JPH1177345A - Laser beam welding machine, automatic welding equipment and normal/defective discrimination method for laser beam welding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To send a normal part only to a next process by monitoring a laser beam irradiating from a laser beam irradiation head and inspecting as to whether laser beam welding is normally conducted. SOLUTION: By irradiating a laser beam 14 generated at a laser beam oscillator 11 from a laser beam irradiation head 13, laser beam welding is conducted for work 5, 7. At this time, the laser beam is monitored by an optical fiber 15, a solar cell 16, a harness 17 and a wave form measuring instrument 18. A MC of the wave form measuring instrument 18 compares a voltage wave form from the solar cell 16 to a voltage wave form data stored in a memory beforehand, a normal/defective discrimination signal is outputted. A selecting machine 20, which is controlled by a normal/defective discrimination signal, selects a work 21 after laser beam welding for a normal part or a defective part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser welding machine, an automatic welding apparatus, and a method for determining the quality of a laser in a laser welding machine.

[0002]

2. Description of the Related Art Conventionally, there has been known laser welding in which a laser oscillated from a laser oscillator is spot-irradiated onto a work through a laser irradiation head.

[0003] In the laser welding as described above, an abnormality detection function for detecting an abnormality of the laser oscillator by monitoring a laser from the laser oscillator is provided. When an abnormality of the laser oscillator is detected by the abnormality detection function, welding is stopped, and as a result, outflow of defective products to the next process is suppressed.

[0004]

However, in conventional laser welding, there is no method for monitoring a laser beam emitted from a laser irradiation head. For this reason, when there is no abnormality in the laser oscillator and there is an abnormality in the laser irradiation head, there is a possibility that the work after welding may be sent to the next step despite the poor welding.

Accordingly, the present invention provides a laser welding machine capable of monitoring only a laser beam emitted from a laser irradiation head and checking whether or not laser welding has been normally performed to send only non-defective products to the next process. It is an object of the present invention to provide a method for determining the quality of a laser in a welding apparatus and a laser welding machine.

[0006]

According to a first aspect of the present invention, there is provided a laser generating means for irradiating a work with a laser generated by the laser generating means, and welding the work. Laser welding means comprising: a laser irradiation means for performing laser irradiation; a monitoring means for monitoring a laser light emitted from the laser irradiation means; and a determination means for determining whether the laser monitored by the monitoring means is good or bad. Is the gist.

According to a second aspect of the present invention, there is provided a laser welding means comprising: a laser generating means; and a laser irradiating means for irradiating a laser generated by the laser generating means to a work and welding the work. Monitoring means for monitoring the laser beam emitted from the laser irradiation means; determining means for determining the quality of the laser monitored by the monitoring means; and a work after laser welding is selected from subsequent steps based on a result of the determining means. The gist of the present invention is an automatic welding apparatus provided with a work selecting means for performing the work.

According to a third aspect of the present invention, there is provided a laser welding means comprising: a laser generating means; and a laser irradiating means for irradiating a laser generated by the laser generating means to a work and welding the work. Monitoring means for monitoring the laser light emitted from the laser irradiation means; and determination means for determining the quality of the laser monitored by the monitoring means, wherein the monitoring means monitors the laser light emitted from the laser irradiation means. The gist of the present invention is a method for determining the quality of a laser in a laser welding machine in which the determination means determines the quality of a laser monitored by the monitoring means.

(Function) In the first aspect of the present invention, the laser generated by the laser generating means is irradiated on the work by the laser irradiation means, and as a result, the work is welded. At this time, the laser irradiated from the laser irradiation means is monitored by the monitoring means. Then, the quality of the laser monitored by the monitoring means is determined by the determination means.

According to the second aspect of the present invention, the work after the laser welding is selected by the work selecting means from a subsequent step based on the result of the determining means. In the invention of claim 3,
The laser emitted from the laser irradiator is monitored by the monitor. Then, the quality of the laser monitored by the monitoring means is determined by the determination means.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention embodied in an automatic welding apparatus for performing spot welding by laser will be described below with reference to FIGS.

