KR100753215B1 - Laser welding apparatus - Google Patents

Abstract

A laser welding system is provided to track a welding line along which welding is conducted and inspect whether a welded portion is defective at the same time during the laser welding. A laser welding system(100) comprises: a welding body(110) which is equipped with a welding laser(111) for outputting a welding beam by welding to project the outputted welding beam onto a welded portion(200), and of which position is moved by driving of a certain actuator(160); a tracking laser(120) installed at one side portion of the welding body to project a tracking beam onto the welded portion; an inspection laser(130) installed at the other side of the welding body to project an inspection beam onto the welded portion; a pair of CMOS(complementary metal-oxide semiconductor) image sensors(140a,140b) installed on an upper part of the welding body to convert and output the tracking beam and the inspection beam into a tracking electrical signal and an inspection electrical signal respectively by receiving a tracking beam and an inspection beam reflected from the welded portion; and a control part(150) for processing the tracking electrical signal outputted from the CMOS image sensors to control the displacement of the actuator, processing the outputted inspection electrical signal to judge whether the welded portion is defective, and controlling on/off of respective beams outputted from the welding laser, the tracking laser and the inspection laser.

Description

Laser welding apparatus

1 is a schematic diagram of a laser welding system according to an embodiment of the present invention;

2 is a flowchart illustrating a transmission path of a welding beam, a tracking beam, and an inspection beam output from the welding laser, the tracking laser, and the inspection laser of FIG. 1;

3 is a schematic view of a welding member to which an embodiment of the present invention is applied;

4 is a schematic diagram of a controller in which a tracking laser and an inspection laser signal reflected after being projected onto the welding part of FIG. 3 are processed;

FIG. 5 is a schematic diagram illustrating an embodiment of a welding part inspection result displayed on the display unit of FIG. 4;

6 is a perspective view showing an embodiment of an actuator providing a displacement to the welding body of FIG.

<Explanation of symbols for main parts of the drawings>

100 ... laser welding system 110 ... welding body

111 Welding laser 112 Optical fiber

113 polarizing lens 114 reflecting mirror

115.Focus lens 120.Tracking laser

130 Inspection laser 140a, 140b CMOS image sensor

150 control unit 151 display unit

152 ... Input 153 ... Decision

154a, 154b ... upper threshold 155a, 155b ... lower threshold

160 ... actuator 200 ... welding member

210 ... first welding member 220 ... second welding member

230 ... welding line 240 ... welding core

The present invention relates to a laser welding system, and more particularly, to a laser welding system capable of inspecting defects of a weld bead and a weld seam, which are traces and welded portions of weld lines to be welded during laser welding.

In general, welding is a process of integrally forming by joining different metal members by heating or melting, and is widely used in various fields including shipbuilding, automobile, construction, railway, nuclear industry, arc welding, resistance welding, and gas. Various methods, such as welding, friction welding, and laser welding, are proposed.

Among them, the laser welding is a method of focusing a laser, which is a concentrated heat source having a high energy density, and projecting the laser to a welding site. Since the laser welding has little heat effect and thermal strain, the laser welding is widely used for precise welding work.

According to the laser welding method, it is possible to shorten the process time, excellence in joining strength and airtightness, and improve productivity. However, as in other welding methods, welding part defects such as material changes, cracks, and pores may occur. .

As the inspection method of the welding defect site as described above, visual inspection or individual inspection by a separate defect detection device may be performed after the welding is completed, but the inspection speed is slow and inefficient, and the accuracy and reliability of the inspection result are deteriorated. .

In addition, since it is not easy to trace the welding line, which is a part to be welded, welding may be performed on an incorrect part, and there is a problem that the welding time is wasted, the operation cost is increased, and productivity may be reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a laser welding system capable of simultaneously realizing traces of weld lines to be welded and defect inspection of welded portions during laser welding.

Other objects and advantages of the invention will be described below and will be appreciated by the embodiments of the invention. Furthermore, the objects and advantages of the present invention can be realized by means and combinations indicated in the claims.

Laser welding system of the present invention for achieving the above object is provided with a welding laser for outputting a welding beam for welding to project the output welding beam to the welding site, the position is moved by the driving of a predetermined actuator Welding body; A tracking laser installed at one side of the welding main body and outputting a tracking beam for searching for a welding site to be welded and projecting the welding beam to the welding site; An inspection laser installed at the other side of the welding body and outputting an inspection beam for inspection of the welded portion and projecting the inspection beam to the welding portion; A pair of CMOS image sensors installed at an upper end of the welding main body and configured to receive a tracking beam and an inspection beam that are reflected after being projected onto the welding part, and convert the output into a tracking electrical signal and an inspection electrical signal, respectively; And controlling the displacement of the actuator by processing the tracking electrical signal output from the CMOS image sensor, and determining whether the welded portion is defective by processing the inspection electrical signal output, and the welding laser, the tracking laser and And a control unit for controlling on / off of each beam output from the inspection laser.

The welding main body may include: an optical fiber to which a welding beam output from the welding laser is transmitted; A polarizing lens for removing a reflection component of the welding beam transmitted through the optical fiber; A reflection mirror for changing a traveling direction of the welding beam passing through the polarizing lens; And a focus lens for focusing the welding beam passing through the reflection mirror and transferring the welding beam to the welding site.

In addition, the tracking beam and the inspection beam reflected from the welding portion may be received by each CMOS image sensor after passing through the focus lens and the reflection mirror in turn.

The control unit may further include a display unit configured to process a tracking electrical signal and an inspection electrical signal output from the CMOS image sensor to visually display the shape of a welding line before welding and a welding surface after welding; An input unit for inputting an upper limit threshold value and a lower limit threshold value, which are criteria for determining whether the weld face is good or bad; And a determination unit configured to process the inspection electrical signal output from the CMOS image sensor to determine whether it is within a range between the upper limit threshold and the lower limit threshold to output a good or bad decision on the welding state of the weld surface. can do.

The determination unit may further output a processing value, the input upper limit threshold value and the lower limit threshold value of the inspection electrical signal for each welding surface part, and the display unit outputs the processed value, upper limit threshold value, and lower limit threshold value. Can be displayed in graph form.

The upper limit threshold and the lower limit threshold may be input to at least one input unit, respectively.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. It should be interpreted as meanings and concepts corresponding to the technical idea of the present invention based on the principle of definition.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

Figure 1 is a schematic diagram of a laser welding system according to an embodiment of the present invention, Figure 2 is a flow chart showing the transmission path of the welding beam, tracking beam and inspection beam output from the welding laser, tracking laser and inspection laser of Figure 1, Figure 6 1 is a perspective view showing one embodiment of an actuator providing a displacement to the welding body of FIG.

As shown, the laser welding system 100 according to the present invention is the welding body 110, the tracking laser 120, the inspection laser 130, a pair of CMOS image sensor (140a, 140b) and the controller 150 It includes.

The welding body 110 is provided with a welding laser 111 for outputting a welding beam for welding to project the output welding beam to the welding portion of the welding member 200, the position by the drive of a predetermined actuator 160 Can be displaced.

Here, the predetermined actuator 160 may be manufactured integrally with the welding body 110 or separately coupled to the outside in order to provide a displacement to the welding body 110, and may be provided in any form that can provide a displacement. Obviously, it can be produced.

As shown in FIG. 6, the predetermined actuator 160 providing the displacement to the welding main body 110 is preferably capable of both a vertical Z-axis displacement and a horizontal Y-axis displacement. It is to be understood that the shape of 160 is not limited to the form of FIG. 6 and may be modified in various ways.

On the other hand, it is apparent that the predetermined actuator 160 can be replaced by a separate robot (not shown) that can provide displacement to the welding body 110.

The welding body 110 further includes an optical fiber 112, a polarizing lens 113, a reflection mirror 114, and a focus lens 115 in addition to the welding laser 111.

