JPH0642993B2 - Distance measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a distance measuring device that measures the distance between a nozzle of a laser processing machine and a target work in a non-contact manner.

[Conventional technology]

Generally, a laser processing machine performs processing such as irradiating the surface of a work with a laser beam focused by a processing lens to weld or cut the work, but in order to increase the efficiency of the processing, The beam waist position of the laser light is adjusted to the work position. In order to align this position, the distance between the nozzle of the processing machine and the work is controlled, and in order to perform this control accurately, a distance measuring device that measures the distance is used.

Conventionally, there is a distance measuring device of this type as shown in FIG. In the figure, 1 is a nozzle of a laser processing machine,
Reference numeral 2 is a coupling for attaching a rangefinder to the nozzle 1, 3 is a first light source for measurement, 4 is a projection lens for focusing the light beam emitted from the first light source 3, and 5 is a work 8 by the light source 3.
A light-receiving lens for imaging the first light spot formed on the
6 is a light receiving element which is installed at the image forming position of the first light spot by the light receiving lens 5 and outputs an electric signal according to the image forming, and 7 is a nozzle 1 which processes the electric signal output from the light receiving element 6 It is a processing circuit that calculates a distance H to the work 8.

The operation of the conventional rangefinder will be described below.

The light beam emitted from the first light source 3 toward the work 8 forms a first light spot of an appropriate size on the surface of the work 8 by the light projecting lens 5. The light-receiving lens 5 images the first light spot and forms an image of the light spot on the light-receiving surface of the light-receiving element 6.

The light receiving element 6 is also called an optical position detector, which generates an electric signal according to the image forming position of the light spot on the light receiving surface. The light spot image forming position P is determined by the values of the currents I _A and I _B generated in the two electrodes of the light receiving element 6. Obtained as. In this equation, the output of the light receiving element 6 produces an output proportional to the position of the light spot image and its intensity.
By introducing a term of (I _A + I _B ) corresponding to the intensity change of the light spot image into the denominator, an output proportional to only the position of the light spot image is obtained.

On the other hand, the distance h from the light spot of the light receiving lens 5 to the workpiece is Can be calculated as Here, L is a fixed value determined only by the device configuration. Further, θ is obtained from the position P of the light spot image described above and the design position of the light receiving lens 5. That is h
Is obtained by using only P corresponding to the displacement of the surface of the work 8 as a variable. Therefore, the distance H between the nozzle 1 of the processing machine and the surface of the workpiece 8 only adds a constant value to h, and H = K.
It can be calculated as P.

K is determined in advance by calculation or actual measurement. The processing circuit 7 calculates the above calculation and sends out the distance H. This distance H becomes information for controlling the nozzle 1 of the laser processing machine.

[Problems to be solved by the invention]

Although the conventional distance measuring device measures the distance H as described above, the position of the light spot on the work 8 cannot be visually confirmed because the first light source 3 for measurement is near infrared light. I did not know the position of the measurement point. Further, since the standoff position (calculated measurement position, laser light focal length) cannot be visually checked, it is difficult to perform initial alignment, and even during machining of the work 8, the standoff position and the work 8 are misaligned. There was a problem that it was not visible.

The present invention has been made to solve the above-mentioned drawbacks of the conventional ones, and a distance measuring device capable of visually confirming a measurement point and clarifying a standoff position is provided. The purpose is to provide.

[Means for solving problems]

Two or more distance measuring devices according to the present invention are arranged at positions sandwiching the first light source, and the emitted light from the first light source is at the same distance as the distance from the nozzle of the processing machine to the focal point of the laser light. A second light source that emits visible light is provided so as to intersect with.

[Action]

The distance measuring device according to the present invention, when the position of the target work and the standoff match by crossing two or more visible lights at the position of the focal length of the laser light on the emitted light from the first light source, 1 Display in spots of visible light at points,
It is displayed that the measurement point is also the same as the visible light spot. Further, when the position of the target work and the standoff are deviated, it is displayed with two or more visible light spots, and it is displayed that the measurement point is between two or more visible light spots.

〔Example〕

An embodiment of the present invention will be described with reference to FIG. In addition,
The same parts as those in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 1, reference numerals 9 and 9 denote second light sources that emit visible light toward the work 8, which are installed at positions sandwiching the first light source 3 which emits measurement light. It is designed to emit visible light in an oblique direction. Reference numerals 10 and 10 are lenses that focus visible light emitted from the second light sources 9 and 9 and form a second light spot at the position of the first light spot formed on the work 8 by the first light source 3. .

Next, the operation of the distance measuring device will be described. First light source 3
The light spot irradiated onto the work 8 by the light receiving lens 5
The light spot is imaged on the light receiving element 6, and the distance H is measured. Since this measurement is the same as the conventional one, its explanation is omitted.

The visible light emitted from the second light source 9, 9 is the lens 10, 1.
0 to form a second light spot on the work 8. At this time, if the work 8 is aligned with the standoff position, the second light spot is aligned with the first light spot 11 (see FIG. 2) formed on the work 3 by the first light source 3. At the same time, as shown in FIG. 2B, the number of visible light second light spots 12 becomes one. When the work 8 deviates from the standoff, the number of second visible light spots 12 becomes two, as shown in A and C of FIG. Therefore, the position of the standoff becomes clear, and the measurement point can be visually observed.

Although the number of the second light sources 9 and 9 for visible light is two in the above-described embodiment, a plurality of second light sources 9 and 9 may be used. Also, the second light source 9
If the standoff position is aligned with the position where the diameter of the second light spot formed by
You can choose one.

〔The invention's effect〕

As described above, according to the present invention, two or more are arranged at positions sandwiching the first light source, and at a position at the same distance as the distance from the nozzle of the processing machine to the focal point of the laser light, the distance from the first light source is increased. Since the second light source that emits visible light intersecting with the emitted light is provided, the position of the measurement point can be visually checked with a simple configuration, and the visible range is wide and can be confirmed from anywhere. Also, since the standoff position can be visually checked, it is easy to set the distance measurement range even in the initial alignment, and the alignment can be easily performed. It is possible to visually check the deviation from and the target workpiece can be safely processed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a distance measuring device according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a conventional distance measuring device, and FIG. 3 is an explanatory diagram of a light spot formed on a work. Reference numeral 1 is a nozzle, 3 is a first light source, 8 is a work, and 9 is a second light source.

Claims (1)

[Claims] 1. A nozzle of a processing machine, which irradiates a target work with light from a first light source through a light projecting lens to form a first light spot on the target work, and images the first light spot. In the distance measuring device for measuring the distance between the target work and the second light source, two or more second light sources are provided at positions sandwiching the first light source and irradiate the target work with visible light. The irradiated visible light is condensed to form a second light spot on the target work, and when the target work is in the standoff position, the second light spot is changed to the first light spot. A distance measuring device having a matching lens.