JPH06170573A - Gap size detecting device for laser beam machine - Google Patents

Abstract

PURPOSE:To enable detecting an exact gap with a small and simple constitution. CONSTITUTION:A working head 12 of a laser beam machine by which a material to be machined is irradiated with a laser beam to be specifically machined and an insulating nozzle holder 16 formed with a through hole 20 in which the laser beam is passed to reach the tip end part of the working head 12 are provided. An electrical conductive compensating electrode 26 is formed on all the periphery of the through hole 20 and a metallic working nozzle 14 is provided on the tip end of the nozzle holder 16 opposing with the material to be machined. A measuring electrode 28 which is insulated from the compensating electrode 26 is provided on the fitting part of the working nozzle to the nozzle holder 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, in order to control the distance between the tip of a processing nozzle and a workpiece in laser processing,
The present invention relates to a gap amount detection device for a laser processing machine that detects the gap amount.

[0002]

2. Description of the Related Art Conventionally, in laser processing for cutting metal, a gap sensor is provided at the tip of the processing nozzle in order to keep a constant distance between the tip of the processing nozzle and a workpiece as a workpiece. The position of the processing head was controlled by the signal from. This gap sensor is disclosed in JP-A-62
As disclosed in Japanese Patent Application Laid-Open No. 156090, an electrode provided integrally with a processing nozzle measures an electrostatic capacity between the processing nozzle and a workpiece, and a change in the electrostatic capacity is detected to perform processing. Some control the position of the nozzle. When measuring the capacitance, the capacitance of the electrode may change regardless of the distance between the electrode and the workpiece due to heat or plasma generated during processing.
Therefore, in order to remove these measurement errors and noise components, like the gap sensor disclosed in the above publication,
Some are provided with a sensor electrode for compensation.

[0003]

However, in the case of the above-mentioned conventional technique, providing the sensor electrode for measurement and the sensor electrode for compensation at the tip of the processing head increases the size of the entire sensor unit. There was a problem. Moreover,
In the case of the above conventional technique, the compensation sensor electrode is located outside the machining nozzle and is affected by various external fields at a position different from that of the measurement sensor electrode, so that there is a problem that accurate compensation cannot be performed. It was In particular, if the compensation sensor electrode is exposed to the outside at a position different from the measurement sensor electrode, changes in capacitance due to surrounding conductors or vertical pieces of the workpiece will be detected, and compensation will cause a large error. There was also the problem of becoming.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides a gap amount detecting device for a laser processing machine having a small size and a simple structure and capable of accurately detecting a gap. With the goal.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a gap amount detecting device for a laser processing machine provided on a processing head of a laser processing device for irradiating a workpiece with a laser beam to perform predetermined processing. The tip of the machining head is provided with an insulating nozzle holder having a through hole through which laser light passes, and a compensating electrode of a conductor is formed on the entire inner circumference of the through hole of the nozzle holder. A metal machining nozzle that faces the workpiece is provided on the laser machining machine, and a measurement electrode that is insulated from the compensation electrode is provided on the machining nozzle mounting portion of the nozzle holder to form a sensor member. It is a detection device.

[0006]

In the gap amount detecting device of the laser beam machine according to the present invention, a nozzle holder made of an insulator is attached to the machining head, and a compensation electrode and a measurement electrode are formed on the nozzle holder,
Measuring the capacitance between the work piece and the measurement electrode,
The measurement value is compensated by the compensation electrode, and the gap can be accurately controlled by the sensor member using the small nozzle holder integrated with the nozzle.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the gap amount detecting device of the laser processing machine according to this embodiment is mounted on a processing head 12 which is provided with a laser beam emitted from a laser oscillator (not shown) and which faces a workpiece. Has been. At the tip of the processing head 12, a processing nozzle 14 for irradiating a workpiece with laser light is provided via a nozzle holder 16. The processing head 12 is attached to a position control mechanism (not shown) and is provided so that the position can be controlled three-dimensionally.

