JP2002011587A - Height profiling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately profile the surface of a steel plate regardless a variation of an inclined angle when a nozzle which emits a laser beam is inclined with respect to the steel plate. SOLUTION: The device is provided with a nozzle 1 with which the steel plate B is irradiated with the laser beam and cut, a vertically driving motor 8, a detecting unit 32 which detects the electrostatic capacity between the nozzle 1 and the steel plate B, a reference value storage part 33 which stores information of the electrostatic capacity when the nozzle is in a reference state with respect to the steel plate, a correction value storage part 34 which stores information of the correction value of the electrostatic capacity when the nozzle is inclined with respect to the steel plate, and a control part 35. The vertically driving motor 8 is driven to profile the steel plate corresponding to a difference when the difference is generated when a signal generated by the detection unit 32 is compared with the information of the reference value at the control part 35 when the nozzle 1 is in the reference state with respect to the steel plate B, and the vertically driving motor 8 is driven to make the nozzle 1 profile the steel plate B after the reference value or the value detected by the detection unit 32 is corrected by the information of the correction value when the nozzle 1 is inclined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of cutting a steel sheet by irradiating a steel sheet from a nozzle with a laser beam, even when the nozzle is inclined. And a height copying apparatus capable of copying so as to maintain the height.

[0002]

2. Description of the Related Art A laser beam is irradiated from a nozzle on a steel sheet to melt and evaporate a base material, and at the same time, an assist gas composed of oxygen gas is injected to burn the base material, and the molten material is injected by the assist gas injection energy. Cutting is performed by moving the nozzle in a desired direction while continuing the process of removing from the base material.

When cutting a steel sheet, the focus position of the laser light is set to an optimum position in accordance with the thickness of the steel sheet to be cut in order to maintain the purity of the assist gas injected together with the laser light from the nozzle. Further, in order to prevent the nozzle from coming into contact with the steel plate having distortion during cutting, the height of the nozzle from the steel plate surface is approximately 2 mm to 3 mm.
Is controlled to be kept within the range.

[0004] When maintaining the height of the nozzle in the above range, a plurality of air height sensors, laser height sensors, or a plurality of air height sensors arranged around the nozzle are used as sensors for detecting the height of the nozzle from the steel plate surface. We used a capacitance type sensor formed in a ring shape, but the detection site was located away from the nozzle and it was not possible to accurately detect the height of the nozzle. When approaching, there is a problem that a part of the sensor arranged around the nozzle comes off the steel plate. For this reason, a sensor configured to detect the capacitance between the nozzle and the steel plate by using the nozzle itself as one pole has been increasingly used.

On the other hand, in the case of relatively thick steel plates processed in factories such as shipbuilding factories and bridge factories, they are often welded in the next process after being cut, so that a groove is formed at the end face when cutting the steel plates. There is. In this case, in gas cutting or plasma cutting, the cutting torch is tilted in accordance with the desired groove angle, and in accordance with the shape of the figure to be cut while maintaining this tilt angle and the height from the surface of the steel sheet. Generally, cutting is performed by moving the nozzle. In these cutting torches, the cutting torch itself is not used as a part of the sensor, but a plurality of height sensors are arranged around the cutting torch, or a ring-shaped capacitance sensor is arranged to form the cutting torch. It is configured to follow the surface of a steel plate.

[0006]

Recently, the output of a laser oscillator has been increased, and accordingly, a relatively thick steel plate can be cut. For this reason, laser cutting equipment is being introduced even in shipbuilding factories and bridge factories. However, in these factories, it is essential to cut a steel plate in a groove, and a reasonable ratio including cutting capacity and cutting equipment is required. There is a demand for the development of a device that can carry out groove cutting.