FIG. 1 shows an automatic welding apparatus 1 according to the present embodiment. The automatic welding device 1 includes a conveyor 2. The conveyor 2 includes a belt conveyor, a roller conveyor, and the like. The conveyor 2 is driven by a drive motor (not shown) and moves in the direction of the arrow in FIG. A plurality of tables 3 each having a mounting surface are fixed to the conveyor 2 at regular intervals.

On the side of the upstream of the conveyor 2,
A work supply device 4 is provided. A plurality of works 5 are accommodated in the work supply device 4, and the works 5 are transported by a conveyor 8 driven by a drive motor (not shown) and supplied one by one to the table 3.

A work supply device 6 is arranged downstream of the work supply device 4. A plurality of works 7 are accommodated in the work supply device 6, and the works 7
The work 5 is transported by a conveyor 9 driven by a drive motor (not shown), and
Supplied individually.

Downstream of the workpiece supply device 6, a laser welding section 10 as laser welding means is disposed.
As shown in FIG. 2, the laser welding portion 10 is provided with a laser oscillator 11 as a laser generating means.
A laser 14 generated by the laser oscillator 11 is emitted from a laser irradiation head 13 as a laser irradiation unit via an optical fiber 12 so that the surface of the work 7 is focused. Then, as the conveyor 2 advances in the direction of the arrow in FIG. 1, the work 7 is melted by the optical energy of the laser 14, and the work 5 and the work 7 are integrated by laser welding.

As shown in FIG. 2, an optical fiber 15 is arranged on the optical path of the laser 14. The position of the optical fiber 15 is set closest to the focal point in a range where the optical fiber 15 is not broken by the laser 14.

A solar cell 16 as a sensor is disposed on the side of the tip of the optical fiber 15. The solar cell 16 is irradiated with a laser 14 via an optical fiber 15, and the light energy of the laser 14 is converted into electric energy (voltage). The solar cell 16 includes a harness 17
Is electrically connected to the waveform measuring instrument 18 via the.

The waveform measuring device 18 is provided with a microcomputer (MC) and a memory (not shown), and the memory previously stores voltage waveform data as a reference value when welding is normally performed. ing. The MC of the waveform measuring device 18 can compare the voltage waveform from the solar cell 16 with the voltage waveform data stored in the memory in advance. And the MC of the waveform measuring instrument 18 is
The voltage waveform from the solar cell 16 is compared with the voltage waveform data stored in the memory in advance, and a pass / fail judgment signal is transmitted to the sorter control unit 29 via the harness 28. That is,
The laser 14 is monitored by an optical fiber 15, a solar cell 16, a harness 17, and a waveform measuring device 18.

In this embodiment, the optical fiber 15, the solar cell 16, the harness 17, and the MC of the waveform measuring device 18 constitute a monitor. In addition, M of the waveform measuring instrument 18
C constitutes determination means.

Downstream of the laser welding section 10, a sorting section 19 as a work sorting means is disposed. The sorting unit 19 is provided with a sorting machine 20 controlled by the sorting machine control unit 29 via a harness 30.
The arm 23 of the sorting machine 20 is provided with hydraulic means (not shown),
It is supported by a pneumatic means, a motor, and the like so as to be able to expand and contract with respect to the shaft 22 and is rotatable 360 degrees around the shaft 22. On the other hand, the sorting machine 20 has an arm 23
A grip portion 24 is formed at the tip of the workpiece 21 so that the workpiece 21 after welding can be gripped. Pallets 25 and 26 are arranged within the movement range of the gripper 24.

The sorting machine 20 includes a sorting machine control unit 29. The sorter control unit 29 receives the work 2 after laser welding from the MC of the waveform measuring instrument 18 through the harness 28.
When a pass / fail judgment signal indicating that the device 1 is a non-defective product is input, a non-defective signal is output. And the good signal is
The input is input to the sorting machine 20 via the harness 30, and the sorting machine 20 places the work 21 on the pallet 25.

On the other hand, when the sorter control unit 29 receives a pass / fail judgment signal indicating that the work 21 after laser welding is defective from the MC of the waveform measuring device 18 via the harness 28, Outputs a good signal. Then, the defective product signal is input to the sorting machine 20 via the harness 30, and the sorting machine 20 places the work 21 on the pallet 26. That is, the sorting unit 19 performs the work 2 after the laser welding based on the quality determination result of the MC of the waveform measuring device 18.
1 is sorted into non-defective products and non-defective products from the subsequent steps.