The nozzle holder 16 is, as shown in FIG.
A through hole 20 formed of ceramics, through which laser light passes, is formed in the central portion, and the processing head 12 is formed on the outer periphery of the upper portion.
Is provided with a male screw portion 22 that is screwed into the mounting portion 13 of
A female screw portion 24 with which the processing nozzle 14 is screwed is formed at the lower end portion of the through hole 20. A metal thin film is formed on the inner peripheral surface of the upper portion of the through hole 20 by vapor deposition or the like, and a lead wire (not shown) is connected to the metal thin film to form a compensation electrode 26. Further, the female screw portion 2 of the nozzle holder 16
4 also has a metal thin film measuring electrode 28 formed by vapor deposition or the like in a state of being insulated from the compensating electrode 26 in the same manner as described above.

The measuring electrode 28 is for detecting the electrostatic capacity due to the gap between the workpiece and the processing nozzle 14, and this electrostatic capacity is controlled by a gap controller provided in a controller (not shown). Based on the above, the above-mentioned interval is calculated and controlled. In addition, the compensating electrode 26 includes a measuring electrode 28 that sandwiches the ceramic nozzle holder 16.
And a capacitance is formed between the two, and based on this capacitance, the gap error in the control device (not shown) cancels the measurement error of the measurement electrode 28.
Lead wires (not shown) are separately connected to the compensation electrode 26 and the measurement electrode 28, and are led out from lead wire insertion portions 30 provided on the sides of the nozzle holder 16.

The machining nozzle 14 is formed with a male screw portion 32 that is screwed into the female screw portion 24 of the nozzle holder 16, and the tip portion 34 of the machining nozzle 14 is formed in a flat shape.
Substantially, this tip portion 34 serves as a measuring sensor member that forms an electrostatic capacitance with the workpiece.

The method of using the gap amount detecting device of the laser beam machine of this embodiment is as follows.
The nozzle holder 16 is attached to the processing nozzle 12, and the processing nozzle 14 is further attached to the nozzle holder 16 in order to measure the capacitance of the gap between the and. Then, the lead wire led out from the nozzle holder 16 is connected to a gap controller (not shown) to perform a predetermined process. At this time,
In order to delicately control the distance between the processing nozzle 14 and the workpiece due to the undulation of the surface of the workpiece, the measuring electrode 28 is used.
The electrostatic capacitance between the processing nozzle 14 and the object to be processed obtained by the above is measured, and the position of the processing nozzle 14 is controlled based on this change. Furthermore, during processing, the processing nozzle 14
The electrostatic capacity obtained by the measurement electrode 28 changes due to the temperature of the nozzle holder 16 itself or the nozzle holder 16 itself, but this change, which is an error component, is canceled by the compensation electrode 26. That is, the measuring electrode 28 and the compensating electrode 26 are connected to the gap controller, and the measuring electrode 28 and the compensating electrode 26 have a variable capacitance and a fixed capacitance between the measuring electrode 28 and the compensating electrode 26. Electrode 28
The fluctuation component due to heat or the like at the time of measuring the capacitance obtained by is compensated.

According to the gap amount detecting and processing apparatus of the laser processing machine of this embodiment, the sensor member for detecting the distance between the processing nozzle and the workpiece is formed by the processing nozzle 14 and the nozzle holder 16, and the structure is small. The nozzle position is simple, and accurate nozzle position control is possible even when processing a workpiece having a complicated shape or processing an edge portion of the workpiece. Moreover, since the compensating electrode 26 is formed on the inner surface of the nozzle holder 16, it is difficult for the compensating electrode 26 to form a capacitance with other members, and accurate compensation is possible.

The nozzle holder of the present invention may be formed by an insulating member, a compensation electrode formed inside, and a measurement electrode formed at a position electrically connected to the processing nozzle. . Therefore, the processing nozzle may be formed integrally with this nozzle holder. Further, the processing nozzle mounting portion of the nozzle holder may be provided with a measurement electrode that is a terminal portion of a lead wire simply connected to the processing nozzle. Also by this, the electrostatic capacity between the machining nozzle and the workpiece is detected, and the distance between the machining nozzle and the workpiece can be measured and controlled.