When the nozzle for irradiating the laser beam is imitated to the steel plate while maintaining a substantially constant height from the steel plate, it is preferable to configure the nozzle as a part of the capacitance sensor. When the nozzle is opposed to the steel plate and the capacitance between the two is detected, the value of the detectable capacitance is set by the area of the tip end surface of the nozzle projected on the surface of the steel plate. For this reason,
When the nozzle is tilted, the area of the tip end surface of the nozzle projected on the surface of the steel sheet changes according to the tilt angle, and the value of the detected capacitance also changes accordingly. Therefore, the value of the detected capacitance includes a value resulting from a change in the height of the nozzle from the steel plate and a value resulting from the inclination of the nozzle. There is a problem that it cannot be realized.

[0008] An object of the present invention is to provide a height copying apparatus that can accurately follow the surface of a steel sheet when a nozzle for irradiating laser light is inclined with respect to the steel sheet, regardless of a change in the inclination angle. It is in.

[0009]

Means for Solving the Problems In order to solve the above problems, a height copying apparatus according to the present invention comprises a nozzle for irradiating a steel sheet with a laser beam to cut the steel sheet; A nozzle elevating member for elevating and lowering, a detecting member for detecting a capacitance between the nozzle and the steel plate to generate a detection signal, and a height which is a state where the nozzle is perpendicular to the steel plate and serves as a reference. A reference value storage unit that stores information on a reference value of capacitance corresponding to the state of the nozzle, an angle output member that outputs a signal corresponding to an inclination angle of the nozzle with respect to the steel plate, and the nozzle is inclined with respect to the steel plate. And a correction value storage unit for storing information on the correction value of the capacitance in the state of the reference height, and driving the nozzle elevating member to set the height of the nozzle from the steel plate in advance. Control to keep at the set value In the state where the nozzle is perpendicular to the steel plate, the control unit compares the detection signal generated from the detection member with the information of the reference value stored in the reference value storage unit. When a difference occurs, the nozzle elevating member is driven according to the difference to cause the nozzle to follow the surface of the steel sheet,
In a state in which the nozzle is inclined with respect to the steel plate, the information of the reference value stored in the reference value storage unit is corrected by the information of the correction value stored in the correction value storage unit, and a detection signal generated from the detection member. When a difference is generated by comparing the information with the corrected reference value, the nozzle elevating member is driven according to the difference so that the nozzle follows the surface of the steel plate, or the capacitance detected by the detecting member is corrected. The correction detection signal is generated by comparing the correction detection signal with the information of the reference value stored in the reference value storage member, and when a difference occurs, the nozzle elevating member is driven according to the difference to drive the nozzle to the steel plate. It is configured so as to follow the surface of.

In the height copying apparatus, the capacitance between the nozzle and the steel plate when the nozzle is perpendicular to the steel plate is stored in the reference value storage unit as a reference value, Is stored in the correction value storage unit when the steel sheet is inclined with respect to the steel sheet, and when the steel sheet is cut in a groove, when the nozzle is inclined at a target angle, a correction corresponding to the inclination angle is performed. Using the value, the information of the reference value stored in the reference value storage unit is corrected so that the corrected reference value corresponding to the inclination angle of the nozzle is used as a reference or the nozzle and the steel plate detected by the detection member are used as a reference. By correcting the detected value of the capacitance between the two, the detected value in the vertical state is corrected irrespective of the inclination angle of the nozzle, and the corrected reference value is used as the corrected detected value. Compare with the capacity value and The corrected detection value and the reference value are compared with each other, and when a difference is generated as a result of the comparison, the nozzle is moved up and down by driving the nozzle elevating member according to the difference, so that the height of the nozzle is constantly changed to a steel plate. Can be imitated so as to be within a substantially constant range from the surface.

When the nozzle is tilted to a target angle and the reference value is corrected in accordance with the tilt angle,
A method of adding and subtracting a value corresponding to the tilt angle to a preset reference value to correct the value, and storing a plurality of angle reference values corresponding to each of the predetermined tilt angles, and setting the nozzle to the target angle There is a method of selecting an angle reference value that matches or corresponds to the tilt angle when the tilt is made, and in any case, the correction can be reliably performed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a height copying apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating the configuration of the height copying apparatus. FIG. 2 is a diagram illustrating the relationship between the nozzle and the steel plate. FIG. 3 is a side sectional view for explaining the configuration of a groove cutting block for inclining the nozzle at a desired angle. FIG. 4 is an external front view of the groove cutting block. FIG. 5 is an external side view of the groove cutting block. FIG. 6 is a view for explaining the configuration of a laser cutting apparatus in which the height copying apparatus according to the present embodiment is preferably mounted.