The optical fiber 112 is an optical signal transmission path through which the welding beam output from the welding laser 111 is transmitted.

The polarization lens 113 is a portion for removing the reflection component of the welding beam transmitted through the optical fiber 112, it can block the optical signal that is diffusely reflected or refracted.

The reflective mirror 114 is a mirror for converting the traveling direction of the welding beam passing through the polarization lens 113 toward the lower welding member 200, the refractive index is preferably within the range of 1: 1. The reflective mirror 114 may be coated with a separate coating resin to increase the reflection efficiency and to protect the reflective mirror 114.

The focus lens 115 is a lens that focuses a welding beam passing through the reflection mirror 114 and transmits the welding beam to a welding site.

That is, the welding beam output from the welding laser 111 of the welding main body 110 passes through the optical fiber 112, the polarizing lens 113, the reflection mirror 114 and the focus lens 115, and then the welding member. It may be projected onto the weld of 200.

The tracking laser 120 is installed on one side of the welding main body 110, and outputs a tracking beam for searching for a welding line 230, which is a welding portion to be welded, that is, a portion connected between welding members. The laser is projected onto the welded area of).

The inspection laser 130 provided in the laser welding system according to the present invention together with the tracking laser 120 is installed on the other side of the welding main body 110, and outputs an inspection beam for inspection of the welded portion. It is a laser to project on the welding part of (200).

The inspection laser 130 is configured to be provided on a surface different from the surface of the welding main body 110 in which the tracking laser 120 is installed, and the tracking laser 120 is based on the welding main body 110. It is preferable to be installed on the opposite side.

This can not only prevent the interference between the tracking beam and the inspection beam output through each laser, but also the tracking of the weld line by the tracking laser 120, welding the welding site by the welding laser 111, the inspection laser ( This is to be configured to enable efficient sequential progress of the weld inspection by 130).

The pair of CMOS image sensors 140a and 140b are installed at the upper end of the welding main body 110 to receive a tracking beam and an inspection beam that are reflected after being projected onto the welding portion of the welding member 200 and receive a tracking electrical signal. An image sensor that converts and outputs an inspection electric signal, respectively, has a low power consumption because it is composed of a complementary metal oxide semiconductor (CMOS).

Here, the tracking beam and the inspection beam reflected after being projected onto the welding portion of the welding member 200 pass through the focus lens 115 and the reflection mirror 114 to each CMOS image sensor 140a and 140b. Can be received.

On the other hand, the wavelength of the welding beam output from the welding laser 111 is in the range of 1069nm to 1090nm, the wavelength of the tracking beam and the inspection beam output from the tracking laser 120 and the inspection laser 130 is 660 It may be in the range of nm to 990 nm, but it should be understood that the wavelength of each beam may be modified in various ranges without being limited thereto.

The controller 150 controls the displacement of the actuator 160 by processing the tracking electrical signal output from the CMOS image sensor 140a, and controls the displacement of the actuator 160 and outputs the inspection electrical signal output from the CMOS image sensor 140b. It is possible to determine whether the welded portion is defective.

3 is a schematic view of a welding member to which an embodiment of the present invention is applied, FIG. 4 is a schematic view of a control unit in which a tracking laser and an inspection laser signal reflected after being projected onto the welding site of FIG. 3 are processed, and FIG. 5 is a display unit of FIG. 4. Figure 1 is a schematic diagram showing an embodiment of the weld site inspection results shown in.

The welding member 200 applied to the present invention may be the first welding member 210 and the second welding member 220 having different heights, as shown in FIG. ) Is the part where welding is actually performed.

Since the shape of the welding member 200 is only one embodiment applied to the present invention, the shape of the welding member applied to the present invention is not limited to FIG. 3, and the present invention enables welding of welding members of various shapes. Of course.

As shown in FIG. 4, the controller 150 may include a display unit 151, an input unit 152, and a determination unit 153.

The display unit 151 processes the tracking electric signal and the inspection electric signal output from the CMOS image sensors 140a and 140b to form the shape of the welding wire 230 before welding and the welding seam 240 which is a welding surface after welding. Can be displayed visually.

According to such a display unit 151, since defects such as cracks and pores generated in the welding core 240 may be visually represented by various screen display means such as LCD, the actual method of checking the degree of defects through the naked eye. Effective alternatives and complements are possible.

In other words, according to the direct visual confirmation method for the degree of defects, there is a difficulty in the verification operation due to the welding heat or a risk of safety accident, and there is an inefficient disadvantage due to the inability to confirm the actual fine defects. Since it can be checked through a separate display means, as well as safety from accidents, the reliability of defect detection results can be guaranteed.

The data may be databased for actual comparison with the actual welded object, contrast, and the like, and may be configured to enable various data use for the welding in the future.

Meanwhile, the input unit 152 may input an upper limit threshold and a lower limit threshold that are a standard for determining whether the welding surface, that is, the welding core 240 is good or bad.

At least one of the upper limit threshold and the lower limit threshold may be input to the input unit 152, so that the reference range of the defect determination may be one or more, and numerical comparison within various ranges is possible.

The determination unit 153 processes the inspection electrical signal output from the CMOS image sensor 140b to determine whether it is within a range between the upper limit threshold value and the lower limit threshold value, so that the welding state of the weld surface is good. Or a portion for outputting a bad judgment. The good or bad determination output from the determination unit 153 may be displayed on the display unit 151.

On the other hand, the determination unit 153 further outputs the processing value of the inspection electric signal, the input upper limit threshold value and the lower limit threshold value for each weld surface, that is, the portion of the welding core 240, and the display unit 151. As shown in FIG. 5, the processed value, the upper limit threshold value, and the lower limit threshold value output may be displayed in a graph form.

FIG. 5 shows a test result of the bead width of the weld seam 240 when two upper and lower thresholds 154a and 154b and 155a and 155b are respectively input to the input unit 152. An exemplary embodiment is shown, and the test result may be processed by the determination unit 153 and displayed on a screen by a predetermined program.

In the graph, the horizontal axis represents the length of the weld seam 240, and the vertical axis represents the measurement result of the bead width for each length.

Here, the first upper limit threshold 154a to the first lower limit threshold 155a range from the first reference range, the second upper limit threshold 154b to the second lower limit threshold 155b based on the vertical axis of the graph. If the range is the second reference range, the illustrated section B may be a defect determination section in which the bead width of the weld seam 240 exceeds each reference range, and section A may be a good determination section.

On the other hand, as shown in Figure 5, the items that can be inspected through the control unit 15O of the present invention, in addition to the bead width, the mismatch of the welding surface (Unscut depth), the undercut depth (Bead slope) ), The excess thickness (Overthickness), discontinuity (Discontinuity), weld seam convexity (Convexity), etc., but the inspection items are not limited to this.

The controller 150 may control on / off of each beam output from the welding laser 111, the tracking laser 120, and the inspection laser 130.

That is, according to the controller 150, the welding laser 111 and the inspection laser 130 is turned off (OFF) by turning on the tracking laser 120, the welding start, that is to be welded Search for the beginning of the weld seam 230, which is a portion of the site and allows the tracking of the weld seam 230 to be performed initially.

When it is determined that the welding line 230 is traced, the welding laser 111 is turned on to perform welding, and the inspection laser 130 is turned on for the welding seam 240 which is a welded portion immediately. Allow the inspection to be carried out.

When welding is completed, the tracking laser 120, the welding laser 111, and the inspection laser 130 are sequentially turned off, and the inspection result is processed and output.

According to the laser welding system 100 of the present invention as described above, the tracking laser 120 for tracking the welding line 230, the welding laser 111 for performing the welding and the inspection laser 130 for inspecting the welded portion By constructing integrally, the welding line tracking process, the welding process, and the inspection process, which are conventionally made separately, can be simultaneously realized.

