JPS6160287A - Control device of position shift of lens in laser welding device - Google Patents

Abstract

PURPOSE:To stabilize the control precision by providing a translucent plate at the radiating position, photographing a molten spot and detecting the lenses position based on the signal. CONSTITUTION:A laser generator 1 and a laser torch 4 are distributed on the movably part of an X-Y table, and a translucent plate 7 such as acrylic and the like is provided under a laser torch 4. Further, under the translucent plate 7, a photographic device 9 is provided to photograph from the back side. The laser torch 4 is moved to the upper part of the plate 7 at each radiation of a laser beam 2 at a constant time, and the laser beam 2 is radiated on the plate 7. At this time, a laser spot 8 is processed for a picture by a photographic device 9 and a picture-processing device 11 to decide the position shift of the lens 3. Thereafter, the position shift is displayed by displays 12, 13 and the position of the lensess 3 is controlled by micrometers 5, 6 to stabilize the control precision at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a lens position shift adjusting device in a laser welding device.

(Prior Art) In recent years, automatic laser welding equipment has been put into practical use, which automatically performs welding while feedback-controlling the movement position of the laser welding equipment using an image processing device. This J
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(Problems to be Solved by the Invention) However, this conventional device has the following problems.

First, the laser beam is usually focused on an IC using a lens, but since there is a limit to the manufacturing precision of this lens, the laser beam is usually focused at a point offset from the central axis determined by the outer diameter of the lens. Tie.

However, since the lens is positioned by the laser beam only by its outer diameter, if the lens is removed for cleaning etc. and reattached, or if the lens is replaced, the focal position will change each time. There was a problem with it shifting.

This change in the optical axis has a significant impact on the quality of processing, so normally after removing the lens, preliminary processing is performed in advance, and work such as checking and adjusting the amount of deviation is performed manually. ing.

However, in the past, the lens misalignment determined from the results of preliminary processing was determined manually and empirically, making it difficult to determine the misalignment m in a constant manner and requiring manual adjustment. Therefore, there was a problem that there were large individual differences, which affected the quality of processing.

Furthermore, when processing a galvanized steel plate or the like, the lens becomes heavily soiled and the lens must be cleaned more frequently, resulting in the problem that adjustment work requires a lot of time.

(Means for Solving the Problems) Therefore, in the present invention, in order to solve the above problems, a semi-transparent plate is provided at the laser beam irradiation position, and the laser beam is applied to the semi-transparent plate. The melting trace produced by irradiation is imaged by an 8-imaging device, which is further image-processed to determine how much the focal point has shifted. 4- Adjust the J-rank purchase J: It's something to eat.

(Example) Hereinafter, an example of the present invention will be specifically described with reference to the drawings. .

Reference numeral 1 denotes a well-known Lehner oscillator, and below it are provided lasers 1 to 4 that direct a lens 3 to the right.

This laser IJ'-oscillator 1 and laser torch 4 are connected to the moving part 15 of the J: sea urchin X-Y table 1/I shown in FIG.
is installed on.

2i, although the X-Y table 14 is shown in a simplified manner in FIG. It is designed to move forward and backward in the direction indicated by X. Therefore, this servo motor 16
By controlling the rotation of the servo motor 17,
The laser torch 4 can be controlled to move to a desired position on the daple 14a.

Next, the laser torch 4 is provided with micrometers 5 and 6 at right angles, respectively, for adjusting the supporting position of the lens 3. This micrometer 5#6
By adjusting the rotation of the micrometer 5, the lens 3 can be moved in the direction indicated by X in the figure, and by adjusting the rotation of the micrometer 6, the lens 3 can be moved in the direction indicated by Y in the figure. It looks like this.

The micrometer 5.6 is a well-known one, and by rotating the knobs 5a, 5a, the lens 3 can be moved in units of, for example, 1/100 mm.

Next, a rectangular acrylic plate 7, which is an embodiment of a semi-transparent plate, is provided below the laser torch 4. An imaging device 9 is provided below this acrylic board 7 to take an image of this acrylic board 7 from a missing point.Furthermore, a signal from this imaging device 9 is input to an image processing device 11. Well-known image processing is performed. Note that the signals processed by this image processing device 11 are input to display devices 12 and 13, respectively.

The display 12 calculates and determines the coordinates of the laser torch mark 8 in the X direction based on the signal from the image processing device 11, and determines the deviation of G'J in the X direction with respect to a predetermined reference position. It's supposed to show what's going on. Similarly, the display 13 displays how much the radar spot trace 8 has shifted in the Y direction with respect to a predetermined reference position.

Incidentally, the deviation displayed on the indicators 12 and 13 is based on the micrometer 5 and the micrometer 6.
The scale value is converted and displayed.

Therefore, the knobs 5a of micrometers 5 and 6 are adjusted according to this displayed value.

By adjusting 6a, the shift in focus of the laser torch 2 irradiated via the lens 3 can be corrected to a predetermined reference position.

Next, the ray IJ'-oscillator 1. Laser Torge 4,
The acrylic plate 7 and the imaging device 9 are attached to an X-Y double 171
Figure 3 shows the state in which it is installed.

In the same figure, laser oscillators 1 and J: and lasers 1 to
As described above, the acrylic plate 7 is installed at the end of the table 14a, and the I-layer imaging device 9 is installed below the acrylic plate 7. has been done.

In the above configuration, when welding, a workpiece (not shown) to be welded is placed on the top of the table 14a. At this time, since the acrylic plate 7 is installed at the end of the table 14a, it does not interfere with the object to be welded.

Further, even if the object to be welded reaches the upper part of the acrylic plate 7, it will not directly affect the welding.

