JPH05337669A - Laser beam machine - Google Patents

Abstract

PURPOSE:To execute a satisfactory laser butting welding by detecting the butting gap center of an object to be worked with a welding line detecting means, detecting a rotational moving amount with a rotational moving amount detecting means, and controlling the position of a laser beam. CONSTITUTION:A welding line detecting sensor 6 detects the butting welding face of a pipe stock 5. Displacement sensors 15a, 15b detect a moving amount in the horizontal surface of both side face parts of the pipe stock 5. Based on both detected values, a sensor controller 16 calculates the moving amount and a rotational moving amount in the horizontal surface of the pipe stock 5. Based on the result of the calculation, a numerical controller 13 drives motors 14a, 14b and 14c, and moves a working head 3 in the X, Z and alpha directions. Even in the case a rotational fine motion occurs in addition to a fine motion in the horizontal surface in the object 5, satisfactory welding can be executed surely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus for performing laser processing such as welding on a workpiece such as a pipe.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a laser processing apparatus used for pipe forming such as a pipe roll material.

As shown in FIG. 3, a laser beam a output from a laser oscillator 1 is guided to a processing head 3 through a plurality of bender mirrors 2 and is condensed by a lens 4 provided inside the processing head. Then, the butt surface b of the pipe-making pipe material 5 is irradiated and laser butt welding is performed. Further, the pipe-making pipe material 5 flows from the upstream side of the processing head 3 in a state of being formed into a pipe shape while being gradually made from flat steel. A welding line detection sensor 6 is provided on the upstream side in the immediate vicinity of the processing head 3.

The welding line detecting sensor 6 is composed of a laser slit projector 7 and a reflected light detecting photoreceiver 8. Based on an image signal obtained from the welding line detecting sensor 6, a welding line gap is detected by a sensor controller 9. The width and the center of the gap can be detected. According to the detected amount of the gap center, the machining head drive motor 11 is operated by the numerical controller 10 so that the position of the machining head 3 can be controlled so as to irradiate the laser beam a to the center of the butt gap of the pipe forming pipe material 5. It has become.

[0005]

In the laser processing apparatus as described above, the behavior of the pipe forming pipe material 5 flowing into the processing head 3 slightly moving in the horizontal plane is as follows.
The welding line detection sensor 6 can reliably detect the center of the butt gap, control the processing head 3, and perform good butt welding. However, in an actual pipe making line, the pipe making pipe material 5
Is accompanied by rotational micromotion in addition to micromotion in the horizontal plane.

Therefore, when the pipe-making pipe material 5 has a slight rotational movement, the laser beam a emitted from the processing head 3 is emitted directly below, so that the laser beam a is obliquely inclined with respect to the butt welding surface b. Laser irradiation will be performed.
When the diameter-to-wall thickness ratio of the pipe-making pipe material 5 is extremely large, slight rotational micromotion is not a problem, but when the diameter-to-wall thickness ratio is small, especially in the case of a pipe having a small diameter and a large wall thickness. When the laser beam A is obliquely applied to the butt-welding surface B, there are fatal drawbacks such as poor butt-welding, shallow penetration, and uneven welding. .

Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to surely perform favorable laser butt welding even when the workpiece has a slight rotational movement in addition to a fine movement in the horizontal plane. It is to provide a laser processing apparatus.

[0008]

In order to achieve the above object, the present invention provides a laser oscillator that oscillates a laser beam, an irradiation unit that irradiates a workpiece with a laser beam from the laser oscillator, and the object to be processed. Welding line detecting means for detecting the butt gap center of the workpiece, rotational movement amount detecting means for detecting the rotational movement amount of the workpiece, gap center detected by the welding line detecting means and the rotational movement The irradiation means for irradiating the workpiece with laser light oscillated from the laser oscillator based on the amount of rotational movement detected by the amount detecting means from the direction normal to the butt welding surface of the workpiece. And a control means for controlling the position of the laser processing apparatus.

[0009]

In the laser processing apparatus of the present invention thus constructed, the laser light output from the laser oscillator is
The workpiece is irradiated through the irradiation means. At this time, if there is fine movement and rotational fine movement in the horizontal plane of the workpiece with respect to the laser light irradiation position of the workpiece, the amount of fine movement is detected in advance on the upstream side of the processing position. Then, based on the detection, the position of the irradiation means is controlled so that the laser irradiation can be performed from the direction of the normal to the gap center of the object to be processed.

Therefore, even if there is rotational fine movement in addition to fine movement in the horizontal plane, the workpiece is irradiated with laser light from the optimum position, so that optimum laser processing can always be performed. it can.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows the entire configuration of the laser processing apparatus according to this embodiment, and the same parts as those in the conventional example are designated by the same reference numerals as those in FIG.

