KR20170133202A - Quality inspection apparatus of laser-welding, and method thereof - Google Patents

Abstract

The present invention relates to a laser welding quality inspection method, and a laser welding quality inspection device. According to the laser welding quality inspection device having a detection unit (100) and a control device unit (600), the control device unit (600) comprises: a data collection module (621); a class classification module (622); and an error data correction module (623). Therefore, the present invention can check a quality of welding.

Description

[0001] The present invention relates to a laser inspection apparatus,

The present invention relates to a laser welding quality inspection method and apparatus, and more particularly, to a laser welding quality inspection method and apparatus for confirming the quality of a welding by checking a bead depth between laser welding using a confocal sensor .

Generally, laser welding is a technique of melting and attaching a welding base material with a laser beam. When a laser beam is irradiated to a metal, a keyhole is generated by the laser beam, the metal around the keyhole melts, and the generated keyhole and the metal melt are continuously moved in the longitudinal direction of the welding, thereby proceeding the welding.

Laser welding is a method of processing a material by using a laser beam focused at a high density. Although it has advantages of low thermal deformation, high productivity, and limited material restriction, it requires precise welding part matching compared to spot welding.

Therefore, it is necessary to precisely check the quality of the welded part. However, since the accurate depth is not measured by the various particles when measuring the laser welded part of the plasma state during the laser welding quality inspection, It is difficult to judge whether the particle is a particle.

Korean Patent Registration Bulletin No. 10-0488692 "Method and system for quality inspection of laser welding" Korean Patent Registration Bulletin No. 10-0488692 "Method and system for quality inspection of laser welding"

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a laser welding quality inspection method and apparatus for confirming the quality of welding through confirmation of bead depth between laser welding using a confocal sensor.

The present invention also provides a laser welding quality inspection method and apparatus for providing a correction function through particle quantization or vector quantization on measurement error data.

However, the objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a laser welding quality inspection apparatus for inspecting quality of laser welding in which a welding laser material moves while melting a welding base material : A laser welding quality inspection apparatus is a device for irradiating a predetermined spot size laser toward a welding base material while moving at the same speed as a welding laser, so as to move the depth of the welding bead formed on the welding base material by the welding laser A detection unit for continuously detecting the signal; A control unit for determining a welding quality from the data collected by the detecting unit; Wherein the control unit includes a data collection module for collecting the depth of the weld bead detected by the detection unit in the form of data displayed on a continuous graph of a plurality of samples of time (X axis) and distance (Y axis); A class classification module that classifies a plurality of samples in which a difference in distance value is continuous below the spot size of the detection laser, into a class; And an error data correction module for determining the number of samples belonging to the class classified by the class classification module as error data when the number of samples belonging to the class is less than the number of reference samples calculated by Equation (1). . The number of reference samples ≤ the spot size / travel distance per pulse (Here, 'spot size' is the spot size of the laser irradiated by the detection unit, and 'travel distance per pulse' , And the 'reference sample number' is defined as a maximum integer among the values calculated by the above equation (1)).

In an aspect of the embodiment of the present invention, the error data correction module calculates the average of the previous sample data and the next sample data for the sample data determined as an error, stores the calculated average in the storage section, compares the sample data, To be vector quantized.

In an aspect of the embodiment of the present invention, it is preferable that the control unit classify the detection unit and the welding laser using a confocal method in which the focal point is shared at one point.

One aspect of the method for inspecting the laser welding quality using the laser welding quality inspection apparatus according to the embodiment of the present invention is that the control apparatus includes a controller that controls the depth of the weld bead detected by the detection unit so that a plurality of samples can be measured with respect to time Collecting data in the form of data displayed on a continuous graph of distance (Y axis); A second step of classifying a plurality of samples in which a difference in distance value is continuous to a spot size of the detector laser, into a class; If the number of samples belonging to the class is less than the number of reference samples calculated by Equation (1), the control unit judges it as error data; A third step comprising the steps of: . The number of reference samples ≤ the spot size / travel distance per pulse (Here, 'spot size' is the spot size of the laser irradiated by the detection unit, and 'travel distance per pulse' , And the 'reference sample number' is defined as a maximum integer among the values calculated by the above equation (1)).

