JPH0647183B2 - Beam welding device control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control device for a beam welding apparatus.

(Prior Art) Currently, a welding technique using a high-density energy source such as a laser beam is actively studied. As an advantage of using this laser beam, for example, taking a member with a flange that has been conventionally joined by seam welding as an example, (1) The flange can be minimized (or joining without a flange is also possible) (2) Concentration Since it is in the heat source, it has a small heat-affected width (thereby causing less thermal deformation of the material).

However, since this laser beam is a concentrated heat source, when performing the flangeless joining described in (1) above, the positioning and the amount of the gap between the two members to be joined have a great influence. That is, if the gap between the two members exceeds the allowable limit value, welding becomes impossible. For example, in the case of welding a thin steel plate, it is known that good welding cannot be performed if there is a gap of about 30% or more of the plate thickness. Therefore, in order to perform good welding, it is absolutely necessary to first (a) prevent the formation of a gap, and (b) reliably irradiate the portion to be joined between the two members with the laser beam.

However, as a practical matter, it is impossible to grind each joint surface of the two members with high precision so that no gap can be formed before welding, in view of cost and man-hours. On the other hand, it is assumed that there is a gap. Then, a method may be considered in which the molten material is sent to the gap in advance and the gap is filled while melting with the laser beam, but this also requires that a certain gap be provided from the beginning, and if the gap amount varies. If this is the case, since unnecessary build-up can be done in a narrow area, the number of grinding processes after welding will increase unnecessarily.

By the way, as a beam welding apparatus as described above, for example, JP-A-59-141392 and JP-A-59-141392 are known.
The one described in Japanese Patent No. 232687 is known. The former prior art is a laser beam irradiation head for beam welding, a position control means of a butting portion formed by an image sensor between members to be welded, and the laser beam irradiation head (especially And a position control drive means for relatively moving the spot portion) relative to the joint surface of the abutting portion between the two members to be welded, and the laser beam by the position control means. The irradiation head is allowed to freely follow along the abutting portion (welding line) between the members to be melted, thereby enabling continuous automatic welding work.

In the latter conventional technique, a member to be welded is supported so as to be movable in a welding portion (butting portion) direction, a beam irradiation head is provided upward through the welding portion, and a continuous feeding device for strip-shaped molten material is provided downward. It is provided so that the molten material can be continuously supplied according to the progress of welding work.

(Problems to be Solved by the Invention) Therefore, by combining the former conventional technique and the latter conventional technique, it is possible to automatically supply and weld a continuous molten material along a butt portion between two members to be welded. Therefore, the above-mentioned problem (b) can be achieved for the time being, but on the other hand, 2
Do not form a gap in the butted part between two welded parts,
Alternatively, the fundamental problem in beam welding, in which the molten material is supplied according to the gap amount, has not been solved at all. That is, if the gap between the abutting portions is larger than a predetermined amount or is not constant, good welding cannot be performed.

(Means for Solving Problems) The present invention has been made for the purpose of solving or ameliorating the above problems, and a welding beam is provided by a position control means at a butting portion between members to be welded. In a beam welding apparatus that controls the relative position of the head and the member to be welded and supplies the molten material by the molten material supply means in accordance with the relative movement of the welding beam head and the member to be welded,
With respect to the welding beam head, two sides of the welding beam emitted from the welding beam head near the spots of the abutting portions between the members to be welded intersect predetermined portions with the abutting portions between the members to be welded. A welding line detection means provided with a slit light source for irradiating with an irradiation spot in a non-parallel predetermined shape intersecting at an angle and an image sensor for detecting reflected light from the slit light source is provided, and a detection signal from the welding line detection means is provided. The position control means is operated to control the position of the welding beam head, and at the same time, the amount of the molten material supplied by the molten material supply means is controlled.

(Operation) According to the above means, the welding line detecting means forms a non-parallel irradiation spot shape in which two sides intersect the abutting portion between the members to be welded at a predetermined intersection angle, and the slit light source. And an image sensor for detecting the reflected light from the welding line detecting means, and the distance between the non-reflecting portions formed by the abutting portions between the members to be welded between the two non-parallel sides of the spot portion of the welding line detecting means. The position of the abutting portion between the members to be welded is detected by the fluctuation of the position of the welded member, the position control means is operated according to the detected value, and the amount of the gap of the abutting portion between the members to be welded is changed from the change in the reflected light amount of the spot. Is specifically detected, and the amount of the melted material supplied by the melted material supply means can be controlled according to the detected value.
Therefore, the beam spot from the welding beam head can always accurately follow the abutting portion between the members to be welded, and it is also possible to supply the molten material according to the gap amount of the abutting portion. Therefore, good welding can always be performed without forming unnecessary build-up.