Prior to describing the configuration of the height copying apparatus, the configuration of the laser cutting apparatus will be schematically described with reference to FIG. A laser cutting device A shown in the figure irradiates a laser beam from a nozzle 1 toward a steel plate B, and controls the moving direction of the nozzle 1 by a numerical control (NC) device so as to cut along the edge of a figure to be cut. It is configured to be able to move and cut a desired shape.

The laser cutting device A comprises a gate-shaped frame 3 movably arranged on a pair of rails 2 laid in parallel.
have. The frame 3 has a saddle 3a arranged along the rail 2 and garter 3b, 3c arranged in a direction perpendicular to the laying direction of the rail 2 and having ends connected to the saddle 3a. I have. A traveling motor 4 for traveling the frame 3 in the direction (y direction) along the rail 2 is disposed on the saddle 3a.

The garter 3b is provided with a traversing carriage 6 driven by the traversing motor 5 and traversing in a direction orthogonal to the rail 2 along the garter 3b. The carriage 1 has a nozzle 1 at its tip via a groove cutting block C.
A torch 7 to which the nozzle 1 is attached, an elevating motor 8 serving as a nozzle elevating member for elevating the torch 7 and the nozzle 1, and an angle setting motor 9 for inclining the nozzle 1 to a desired angle are provided.

A laser oscillator 10 is mounted on the garter 3c, and a laser light path 11 is formed between the laser oscillator 10 and the torch 7. The laser beam path 11 transmits the laser beam emitted from the laser oscillator 10 to the torch 7 and the nozzle 1.
And the optical path length is kept constant irrespective of a change in position due to the traversing of the carriage 6. For this purpose, a reversing unit 12 having a pair of reversing mirrors in the laser beam path 11 and moving by half the moving distance of the carriage 6 in the same direction as the moving direction of the carriage 6 is provided.

A control panel 13 having an operation panel 13a is mounted on the garter 3b or the garter 3c.
The control unit of the NC apparatus and the height copying apparatus is built in the apparatus. The operation panel 13a is provided with an input member 14 for inputting information such as a figure to be cut and information such as a thickness of the steel plate B, and a display 15 for displaying various information.

In the laser cutting apparatus A configured as described above, information such as a figure to be cut from the steel plate B and information such as a thickness are inputted through the input member 14, and the laser oscillator 10 is driven to drive the laser oscillator 10. Laser light emitted from 10
The nozzle 1 is two-dimensionally driven by driving the traveling motor 4 and the traversing motor 5 based on the input graphic information while irradiating the nozzle 1 to the steel plate B through the nozzle 11 and irradiating the nozzle 1 through the nozzle 1. By moving the steel sheet B, the steel sheet B can be cut along with the movement of the nozzle 1.

Next, the groove cutting block C will be described with reference to FIGS.
The configuration will be schematically described. The groove cutting block C shown in the figure is configured so that the nozzle 1 can be inclined at a desired angle with respect to the steel plate B.
It has a plurality of cylindrical bodies 22a to 22d and a cylindrical body 22e which are formed in a letter shape and have mirrors 21a to 21d respectively arranged at the bending portions.
By fitting a to 22e with each other, the overall shape is formed in a crank shape, and each of the cylindrical bodies 22a to 22e is configured to be rotatable with each other. The nozzle 1 is attached to the fifth cylinder 22e.

