JPS61279390A - Laser beam machining equipment - Google Patents

Abstract

PURPOSE:To perform the laser beam machining without any welding defect of misalignment, etc. by finding the position of a work line by detecting the leaked magnetic flux of the gap part caused by the arc discharging current between electrode and work and by controlling the progressing direction of a laser head. CONSTITUTION:A magnetic loop is formed inside a work 8 and a leakage magnetism is induced on a gap part. In this case, the output from two pieces of magnetic sensors 12 is compared by a comparator 21 and the magnetic sensor 12 is scanned by the driving part 13, 20 consisting of a motor driving circuit 22, motor 23 and jig 24 until the outputs of the two sensors 12 become equal. And the position of the laser head is controlled by the laser head driving part 34 by converting into a digital signal by A/D convertor 26 by reading our with a linear potentiometer 25 the position thereof and by finding the position of a work line by processing with input circuit 27, CPU 28, memory 29 and output circuit 30.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a laser beam processing device, which achieves high machining efficiency and high quality by immediately adding arc discharge. be.

[Conventional technology]

Conventionally, there have been devices of this type as shown in FIGS. 5 and 6. FIG. 5 is a longitudinal sectional view showing a conventional laser beam machining apparatus using arc discharge, and FIG. 6 is a longitudinal sectional view showing the main parts thereof.

In the figure, (l) is a laser oscillator, (2) is a laser beam emitted from laser oscillator 0), (2a) is a condensed beam, and (3) is a laser beam for guiding the laser beam (2) to the processing part. Bend me to bend the beam (2)
-, t4+ are condensing optical systems for condensing the laser beam (2) to the energy aspiration button suitable for the purpose of the sword craftsman.

(5) is provided at the bottom of the condensing optical system (4), and is coaxial with the condensed beam (2a) and is composed of a cylindrical electrically insulating material. There is an annular electrode coaxial with the provided focused beam (2a), and (7) is an assist gas supply port.

Further, (8) is a workpiece, and (9) is an arc discharge power source that applies a voltage between the electrode (6) and the workpiece (8) and generates arc discharge.

In the conventional laser beam processing apparatus configured as described above, the laser beam (2) is focused by the condensing optical system (4).
The light is focused on a spot with a high energy density of 106 to 108 W/cR2, and is irradiated onto the surface of the workpiece +81 to perform processing such as cutting, welding, and heat treatment. On the other hand, at the same time as the laser beam (2) is emitted.

Assist gas nozzle (5
A voltage is applied by an arc discharge power source (9) between the condensed beam (2a) provided at the tip of the condensing beam (2a), the coaxial annular electrode (6), and the workpiece (8). For this reason, the gas supply port (
Combined with the action of the assist gas introduced from 6),
A gap occurs between the electrode (6) and the workpiece (81).

The assist gas is heated to a high temperature by this arc, and a part of the assist gas dissociates and becomes a high-temperature gas mass α surrounding the focused beam (2a), and the workpiece (8) is heated to a high temperature.
) is simultaneously injected with the focused beam (2a). In this way, the laser beam processing device that utilizes laser beam processing uses a high-energy-density focused laser beam (2a) and a high-temperature gas plasma α1 formed to surround the focused laser beam (2a) to process the workpiece. Since KIfl is used so that the object +81 is irradiated at the same time, the processing efficiency of cutting, welding, and heat treatment increases. Especially in welding, gap tolerance etc. have been significantly improved. FIG. 7 is a longitudinal cross-sectional view of a main part of a further improved laser beam machining device using arc discharge. In order to prevent wear of the electrode (6), The reliability of the device has been improved by providing a shield nozzle αD outside the assist gas nozzle provided with the assist gas nozzle, and the device has been put into practical use. Note that (7a) is a shield gas supply pipe.

On the other hand, when a 1jl current flows through a magnetic material such as iron, a magnetic field is generated around the current. If there is a gap in this material, magnetic flux leaks from this gap. When welding is performed by generating a large current arc discharge between the workpiece (81) and the electrode (6) provided on the arc welding torch α9, this principle is shown in Fig. 8, which shows 6 parts. Welding line image A arc welding apparatus has been devised.Magnetic flux leaks from the gap 0 forming the processed line due to the current flowing through the workpiece 1B1.

Therefore, while moving the leakage magnetic sensor α side in the direction perpendicular to the gap part a■, that is, in the Y direction, by the sensor drive unit, the position where the leakage magnetic flux is maximum is determined by the sensor signal processing circuit I and the position reader αe. Detect.

This is taken into account by the control device, that is, the automatic copying processor αη, and the distance difference between the welding torch sensor and the leakage magnetic sensor α is processed and the position of the welding torch acJ is controlled.

The weld line is copied using a welding torch block brocade.

[Problem that the invention seeks to solve]

Laser welding can perform narrow and deep welding, but
In order to perform such welding, it is necessary to align the weld line and the beam irradiation position with high precision. Adding an arc improves the zero-force efficiency, and the tolerance for positioning is quite wide.However, when welding thin plates, etc.

Pre-processing accuracy of the workpiece to be welded is also not very good.

As deformation occurs during welding, many welding defects such as misalignment and poor fusion occur, which greatly hinders automation.

This invention was made to solve the above-mentioned problems, and aims to improve the quality and reliability of laser welding, as well as welding that can be easily applied to objects with complex shapes. The purpose of this invention is to obtain a laser beam processing device equipped with an automatic line tracing function.

[Failure to solve problem skin]

A laser beam processing apparatus according to the present invention includes an optical system for condensing a laser beam, an assist gas nozzle provided coaxially with the laser beam, an electrode provided coaxially with the laser beam at the tip of the assist gas nozzle, and this electrode. and an arc discharge W power supply that applies a voltage between the workpiece and the workpiece and generates a discharge current by the discharge current caused by the arc discharge.

A magnetic sensor that detects leakage magnetic flux generated in the gap forming the processing line of the workpiece, a drive unit for this magnetic sensor, and a sensor signal that processes the signal detected by the magnetic sensor to determine the position of the Loe wire. A laser head driving section is provided for controlling the position of the laser head based on the ann cotton wire position signal obtained by the processing means and the sensor signal processing means.

The above processing line is automatically scanned.

[Effect]

The laser beam processing device according to the present invention
The processing line is automatically identified by detecting the leakage magnetic flux at the gap generated by the etx flow, and the direction of laser welding is controlled, ensuring that the processing line and the beam irradiation position are always aligned. High-quality welding without welding defects such as misalignment can be performed completely automatically.

[Embodiments of the invention]

FIG. 1 is a vertical cross-sectional configuration diagram showing a laser beam processing device according to an embodiment of the invention, and FIG. 2 is a perspective view showing the inside with a portion of the main part thereof cut away. In the figure, α2 is due to the discharge current due to arc discharge.

A magnetic sensor that detects the leakage magnetic flux generated in the gap formed by the processing line (1,1″f) of the covered loe object (8), a31 is a drive unit for scanning this magnetic sensor, ■ is these magnetic sensor α2 and the drive unit This is a drive unit that rotates the sensor storage unit α3 around the laser beam as the central axis.

FIG. 3 is a block diagram showing a laser beam processing apparatus according to an embodiment of the present invention, and FIG. 4 is a flow chart showing its operation.

When a current flows through the electrode (6) in the thickness direction of the workpiece (8), a magnetic loop is created within the workpiece (8). When the object to be welded (81) is a steel material, leakage magnetism on the Loe wire (11) is induced due to the difference in relative magnetic coefficient with the air between the processed wires. The ?tl forces from these two magnetic sensors α2 are compared by a comparator Q1).

The drive circuit of the sensor moving piece motor (c) and the sensor moving piece motor (
c) The magnetic sensor (13) is scanned by the drive unit α3 (to) consisting of a jig for moving the sensor, etc., and its position is read by the linear potentiometer.

The A/D converter (1) converts the output signal into a digital signal and sends the output signal to the input circuit, CPσ, and memory wire.

and an output circuit (to) to process and determine the position of the processing line. laser head based on this position signal.

The position is controlled by a laser head drive section (b) consisting of a drive circuit Gn for the head movement fi21Pf4 motor, a head movement m motor, and a head movement jig (c).

Drive unit (13m can follow complex shapes.

The entire sensor storage section is rotatably driven around the laser head as a central axis, making it possible to completely automatically weld, for example, a circular shape.

FIG. 4 is a flowchart showing the procedure for detecting a welding line. When detection is started, the sensor storage section first rotates in step (b)), and a rough welding line is detected. When the signal is detected (step 3).
f! Scanning 1ki sensor U (step (to))
, the encoder detects the point where the two magnetic sensor signals are equal to U (step (to)). Then, the welding or Loe line is calculated (step @), and the laser head is driven (step (to)).

If the curve suddenly changes, start rotating the sensor again. In this way, the bath welding line and the beam irradiation position are always aligned, and high-quality welding without welding defects such as misalignment can be performed completely automatically.

In addition, in the above embodiment, the sensor drive section is set to two stages: the drive section side and the drive section □□□, but the function of the drive section
It may be included in 1).

〔Effect of the invention〕

As described above, according to the present invention, automatic welding line tracing A function is added to laser welding using high-temperature gas plasma. can be implemented.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional configuration diagram showing a laser beam processing device according to an embodiment of the present invention, FIG. 2 is a partially cutaway perspective view of the main part of the device, and FIG. 3 is an embodiment of the present invention. A block diagram showing a laser beam processing device according to an example, FIG. 4 is a flowchart showing its operation, FIG. 5 is a vertical cross-sectional configuration diagram showing a conventional laser beam processing device, and FIG. 6 is a vertical cross-sectional view showing its main parts. , FIG. 1 is a vertical sectional view showing the main parts of an improved conventional laser beam processing device, and FIG. 8 is a block diagram showing a conventional automatic image h-arc welding device. In the figure, (2) is the laser beam, (4) is the focusing optical system, (5) is the assist gas nozzle, (6) is the electrode, +
81 is the workpiece, (9) is the discharge power supply, (I3 is the magnetic sensor. , (a) is a memory, and (b) is a laser head drive unit. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A laser beam processing device that processes a workpiece using a high-energy-density laser beam emitted from a laser head, an optical system that focuses the laser beam, an assist gas nozzle provided coaxially with the laser beam, An electrode is provided at the tip of the assist gas nozzle coaxially with the laser beam, an arc discharge power source applies a voltage between the electrode and the workpiece, and generates an arc discharge, and a discharge current generated by the arc discharge is used to generate the workpiece. a magnetic sensor for detecting leakage magnetic flux generated in a gap forming a processing line of a workpiece; a drive unit for the magnetic sensor; a sensor signal processing means for processing signals detected by the magnetic sensor to determine the position of the processing line; and a laser beam machining device comprising: a laser head driving section that controls the position of the laser head based on the position signal of the machining line obtained by the sensor signal processing means, and automatically tracing the machining line. .