Next, the operation of the automatic welding apparatus 1 according to the present embodiment configured as described above will be described. Automatic welding equipment 1
Tables 3 are fixed to the conveyor 2 at equal intervals, and the work 5 is supplied from the work supply device 4 onto the table 3. The work 7 is supplied from the work supply device 6 onto the table 3 to which the work 5 is supplied as the conveyor 2 proceeds downstream.

When the conveyor 2 travels further downstream, spot welding by the laser 14 is performed on the works 5 and 7 by the laser welding unit 10. The laser 14 emitted from the laser irradiation head 13 is
5, monitored by the solar cell 16, the harness 17, and the waveform measuring device 18. The MC of the waveform measuring device 18 compares the voltage waveform from the solar cell 16 with the voltage waveform data stored in the memory in advance, and transmits a pass / fail determination signal to the sorter control unit 29 via the harness 28.

When the sorting machine 20 controlled by the sorting machine control unit 29 receives a pass / fail judgment signal indicating that the work 21 after welding is a good product from the MC of the waveform measuring device 18, 21 is placed on a pallet 25. On the other hand, the sorting machine 20 is provided with the MC of the waveform measuring device 18.
If the pass / fail judgment signal indicating that the welded work 21 is defective is input from the pallet 2
6. Place on top. That is, the work 21 after welding is sorted into a good product and a defective product.

As described in detail above, according to the automatic welding apparatus 1 of the present embodiment, the following effects can be obtained. (1) When spot welding the work 5 and the work 7 with the laser 14, the laser 14 irradiated from the laser irradiation head 13 was monitored by the optical fiber 15, the solar cell 16, the harness 17, and the waveform measuring device 18. Therefore, it is possible to know whether or not the welding has been performed normally.

Since the laser 14 is monitored by the optical fiber 15, the solar cell 16, the harness 17, and the waveform measuring device 18, expensive components such as a CCD (charge coupled device) sensor need not be used. Laser 14 at low cost
Can be monitored.

(2) The waveform measuring device 18 compares the voltage waveform from the solar cell 16 with the voltage waveform data stored in the memory in advance, and sends a pass / fail judgment signal to the sorter control section 29 via the harness 28. Conveyed.

When the sorting machine 20 controlled by the sorting machine control unit 29 receives a pass / fail judgment signal indicating that the welded work 21 is a non-defective product from the MC of the waveform measuring device 18, 21 was placed on a pallet 25. On the other hand, the sorting machine 20 is provided with the MC of the waveform measuring device 18.
If the pass / fail judgment signal indicating that the welded work 21 is defective is input from the pallet 2
6. That is, the work 21 after welding was sorted into non-defective products and defective products.

Therefore, only non-defective products can be sent to the next step. Note that the embodiment of the present invention may be modified as follows, and in that case, the same operation and effect can be obtained.

(1) In the above embodiment, the solar cell 16 is used as a sensor, but a photodiode, a phototransistor, or the like may be used instead of the solar cell 16. In this case, the photodiode and the phototransistor are irradiated with the laser 14 irradiated from the laser irradiation head 13 via the optical fiber 15, and the light energy of the laser 14 is converted into electric energy (current).

On the other hand, in the memory of the waveform measuring device 18, current waveform data for normal welding is stored in advance. The MC of the waveform measuring device 18 can compare the current waveform from the photodiode and the phototransistor with the current waveform data stored in the memory in advance. And
The MC of the waveform measuring device 18 compares the current waveform from the photodiode and the phototransistor with the current waveform data stored in the memory in advance, and transmits the comparison result to the sorter control unit 29 via the harness 28.

(2) In the above embodiment, the solar cell 16 is irradiated with the laser 14 irradiated from the laser irradiation head 13 through the optical fiber 15 by disposing the optical fiber 15 on the optical path of the laser 14. However, the following configuration may be adopted.

