JPS5987990A - Laser beam machine - Google Patents

Abstract

PURPOSE:To make the center of a joint to coincide with the center of a welding head and to obtain good welding quality by uniting a reflection mirror for laser light, a condenser lens and the welding head to one body, and moving the same by following up to the joint of an object to be worked. CONSTITUTION:A welding head at the front end of a cover 13 supported on a movable base 12 which supports a reflection mirror 3 is made to correspond to the meandering joint part 6a of a work 6 moved by a traveling base 7. The laser light from the oscillator 1 is bent by the mirror 3, is condensed with a lens 4 through a cover 13 and is focused, via a head 5, to the joint part 6a, whereby welding is accomplished. A sensor 8 in front of the direction where the work 6 advances from the head 5 projects light and detects the same, and detects the meandering line of the joint from the decrease in the light intensity on account of the irregular reflection in the joint part. The detected line is converted to a signal by a position detector 9, and a controller 10 feeds the signal to a driving part 11 so as to make the head 5 to coincide with the joint part. The driving part 11 rotates forward and backward a screw bar 11A to move the base 12 to the right and left thereby moving the head 5 always to the prescribed position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser processing machine suitable for detecting longitudinal joints of steel pipes and automatically welding them.

In the past, as a method for automatically welding joint 1 by detecting the joint between steel plates and steel pipes, a guide roller was mechanically inserted into the joint, and the welding machine's torch (welding head) was integrated with this roller. One method is to move the torch by magnetically swinging the detection unit to detect changes in the magnetic flux at the joint, and the other is to move the torch through a separate processing means.

- There is also a method using an optical camera.

On the other hand, in the case of laser welding machines that can obtain a high-coverage heat source by concentrating light, a condition for obtaining high-quality products is that the seam and the weld (spot) center match.

For example, when performing TiG welding, the weld bead width is approximately 3
m, so even if the center is off by 0.3 mm, it will not significantly affect the welding quality.In contrast, in the case of laser welding, the corresponding bead width can be reduced to about 0.5 mm or less.
A deviation of 0.3 mm has a fatal negative effect on quality. Possible solutions include a method that increases the accuracy of conventional detection methods, and a method that uses a high-precision optical fiber sensor, for example.

However, a laser welding machine with an output of 1 kW or more that welds steel has a condensing lens, a part of the reflecting mirror, etc. in addition to the welding head, and the weight of a conventional Ti() welding torch is several kilograms. However, in a laser welding machine, the torch weighs several tens of kilograms or more, so it is difficult to move the torch integrally with the detection unit, and it is also difficult to obtain accuracy.

An object of the present invention is to provide a laser welding machine that achieves good joint quality by aligning the center of the seam with the center of the bath weld.

For this purpose, a laser beam reflecting mirror, a condensing lens, and a welding head are integrated, and these are moved to follow the seam.

Hereinafter, the present invention will be explained in detail using FIGS. 1 and 2.

Laser light 2a within laser oscillator 1 is guided to the outside (2
1)) The laser beam is reflected downward by the reflection mirror part 3 (laser beam 2C), focused by the condensing lens 4, and irradiated via the welding head 5 onto the joint part 6a of the workpiece 6 having the joint. be welded. A workpiece 6 is placed on a traveling table 7, and is moved integrally with the traveling table from a fixed table 15 via a bearing.

On the other hand, the joint 6a of the workpiece 6 has a meandering line as shown in FIG. 2, and in order to detect this line, the sensor head 8
The welding head 5 is also arranged forward in the direction of movement of the C proboscis 6 to be processed. The sensor 8 is constituted by an original fiber 8A having a large number of light emitting/receiving parts optically arranged perpendicularly to the direction in which the seam travels. The light projected onto the joint 6a undergoes diffuse reflection and its light intensity decreases, and is received by the fiber of the light receiving section, where it is distinguished from the light intensity of other fibers that do not cause a decrease in light due to diffuse reflection. 9
It will be treated as No. 1. Konoha number p city 1] 1n
In the width section 10, a signal 1.delta.- is sent to a drive section 11 such as a gad motor in order to align the four contact head 5 with the inner seam capital.