(Embodiment) FIGS. 1 to 3 show a control device for a beam welding apparatus according to an embodiment of the present invention.

First, in FIG. 1, reference numeral 1 denotes a beam welding apparatus. The beam welding apparatus 1 is controlled by a numerical controller 2 so as to be arbitrarily movable in an XY plane direction (Patent Claim 1). (Corresponding to the position control means in the range of 3) and the welding line l of the butting portion between the two members to be welded W ₁ and W ₂ (see FIG. 2) installed on the XY table 3. A beam head 4 located above and for irradiating a laser beam on the welding line l, a laser generator 5 connected to the beam head 4, and a beam irradiation spot on the welding line l of the beam head 4. FIG. 2 shows a welding material supply device 8 for continuously supplying a linear welding material 6 to the welding line 1 and a welding line 1 surface near the front side in the welding proceeding direction of the beam spot irradiated from the beam head 4 onto the welding line l. Virtual line Two sides and a welding line detection means 12 for detecting the position and width of the welding line l by irradiation spot of substantially V-shaped crossing the welding line l with a predetermined crossing angle as shown.

The beam head 4 reflects the laser beam generated by the laser tube in the laser generator 5 into a predetermined light beam by, for example, a cylindrical lens and then reflects the light beam.
The beam spot for welding is formed on the welding line 1 by being reflected in the direction of the welding line 1 and further focused into a beam through a focus lens (focus-adjustable objective lens) 11. There is.

Further, the melt supply device 8 is provided with a guide portion 13 and feed rollers 14 and 14 for continuously supplying the linear melt 6 to the beam spot, and the feed rollers 14 and 14 are provided.
Is driven by a stepping motor 15 for controlling the feed amount. Therefore, the linear molten material 6 is sequentially supplied from the feed rollers 14, 14 to the beam spot position through the guide portion 13, and the supply amount thereof is adjusted by the stepping motor 15 after all.

Further, the welding line detecting means 12 is provided with a laser light source 7
From the laser beam to parallel rays through a predetermined optical system, and then through the V-shaped slit plate 16 the member to be welded W ₁ ,
By projecting on the welding line 1 between W ₂ and the welding lines 1 and 2 on the welding line 1 as shown in FIG.
A slit light source unit 17 forming substantially non-parallel V-shaped irradiation spots where sides P ₁ and P ₂ intersect with each other at a predetermined intersection angle.
And an image sensor 18 which receives the reflected light from the slit light source 17 that has passed through the irradiation spot portion and generates an electric signal according to the input value. The image sensor 18 further reflects the reflected light from the V-shaped irradiation spot, which is received and reflected by a half mirror (one-way transmissive reflecting mirror) 19 interposed in the light projection system path on the slit light source 17 side. The light is further reflected upward at 21 and is incident on the image pickup unit 22. In the imaging unit 22,
A change in the shape of the irradiation spot and a change in the light amount of the reflection portion are detected from the incident light, converted into a digital signal, and the output thereof is input to the welding control unit 20. The welding control unit 20 determines the third
The control operation shown in the flow chart of the figure is performed.

That is, the irradiation light having a V-shaped projection surface consisting of parallel rays from the slit light source unit 17, the welded as described above member W _1, W ₂ of the butt section 2 sides irradiated weld line on l of P ₁ , P ₂ irradiates with a V-shaped irradiation spot which intersects the welding line 1 at a predetermined intersection angle. Therefore, the area A of the reflecting surfaces on both sides P ₁ and P ₂ varies depending on the width of the welding line l, that is, the gap amount of the butted portion. Further, a portion C ₁ that crosses the two sides P ₁ and P ₂ of the V-shaped irradiation spot,
The length l ₁ on the welding line l between C ₂ is equal to the above welding line l
It fluctuates by shifting from the top to the left or right in the horizontal direction. Then, each of these fluctuation amounts becomes the fluctuation of the input value to the image pickup unit 22 of the image sensor 18 as it is.

Therefore, first, in step S ₁ , the V-shaped irradiation spot 2
From the variation of the length l ₁ on the welding line 1 between the sides P ₁ and P ₂ , a relative positional variation of the welding beam head 4 and the welding line 1 in the left-right direction is detected (l ₁ detection). To step S ₂
In the detected value l ₁ is compared with a reference value a indicating the center point, l _1> predetermined amount of the X-Y table 3 to the left by operating the numerical control device 2 in step S ₃ in the case of a Driving, and in the case of l ₁ <a, XY
The table 3 is driven to the right by a predetermined amount in step S ₄ , and the beam spot from the beam head 4 is always aligned with the center of the welding line l, that is, the position of l ₁ is always constant (l ₁ = a). Do.

