JPS62137187A - Laser spot welding equipment - Google Patents

Abstract

PURPOSE:To increase the stability and efficiency in laser machining by providing the control means which adjusts the laser output by setting the nugget diameter of the body to be worked to the reference nugget diameter. CONSTITUTION:The outgoing laser beam from a laser oscillator 1 is condensed by a laser machining part 2 and projected on the body to be worked. The nugget shape is subjected to an image processing by a camera part 3 to the body to be worked and fed to an image processing controller 4 as a video signal. The controller 4 performs A/D (analog/digital) conversion of the video signal and decides the size of the nugget diameter A of the body to be worked based on the preset reference nugget diameter. The necessary laser output for obtaining this reference nugget diameter is then selected and a signal is transmitted to a laser power source input controller 6. The controller 6 feeds back the input level to the laser oscillator 1 with D/A conversion of this signal to produce the necessary laser output.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a processing device using a laser beam, and in particular to evaluating the shape of a processed nugget by image processing.

This invention relates to a laser spot welding device that automatically controls laser output necessary for inspection and processing.

Conventional technology Conventionally, the method for inspecting the processing of workpieces using laser spot welding equipment is to equip the laser output side with a peak hold type power monitor, which indirectly monitors fluctuations in the laser output necessary for processing. Furthermore, after machining, the appearance of the workpiece was inspected using a tool microscope, etc.

In such an inspection method, the automatic line is temporarily stopped during the inspection, and a production plan that takes into account operational loss time is required. In addition, even if the laser output is monitored by the power monitor during operation, if a problem occurs in the optical system that focuses the laser beam or in the holding of the workpiece jig, even if the power monitor is accurate, defective products may be produced. As a result, an accident may occur where the power monitor is overly trusted and a large number of defective products are produced. Therefore, the operator must constantly monitor the machining status, which places a heavy burden on the operator on the automatic line, and has the drawback of lacking efficiency as a lathe process.

Purpose of the Invention The present invention has been made to eliminate the above-mentioned drawbacks of the conventional method, and includes a method of evaluating and inspecting the nugget diameter of a workpiece processed with a laser beam based on a reference nugget diameter through image processing. It is an object of the present invention to provide a laser spot welding device that facilitates laser processing in one line by being equipped with a control device that automatically controls the laser output necessary for processing.

Structure of the Invention The laser spot welding apparatus according to the present invention includes an oscillation means for emitting a laser beam, a processing optical means for condensing the laser beam in accordance with the processing of a workpiece, and a laser spot welding apparatus that uses a nugget diameter of the workpiece as a reference nugget. It is characterized by omitting a control means for adjusting the laser output according to the diameter.

EXAMPLES Next, the present invention will be explained in more detail with reference to the drawings showing examples of the present invention.

FIG. 1 is a block diagram showing an embodiment of a laser spot welding apparatus according to the present invention. In the figure, a laser beam emitted from a laser oscillator 1 is focused by a laser processing section 2 and irradiated onto a workpiece. The nugget shape of the workpiece is image-processed by the camera section 3 and sent to the image processing controller 4 as a video image. The camera section 3 is actually incorporated into the II Loe optical system, and the magnification and illumination, which affect image processing accuracy, can be adjusted.

The image processing controller 4 converts the video signal 8 into A/D (analog/digital), and determines the nugget diameter A of the workpiece as shown in FIG. 2 based on a preset reference nugget diameter. Then, select the necessary laser output from the laser output car addition energy characteristic diagram in FIG. . The laser power input controller 6 performs D/A (digital/analog) conversion on this signal, feeds back the input level to the laser oscillator 1, and produces the necessary laser output. In addition, 5
is a monitor.

The laser spot welding device according to the present invention does not need to scan and detect the nugget diameter of the workpiece or perform image processing each time due to the stability of the laser output, so it can respond to speed-up.
It's quite possible. Further, if an extreme machining error occurs due to an abnormality in holding a jig on the automatic line side, damage to the jig by the laser beam can be prevented by sending an emergency stop signal based on the judgment content of the image processing controller 4. As described above, since it is no longer necessary for the operator to constantly monitor the machining state, stability and efficiency of laser machining in an automatic line can be achieved.

As described in detail, according to the present invention, by providing a control means for adjusting the laser output to match the nugget diameter of the workpiece to the reference nugget diameter, it is possible to inspect the appearance of the workpiece after processing. This eliminates the need for the operator to constantly monitor the machining status, and provides a laser spot welding device that has the stability and efficiency of radar machining on an automatic line.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a laser spot welding device according to the present invention, FIG. 2 is an image diagram of a processed nugget,
FIG. 3 is a characteristic diagram of laser output and processed nugget diameter. Explanation of symbols of main parts 1... Laser oscillator 2... Laser processing section 3... Camera section

Claims (1)

[Claims] an oscillation means that emits a laser beam; a processing optical means that focuses the laser beam in accordance with the processing of a workpiece;
1. A laser spot welding device comprising: a control means for adjusting laser output to match a nugget diameter of a workpiece to a reference nugget diameter.