KR102591938B1 - Laser scanning-based electric resistance welding quality determination system and method - Google Patents

Abstract

The present invention relates to a laser scanning-based resistance spot welding quality judgment system and method. A laser scanning-based resistance spot welding quality judgment system that determines the quality of a resistance spot weld that is pressed and welded by a pair of electrodes, wherein the resistance Welder performing spot welding; A laser scanner for 3D scanning the surface welded by the welder; And a control unit that measures characteristic values consisting of the diameter, height, area, and volume of the surface indentation through the image scanned by the laser scanner, and controls the welder, wherein the control unit measures the characteristic values through the characteristic values. It is characterized by predicting the nugget diameter of resistance spot welding and allowing weld quality defects to be determined.
Additionally, a laser scanning step of allowing an image of the resistance spot welding surface to be scanned by the laser scanner; A characteristic value measurement step of allowing characteristic values consisting of the diameter, height, area, and volume of the indentation caused by resistance spot welding to be measured by the control unit through the image; A welding quality judgment step of allowing the nugget diameter to be predicted by the control unit through the characteristic values; A defect detection step of allowing defects in resistance spot welding to be determined by the control unit through the image; And a welder calibration step of allowing the electrodes of the welder to be replaced or realigned according to the defect by the control unit, wherein the welder calibration step includes predicting the nugget diameter of the resistance spot welding performed by non-destructive testing and It is characterized by allowing the welder to be corrected based on defect determination.
In addition, according to the present invention, the quality judgment work of resistance spot welding can be automated, and reliability and speed of quality judgment can be obtained.

Description

Laser scanning-based electric resistance welding quality determination system and method}

The present invention relates to a laser scanning-based resistance spot welding quality judgment system and method. More specifically, it is a method of predicting the nugget diameter, which is a welding quality index of resistance spot welding for steel and Al materials, and detecting defects, using 3D scanning. This relates to a laser scanning-based resistance spot welding quality judgment system and method that evaluates the size and defects of the nugget in real time at the same time as measurement using the characteristic values of the surface indentation of the spot weld.

In general, welding is the process of joining metal materials of the same type or different types by applying heat and pressure to form a direct bond between solids, and is a general term for metallurgical joining methods of metals. In addition, there are several different welding processes depending on various conditions such as base material and welding electrode. Among them, resistance spot welding is one of the simple and widely used welding processes, allowing overlapping materials to be joined inexpensively without the need for disassembly. In particular, it is widely used, being used in approximately 5,000 to 6,000 hits during the automobile production process. Resistance spot welding is a welding process that uses electric resistance to join two metals by placing them face to face and using resistance heat generated by passing appropriate mechanical pressure and electric current. However, in evaluating the quality of resistance spot welding, the quality is evaluated through one-dimensional inspection such as surface inspection with the naked eye and a microscope, and nugget diameter inspection through cutting the weld zone, which consumes pre-processing time and is not used in actual car body welding sites. There is a problem that it cannot be done.

As a prior document to solve this problem, looking at Republic of Korea Patent Publication No. 10-1799051, a method and device for inspecting a weld bead using laser scanning is disclosed.

However, this conventional technology has the problem of being disadvantageous in speed and automation, and the reliability of quality judgment through the surface characteristic values of the dotted part cannot be obtained.

(Prior Document 1) Republic of Korea Patent Publication No. 10-1799051 (2017.11.20.)

The present invention was developed to solve the problems of the prior art as described above, and predicts the nugget diameter using a quality prediction method using the indentation shape of resistance spot welding to enable reliability, speed, and automation of quality judgment. There is a purpose.