In addition, according to the present invention, the tracking process of the welding line 230 and the quality inspection result of the welded portion are confirmed in real time by the controller 150, thereby improving reliability and accuracy of the inspection result as well as for problems such as poor welding. Quick checks can reduce work time, reduce operating costs, and contribute to increased productivity and labor costs.

In addition, the laser welding system 100 as described above can be miniaturized to secure a working space and improve applicability to linear and nonlinear curved welding and to welding parts having various sizes and shapes.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is described by the person of ordinary skill in the art to which the present invention pertains. Various modifications and variations are possible without departing from the scope of the appended claims.

The laser welding system of the present invention provides the following effects.

First, the welding line tracking process, the welding process, and the inspection process can be simultaneously realized by integrally configuring the tracking laser for tracking the weld line, the welding laser for performing the welding, and the inspection laser for inspecting the welded portion.

Second, the tracking of welds and the quality inspection of welding areas are confirmed in real time, which not only improves the reliability and accuracy of the inspection results, but also enables quick confirmation of welding defects, which reduces work time, reduces operating costs, and improves productivity and labor costs. Provide savings.

Third, the control unit processes the signal output from the image sensor to visually express cracks or pores generated at the welded portion through the display unit, thereby making it possible to visually check the degree of defects.

Fourth, it is possible to determine whether it is within the range between the upper limit threshold and the lower limit threshold to determine whether the welding state of the weld surface is good or bad, and at least one upper limit threshold or the lower limit threshold is input to determine the failure. The reference range of can be one or more, and numerical comparison within various ranges is possible.

Fifth, it can be miniaturized to secure a working space and can be improved in the application of linear and nonlinear curve welding and welding of parts having various sizes and shapes.

Claims (6)

A welding body provided with a welding laser for outputting a welding beam for welding to project the output welding beam onto a welding portion, the position of the welding body being moved by driving of a predetermined actuator; A tracking laser installed at one side of the welding main body and outputting a tracking beam for searching for a welding site to be welded and projecting the welding beam to the welding site; An inspection laser installed at the other side of the welding body and outputting an inspection beam for inspection of the welded portion and projecting the inspection beam to the welding portion; A pair of CMOS image sensors installed at an upper end of the welding main body and configured to receive a tracking beam and an inspection beam that are reflected after being projected onto the welding part, and convert the output into a tracking electrical signal and an inspection electrical signal, respectively; And The displacement of the actuator is controlled by processing the tracking electrical signal output from the CMOS image sensor, and the welding laser, the tracking laser, and the welding laser are determined by determining whether the welded portion is defective by processing the output inspection electrical signal. It includes a control unit for controlling the on / off of each beam output from the inspection laser, The control unit, A display unit for visually displaying the shape of the welding line before welding and the welding surface after welding by processing the tracking electrical signal and the inspection electrical signal output from the CMOS image sensor, and an upper limit threshold as a reference for determining whether the welding surface is good or bad. And an input unit to which a lower limit threshold value is input, and processing the inspection electric signal output from the CMOS image sensor to determine whether it is within a range between the upper limit threshold value and the lower limit threshold value, so that the welding state of the weld surface is good. Or a determination unit for outputting a defect determination. According to claim 1, The welding body, An optical fiber to which a welding beam output from the welding laser is transmitted; A polarizing lens for removing a reflection component of the welding beam transmitted through the optical fiber; A reflection mirror for changing a traveling direction of the welding beam passing through the polarizing lens; And And a focus lens for focusing the welding beam passing through the reflection mirror and transferring the welding beam to the welding site. The method of claim 2, wherein the tracking beam and the inspection beam reflected from the welding site, And passing through the focus lens and the reflection mirror in turn and received by each CMOS image sensor. delete The method of claim 1, wherein the determination unit, Further outputs a processing value of the inspection electric signal for each welding surface portion, the input upper limit threshold value and the lower limit threshold value, And the display unit displays the processed value, the upper limit threshold value, and the lower limit threshold value in the form of a graph. The method according to claim 1 or 5, And at least one upper limit threshold value and one lower limit threshold value are respectively input to the input unit.

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