A gear 23 is fixed to the first cylinder 22a fixed to the torch 7, and a gear 24 is fixed to the fourth cylinder 22d to which the nozzle 1 is attached. These gears 23,
24 has gears 25a, 25b and gears 26a,
Gears 25 and 26 integrally formed with a gear 26b (gear 25a and gear 26a, and gear 25b and gear 26b have the same number of teeth) mesh with each other, and one of the gears (for example, gear 25) is an angle setting motor. 9 to rotate.

Therefore, when the angle setting motor 9 is driven, the gear 25 rotates, the gear 25a rotates around the gear 23, and the gear 25b rotates the gear 24 at the same time. For this reason, the second cylinder 22b rotates without changing the position in the height direction,
Accordingly, the third cylinder 22c moves upward while tilting, and at the same time, the fourth cylinder 22d rotates while moving upward along with the inclination of the third cylinder 22c to rotate the fifth cylinder 22d. The body 22e is tilted.

Note that the rotation angle of the fourth cylinder 22d is always the second angle.
The gear ratio is set so as to be twice the rotation angle of the cylindrical body 22b, and the distance between the optical axis of the second cylindrical body 22b and the optical axis of the fourth cylindrical body is set to the fourth optical axis. Is set to be equal to the distance from the laser beam to the focal point 27 of the laser beam. Therefore, when the second cylindrical body 22b is rotated by the angle θ, the inclination angle of the nozzle 1 with respect to the steel plate B also becomes θ.

The nozzle 1 has a function as a pole constituting a sensor for detecting the capacitance between the nozzle 1 and the steel plate B. For this reason, a lead 28 is formed at a mounting portion of the nozzle 1, and the lead 28 is connected to a control unit 35 built in the control panel 13 via the detection unit 32.

In particular, in the capacitance type sensor, the distance between the poles (the distance between the tip surface 1a of the nozzle 1 and the steel plate B, the height of the nozzle 1 from the steel plate B) and the area of the opposing poles (the nozzle 1
The value of the capacitance is set by the area of the front end surface 1a). For this reason, by setting the area of the tip surface 1a of the nozzle 1 in advance, it is possible to detect the capacitance according to the distance between the tip surface 1a and the steel plate B.

In the figure, reference numeral 29 denotes a lens, which has a function of condensing a laser beam on a focal point 27.

Next, the configuration of the height copying apparatus according to this embodiment will be described with reference to the block diagram of FIG. 1, and at the same time, the relationship between the nozzle 1 and the steel plate B will be described with reference to FIG.

In FIG. 1, reference numeral 31 denotes an NC unit, which includes information on a figure to be cut inputted from the input member 14 and a steel plate B.
A primary storage unit for temporarily storing information such as a cutting speed based on the thickness of the steel plate and information on a groove angle when cutting the steel plate B, and a storage in which a program for performing the cutting is written. And an operation unit. When the cutting of the steel plate B is started, the drive of the angle setting motor 9 is controlled, and when the cutting is executed, the drives of the traveling motor 4 and the traverse motor 5 are controlled.

Reference numeral 32 denotes a detection unit which is connected to a lead 28 provided at a mounting portion of the nozzle 1 with respect to the groove cutting block C, converts the detected capacitance into an electric signal, and controls the control unit.
It has the function of transmitting to 33.

Reference numeral 33 denotes a reference value storage unit which arranges the nozzle 1 vertically with respect to the steel plate B and sets the nozzle 1 at an optimum height (distance from the surface of the steel plate B of the nozzle 1) to execute cutting. Information corresponding to the capacitance at the time, that is, a reference value is stored.

Numeral 34 denotes a correction value storage unit, which changes in accordance with the inclination angle of the nozzle 1 when the nozzle 1 is inclined with respect to the steel plate B and is set at an optimum height for executing groove cutting. Correction information for correcting the value of the capacitance is stored. This correction information is obtained when the nozzle 1 is inclined with respect to the steel plate B and the height is changed so that the inclined nozzle 1 can perform cutting in a good state with respect to the steel plate B. Since the capacitance changes, the reference value or the detected value is corrected in accordance with the change in the inclination angle.