In a laser scanning-based resistance spot welding quality judgment method using a laser scanning-based resistance spot welding quality judgment system in a preferred embodiment of the present invention, an image of the resistance spot welding surface is scanned by the laser scanner. A laser scanning step; A characteristic value measurement step of allowing characteristic values consisting of the diameter, height, area, and volume of the indentation caused by resistance spot welding to be measured by the control unit through the image; A welding quality judgment step of allowing the nugget diameter to be predicted by the control unit through the characteristic values; A defect detection step of allowing defects in resistance spot welding to be determined by the control unit through the image; And a welder calibration step of allowing the electrodes of the welder to be replaced or realigned according to the defect by the control unit, wherein the welder calibration step includes predicting the nugget diameter of the resistance spot welding performed by non-destructive testing and It is characterized by allowing the welder to be corrected based on defect determination.

As a means of solving the above problems, the present invention has the effect of enabling the quality judgment work of resistance spot welding to be automated and achieving reliability and speed in quality judgment.

In addition, the present invention has the effect of improving speed through a non-destructive process that allows the process of physically destroying the specimen to be omitted for quality judgment and enabling field-friendly quality inspection to be performed in real time.

1 is a configuration diagram of a laser scanning-based resistance spot welding quality judgment system according to a first embodiment of the present invention.
Figure 2 is a schematic diagram of a laser scanning-based resistance spot welding quality judgment system according to the first embodiment of the present invention.
Figure 3 is a flowchart of a laser scanning-based resistance spot welding quality determination method according to the first embodiment of the present invention.
Figure 4 is a flowchart of the characteristic value measurement step in the laser scanning-based resistance spot welding quality determination method according to the first embodiment of the present invention.
Figure 5 is a diagram showing the process of securing the cross-sectional line of the surface indentation through laser scanning.
Figure 6 is a diagram showing the process of extracting the indentation diameter and height from the surface characteristic values at the secured cross section line.
Figure 7 is a diagram showing the plane conversion image of cross-section lines and the measurement area of surface characteristic values (indentation circumference, indentation area, indentation volume).
Figure 8 is a correlation graph between surface property values and nugget diameter values.
Figure 9 is a diagram showing the process of measuring the bending height in a cross-sectional line image.
Figure 10 is a detailed flowchart of the defect detection step according to the first embodiment of the present invention.
Figure 11 is a flowchart of the edge welding defect detection step according to the first embodiment of the present invention.
Figure 12 is a diagram showing the cross-sectional line analysis process for determining edge welding defects.
Figure 13 is a flowchart of the electrode wear defect detection step according to the first embodiment of the present invention.
Figure 14 is a laser scanning cross-sectional image of a wear electrode welded portion, (a) is a scanning cross-sectional image of a normal electrode and a worn electrode welded portion, and (b) is a diagram showing the process for determining a wear defect.
Figure 15 is a diagram showing the analysis process for comparing and determining defects in welds to which normal electrodes and worn electrodes are applied. (a) is a cross-sectional image of a weld to which normal electrodes are applied, and (b) is a cross-sectional image of a weld to which worn electrodes are applied.
Figure 16 is a flowchart of the electrode misalignment defect detection step according to the first embodiment of the present invention.
Figure 17 is a diagram showing the analysis process based on the highest point of the cross-sectional line for determining electrode misalignment and surface flaking defects.
Figure 18 is a diagram showing the analysis process based on the lowest point of the cross-sectional line for determining electrode misalignment and surface flaking defects.

The terms used in this specification will be briefly explained, and the present invention will be described in detail.

The terms used in the present invention are general terms that are currently widely used as much as possible while considering the function in the present invention, but this may vary depending on the intention or precedent of a person working in the art, the emergence of new technology, etc. Therefore, the terms used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, rather than simply the name of the term.

When a part in the entire specification is said to “include” a certain element, this means that it does not exclude other elements but may further include other elements, unless specifically stated to the contrary.

Below, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein.

Specific details, including the problem to be solved by the present invention, the means for solving the problem, and the effect of the invention, are included in the examples and drawings described below. The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings.

Hereinafter, the laser scanning-based resistance spot welding quality determination system and method of the present invention will be described with reference to the attached drawings.