Next, when it is desired to adjust the position of the lens 3, the following operation is performed. First, the servo motor 16
and servo motor 17 to drive the laser torch 4.
is moved to the reference position on the second part of the acrylic plate 7. This reference position is, for example, the center of the acrylic plate 7.

Next, when this movement is completed, the laser oscillator 1 is excited and the acrylic plate 7-1- is irradiated with a beam 2 of the acrylic plate 7-1.
If the positions of the rays (j-spora 1 to marks 8) on this acrylic plate 70 are deviated, it means that the position L1 of the lens 3 is deviated. By processing the image in the image processing device 11 and making a determination, it is possible to determine whether there is a deviation from the reference position (J). .

Will Tsutsuka explain this judgment method here? j-rudo,
1Ii2 (tJA equipment 9, for example, is a type that has a built-in CCD, and the image of the acrylic plate 7 from the back side is projected onto this CCD.CCr) Each of the photoelectric elements outputs a signal of O or 1 depending on whether it is bright or dark.

The image captured by this dancing image device 9 is input to an image processing device 11 and undergoes predetermined image processing. Here, in the image processing device fff11, the image captured by the prefectural uniformity device 9 is allocated to a predetermined area of a RAM (not shown) built into the image processing device 11.

Therefore, by the above process, for example, the acrylic plate 7 is
As shown in the figure, the data is divided into sections GJ at predetermined intervals, and each section corresponds to, for example, addresses from 000 to AOFF in the RAM. Here, if the reference position is taken approximately at the center, this will be address A077. Then, the laser spot trace 8 is at the reference position fFff
If it were formed diagonally below iB1 (address AO83) in the drawing, it would be offset by -4 in the X direction and -4 in the Y direction.

Therefore, this deviation is calculated and determined by the image processing device 11,
By performing a predetermined conversion and displaying the result on the display 12 and the display 13, the adjustment amounts of the micrometers 5 and 6 can be displayed.

In this way, the shift in the focal position of the lens 3 can be easily adjusted in this example.

Next, an embodiment will be described in which the adjustment of the lens 3 that has been adjusted is automatically performed.

Laser oscillator 1 [Continuous operation for 1 hour /f] is built in laser oscillator 1! 2. An internal mirror (not shown) may undergo thermal deformation, and the origin of the output beam may change. Then, lens 3 of laser beam 2
Since the angle of entry Q4 changes, it is desirable to readjust the position of the lens 3.

Therefore, in this embodiment, in order to automatically adjust the lens 3 during continuous operation, the following J: Yes configuration is used (747-).

However, in this actual Mli example, one control circuit is provided after the image processing device 11 (furthermore, this control circuit 19 controls the pulse motor 22 and the pulse motor 23 via the drive circuit 20 and the drive circuit 21). The pulse motor 22 and the pulse motor 23 are connected to the micrometer 5 to drive the micrometer 5.
The micrometers 5 and 6 are attached to their rear ends so that the knobs 5a and 3a of the micrometers 6 can be rotated.

In the above-described configuration, the control circuit 19 generates an interrupt at predetermined time intervals (for example, one hour) to the unillustrated control circuit of the unillustrated servo motors 16 and 17. When this interrupt occurs, the stub motor 16 and servo motor 17 move the laser torch 4 to the reference position on the acrylic plate 7 according to a predetermined interrupt routine. After this movement, the laser beam 2 is irradiated from the laser tope 4 to the acrylic plate 7, and the deviation between the reference point and the laser spot trace 8 is determined in the same manner as described above.
In other words, find the deviation. Once this deviation is determined, the control circuit 19 controls the pulse motor 22 via the drive circuit 20.
is driven to move the lens 3 by a predetermined amount in the Y-axis direction, and further, a pulse motor 23 is driven via a drive circuit 21 to move the lens 3 by a predetermined amount in the X direction.

By doing this, automatic correction becomes possible during continuous operation.

In this example, servo motors were used for 16 and 17, but step motors could also be used. Of course, this is a good thing.

<Effects of the Invention> In the present invention, a laser beam is used to form a spot mark on a semi-transparent plate, and this spot mark is
By using image processing to determine whether the mark is off by one point from the it f% 1st place, and adjusting the position of the lens installation based on this determination result,
An excellent feature unique to the present invention is that readjustment when cleaning or replacing the lens can be performed accurately and extremely easily.

Moreover, unlike manual adjustment, the amount of deviation can be objectively grasped numerically, so there are no individual differences in the amount of adjustment, and the accuracy is always stable.
The favorable characteristic of being able to do so is also right.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is an explanatory diagram showing the overall configuration of the present invention, and FIG.
A line cross-sectional view, Figure 3 is a partially cutaway perspective view showing how this example is applied to an automatic welding device, and Figure 4 is a determination of the small deviation between the laser spot mark formed on the acrylic plate and the reference position. FIG. 5 is an explanatory diagram showing an example of automatically adjusting a micrometer, and FIG. 6 is a plan view showing a micrometer equipped with a pulse motor. 1...Laser oscillator 2...Laser beam 3...Lens 4...Laser torch 5.6...Micrometer 7...Acrylic plate 8...Laser spot trace 9...Imaging device 11... Image processing device 12.13... Display 1/I... X-Y table 14a... 7-pull 15... Moving unit 16.17... Servo motor 18... Moving axis 19...control circuit 20.21...drive circuit

Claims (1)

[Claims] A lens position shift adjustment device in a laser welding device having an adjustment device for adjusting the attachment position of a lens provided in the laser device, the translucent plate provided at a position irradiated with a laser beam from the laser welding device. , an imaging device that images the spot after being melted by the laser beam irradiation from below the semi-transparent plate, and an image processing device that detects the position of the spot trace based on the imaging signal from the imaging device. A lens position shift adjustment device in a laser welding device, characterized in that: