JPH0521673B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a laser processing device, and more particularly to a device that performs processing by detecting processing intervals.

[Technical background of the invention and its problems]

In laser processing, the bottom plate 1 is
When welding the member 2 and the member 2, the laser beam 3 is focused by a condenser lens 4, and the processing spot 5 is irradiated onto the member 2 to perform welding. At this time, member 2
It is preferable that the width W is larger than or approximately the same as the diameter d of the processing spot 5. Also,
It is necessary to position the processing spot 5 and the member 2 so that the processing spot does not protrude from the member 2 so as not to damage the surface of the bottom plate 1. For example, an edge position detection method is available as an optical method for such positioning. In other words, a light beam is incident on the object obliquely, bright spots on the object are observed from above, especially at the edges, the bright spots from the edges are measured, and the processing spot is placed within the area obtained by this measurement. was under control. However, there was a problem in that measurement errors were likely to occur due to the roundness of the edges.

[Purpose of the invention]

An object of the present invention is to provide a processing apparatus equipped with a detection device that performs positioning for irradiating a laser beam only within a processing area.

[Summary of the invention]

Two or more light projecting means are provided in a light projecting posture to form a light condensing spot at both ends between the limit points in the processing area, and the reflected light is imaged at the light condensing spot, and an aperture is arranged at that position. The state detected from all the openings of the aperture is determined as the position for irradiation with the processing laser beam.

[Embodiments of the invention]

FIG. 1 shows one embodiment of the present invention, and the same parts as those shown in FIG. 5 will be described with the same reference numerals.
In addition, in the figure, the light beam is shown by the central axis line for convenience. That is, a pair of light projecting devices 1 for measurement.
0, 11, and these devices are arranged so that the converging spots 12a, 13a of the focused beams 12, 13 obliquely enter and image the limit points 14a, 14b on the processing surface of the member 2. ing. Above the member 2, a condensing lens 15 narrowed by convergent beams 12 and 13 and a semi-transparent mirror 16 held at an angle of 45 degrees are sequentially provided to direct the reflected light 12c and 12d from the condensing spot to a predetermined position. It is designed to form an image. 17 is an aperture, and a plurality of openings 18 formed in this aperture
is provided at a location that corresponds to the image formation position by the condenser lens 15. A photodetector 19 is provided behind the aperture 17 and detects the light that has passed through the aperture 18. Reference numeral 20 denotes a laser oscillation device, and the emitted laser beam 21 passes through a reflecting mirror 22 installed above the member 2 at an angle of 45 degrees and a condensing lens 23 disposed coaxially with the condensing lens 15. 2
The light is starting to enter the sky. The output signal of the photodetector 19 is input to a control section (not shown) within the laser oscillation device 20. In this case, the output signal is output when light from all of the apertures 18 is detected. Note that the relative positions of the light projecting devices 10, 11, the condensing lens 15, the semi-transparent mirror 16, the aperture 17, the photodetector 19, the reflecting mirror 22, and the condensing lens 23 are always constant.

The operation of the above configuration will be described next. The condensing spots 12a and 13a are the limit points 14a and 14a of the member 2, respectively.
14b, each spot image 24 of the reflected light 16a, 16b is irradiated as shown in FIG.
The light beams a and 24b pass through the aperture 18 and enter the photodetector 19. If the member 2 is significantly shifted from the position shown in FIG. 1, the focused beams 12 and 13 will illuminate the points 25a and 25b on the surface of the bottom plate 1. In this case, as shown in Figure 2b, the distance between points 25a and 25b is the limit point 14a and 14b.
The spot images 26a and 26b formed by the reflected light from the points 25a and 25b are narrower than that of the aperture 18.
An image is formed in between. On the other hand, if the member 2 is shifted to the right in the figure by about half its width W, the spot irradiated onto the member 2 will be reflected and become a spot image 27a passing through the aperture 18, as shown in FIG. 2C. The spot irradiated onto the surface of the bottom plate 1 due to the misalignment is reflected and becomes a spot image 27b formed on the aperture 17 and does not pass through the opening 18.

FIG. 3 shows a light intensity signal obtained by the photodetector 19 in the above operation. In other words, when the bottom plate 1 and the member 2 move laterally as one, A in the figure
The areas B and B correspond to FIG. 2b, and the areas B,
Area D corresponds to C in the figure, and area C corresponds to a in the same figure. Further, the length of the regions B and D is equal to the interval between the condensing spots 12a and 13a, and the length of the region C is equal to the width W of the member 2 minus this interval. From this, if the laser beam 3 is emitted by emitting a gate signal that causes the laser device to oscillate between the region C and irradiates it onto the member 2, the processing spot 5 can be positioned without protruding from above the member 2. become.

Note that the member is not a long body as in the above embodiment, but
In the case of a rectangular member, a rectangular member 3 is used as shown in FIG.
Detection may be performed by providing a light projecting device so as to illuminate the four condensing spots 31a to 31d with respect to zero, and by providing apertures having openings corresponding to these converging spots 31a to 31d.

〔Effect of the invention〕

The aperture openings are set in accordance with the spacing between the critical points in the processing area, and the laser beam is not emitted unless the reflected light that has passed through all the openings is detected, so the laser beam can be irradiated without protruding from outside the processing area. As a result, it is now possible to accurately perform laser processing on surfaces that do not want to be damaged, without having to add covers or other extra measures.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
3 shows the relationship between the movement of the member and the intensity of light received by the photodetector. FIG. 4 shows the principle of another embodiment of the present invention. The figure is a perspective view showing an example of a general laser welding process. DESCRIPTION OF SYMBOLS 1... Bottom plate, 2... Member, 10, 11... Light projector, 14a, 14b... Limit point, 15... Condensing lens, 17... Aperture, 18... Opening, 1
9...Photodetector, 20...Laser oscillator, 21...
...laser light.

Claims (1)

[Claims] 1. Two or more light projection devices that obliquely irradiate limit points in the processing area to form a focused spot, and a laser irradiation device that irradiates a laser beam with a spot diameter within a range regulated between the limit points. , a condenser lens that reimages the light reflected by the condensing spot, and a plurality of apertures formed at distances corresponding to the distance between the limit points, and these apertures are formed by the condenser lens. an aperture arranged at a position where the image is formed; a photodetector for detecting the light passing through the aperture; and a photodetector for detecting the light passing through the aperture; A laser processing device comprising: a control section that outputs a start signal.