First, referring to FIGS. 1 and 2, the present invention provides a laser scanning-based resistance spot welding quality judgment system that determines the quality of resistance spot welding that is pressed and welded by a pair of electrodes, and the resistance spot welding is A welder 100, a laser scanner 200 that 3D scans the surface welded by the welder 100, and an image scanned by the laser scanner 200 to determine the diameter, height, area and It includes a control unit 300 that measures one or more characteristic values of the volume and controls the welder 100. In addition, the control unit 300 is characterized in that it predicts the nugget diameter of resistance spot welding through the characteristic values and allows welding quality defects to be determined.

More specifically, the welder 100 performs resistance spot welding in which two metal plates are joined together through resistance heat generated by touching two metal plates and passing pressure and current through a pair of electrodes. In addition, the welder 100 can be controlled by the control unit 300 to control the pressure applied to the electrode, the energizing voltage, and the electrode position alignment. At this time, the metal sheet is mainly used as a steel or Al material. When these metal sheets are joined by resistance spot welding, welding nuggets and indentations are formed, and welding quality can be confirmed through inspection of the indentations and nuggets. do.

In addition, the laser scanner 200 is provided on one side of the welder 100 and serves to scan nuggets and indentations created on a metal plate on which a resistance spot welding process has been performed. In addition, the laser scanner 200 is equipped with a laser vision to obtain not only a 3D image but also a 2D image of the welded area.

In addition, the control unit 300 secures the cross-sectional line of the indentation through the image scanned by the laser scanner 200 to detect edge welding defects of the resistance spot welding, electrode wear defects of the welder, electrode misalignment, and surface A blowing defect is determined, and the electrodes of the welder can be replaced or realigned according to the defect.

For example, the control unit 300 enables nugget diameters according to various types of electrodes and materials to be predicted through prediction equations 1 to 3 below.

Prediction equation 1 below allows the nugget diameter to be predicted through the surface characteristic values of resistance spot welding using a dome-type electrode when the plate is made of steel.

[Prediction Equation 1]

y = (1.714D - 4.729)mm,

y = (23.325H + 0.123)mm,

y = (0.436C - 2.947)mm,

y = (0.213A - 0.477)mm,

y = (1.049V + 1.646)mm,

y = (-2.94 - 0.197A + 3.7C + 0.196V - 10.2D + 15.05H)mm

At this time, D is the indentation diameter, C is the indentation circumference, A is the indentation area, and V is the indentation volume.

Prediction equation 2 below allows the nugget diameter to be predicted through the surface characteristic values of resistance spot welding using a radius type electrode when the plate is made of Al.

[Prediction Equation 2]

y = (1.404D - 7.066)mm,

y = (27.133H + 3.823)mm,

y = (0.447C - 7.066)mm,

y = (0.097A - 0.816)mm,

y = (0.74V + 4.503)mm,

y = (8.3 + 0.129A - 1.38D + 1.8C + 0.258V + 10.8H)mm

Prediction equation 3 below allows the nugget diameter to be predicted through the surface characteristic values of resistance spot welding using a multi-ring type electrode when the plate is made of Al.

[Prediction Equation 3]

y = (0.772D - 1.565)mm,

y = (26.071H + 3.004)mm,

y = (0.245C - 1.562)mm,

y = (0.061A + 1.453)mm,

y = (1.119V + 3.401)mm

Hereinafter, the laser scanning-based resistance spot welding quality determination method according to the present invention will be described.

Referring to FIG. 3, in the laser scanning-based resistance spot welding quality judgment method using the laser scanning-based resistance spot welding quality judgment system, an image of the resistance spot welding surface can be scanned by the laser scanner 200. A laser scanning step (S100) that allows the control unit 300 to measure characteristic values consisting of the diameter, height, area, and volume of the indentation by resistance spot welding through the image. (S200), a welding quality judgment step (S300) in which the nugget diameter can be predicted through the characteristic values by the control unit 300, and a defect in resistance spot welding through the image by the control unit 300. It includes a defect detection step (S400) that allows this to be determined and a welder calibration step (S500) that allows the control unit 300 to replace or realign the electrodes of the welder 100 according to the defect. And, the welder calibration step (S500) allows the welder 100 to be calibrated based on nugget diameter prediction and defect determination of the resistance spot welding performed through non-destructive testing.