The screw shaft IIA of the drive unit 11 rotates in forward and reverse directions.

The iJta stand that is engaged with the screw shaft 11A has a
It moves in the left-right direction on the pedestal 14 via the rollers 12A. An inclined support base 12B is attached to the upper side of the movable base 12, and the laser beam 2b is reflected downward by the reflection mirror portion 3 attached to the support base 12B (2C). The cover 13 attached to the lower side of the movable table 12 covers the workpiece 6.
The laser beam 2C passes through the inside of the cover 13 while extending in the direction of. A focusing lens 4 and a processing head 5 are attached to the tip of the cover 13. The carriage 7 on which the workpiece 6 is placed moves along the longitudinal direction of the workpiece via the row 27A. The roller 7A is coupled with a rail 15A installed on the fixed base 15 and moves along the rail 15A.

Next, the operation of the cutting machine will be explained.

When the reference scale part 0 of the optical fiber 8A is located at the seam part XI, the light of the optical fiber 8A of the reference scale part O illuminates the first seam part Xl. The light is diffusely reflected at the first stray eye part X1 and is diminished. The light on the reference scale 0 is on the other scales 1~81-1~-8
Since the light is received weaker than the original, the position detector 9 detects the joint part X1.
Detect the position of. A signal from the position detector 9 is sent to the control section 10. The control unit 10 does not instruct the drive unit 11 to rotate. In other words, the movable platform is at the reference position. Therefore, the V-za light 2C is irradiated from the processing head 5 to the 7g joint 6a, and the joint is welded and closed, thereby forming a steel pipe.

Furthermore, when the sensor 8 moves in the direction of the arrow and comes to the joint part X2, the light on the scale 3 becomes weaker than the reference scale 0, so that the position detector 9 can detect the vertical position. Based on the signal from the position detector 9, the control section 9 instructs the drive section 11 to rotate, and the drive section 11 rotates in one direction to move the movable base 12 to the right. Moreover, at the time of the joint part X3, the driving part 11
rotates in the opposite direction to that described above and moves the movable base 12 to the left.

In this way, in the laser processing machine of the present invention, the meandering joint is irradiated with light from the optical sensor, the strength and weakness of the light are used to produce a predetermined position using the position detector, and then the signal from the position detector is sent to the control unit. By rotating the drive unit at the opening part and moving the movable table, the machining head is always moved to a predetermined position and the joint is welded, so it is possible to weld the meandering joint. It can be done automatically.

Moreover, the support stand 12I3 formed in an inclined shape can increase rigidity. Therefore, since the reflecting mirror 3 and the cover 13 are attached to the support base 12B, deformation of the reflecting mirror 3 and distortion of the cover 13 and the processing head 5 can be reduced.

As described above, according to the laser processing machine of the present invention, e.g. meandering of the seam portion can be automatically detected.

[Brief explanation of the drawing]

Claims (1)

[Claims] 1. A laser beam from a laser oscillator is bent in a right angle direction by a reflecting mirror, and is irradiated to a joint part of the workpiece through a processing head, so that the joint part is in contact with the joint part by 7d, and the reflecting mirror is supported, and a movable movable base, a cover supported by the movable base and through which the laser beam from the reflecting mirror passes, a processing head corresponding to the joint provided at the tip of the cover, and a processing head corresponding to the processing head, In addition, there is a sensor that irradiates light to the joint, a tL position detector that detects the position based on the strength of the light from the sensor, an output section that inputs No. 1d from the position detector, and an output from the adjustment section. A laser processing machine characterized by comprising: a drive unit that rotates forward and backward in response to a signal and moves a movable table by this rotation.