JPH11284284A - Laser power stabilizing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain laser output at a constant level from the beginning by suppressing phart term variations at the beginning of output of a laser device and to also maintain long term constancy of level for through a relatively simple method. SOLUTION: At the beginning of laser output of a laser device, variations of the laser output with respect to controlling signals 9 to a laser electrical source 3 are measured and variation patterns are recorded. The controlling signals 9 are corrected according to the variation patterns at the beginning of next laser output to suppress variations in a short duration at the beginning of laser power output and to maintain the laser power at a constant level. In this case, it is preferable to record the variation patterns of laser output at every beginning of laser output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser output stabilization method, and more particularly to a laser output stabilization method for suppressing fluctuations in laser output of a laser device in a laser welding machine or the like in a short term and a long term to keep the laser output constant. It is about the method.

[0002]

2. Description of the Related Art The laser output of a laser device in a laser welding machine or the like has a short-term fluctuation at the start of laser output due to the effect of a thermal lens effect. For this reason, it is necessary to output a dummy laser to maintain a constant laser output, and to bring the laser oscillator into a thermal equilibrium state.

In addition, there are long-term fluctuations due to deterioration of the lamp, aging of the reflectance and transmittance of the optical system, and the like. For this reason, it was necessary to periodically measure the laser output and adjust the output in order to always maintain a constant laser output.

As a method of adjusting the laser output, for example, there is a technique (laser output correction method of a laser processing machine) described in JP-A-64-18285. This technology is
The laser output power is automatically corrected over time and other changes over time.

That is, when the laser is started, the actual laser output is measured by an output measuring device with respect to the laser output command value, and a correction value coefficient between the laser output command value and the actual laser output is obtained. The control is performed such that an output equal to the command value is obtained by referring to the correction coefficient during processing.

[0006]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. Sho 64-18
Although the technology described in Japanese Patent Publication No. 285 can surely automatically correct the aging of the laser output power and the change over time during laser processing, the main problem of the present invention is to start laser output. There is no description on how to suppress so-called short-term fluctuations of the laser output at the time and keep it stable from the first laser output. That is, the correction coefficient is obtained after the laser output is stabilized.

Therefore, this conventional technique has a problem that fluctuations in the initial laser output at the start of laser output cannot be controlled. This causes a problem that the cycle time of the laser device is inevitably reduced. In particular, in a laser processing apparatus or the like that frequently performs on / off control of the laser output, the processing performance is significantly reduced.

The present invention has been made in view of the above points, and it is possible to suppress a short-term fluctuation at the start of laser output of a laser device and keep it constant from the beginning by a relatively simple method. Another object of the present invention is to provide a laser output stabilization method capable of maintaining a constant laser output for a long period of time.

[0009]

In order to solve the above-mentioned problems, according to the present invention, at the start of laser output of a laser device, a change in laser output with respect to a control signal to a laser power supply is measured, and the change pattern is recorded. In addition, by correcting the control signal according to the fluctuation pattern at the start of the next laser output, short-term fluctuation of the laser output at the start of the laser output is suppressed, and the laser output is kept constant. At that time, the variation pattern of the laser output can be recorded every time the laser output starts. When correcting the control signal using the recording result of the fluctuation pattern of the laser output,
The recording result of the laser output fluctuation pattern at the start of the immediately preceding laser output can also be used. In addition, during continuous laser output after the start of laser output, a fixed number of laser output values emitted immediately before are measured to detect a fluctuation amount, and a control signal is corrected according to the fluctuation amount, thereby achieving a long-term operation. Fluctuations in the laser output can be suppressed, and the laser output can be kept constant. Further, upon detecting the fluctuation amount of the laser output value, the laser output value is obtained by measuring the N laser output values emitted immediately before to obtain an average value and comparing the average value with a predetermined expected value. The amount of change in the value can also be detected. Further, a laser device, a laser oscillator, a power supply for supplying power to the lamp of the laser oscillator, a laser output detector for monitoring the power of laser light output from the laser oscillator,
It is also possible to use a controller that takes in the signal from the laser output detector and controls the output of the power supply.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an apparatus for realizing a laser output stabilizing method according to an embodiment of the present invention. FIG. 2 is a timing chart showing measurement of laser output in advance, and FIG. FIG. 4 is a timing chart showing laser output, and FIG. 4 is a timing chart at the time of continuous laser output.