More specifically, in the laser scanning step (S100), the surface of the resistance spot weld is scanned through the laser scanner 200, so that images of the indentation diameter, height, area, and volume of the weld portion can be collected.

Next, in the characteristic value measurement step (S200), the image collected by the laser scanner 200 is processed through the control unit 300 to obtain characteristic values including the indentation diameter, height, circumference, area, and volume. Allow this to be created. In more detail, referring to FIG. 4, in the characteristic value measurement step (S200), the 2D cross-sectional line of the indentation can be extracted by the control unit 300 through the 3D image measured by the laser scanner 200. It includes a cross-sectional line extraction step (S210) and a characteristic value extraction step (S220) that allows the control unit 300 to extract the characteristic value through the 2D cross-sectional line.

The cross-sectional line extraction step (S210) causes a 2D cross-sectional line to be formed on the image collected by the laser scanner 200. For example, referring to (b) and (c) of Figures 5, the cross-sectional line extraction step (S210) causes a circular line with a diameter of 10 mm larger than the indentation to be formed outside the indentation in the indentation image. In addition, in the section line extraction step (S210), based on a point (R1) of the circular line, a tangent (n1) is formed that is in contact with the point (R1) and the circular line and has a length equal to the diameter of the circular line. do. In addition, in the section line extraction step (S210), a 2D section line is formed by arranging at least 500 intersection lines at intervals of 0.02 mm in the direction perpendicular to the tangent n1. At this time, the formed 2D cross-section line may be formed as shown in (d) of FIG. 5.

The characteristic value extraction step (S220) allows the characteristic value of the indentation portion to be extracted from the 2D cross-section line formed in the cross-section line extraction step (S210). Referring to FIG. 6, in the characteristic value extraction step (S220), a point 20㎛ lower than the height of the base material on the 2D cross-section line is selected as the start area of the indentation, and a parallel line connecting the starting point of the designated indentation on both base materials is drawn. form Afterwards, the indentation diameter, which is one of the surface characteristic values, is extracted from the lengths of both sides of the 2D cross-sectional line (S220). In addition, in the characteristic value extraction step (S220), the indentation height value is extracted by connecting a parallel line connecting the indentation start point and the point with the lowest value on the cross-sectional line. In addition, in the characteristic value extraction step (S220), as shown in (a) of FIG. 5, about 500 to 600 indentation length and diameter values are extracted from the tangent line (n1) at one point, and then the reference point ( The angle of R1) is moved 10° along the circumference and the characteristic value extraction is repeated until the reference circle is rotated 360° to extract the values of the indentation diameter and height. Additionally, referring to FIG. 7, in the characteristic value extraction step (S220), the indentation circumference, which is one of the surface characteristic values, can be extracted by utilizing the indentation diameter value extracted by a plurality of cross-sectional lines. In addition, the characteristic value extraction step (S220) converts a plurality of cross-sectional lines into surfaces so that the indentation area and volume, which are one of the surface characteristic values, can be extracted based on the indentation start point.

Next, in the welding quality judgment step (S300), the nugget diameter is predicted through the characteristic values measured in the characteristic value measurement step (S200) so that the quality of the weld can be judged. Figure 8 is a correlation graph of surface characteristic values according to nugget diameter. In the welding quality judgment step (S300), various types of electrodes are used by the control unit 300 through the following prediction equations 1 to 3 to predict the nugget diameter derived from the correlation of surface characteristic values according to the nugget diameter. and material so that the nugget diameter can be predicted.

[Prediction Equation 1]

y = (1.714D - 4.729)mm,

y = (23.325H + 0.123)mm,

y = (0.436C - 2.947)mm,

y = (0.213A - 0.477)mm,

y = (1.049V + 1.646)mm,

y = (-2.94 - 0.197A + 3.7C + 0.196V - 10.2D + 15.05H)mm

At this time, D is the indentation diameter, C is the indentation circumference, A is the indentation area, and V is the indentation volume.

Prediction equation 2 below allows the nugget diameter to be predicted through the surface characteristic values of resistance spot welding using a radius type electrode when the plate is made of Al.

[Prediction Equation 2]

y = (1.404D - 7.066)mm,

y = (27.133H + 3.823)mm,

y = (0.447C - 7.066)mm,

y = (0.097A - 0.816)mm,

y = (0.74V + 4.503)mm,

y = (8.3 + 0.129A - 1.38D + 1.8C + 0.258V + 10.8H)mm

Prediction equation 3 below allows the nugget diameter to be predicted through the surface characteristic values of resistance spot welding using a multi-ring type electrode when the plate is made of Al.

[Prediction Equation 3]

y = (0.772D - 1.565)mm,

y = (26.071H + 3.004)mm,

y = (0.245C - 1.562)mm,

y = (0.061A + 1.453)mm,

y = (1.119V + 3.401)mm

At this time, prediction equation 3, which predicts the nugget diameter when the welder 100 performs resistance spot welding using a multi-ring electrode, has a bend number of 0.05 mm or more in height from the cross-section line, as shown in Figure 9. It is derived through the value of the number of bends in the cross-section line.

Next, the defect detection step (S400) serves to detect welding defects, including edge welding defects, electrode wear defects, and surface flaking defects, from the cross-section line formed by processing the image collected by the laser scanner 200. Do it. In more detail, referring to FIG. 10, the defect detection step (S400) includes an edge welding defect detection step (S410) of detecting an edge welding defect of the resistance spot welding, and an edge welding defect detection step (S410) of detecting an electrode wear defect of the welder 100. It includes an electrode wear defect detection step (S420) and an electrode misalignment detection step (S430) for detecting electrode misalignment and surface flaking defects of the resistance spot welding.

Referring to Figures 11 and 12, the edge welding defect detection step (S410) is performed by the control unit 300, at the indentation start point (S) based on the cross-sectional line extracted in the characteristic value measurement step (S200). Compare the height difference between the height of the point (E), which is 1 mm apart in the centrifugal direction, and the starting point (S). Thereafter, if the height difference between the spaced point (E) and the starting point (S) is less than 0.5 mm, it can be judged to be an edge welding defect (S411). On the other hand, if the height difference between the spaced point (E) and the starting point (S) is greater than 0.5 mm, it can be judged to be an edge welding defect (S412).