In an aspect of the embodiment of the present invention, in the third step, the sample data determined as an error is calculated as an average of the previous sample data and the next sample data, and stored in the storage unit to compare the sample data to obtain a similar pattern It is preferable to approximate vector quantization.

The laser welding quality inspection method and apparatus according to an embodiment of the present invention provides an effect of confirming the quality of welding through confirmation of bead depth between laser welding using a confocal sensor.

In addition, since the laser welding quality inspection method and apparatus according to another embodiment of the present invention provides a correcting function through vector quantization, accurate depth is not measured by various particles when inspecting the quality of a welded portion, It is possible to solve the problem that it is difficult to judge whether the value is a normally dissolved part or a particle. With this confocal method and vector quantization, the laser power is precise enough to check the quality during welding in the range of 30 ~ 100W.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a laser welding quality inspection apparatus according to an embodiment of the present invention. FIG.
Fig. 2 is a block diagram showing a configuration of a control unit of the laser welding quality inspection apparatus of Fig. 1; Fig.
3 is a conceptual diagram for explaining the operation principle of the laser welding quality inspection apparatus of FIG.
4 is a diagram showing the concept of the lateral direction D1 and the longitudinal direction D2 of the laser welding cross section used in the laser welding quality inspection apparatus according to the embodiment of the present invention.
Fig. 5 is a longitudinal sectional view (D2) of the weld bead in Fig. 4; Fig.
Fig. 6 is a view showing a weld bead lateral direction (D1) cross section in Fig. 4;
FIG. 7 is a graph showing the results of a real-time measurement sampling of the weld bead when the weld proceeds along the weld bead lateral direction (D1) cross-section in FIG.
8 is a graph showing depth measurement results using a confocal system of the laser welding quality inspection apparatus of FIG.
FIG. 9 is a graph showing the measured results of particles in a plasma or malfunction data of a detection unit in the laser welding quality inspection apparatus of FIG. 1;
10 is a graph for explaining the class classification concept by the laser welding quality inspection apparatus of FIG.
11 is a graph for explaining the concept of error data analysis by the laser welding quality inspection apparatus of FIG.
12 is a flowchart showing a laser welding quality inspection method according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description of preferred embodiments of the present invention will be given with reference to the accompanying drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In the present specification, when any one element 'transmits' data or signals to another element, the element can transmit the data or signal directly to the other element, and through at least one other element Data or signal can be transmitted to another component.

1 is a view showing an apparatus 1 for laser welding quality inspection according to an embodiment of the present invention. 2 is a block diagram showing a configuration of the control unit 610 in the laser welding quality inspection apparatus 1 of FIG. 3 is a conceptual diagram for explaining the operation principle of the laser welding quality inspection apparatus 1 of FIG.

Referring to FIGS. 1 and 2, the laser welding quality inspection apparatus 1 is characterized in that the quality of the welding base material 700 welded by the welding laser 400 is substantially the same as that of the welding base material 700 Measure the depth of the weld bead. The welding laser 400 and the welding base material 700 are welded by the welding laser 400 while one of the welding laser 400 and the welding base material 700 relatively move linearly with respect to the other. For example, the laser beam irradiated from the welding laser 400 is refracted in a predetermined direction by the welding laser mirror 300, and then is condensed on the surface of the welding base material 700 by the condenser lens 500.

In the present embodiment, the laser welding quality inspection apparatus 1 includes a detection unit 100 and a control unit 600. The detection unit 100 measures the depth of the weld bead formed on the welding base material 700 by the welding laser 400. At this time, the detecting unit 100 irradiates the laser with a preset spot size, and the laser thus irradiated can be refracted by the measuring laser mirror 200 and directed to the welding base material 700. For example, the detection unit 100 can measure the depth of the weld bead formed on the welding base material 700 from the time when the laser is reflected by the welding base material 700 or the like. The control unit 600 extracts data from the depth of the weld bead of the base material 700 measured by the detection unit 100 and determines the quality of the weld based on the extracted data. The control unit 600 includes an input / output interface 610, a control unit 620, a storage unit 630, and an input / output unit 640.