As shown in FIG. 1, the laser device according to the present embodiment has a laser oscillator 1, a power supply 3 for supplying power to a lamp 2 of the laser oscillator 1, and a rod 4 of the laser oscillator 1. It comprises a laser output detector 6 for monitoring the power of the laser light 5, and a controller 8 for controlling the output of the power supply 3 and taking in a signal 7 from the laser output detector 6.

The controller 8 outputs a control signal 9 for the power supply 3 based on the signal 7 from the laser output detector 6.

In the short-term stabilization method of the laser output, as shown in FIG. 2, a controller 8 outputs a constant control signal 9 to the power supply 3 in advance, and the laser output value corresponding thereto is converted into a laser output detector 6 as shown in FIG. And records the fluctuation pattern of the laser output.

Next, as shown in FIG. 3, at the start of the laser output, the laser output can be kept constant by correcting the control signal 9 according to the variation pattern of the laser output measured in advance.

In the long term stabilization method of the laser output, as shown in FIG. 4, before the laser output 10, N laser output values emitted before the laser output are measured to obtain an average value. .

Next, the amount of change is calculated by comparing the average value with a predetermined expected value.
The laser output can be kept constant by correcting the control signal 9 in accordance with the amount of the change to obtain the corrected control signal 2.

As described above, according to the present embodiment, by suppressing the short-term fluctuation of the laser output at the start of the laser output, it is possible to eliminate the dummy laser output for bringing the laser oscillator into a thermal equilibrium state. Therefore, the cycle time of the laser device can be improved, and the life of the lamp can be extended.

Further, by measuring the average of the laser output value during continuous laser emission and correcting the control signal,
It is possible to automatically correct long-term fluctuations in laser output.

[0019]

As described above, according to the present invention, the short-term fluctuation at the start of laser output of the laser device can be suppressed and kept constant from the beginning by a relatively simple method. Also, the laser output can be kept constant.
Thereby, in particular, in a laser processing apparatus or the like that frequently performs on / off control of the laser output, the processing performance can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an apparatus for performing a laser output stabilizing method according to an embodiment of the present invention.

FIG. 2 is a timing chart showing measurement of laser output in advance according to the embodiment of the present invention.

FIG. 3 is a timing chart showing a corrected laser output according to the embodiment of the present invention.

FIG. 4 is a timing chart at the time of continuous laser output according to the embodiment of the present invention.

[Description of sign]

 Reference Signs List 1 laser oscillator 2 lamp 3 power supply 4 rod 5 laser beam 6 laser output detector 7 signal 8 controller 9 control signal 10 laser output 20 corrected control signal

Claims (6)

[Claims] At the start of laser output of a laser device, a change in laser output with respect to a control signal to a laser power supply is measured, and the change pattern is recorded. A laser output stabilization method characterized by suppressing a short-term fluctuation of the laser output at the start of the laser output and correcting the laser output to be constant by correcting the control signal. 2. The laser output stabilizing method according to claim 1, wherein the recording of the fluctuation pattern of the laser output is performed every time the laser output starts. 3. The method according to claim 1, wherein when correcting the control signal using the recording result of the laser output variation pattern, the recording result of the laser output variation pattern at the time of starting the immediately preceding laser output is used. 3. The laser output stabilizing method according to 1 or 2. 4. During continuous laser output after the start of laser output, by measuring a predetermined number of laser output values emitted immediately before and detecting a variation and correcting a control signal according to the variation, The laser output stabilizing method according to any one of claims 1 to 3, wherein a long-term fluctuation of the laser output is suppressed and the laser output is kept constant. 5. The method according to claim 1, wherein when detecting the amount of change in the laser output value, an average value is obtained by measuring N laser output values emitted immediately before, and comparing the average value with a predetermined expected value. 5. The laser output stabilizing method according to claim 3, wherein a fluctuation amount of the laser output value is detected. 6. A laser oscillator, a power supply for supplying power to a lamp of the laser oscillator, a laser output detector for monitoring the power of laser light output from the laser oscillator, and a laser output detector for the laser device. 6. The laser output stabilizing method according to claim 1, further comprising using a controller that takes in a signal from a device and controls output of a power supply.