Next, the image sensor 18 detects the variation of the width of the welding line 1, that is, the size α of the gap at the abutting portion, from the variation of the area A of the reflection surface of the V-shaped irradiation spot as described above. The detection signal is supplied to the welding control unit 20. Therefore, first in step S ₅ , the gap amount α is detected, and then in step S ₆ , the detected amount α is compared with a predetermined reference value b. As a result, in the case of α> b, first in step S ₇ , the calculation X = (α-b) K for determining the output of the laser beam is performed to calculate the output up value, and then the process proceeds to step S ₈ . Note that X is the output value of the laser beam, b is the amount of reflected light in the maximum allowable gap amount of the welding line 1, and K is a calculation constant. In step S _8, operation of the welding material supply amount corresponding to the magnitude of the gap (X · K)
The stepping motor 1 according to the calculated value.
Drive 5 As a result, the welding work is performed with the optimum beam capacity and the optimum amount of molten material corresponding to the actual gap amount.

(Effects of the Invention) As described above, the present invention controls the relative position of the welding beam head and the member to be welded by the position control means at the abutting portion between the members to be welded, and In a beam welding apparatus for supplying a molten material by a molten material supply means in accordance with relative movement between a welding beam head and a member to be welded, the welding beam irradiated from the welding beam head is applied to the welding beam head. A slit light source for irradiating the vicinity of the spot on the abutting portion between the members to be welded with an irradiation spot having a non-parallel predetermined shape whose two sides intersect the abutting portion between the members to be welded at a predetermined crossing angle, and this slit light source. A welding line detecting means provided with an image sensor for detecting reflected light from the welding line detecting means, and the position control means is operated by a detection signal from the welding line detecting means. In this way, the position of the welding beam head is controlled and the amount of the molten material supplied by the molten material supply means is controlled.

Therefore, according to the present invention, the welding line detecting means forms a slit light source which forms a non-parallel irradiation spot shape in which two sides intersect with the abutting portion between the members to be welded at a predetermined crossing angle and reflection from the slit light source. And an image sensor for detecting light. Due to a variation in the distance between the non-reflecting portions formed by the abutting portions between the members to be welded between the two non-parallel sides of the spot portion of the welding line detecting means, The position of the butted portion between the members to be welded is detected, the position control means is operated according to the detected value, and the gap amount of the butted portion between the members to be welded is specified from the change in the reflected light amount of the spot portion. It is possible to control the amount of the melted material supplied by the melted material supply means according to the detected value. Therefore, the beam spot from the welding beam head can always follow the butted portions between the members to be welded accurately, and it is possible to supply the molten material according to the gap amount of the butted portions. Good welding can always be performed without forming unnecessary build-up.

[Brief description of drawings]

FIG. 1 is a control system diagram showing a control device of a beam welding apparatus according to an embodiment of the present invention, and FIG. 2 is a plan view of a welded portion showing an irradiation spot shape by the welding line detection means of FIG. FIG. 3 is a flow chart showing the control operation of the apparatus of the above embodiment. 1 ... Beam welding device 2 ... Numerical control device 3 ... XY table 4 ... Welding beam head 5 ... Laser generator 6 ... Melt material 7 ... Laser light source 8 ... Melt material supply device 15 ... Stepping motor 17 …… Slit light source section 20 …… Welding control unit l …… Welding line

Claims (1)

[Claims] 1. A relative position between a beam head for welding and a member to be welded is controlled by a position control means according to a butting portion between the members to be welded, and the beam head for welding and the member to be welded are relative to each other. In a beam welding apparatus for supplying a molten material by a molten material supply means in response to movement, a spot portion on a butting portion between the members to be welded of a welding beam irradiated from the welding beam head to the welding beam head. A slit light source that irradiates a vicinity with two non-parallel irradiation spots of a predetermined shape in which two sides intersect the abutting portion between the members to be welded at a predetermined intersection angle, and an image sensor that detects reflected light from the slit light source. A welding line detecting means provided with, and the position control means is operated by a detection signal from the welding line detecting means to control the position of the welding beam head. Control device for beam welding apparatus comprising so as to control the welding material supply amount of the welding material supply means with Nau.