As shown in FIG. 1, a laser beam a output from a laser oscillator 1 is guided to a processing head 3 via a bender mirror 2, condensed by a lens 4, and a pipe forming pipe material 5 is butted. The surface b is irradiated. The machining head 3 can be moved in the X direction by the X-axis drive motor 14a, in the Z direction by the Z-axis drive motor 14b, and in the α direction by the α-axis drive motor 14c according to a command from the numerical controller 13. The bender mirror 2 is configured so that the laser beam b is emitted from the center of the processing head 3 regardless of which of the X, Z, and α axes is moved.

On the upstream side of the processing head 3, a welding line detection sensor 6 is provided for detecting the butt welding surface in advance, which irradiates the pipe material 5 with laser slit light. It is composed of a laser slit light projector 7 and a reflected light detection light receiver 8. Displacement sensors 15a and 15b for measuring the movement amount of the pipe material 5 in the horizontal plane are provided on both sides in the horizontal plane of the pipe material 5 near the weld line detection portion. Incidentally, 16 is a sensor controller for controlling these sensors.

In the laser processing apparatus of this embodiment having the above-described structure, the pipe material 5 is supplied from the laser slit projector 7 of the welding line detecting sensor 6 provided on the upstream side of the processing head 3.
The reflected light of the laser slit light irradiated on the light is detected by the light receiver 8, and the sensor controller 16 can detect the center of the butt gap of the pipe material 5 from the image data. Also, a displacement sensor provided near the welding line detection sensor 6
15a and 15b can detect the amount of movement of the pipe member 5 on both side surface horizontal planes. Here, referring to FIG. 2, the gap center data by the welding line detection sensor 6 and the displacement sensor
A logical operation for calculating the movement amount and the rotational movement amount of the pipe material 5 in the horizontal plane, which is performed by the sensor controller 16, from the movement data in the horizontal plane by 15a and 15b will be described. First, A is the distance data of the gap center position by the welding line detection sensor 6, B is the displacement data by the displacement sensor 15a, C is the displacement data by the displacement sensor 15b, and from these data, the diameter D of the repipe material is D = B + C. Equation 1) The distance E from the sensor reference position to the pipe center after slight movement is E = (C−B) / 2 (2) Equation (2) Therefore, the rotation angle θ of the pipe material is θ = sin ⁻¹ {by the trigonometric function calculation. (2A-C + B) / (B + C)} (3) Equation can be calculated. Incidentally, in the formula (3), E = A
In the case of, θ = 0 °, and there is no rotational movement.

Since the component E of the movement of the pipe material in the horizontal plane and the component θ of the rotation of the pipe can be calculated and calculated by the above logical operation, the numerical control unit 13 makes the X-axis drive motor based on these data. 14a, the Z-axis drive motor 14b, and the α-axis drive motor 14c can be simultaneously controlled to control the position of the processing head 3 so that the laser beam a can be irradiated from the normal direction of the center of the butt gap of the pipe material 5. it can.

Therefore, even if the pipe material 5 is rotated in addition to being moved in the horizontal plane, the position of the processing head is controlled and the laser irradiation can be performed in real time from the direction normal to the welding butt surface, so that it is always possible. This is the optimum laser welding process.

In the above embodiment, a contact type sensor is used as the displacement sensor for detecting the amount of movement in the horizontal plane. However, this sensor is an eddy current type, electrostatic capacitance type, laser optical type displacement sensor. The same effect can be achieved by using.

Further, it is not always necessary to provide two displacement sensors, and if the diameter of the pipe is stored in the sensor controller as input data in advance, only one displacement sensor is used to measure the amount of displacement in the horizontal plane, and calculation is performed. Can also calculate the rotational movement amount using the diameter data of the input data. Furthermore, by providing a vertical movement amount detection sensor in addition to the movement amount detection sensor of the pipe material in the horizontal plane,
More advanced position control processing can be performed.

The welding line detection sensor is not limited to the structure of this embodiment, and any optical cutting type sensor, leak magnetic detection type sensor, or triangulation type sensor may be used as long as it can detect the center of the butt gap. Any sensor may be used.

[0020]

As described above, according to the present invention, excellent laser butt welding can be surely realized even when the workpiece has a slight rotational movement in addition to a fine movement in the horizontal plane.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating a logical operation in the sensor controller shown in FIG.

FIG. 3 is a schematic configuration diagram showing a conventional laser processing apparatus.

[Explanation of symbols]

 1 ... Laser oscillator 3 ... Processing head 5 ... Pipe-making pipe material 6 ... Welding line detection sensor 13 ... Numerical control device 15a, 15b ... Displacement sensor 16 ... Sensor controller

Claims (1)

[Claims] 1. A laser oscillator that oscillates a laser beam, an irradiation unit that irradiates a workpiece with a laser beam from the laser oscillator, and a welding line detection unit that detects a butt gap center of the workpiece. Based on the rotational movement amount detection means for detecting the rotational movement amount of the workpiece, the gap center detected by the welding line detection means, and the movement amount detected by the rotational movement amount detection means, the laser A laser processing apparatus comprising: a control unit that controls the position of the irradiation unit so that the laser beam oscillated from the oscillator is irradiated from the normal direction of the butt welding surface of the workpiece.