As shown in FIG. 2, the nozzle 1 can be set at a desired angle in a range from a state perpendicular to the steel plate B (this state is assumed to be 0 degree) to a state inclined at 45 degrees. Have been. The reference value is a value of the capacitance when the nozzle 1 is in a state perpendicular to the steel plate B (a state in which the front end surface 1a faces parallel to the steel plate B, a reference state),
When the nozzle 1 is inclined at a desired angle from this state, the tip surface 1a is also inclined with respect to the steel plate B, and the projected area of the tip surface 1a with respect to the steel plate B is reduced. For this reason, the value of the capacitance in the reference state is different from the value of the capacitance in the state inclined at a desired angle, and the degree of change is proportional to the magnitude of the inclination angle.

Therefore, the capacitance is measured in advance for each inclination angle of the nozzle 1, and when the nozzle 1 is inclined at the time of actual cutting, the capacitance value corresponding to this inclination angle is used as a reference. It is possible to correct the value or the detected value.

In the laser cutting, the inclination angle of the nozzle 1 is set starting from the position of the focal point 27 of the laser light emitted from the nozzle 1. That is, the position of the focal point 27 on the steel plate B is constant irrespective of whether the vertical cutting or the groove cutting is performed, and the angle of the nozzle 1 is set around the position. The focal point 27 is preferably formed at the same position as the projection position of the optical path 11 of the laser beam passing through the torch 7. By setting the focal point 27 in this way, the cutting point when cutting the figure to be cut is obtained. It is possible to make the movement path of the nozzle 1 coincide with the outline of the figure.

Strictly speaking, the capacitance between the inclined nozzle 1 and the steel plate B has a different value for each angle. But,
From the point of view of performing laser cutting, a change in the range of once or several degrees does not necessarily have a great adverse effect on cutting. The groove angle formed when the steel sheet B is grooved is not set every one degree, but is limited to a certain degree (for example, 10 degrees, 15 degrees).
Degrees, 30 degrees, 45 degrees, etc.).

For this reason, in the present embodiment, the angle between 90 degrees and 45 degrees is used.
The range up to degrees is divided into a plurality of angle ranges, and when a tilt angle is set for the nozzle 1, correction corresponding to the angle range including the tilt angle is performed. For example, the angles are 0 to 9 degrees, 10 to 19 degrees, 20 to 29 degrees,
Nozzle 1 is set in the range of 30 to 39 degrees and 40 to 45 degrees.
When the inclination angle is set in the range of 0 to 10 degrees, the capacitance is detected using the reference value without any particular correction. Is configured to be able to be corrected with a larger value as the range shifts to a larger value.

When correcting according to the change in the inclination angle of the nozzle 1, there are a case where the information of the reference value stored in the reference value storage unit 33 is corrected and a case where the detection value detected by the detection unit 32 is corrected. In any case, it is possible to perform control without any difference.

A control unit 35 receives a signal transmitted from the detection unit 32 according to the capacitance between the nozzle 1 and the steel plate B, compares this signal with, for example, a reference value, and determines the difference between the two. Is calculated, and when a difference is generated, a signal for driving the elevating motor 8 is generated and transmitted to the NC device 31 so as to eliminate the difference.

The angle output member for outputting a signal corresponding to the inclination angle of the nozzle 1 is not particularly limited.
Sensors that mechanically detect the inclination angle of the nozzle 1 may be used, a pulse oscillator attached to the angle setting motor 9 may be used, and groove angle information transmitted from the NC device 31 may be used. good.

Next, a description will be given of a procedure for cutting a steel sheet B with a groove by the laser cutting apparatus A configured as described above.
At the same time, a procedure in which the nozzle 1 follows the steel plate B will be described.

The information of the figure to be cut, the information of the thickness of the steel plate B, and the information of the groove angle to be cut are input to the NC device 31 in advance. , A driving program for the traversing motor 5 is set.