[0014]

According to the present invention, the nozzle member of the machining head is integrally provided with the sensor member for detecting the distance between the machining head and the workpiece. Therefore, the structure is simple and the compensation electrode is externally provided. The compensation accuracy is extremely high because it is provided at a position where it is not exposed.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a gap amount detecting and processing apparatus of a laser processing machine according to the present invention.

FIG. 2 is a vertical sectional view of a nozzle holder of this embodiment.

FIG. 3 is a bottom view of the nozzle holder of this embodiment.

FIG. 4 is a vertical sectional view of a nozzle of this embodiment.

[Explanation of symbols]

 12 processing head 14 processing nozzle 16 nozzle holder 20 through hole 26 compensation electrode 28 measurement electrode

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[Procedure amendment]

[Submission date] October 27, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

[0003]

However, in the case of the above-mentioned conventional technique, providing the sensor electrode for measurement and the sensor electrode for compensation at the tip of the processing head increases the size of the entire sensor unit. There was a problem. Moreover,
In the case of the above conventional technique, the compensation sensor electrode is located outside the machining nozzle and is affected by various external fields at a position different from that of the measurement sensor electrode, so that there is a problem that accurate compensation cannot be performed. It was In particular, if the compensation sensor electrode is exposed to the outside at a position different from the measurement sensor electrode, changes in capacitance due to surrounding conductors or vertical pieces of the workpiece will be detected, and compensation will cause a large error. There was also the problem of becoming. Furthermore, during laser processing, the electrodes may be temporarily short-circuited due to spatter that jumps up sharply from the workpiece, which causes a variation in the capacitance detection value, and there is also the problem that stable detection cannot be performed. It was

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

In the gap amount detecting device of the laser beam machine according to the present invention, a nozzle holder made of an insulator is attached to the machining head, and a compensation electrode and a measurement electrode are formed on the nozzle holder,
Measuring the capacitance between the work piece and the measurement electrode,
The measurement value is compensated by the compensation electrode, and the gap can be accurately controlled by the sensor member using the small nozzle holder integrated with the nozzle. Further, by forming the compensating electrode inside the nozzle holder, the compensating electrode is protected from scattering of the spatter, and the energization between the both electrodes due to the spatter is prevented.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014]

According to the present invention, the nozzle member of the machining head is integrally provided with the sensor member for detecting the distance between the machining head and the workpiece. Therefore, the structure is simple and the compensation electrode is externally provided. Since it is provided in a position that is not exposed to the outside, even if the spatter jumps up sharply from the work piece during laser processing, a short circuit does not occur with the measurement electrode, and the compensation accuracy is extremely high, providing a stable and accurate gap. Quantity detection can be performed.

Claims (2)

[Claims] 1. A gap amount detection device for a laser processing machine, which is provided on a processing head of a laser processing device for irradiating a workpiece with a laser beam to perform predetermined processing, and which detects a gap between the processing head and the workpiece. In this, a nozzle holder made of an insulator having a through hole through which a laser beam passes is provided at the tip of the processing head, and a compensating electrode of a conductor is formed on the entire inner circumference of the through hole of the nozzle holder. A metal processing nozzle facing the workpiece is provided at the tip of the nozzle holder, and a sensor electrode is formed at the processing nozzle mounting portion of the nozzle holder by providing a measurement electrode that is insulated from the compensation electrode. A gap amount detection device for a laser processing machine, characterized in that 2. The measuring electrode and the compensating electrode of the nozzle holder are formed of a metal thin film, and lead wires are connected to the measuring electrode, and the measuring electrode has a flat surface whose tip is parallel to the workpiece. 2. A gap amount detecting device for a laser beam machine according to claim 1, wherein said metal processing nozzle is detachably provided.