In place of the optical fiber 15, a half mirror 27 is arranged as shown in FIG. By arranging a sensor such as a solar cell 16, a photodiode, and a phototransistor at a focal point via the half mirror 27, the laser 14 irradiated from the laser irradiation head 13 is applied to the solar cell 16, the photodiode, the phototransistor, and the like. Irradiate.

Alternatively, the optical fiber 15 is omitted, and the laser 14 irradiated from the laser irradiation head 13 is directly
Irradiation may be performed on a sensor such as a solar cell 16, a photodiode, or a phototransistor.

While the embodiments of the present invention have been described above, technical ideas other than the claims that can be grasped from the embodiments will be described below together with their effects. (1) In the laser welding machine according to (1) or (2), the monitor means includes: an optical fiber disposed on an optical path of the laser irradiated from the laser irradiation means; And a waveform measuring instrument electrically connected to the sensor.

With this configuration, since the monitoring means is composed of the optical fiber, the sensor, and the waveform measuring instrument,
It is not necessary to use expensive components such as a D (charge-coupled device) sensor, and it is possible to monitor the laser irradiated from the laser irradiation means at relatively low cost.

(2) The laser welding machine according to (1), wherein the optical fiber is arranged on the optical path of the laser, closest to the focal point in a range where the optical fiber is not broken.

In this way, the optical fiber can be protected from the laser, and the output of the laser can be more accurately transmitted to the waveform measuring device via the sensor. Therefore, the quality of welding can be determined based on the more accurate laser output.

[0040]

As described in detail above, according to the first aspect of the present invention, a laser generated by the laser generating means is irradiated on the work by the laser irradiation means, and as a result, the work is welded. . At this time, the laser irradiated from the laser irradiation means was monitored by the monitoring means. Then, the quality of the laser monitored by the monitor was determined by the determiner. For this reason, it is possible to know the quality of welding to the work.

According to the second aspect of the present invention, the work after the laser welding is selected by the work selection means from the subsequent steps based on the result of the determination means. For this reason, only good products can be sent to the next process.

According to the third aspect of the present invention, the laser emitted from the laser irradiator is monitored by the monitor. Then, the quality of the laser monitored by the monitor was determined by the determiner. For this reason, it is possible to know the quality of the welding to the workpiece, and to send only the non-defective product to the next process.

[Brief description of the drawings]

FIG. 1 is a plan view of an automatic welding apparatus according to the present embodiment.

FIG. 2 is a plan view of the laser welded portion.

FIG. 3 is another example of a laser weld.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Automatic welding apparatus, 5 ... Work, 7 ... Work, 10 ... Laser welding part as laser welding means, 11 ... Laser oscillator as laser generation means, 13 ... Laser irradiation head as laser irradiation means, 14 ... Laser, Reference numeral 15: an optical fiber constituting the monitoring means, 16: a solar cell as a sensor constituting the monitoring means, 17: a harness constituting the monitoring means, MC: a microcomputer as a judging means constituting the monitoring means, 18: waveform measurement Vessel, 19 ... sorting part as means for selecting work, 21 ... work.

Claims (3)

[Claims] A laser generating means for irradiating the workpiece with a laser generated by the laser generating means, and a laser irradiating means for welding the workpiece; and irradiating from the laser irradiating means. A laser welding machine comprising: a monitoring unit that monitors the laser beam; and a determination unit that determines whether the laser monitored by the monitoring unit is acceptable. 2. A laser welding means comprising: a laser generating means; a laser emitting means for irradiating a laser generated by the laser generating means onto a work and welding the work; and irradiating from the laser irradiating means. Monitoring means for monitoring the laser, and determination means for determining the quality of the laser monitored by the monitoring means, and work selection means for selecting a work after laser welding from a subsequent process based on the result of the determination means Automatic welding equipment equipped with. 3. A laser welding means comprising: a laser generating means; a laser generated by the laser generating means; and a laser irradiating means for irradiating the workpiece with a laser, and irradiating from the laser irradiating means. Monitoring means for monitoring the laser that has been monitored, and determination means for determining the quality of the laser monitored by the monitoring means. The monitoring means monitors the laser emitted from the laser irradiation means, and the determination means A method for determining the quality of a laser in a laser welding machine, wherein the quality of the laser monitored by the monitoring means is determined.