The angle setting motor 9 is driven according to the inputted angle information of the nozzle 1, and the nozzle 1 is tilted to a target angle. At the same time, the angle information of the nozzle 1 is transmitted from the NC device 31 to the control unit 35, and the control unit 35 receiving the angle information reads out the correction value corresponding to the tilt angle of the nozzle 1 from the correction value storage unit 34. The correction value corrects, for example, the reference value stored in the reference value storage unit 33, or corrects the detection value detected by the detection unit 32 (hereinafter, in this embodiment, the correction of the reference value is assumed. explain).

When the reference value is corrected, as described above, when the nozzle 1 is tilted to a target angle, an angle correction value corresponding to the tilt angle is set in advance.
A method of correcting the angle by adding or subtracting the angle correction value to or from a reference value;
A method in which a plurality of angle reference values are set in correspondence with each assumed inclination angle, and when the nozzle 1 is inclined to a target angle, an angle reference value that matches or corresponds to the inclination angle is selected. Therefore, any method may be adopted.

After correcting the reference value as described above, the capacitance between the nozzle 1 and the steel plate B is detected, and the detection unit 31 generates an electric signal corresponding to the detected capacitance. It is transmitted to the control unit 35. In the control unit 35, the detection unit 31
Comparing with the reference value corrected based on the electric signal from
The difference between the two is calculated. And when there is a difference,
A drive signal for raising and lowering the nozzle 1 is generated so as to eliminate this difference, and the lifting motor 8 is raised and lowered. Normally, the nozzle 1 has been raised to the retreat position sufficiently separated from the steel plate B until the cutting is started, and thus the drive signal is a signal for driving the elevating motor 8 in a direction to lower the nozzle 1.

As the nozzle 1 approaches the steel plate B, the difference between the electric signal transmitted from the detection unit 32 to the control unit 35 and the corrected reference value decreases, and finally, the two coincide with each other. The lowering of the nozzle 1 stops. At this time, nozzle 1
The distance from the steel sheet B is set to a value that can maintain a good cutting state (the quality of the cut surface and the shape of the root face corresponding to the outer shape of the figure) when the steel sheet B is cut. You.

After setting the angle of the nozzle 1 as described above, the laser oscillator 10 emits a laser response. The laser beam guided along the laser beam path 11 is transmitted from the nozzle 1 to the steel plate B.
To melt and evaporate the base material of the steel sheet B. At this time, the melted base material is burned by the assist gas injected from the nozzle 1 simultaneously with the laser beam, and the melt is removed from the base material by the assist gas to form a groove penetrating in the thickness direction.

Further, by driving the traveling motor 4 and the traverse motor 5 to move the nozzle 2 two-dimensionally in a state where the melting, burning and elimination of the molten material of the steel sheet B are continued,
It is possible to cut the target figure from.

In the process of cutting the steel plate B by irradiating the laser beam from the nozzle 1, the detection unit 32 continuously
And the capacitance between the steel plate B and the detected capacitance is converted to an electric signal and transmitted to the control unit 35. For example, when the distance between the nozzle 1 and the steel plate B is reduced due to the occurrence of distortion in the steel plate B, the value of the capacitance detected by the detection unit 32 changes, and accordingly, the electric signal changed from the detection unit 32 Is transmitted to the control unit 35. The control unit 35 having received the electric signal compares the electric signal with the corrected reference value, and as a result, a difference occurs between the two. Then, a drive signal corresponding to the difference is generated and transmitted to the elevating motor 8, and the elevating motor 8 is raised so that the nozzle 1 is separated from the steel plate B.

As described above, when cutting the groove of the steel sheet B, it is possible to keep the height of the nozzle 1 from the steel sheet B within a substantially constant range. That is, it is possible to control the nozzle 1 so as to follow the steel plate B.

When the figure to be cut has a contour line combining a straight line and a curved line, the traversing carriage 6 is provided with a turning device (not shown) to turn the torch 7 and the nozzle 1. It is necessary to control the turning device such that the direction of inclination of the nozzle 1 always coincides with the direction of the normal to the contour line. As such a turning device, a turning device used in a gas cutting device or a plasma cutting device can be adopted.

