is attached to the detection sensor 30 of the detection unit main body 1 located at the predetermined position.
When a comes into contact, a detection signal is output from the detection sensor 30, and the numerical control device inputs the detection signal and simultaneously stops the movement of the holder base 9, that is, the movement of the movable table 10.

At the same time when the movement of the holder base 9 is stopped, the holder base 9 is stopped from the initial position Z0 to the stop position Zs.
The coordinate position Zt of the blade edge 7a of the tool 7 in the Z direction is calculated based on the movement amount (Zst-Z0) up to t. The calculated coordinate position Zt is compared with the reference coordinate position Zr, and the difference δz (= Zt−Zr) is calculated. Since the coordinate position of the cutting edge 7a of the tool 7 deviates from the reference coordinate position by the calculated difference δz, the coordinate position of the cutting edge 7a of the tool 7 is corrected with respect to the reference coordinate position Zr in accordance with the difference δz. The coordinate position of the cutting edge 7a of the tool 7 thus obtained is stored in the memory of the numerical controller as a true coordinate position.

After this position correction, the dummy work 2 is removed from the chuck 3, and the detection part main body 20 including the detection sensors 30 and 32 is evacuated to the outside of the processing area, that is, the processing area interferes with the processing. The obstacles are removed, a space is ensured in which the turning of the work W can be stably performed, and the detection sensors 30 and 32 are protected from chips, cutting fluid, and the like.

Next, instead of the dummy work 2, the work is attached to the chuck 3, and the corrected cutting edge 7 of the tool 7 is attached.
Processing is started from the coordinate position of a.

The blade edge position correction in the XZ direction is as follows.
Right-handed tool 7 or left-handed tool 7 shown in FIG. 1 (b)
It is possible to perform the same procedure for each of the above.

The tool edge detecting device 4 configured as described above
In No. 0, the dummy work 2 is attached to the chuck 3 when the blade edge position is corrected due to the exchange of the tool, so that the detection sensors 30 and 32 attached to the dummy work 2 meet the attachment condition of the work to the chuck 3. The tool 3 is attached to the chuck 3 under the same conditions, and the position of the cutting edge 7a of the tool 7 is detected by the detection sensors 30 and 32 under the condition that the work is affected by the same heat. As a result, the blade edge position can be corrected in consideration of the thermal deformation of the chuck 3.

Further, since the dummy work 2 forming a support member for supporting the detection sensors 30 and 32 can be easily constructed so as to reduce the mechanical and thermal elastic deformation, the elastic deformation amount of the dummy work 2 can be reduced. It can be suppressed to a small value, and it is possible to prevent a decrease in the tool edge position detection accuracy due to the elastic deformation of the support members of the detection sensors 30 and 32.

In the present embodiment, the dummy work 2 is attached to and detached from the chuck 3 by a work loading device, but instead of this, the work is manually performed by an operator as needed. The dummy work 2 may be attached to and detached from the chuck 3. Furthermore, taking out and storing the dummy work 2 from the storage position,
By providing a device for automatically carrying the dummy work 2 between the storage position and the chuck 3 and attaching and detaching the dummy work 2 to and from the chuck 3, the handling work on the dummy work 2 can be further simplified. it can.

[0039]

As described above, according to the tool edge detecting device of the first aspect, a dummy work similar to a workpiece, which is attachable to and detachable from the gripping means, and attached to the dummy work, has a contact portion. When the cutting edge of the tool comes into contact, it is provided with a detection sensor that detects the contact and outputs a detection signal used for the cutting edge position correction function. By holding with the gripping means, the detection sensor attached to the dummy work is attached to the gripping means under the same conditions as the attachment conditions of the gripping means to the workpiece,
The blade edge position can be corrected in consideration of the thermal deformation of the gripping means.

Further, since the dummy work forming the support member for supporting the detection sensor can be easily constructed so as to reduce the mechanical and thermal elastic deformation, the dummy work is caused by the elastic deformation of the support member. It is possible to eliminate the decrease in the blade edge position detection accuracy.

[Brief description of drawings]

FIG. 1 is a diagram showing a main part of an NC lathe on which an embodiment of a tool edge detection device according to the present invention is mounted.

FIG. 2 is an NC equipped with a conventional tool edge detection device.
It is a figure which shows the principal part of a lathe.

[Explanation of symbols]

 1 Detection Unit Main Body 2 Dummy Work 3 Chuck 7 Tool 7a Blade Edge 30, 32 Detection Sensor 40 Tool Blade Edge Detection Device

Claims (1)

[Claims] 1. A tool cutting edge detection device used in a machine tool having a cutting edge position correcting function for correcting a cutting edge position of a tool for machining a workpiece held by the gripping means, the gripping means being similar to the workpiece. A removable dummy work, and a detection sensor that is attached to the dummy work and that detects the contact when the blade edge of the tool comes into contact with the contact portion and outputs a detection signal used for the blade edge position correction function. A tool edge detection device characterized in that