JPS5840349B2 - Laser output monitoring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser output monitoring system, and particularly to a laser output monitoring system in a pulse laser welding apparatus that continuously welds a predetermined number of welding points.

In recent years, the use of lasers in the field of processing has been widely studied, and some of them have already been put to practical use, for example, in the field of welding.

Welding quality in laser welding is largely influenced by the output of the laser used.

Therefore, in order to maintain stable welding quality, it is necessary to monitor that the laser output is maintained within a predetermined output range.

FIG. 1 is a diagram showing an example of a conventional laser output monitoring method in a pulsed laser welding device.

In FIG. 1, a laser pulse 2 sent out from a light emitting device 1 passes through reflecting mirrors 3 and 4 and a lens 5.
It is transmitted to the workpiece 6 to be welded.

The reflecting mirror 4 transmits a part of the incident laser pulse 2 and inputs it to the light conversion element 8 as transmitted light 7 for monitoring the laser pulse output.

The light conversion element 8 outputs a voltage proportional to the input transmitted light 7 and transmits it to the integrating circuit 9.

The integrating circuit 9 is controlled by a timing control circuit 12 activated by a trigger signal 13 sent from the light emitting device 1, integrates the input voltage during the laser pulse sending period, and converts the obtained output value into a converting circuit. 10.

The conversion circuit 10 converts the received output value (analog signal) into a digital signal and transmits it to the determination circuit 11.

The determination circuit 11 receives digital signals corresponding to the upper and lower limits of a predetermined output range in which the output value of the laser pulse 2 should be maintained in order to maintain the welding quality of the workpiece 6.
It is supplied from an upper limit value setting circuit 14 and a lower limit value setting circuit 15.

The judgment circuit 11 judges whether the received digital signal is within the range indicated by the upper limit value and the lower limit value supplied from the upper limit value setting circuit 14 and the lower limit value setting circuit 15, and displays the judgment result on a display device. 16.

The above process welds one welding point of the workpiece 6,
It is repeated each time the laser pulse 2 is sent out from the light emitting device 1.

As is clear from the above explanation, in the conventional laser output monitoring system, each time one welding point is welded, the light emitting device 1
It is determined whether the output of the laser pulse 2 transmitted from the laser pulse 2 is maintained within a predetermined output range, and the determination result is displayed on the display device 16.

Therefore, when welding a predetermined number of welding points included in one workpiece 6 in succession, it is necessary to monitor the display state of the display device 16 each time weld each welding point.

Furthermore, as the welding speed increases, it becomes difficult for the display device to faithfully display the determination results, making it impossible to reliably monitor the laser output.

An object of the present invention is to eliminate the drawbacks of the conventional laser output monitoring method as described above, and to provide a laser that can reliably monitor laser output even when a predetermined number of welding points are continuously welded. The goal is to realize an output monitoring method.

The purpose of this is to monitor the output of a pulse laser welding device that continuously welds a predetermined number of welding points, and count the number of laser pulse outputs that are within a predetermined output range. This is achieved by providing a circuit for comparing the number of laser pulse outputs with the predetermined number of welding points, and comprehensively determining the quality of the predetermined number of welds.

An embodiment of the present invention will be described below with reference to FIG.

FIG. 2 is a diagram illustrating a laser output monitoring system according to an embodiment of the present invention.

The difference between FIG. 2 and FIG. 1 is that a counting circuit 17 and a welding point number setting circuit 1 are provided between the determination circuit 11 and the display device 16.
9 is inserted.

Note that in FIG. 2, the light emitting device 1, laser pulse 2, reflecting mirrors 3 and 4, lens 5, and workpiece 6 that constitute the pulsed laser welding apparatus are omitted.

It is assumed that one welding object (not shown) includes ten welding points, and the pulse laser welding device continuously welds the ten welding points.

In order to weld each welding point, each time a laser pulse is sent out from a light emitting device (not shown), the transmitted light 7 is converted into voltage by the light conversion element 8 in the same process as in FIG. After being converted into a digital signal by the laser pulse sending period integration signal conversion circuit 10, the determination circuit 11 determines whether or not the output is within a predetermined output range, and outputs the determination result (for example, a pass signal). .

Therefore, if the outputs of the laser pulses sent out from the light emitting device (not shown) during ten consecutive welding operations are all within the predetermined output range, the determination circuit 11 outputs 1
0 pass signals are output.

These ten pass signals are counted by the counting circuit 17, and the counting result (10 in this case) is transmitted to the comparison circuit 18 when a series of welding for one workpiece is completed.

The comparison circuit 18 is supplied with the number of welding points (10 in this example) included in the workpiece from the welding point number setting circuit 19.

The comparison circuit 18 compares the received counting result with the number of welding points (10 points) supplied.

This time, the counting result is 10, which matches the number of welding points, so a matching signal is transmitted to the display device 16.

Based on the received coincidence signal, the display device 16 displays that all welding points of the current workpiece are welded with laser pulses kept within a predetermined output range, and that welding quality is maintained.

If 1 out of 10 welding points included in one workpiece
If the laser pulse output does not fall within the predetermined output range at any point, the number of pass signals output from the determination circuit 11 will not reach 10.

Therefore, the counting result transmitted from the counting circuit 17 to the comparing circuit 18 is also 9 or less, and the comparing circuit 18 receives the counting result from the welding point number setting circuit 19, which is the number of welding points (10 points).
16, and display the mismatch signal on the display device
to communicate.

Based on the received discrepancy signal, the display device 16 displays that all welding points of the current workpiece are not welded with the laser pulse maintained within the predetermined output range, and the welding quality is not maintained. .

As is clear from the above description, according to the present embodiment, the display device 16 shows that all welding points of one workpiece, including 10 welding points, are laser beams that are maintained within a predetermined output range. Displays whether or not welding was performed by pulse.

Therefore, welding quality is determined comprehensively for each workpiece.

Note that FIG. 2 is only one embodiment of the present invention, and the number of welding points included in one workpiece is not limited to 10, for example, and any other number may also be used. The effect of the invention remains the same.

As described above, according to the present invention, in a pulsed laser welding device that continuously welds a predetermined number of welding points, the laser pulse output during the predetermined number of welds is comprehensively monitored to ensure welding quality. is managed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a conventional laser output monitoring method in a pulsed laser welding apparatus, and FIG. 2 is a diagram showing a laser output monitoring method according to an embodiment of the present invention. In the figure, 1 is a light emitting device, 2 is a laser pulse, 3 and 4 are reflecting mirrors, 5 is a lens, 6 is an object to be welded, 7 is transmitted light, 8 is a light conversion element, 9 is an integration circuit, 10 is a conversion circuit, 1
1 is a judgment circuit, 12 is a timing control circuit, 13 is a trigger signal, 14 is an upper limit value setting circuit, 15 is a lower limit value setting circuit, 16 is a display device, 17 is a counting circuit, 18 is a comparison circuit, 19 is a welding point number setting The circuit is shown.

Claims (1)

[Claims] 1. In a pulsed laser welding device that continuously welds a predetermined number of welding points, a circuit that monitors the output of the pulsed laser welding device and counts the number of laser pulse outputs within a predetermined output range. and a circuit that compares the number of laser pulse outputs with the predetermined number of welding points, and comprehensively determines the quality of the predetermined number of welds.