3, the drawing number 11 is a detection area irradiation area indicating a mechanism by the detection part 100, the drawing number 12 is a fiber laser irradiation area indicating a mechanism by the welding laser 400, The drawing number 13 is a part deformed by a laser by plasma, and the drawing number 14 is a welding base material area in a plasma state.

That is, according to the refraction by the welding laser mirror 300 in accordance with the welding laser irradiation by the welding laser 400 and the laser welding by the condensed laser beam by the condenser lens 500, The welding base material 700 is melted in a round shape. It can be seen that the welding base material region 14 shown in FIG. 3 substantially melts and becomes a plasma state.

More specifically, as shown in FIG. 1, when three welding base materials 700 are placed and welded, the respective welding base materials 700 are melted in stages and then solidified, Therefore, the quality of the welding is determined. The quality of the welding is judged according to whether or not the welding base material 700 is substantially melted at a uniform depth. In the present invention, the depth of the welding base material 700 is measured in real time, .

Here, the control unit 600 real-time measures the welding depth of the weld bead using the confocal method. In addition, since the accurate depth is not measured by various particles during the laser irradiation part measurement of the plasma state, the control unit 600 uses an algorithm for determining whether the depth measurement value is a normally dissolved part or a particle, .

Next, Fig. 4 is a diagram showing the concept of cutting in the lateral direction D1 and the longitudinal direction D2 with respect to the laser welding cross section. Fig. 5 shows the longitudinal (D2) cut plane of the weld bead, and Fig. 6 shows the weld bead lateral (D1) cut plane. Here, the 'lateral direction D1' means a direction parallel to the direction in which the welding laser 400 moves relative to the welding base material 700, 'longitudinal direction D2' means 'lateral direction D1' Quot; direction. ≪ / RTI >

The depth D1_h1 of the weld bead can be measured by the cut surface in the longitudinal direction D2 of the weld bead as shown in FIG. 5, and the depth of the weld bead D2_h1 to D2_hn, where n is a natural number of 2 or more) can be measured in real time as shown in FIG.

That is, FIG. 7 is a graph showing real-time measurement sampling results of the weld bead when the welding progresses along the cutting surface in the lateral direction D1 of the weld bead. Here, the control unit 600 obtains the depth measurement result using the confocal method in which the focus of the detection unit 100 and the welding laser 400 are shared at one point, .

Meanwhile, the control unit 600 using the confocal method as shown in FIG. 1 real-time measures the welding bead using a confocal method. At this time, as shown in FIG. 9, inaccurate data may be generated for each section in a shape that is soar as upward or downward as shown in FIG. 9 due to particles in the plasma of the welding base material 700 or malfunction of the detecting unit 100. In order to solve this problem, in the present embodiment, an algorithm is used in which a class is generated by vector quantizing data selection, and data not corresponding to a class is deleted. In this embodiment, the control unit 620 includes a data collection module 621, a class classification module 622, and an error data correction module 623 in this embodiment.

More specifically, the data acquisition module 621 calculates the distance D1 from the depth of the weld bead detected by the detection unit 100 after the data session connection through the input / output interface 610 to the detection unit 100, (D1_h1 to D1_hn, where n is a natural number of 2 or more) and depth (D2_h1) of the longitudinal direction (D2) weld bead. Particularly, the data collection module 621 acquires real-time measurement sampling data of the weld bead when the welding progresses along the cutting edge in the lateral direction D1 of the weld bead, and then generates a graphical graph which is a result of real- And may be stored in the storage unit 630. Substantially the data collection module 621 can collect the depth of the weld bead detected by the detector 100 in the form of a plurality of samples in the form of data displayed on a continuous graph of time (X axis) and distance (Y axis) have.

The class classification module 622 performs vector quantization on the sample data measured in real time. More specifically, the class classification module 622 classifies the sample data into a time range (X-axis) and a distance value between two samples (X-axis) to perform class classification by dividing the sample data into a plurality of clusters Y axis).