[0050]

As described above in detail, in the height copying apparatus according to the present invention, the reference value stored in the reference value
Alternatively, the detection value of the capacitance between the nozzle and the steel plate detected by the detection member is corrected using the correction value corresponding to the tilt angle of the nozzle, and a difference is generated by comparing the correction value with the corresponding information. When the nozzle is moved up and down by driving the nozzle elevating member according to the difference, the height of the nozzle is always within a substantially constant range from the surface of the steel sheet regardless of the inclination angle of the nozzle. Can be imitated.

For this reason, even when the steel sheet is distorted, the nozzle does not come into contact with the steel sheet, and since the height of the nozzle is always within a certain range from the surface of the steel sheet, the steel sheet is distorted. Even in this case, accurate bevel cutting can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a height copying apparatus.

FIG. 2 is a diagram illustrating a relationship between a nozzle and a steel plate.

FIG. 3 is a side sectional view illustrating a configuration of a groove cutting block for inclining a nozzle at a desired angle.

FIG. 4 is an external front view of a groove cutting block.

FIG. 5 is an external side view of a groove cutting block.

FIG. 6 is a view for explaining a configuration of a laser cutting apparatus in which it is preferable to mount the height copying apparatus according to the present embodiment.

[Explanation of symbols]

 Reference Signs List A Laser cutting device B Steel plate C Groove cutting block 1 Nozzle 1a Tip surface 2 Rail 3 Frame 3a Saddle 3b, 3c Garter 4 Traveling motor 5 Traversing motor 6 Traversing carriage 7 Torch 8 Elevating motor 9 Angle setting motor 10 Laser oscillator 11 Laser beam path 12 Reversing unit 13 Control panel 13a Operation panel 14 Input member 15 Display 21a-21d Mirror 22a-22e Cylindrical body 23-26 Gear 27 Focus 28 Lead 29 Lens 31 NC unit 32 Detection unit 33 Reference value storage unit 34 Correction value storage unit 35 Control unit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tatsuya Moriki 3-35-16 Nishi Koiwa, Edogawa-ku, Tokyo F-term in Koike Oxygen Industries Co., Ltd. 4E068 AE00 CA12 CB03 CC06 CH04 DB01

Claims (1)

[Claims] 1. A nozzle for cutting a steel sheet by irradiating the steel sheet with a laser beam, a nozzle elevating member for moving the nozzle up and down with respect to the steel sheet, and detecting a capacitance between the nozzle and the steel sheet. A detection member that generates a detection signal, and a reference value storage unit that stores information on a reference value of capacitance corresponding to a state in which the nozzle is perpendicular to the steel plate and has a reference height. And an angle output member that outputs a signal corresponding to an inclination angle of the nozzle with respect to the steel plate, and correction of capacitance in a state where the nozzle is inclined with respect to the steel plate and at a reference height. A correction value storage unit that stores value information, and a control unit that drives the nozzle elevating member to control the height of the nozzle from the steel plate to be maintained at a preset value, wherein the nozzle is In the state perpendicular to the steel plate, the above control When a difference is generated by comparing the detection signal generated from the detection member in the section with the information of the reference value stored in the reference value storage section, the nozzle elevating member is driven in accordance with the difference and the nozzle is made of a steel plate. In the state where the nozzle is inclined with respect to the steel plate, the information of the reference value stored in the reference value storage unit is corrected by the information of the correction value stored in the correction value storage unit, and the detection member When a difference is generated by comparing the generated detection signal with the corrected information of the reference value, the nozzle elevating member is driven in accordance with the difference to cause the nozzle to follow the surface of the steel plate or to detect the static value detected by the detecting member. The capacitance is corrected to generate a correction detection signal, and the correction detection signal is compared with the information of the reference value stored in the reference value storage member, and when a difference occurs, the nozzle elevating member is driven according to the difference. So that the nozzle follows the surface of the steel plate. Copying height apparatus characterized by the.