)를 측정한다(S423). 또한, 상기 가로선과 연결선의 각도(

)가 비교될 수 있도록 한다(S424). 이때, 상기 가로선과 연결선의 각도(

)가 130° 이상이면 전극마모결함이라고 판단될 수 있도록 한다(S425). 이후, 상기 가로선과 연결선의 각도가 130° 미만인 경우, 도 13 및 도 15를 참조하여, 상기 단면라인에서 가장 낮은 높이 값을 나타내는 최저점을 기준으로, 좌우 3mm 내 지점의 단면라인과 교차되는 가로선을 형성한다(S426). 그리고, 상기 단면라인의 위 상기 가로선과의 교차점 및 상기 교차점과 인접한 두 압흔 시작점이 각각 연결되도록 하는 연결선을 다수개 형성한다(S426). 또한, 상기 연결선 중 상기 가로선과의 각도가 최대를 이루도록 하는 연결선이 선별될 수 있도록 한다(S426). 그리고, 상기 가로선이 선별된 두 연결선에 각각 교차되며 형성된 두 교차점 간 거리 D를 측정한다(S427). 이후, 상기 두 교차점 간 거리 D가 2.5mm보다 초과되는지 비교한다(S428). 이때, 상기 두 교차점 간 거리 D가 2.5mm 이상인 경우 전극마모결함이라고 판단될 수 있도록 한다(S429). 그리고, 상기 두 교차점 간 거리D가 2.5mm 이하인 경우 정상용접이라고 판단될 수 있도록 한다(S430).13 and 14, the electrode wear defect detection step (S420) is performed by the control unit 300 at the indentation start point and the low point of the cross-section line based on the cross-section line extracted in the characteristic value measurement step (S200). A connection line is formed connecting the intersecting horizontal lines, and electrode wear defects can be determined through the angle of the horizontal line and the connection line. First, based on the cross-section line extracted in the characteristic value measurement step (S200), a horizontal line that intersects the cross-section line is formed at a point within 3 mm on the left and right from the highest point representing the lowest height value (S421). Additionally, a connection line is formed from the intersection of the horizontal line and the cross-sectional line to the indentation start point adjacent to the intersection (S422). In addition, the angle between the horizontal line and the connecting line (

) is measured (S423). In addition, the angle between the horizontal line and the connecting line (

) can be compared (S424). At this time, the angle between the horizontal line and the connecting line (

) is greater than 130°, it can be judged to be an electrode wear defect (S425). Thereafter, when the angle between the horizontal line and the connecting line is less than 130°, with reference to FIGS. 13 and 15, a horizontal line is drawn that intersects the cross-section line at a point within 3 mm left and right based on the lowest point representing the lowest height value in the cross-section line. Form (S426). Then, a plurality of connection lines are formed to connect the intersection point of the cross-sectional line with the horizontal line and the two indentation start points adjacent to the intersection point (S426). In addition, among the connection lines, the connection line that maximizes the angle with the horizontal line can be selected (S426). Then, the horizontal line intersects each of the two selected connection lines, and the distance D between the two intersection points formed is measured (S427). Afterwards, it is compared whether the distance D between the two intersection points exceeds 2.5 mm (S428). At this time, if the distance D between the two intersection points is 2.5 mm or more, it can be judged to be an electrode wear defect (S429). Also, if the distance D between the two intersection points is 2.5 mm or less, it can be judged as normal welding (S430).

Referring to FIG. 16, in the electrode misalignment detection step (S430), when the electrode of the welder 100 is misaligned by the control unit 300, the shape of the nugget is formed in one direction, resulting in surface flaking. so that it can be detected. First, the cross-sectional line with the maximum indentation diameter is selected from among the cross-sectional lines extracted in the characteristic value measurement step (S200) (S431). Also, referring to FIG. 17, a horizontal line is formed connecting the indentation starting points S1 and S2 on both sides of the cross-sectional line where the indentation diameter is the maximum (S432). Then, an upper connection line is formed connecting the highest point (E) of the cross-sectional line and the indentation start point (S1) (S433). Additionally, the angle α between the horizontal line and the upper connection line can be measured (S434). Thereafter, with reference to FIG. 18, a lower connection line is formed connecting the lowest point (L) of the cross-sectional line and the indentation start point (S2) (S435). Then, the angle β between the lower connection line and the horizontal line can be measured (S436). Afterwards, by substituting the angles α and β into the prediction equation 4 below, the angles θ ₁ and Allow θ ₂ to be derived (S437).

[Prediction Equation 4]

θ ₁ = 2.1α + 0.416

θ ₂ = -3.76β + 17.42

At this time, the angle θ is greater than ₁ If θ ₂ is large, it can be judged to be an electrode misalignment defect (S438). On the other hand, angle θ greater than ₁ If θ ₂ is small, it can be judged as normal welding (S439).

Next, in the welder calibration step (S500), the electrodes of the welder 100 can be replaced or realigned by the control unit 300 according to the type and degree of defect determined in the defect detection step (S400). Ensure that welding quality is maintained.