In the example of "(1,0), (2,5), (3,8), ..., (299,10), (300,93), (301,95), (302,13) The class classification module 622 divides the distance value difference between the first (1,0) and second (2,5) sample data by 5 (5-0), (2) (3,8), (3) the distance value difference between the 299th (299,10) and the 300th (300,93) sample data: 83 (93-10) (4) The distance difference between the 300th (300, 93) and 301st (301,95) sample data: 2 (95-93). Therefore, the class classification module 622 can classify the first sample, the 299th sample, the 300th sample, and the 301th sample into different classes. 10 is a diagram showing a graph form in which classes are classified.

The error data correction module 623 can perform error data extraction when the class classification module 622 completes class classification according to distance calculation between sample data. At this time, the error data correction module 623 determines whether the number of samples belonging to the class classified by the class classification module 262 is more than or less than the reference number of samples calculated by the following formula (1) .

[Equation 1]

Reference sample number ≤ Spot size / Travel distance per pulse

Here, 'spot size' is the spot size of the laser irradiated by the detector 100, 'travel distance per pulse' is the travel distance per pulse of the laser of the detector 100, 'reference sample number' Is defined as the maximum integer among the values calculated by Equation (1).

As a more specific example, it is preferable to adjust the sampling distance to 0.5 mu m when the spot size of the laser irradiated by the detector 100 used in the experiment is 7 mu m and the maximum resolution is 0.01 mu m. Here, the class classification module 622 has the same moving speed of the welding laser 400 and the detection unit 100, and the detection unit has a spec of a laser pulse of 200 kHz, pod: 1, a moving speed of 100 mm / s, The moving distance per 1 pulse can be calculated by "1/200000 × 100 (mm) = 0.5 μm". Thereafter, the class classification module 622 determines that 14 or more samples are smaller than the spot size of the laser of the detector 100 by "7 (spot size) /0.5 (movement distance per pulse) = 14 The case of continuing with a difference of? Therefore, a distance greater than or equal to the spot size between less than 14 samples can be recognized by particle or measurement error data. Therefore, in the above example, the error data correction module 623 determines the class including the 300th sample and the 301st sample (see e1 area in FIG. 11) as error data.

In addition, the error data correction module 623 calculates the average of the previous sample data and the next sample data for the sample data determined to be error, stores it in the storage unit 630, compares the sample data with each other, Lt; / RTI > In the above example, the error data correction module 623 corrects the distance value of the 300th sample and the 301st sample to the distance data of the previous sample data and the subsequent sample data, i.e., the distance values of the 299th sample data and the 302th sample data And 11, which is an average of 13, is corrected to 12, which is an integer rounded, and stored in the storage unit 630.

12 is a flowchart illustrating a laser welding quality inspection method according to an embodiment of the present invention.

Referring to FIG. 12, first, the control unit 600 performs a first step of data collection through the detection unit 100 (S110). More specifically, the control unit 600 acquires real-time measurement sampling data of the weld bead when the welding progresses along the cutting plane in the lateral direction D1 of the weld bead, And generates a graphical graph, which is a result of real-time depth measurement, and stores it in the storage unit 630. Here, the control unit 600 divides the sample data into a plurality of clusters in order to carry out the vector quantization process on the real-time measurement sample data, and then performs the sample classification on the time range (X-axis) Distance value (Y axis).

After the first step S110, the control unit 600 performs a second step of classifying the sample data with respect to the sample data (S120). More specifically, the control unit 600 classifies successive samples of the sample data generated in the first step S110 as a class with a difference in distance value less than the spot size of the laser of the detection unit 100 as a class.

After the second step S120, the control unit 600 performs a third step of analyzing and correcting the error data (S130). That is, when class classification according to the distance calculation between sample data is completed in the second step S120, the control unit 600 performs error data extraction. Here, the error data extraction is performed on the class including the samples that are less than the reference sample number among the classified classes, and determines this as error data. In addition, the control unit 600 calculates the average of the previous sample data and the next sample data for the sample data determined as an error, stores the result in the storage unit 630, compares the sample data, Quantize.

The present invention can also be embodied as computer-readable codes on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored.

Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device and the like, and also implemented in the form of a carrier wave (for example, transmission over the Internet) .

The computer readable recording medium may also be distributed over a networked computer system so that computer readable code can be stored and executed in a distributed manner. And functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers skilled in the art to which the present invention pertains.

As described above, preferred embodiments of the present invention have been disclosed in the present specification and drawings, and although specific terms have been used, they have been used only in a general sense to easily describe the technical contents of the present invention and to facilitate understanding of the invention , And are not intended to limit the scope of the present invention. It is to be understood by those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

1: Laser welding quality inspection system
11: detection area irradiation area
12: Laser laser irradiation area
13: Plasma-deformed part
14: welding base material area
100:
200: laser mirror for measurement
300: laser mirror for welding
400: welding laser
500: condenser lens
600:
610: I / O Interface
620:
621: Data acquisition module
622: Classification module
623: Error Data Correction Module
630:
640: Input / output unit
700: welding base material

Claims (5)

A laser welding quality inspection apparatus for inspecting quality of laser welding in which a welding laser (400) is moved while melting a welding base material (700), the apparatus comprising:
The laser welding quality inspection apparatus (1)
A laser of a predetermined spot size is irradiated to the welding base material 700 while moving at the same speed as the welding laser 400 so that the depth of the welding bead formed in the welding base material 700 700) in a direction in which the detection unit (100) moves;
A control unit 600 for determining the welding quality from the data collected by the detecting unit 100; Lt; / RTI >
The control unit 600,
A data collection module 621 for collecting the depth of the weld bead detected by the detection unit 100 in the form of data displayed on a continuous graph of a plurality of samples over time (X axis) and distance (Y axis);
A class classification module 622 for classifying a plurality of samples in which a difference in distance value is continuous to a spot size of the laser of the detector 100, into a class; And
An error data correction module (623) for determining the number of samples belonging to the class classified by the class classification module (262) as error data when the number of samples belonging to the class is less than the reference number of samples calculated by Equation (1); The laser welding quality inspection apparatus comprising:

[Equation 1] Number of reference samples ≤ Spot size / travel distance per pulse
Here, 'spot size' is the spot size of the laser irradiated by the detector 100, 'travel distance per pulse' is the travel distance per pulse of the laser of the detector 100, 'reference sample number' Defined as the largest integer among the values calculated by Equation 1
The method according to claim 1,
The error data correction module 623,
The error is determined to be an average of the previous sample data and the next sample data, and the result is stored in the storage unit 630 to compare the sample data and approximate the sample data in a similar pattern.
The method according to claim 1,
The control unit 600,
A laser welding quality inspection apparatus using a confocal system in which a focal point of a detection unit (100) and a welding laser (400) are shared at one point.
A method for checking laser welding quality using the laser welding quality inspection apparatus according to any one of claims 1 to 3, the method comprising:
The control unit 600 controls the depth of the weld bead detected by the detecting unit 100 to be a first step of collecting a plurality of samples in the form of data displayed on a continuous graph of time (X axis) and distance (Y axis) ;
A second step of the control unit 600 classifying a plurality of samples in which a difference in distance value is continuous to a spot size of the laser of the detector 100, into a class;
If the control unit 600 determines that the number of samples belonging to the class is less than the reference number of samples calculated by Equation (1), it is determined that the data is erroneous data; The laser welding quality inspection apparatus comprising:
[Equation 1]
Reference sample number ≤ Spot size / Travel distance per pulse
Here, 'spot size' is the spot size of the laser irradiated by the detector 100, 'travel distance per pulse' is the travel distance per pulse of the laser of the detector 100, 'reference sample number' Defined as the largest integer among the values calculated by Equation 1
5. The method of claim 4,
In the third step,
And calculating the average of the previous sample data and the next sample data and storing the average of the previous sample data and the next sample data in the storage unit 630 and comparing the sampled data with the similar pattern.

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