Therefore, the present invention has the effect of enabling the quality judgment work of resistance spot welding to be automated and achieving reliability and speed in quality judgment. In addition, the present invention has the effect of improving speed through a non-destructive process that allows the process of physically destroying the specimen to be omitted for quality judgment and enabling field-friendly quality inspection to be performed in real time.

The embodiments described above should be understood in all respects as illustrative and not restrictive, and the scope of the present invention is indicated by the claims described later rather than the detailed description above, and the meaning and scope of the claims and their equivalents. All changes or modified forms derived from the concept should be construed as falling within the scope of the present invention.

100: welder
200: Laser scanner
300: control unit

Claims (5)

In a laser scanning-based resistance spot welding quality judgment system that determines the quality of resistance spot welding that is pressed and welded by a pair of electrodes,
a welder performing the resistance spot welding;
A laser scanner for 3D scanning the surface welded by the welder; and
It includes a control unit that measures surface characteristic values through the image scanned by the laser scanner and controls the welder,
The control unit allows the 2D cross-sectional line of the indentation to be extracted through the image measured by the laser scanner, and forms a circular line with a diameter of 10 mm larger than the indentation on the 2D cross-sectional line. A tangent line of the same length as the diameter is formed, and at least 500 intersecting lines perpendicular to the tangent line are arranged at intervals of 0.02 mm, and the circumference, area, and volume of the indentation can be extracted through the 2D cross-section line. , A laser scanning-based resistance spot welding quality judgment system, characterized in that it predicts the nugget diameter of resistance spot welding through the characteristic values and allows welding quality defects to be determined. According to paragraph 1,
The control unit,
The cross-sectional line of the indentation is secured through the image scanned by the laser scanner to determine edge welding defects of the resistance spot welding, electrode wear defects of the welder, electrode misalignment, and surface flaking defects, and according to the defects, the welder A laser scanning-based resistance spot welding quality judgment system that allows electrode replacement and realignment. In the laser scanning-based resistance spot welding quality judgment method using the laser scanning-based resistance spot welding quality judgment system of claim 1,
a laser scanning step of allowing an image of the resistance spot welding surface to be scanned by the laser scanner;
A characteristic value measurement step of allowing surface characteristic values to be measured through the image by the control unit;
A welding quality judgment step of allowing the nugget diameter to be predicted by the control unit through the characteristic values;
A defect detection step of allowing defects in resistance spot welding to be determined by the control unit through the image; and
A welder calibration step of allowing the electrodes of the welder to be replaced or realigned according to the defect, by the control unit,
The characteristic value measurement step is,
A cross-sectional line extraction step of allowing the 2D cross-sectional line of the indentation to be extracted by the control unit through the 3D image measured by the laser scanner; and
A characteristic value extraction step of allowing the characteristic value to be extracted by the control unit through the 2D cross-section line,
The welder calibration step allows the welder to be calibrated based on nugget diameter prediction and defect determination of the resistance spot welding performed by non-destructive testing,
In the cross-sectional line extraction step, a circular line with a diameter 10 mm larger than the indentation is formed on the 2D cross-sectional line, a tangent line with a length equal to the diameter of the circular line is formed, and an intersection line perpendicular to the tangent line is formed. At least 500 items should be listed at 0.02mm intervals.
The characteristic value extraction step allows the circumference, area, and volume of the indentation to be extracted through the 2D cross-section line,
The welder calibration step is a laser scanning-based resistance spot welding quality judgment method, characterized in that the welder is calibrated based on nugget diameter prediction and defect determination of the resistance spot welding performed by non-destructive testing. According to paragraph 3,
The defect detection step is,
An edge welding defect detection step of detecting an edge welding defect of the resistance spot welding;
An electrode wear defect detection step of detecting electrode wear defects of the welder; and
A laser scanning-based resistance spot welding quality judgment method comprising: an electrode misalignment detection step of detecting electrode misalignment and surface flaking defects of the resistance spot welding.
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