WO2021065066A1

WO2021065066A1 - Welding defect detecting device, welding device, and welding defect detecting method

Info

Publication number: WO2021065066A1
Application number: PCT/JP2020/019014
Authority: WO
Inventors: 裕企雄佐藤; 督生川崎; 郁馬肥後; 光彦渡邉
Original assignee: 三菱電機株式会社
Priority date: 2019-09-30
Filing date: 2020-05-12
Publication date: 2021-04-08

Abstract

A welding defect detecting device (2) is provided with: a laser displacement sensor (50) which measures the positions of the plate surface of a plate-shaped member (110) and the plate surface of a plate-shaped member (120) in an overlapping direction; a determining unit (60) which, on the basis of the positions of the plate surface of the plate-shaped member (110) and the plate surface of the plate-shaped member (120) in the overlapping direction measured by the laser displacement sensor (50), obtains the size of a gap between the plate-shaped member (110) and the plate-shaped member (120), and if the obtained gap size exceeds a threshold, determines that there is a welding defect in a welded portion; and a reporting unit (70) which reports that there is a welding defect if the determining unit (60) has determined that there is a welding defect in the welded portion.

Description

Welding defect detection device, welding device and welding defect detection method

This disclosure relates to a welding defect detection device, a welding device, and a welding defect detection method.

Some welding defect detection devices detect welding defects by observing the shape of the melted and solidified portion of the welded portion, that is, the shape of the bead.

For example, Patent Document 1 describes a scanner device that measures the surface shape of a member to be welded in a certain region centered on the weld line of the bead, and the height of the bead swelling from the coordinate data of the surface shape measured by the scanner device. A welding defect detecting device including a calculation device for detecting a welding defect from the obtained and obtained height is disclosed.

In Patent Document 2, an image sensor that images a region including a bead of a member to be welded and an edge portion are extracted from the image captured by the image sensor, and a misalignment of the bead and an abnormality in the width of the bead are detected from the extracted edge portion. A welding defect detection device including an arithmetic unit for performing a welding defect is disclosed.

Japanese Unexamined Patent Publication No. 2005-14026 Japanese Unexamined Patent Publication No. 2005-14027

Parts such as exteriors and interiors of automobiles, railways, elevators, etc. may be joined to other members by lap welding in which two plate-shaped members are lapped and welded. For example, a plate-shaped member for reinforcement may be superposed on a plate-shaped member for exterior or interior, and the superposed plate-shaped member may be joined by lap welding. Then, in order to make the welded portion inconspicuous and enhance the design, the lap welding may be performed by laser welding in which laser light is irradiated and welded.

In the case of such lap welding, penetration may not be formed from one plate-shaped member to the other plate-shaped member. In other words, the melting of the upper plate may not reach the lower plate. As a result, welding defects may occur. For example, if the plate-shaped member is warped or the end face shape of the plate-shaped member is deformed, the melting of the upper plate may not reach the lower plate, and as a result, welding defects may occur. is there. Therefore, even in such lap welding, it is desired to detect welding defects by a welding defect detecting device.

However, the welding defect detection device described in Patent Document 1 only obtains the height of the bead swelling. Therefore, it is difficult for the welding defect detecting device described in Patent Document 1 to accurately detect the welding defect of the above-mentioned lap welding.

The welding defect detecting device described in Patent Document 2 also only detects the misalignment of the bead and the width abnormality of the bead. Therefore, it is difficult to accurately detect the welding defect of the above-mentioned lap welding.

The present disclosure has been made in order to solve the above problems, and an object of the present disclosure is to provide a welding defect detecting device, a welding device, and a welding defect detecting method capable of accurately detecting welding defects in lap welding.

In order to achieve the above object, the welding defect detection device according to the present disclosure has a first plate-like member, which is superposed on one plate surface and whose end surface is arranged on one plate surface. A welding defect of a welded portion of a two-plate member formed at a position separated from the end face by a certain distance is detected. The welding defect detection device includes a position sensor, a determination unit, and a notification unit. The position sensor measures the position of the plate surface of the first plate-shaped member and the plate surface of the second plate-shaped member in the superposition direction. The determination unit is a gap between the first plate-shaped member and the second plate-shaped member based on the position in the overlapping direction between the plate surface of the first plate-shaped member and the plate surface of the second plate-shaped member measured by the position sensor. If the size of the obtained gap exceeds the threshold value, it is determined that the welded portion has a welding defect. When the determination unit determines that the welded portion has a welding defect, the notification unit notifies that there is a welding defect.

According to the configuration of the present disclosure, the determination unit is the first on the end face based on the position in the overlapping direction of the plate surface of the first plate-shaped member and the plate surface of the second plate-shaped member measured by the position sensor. The size of the gap between the plate-shaped member and the second plate-shaped member is obtained, and the presence or absence of welding defects is determined from the obtained gap size. According to the present disclosure, welding defects in lap welding can be accurately detected.

Perspective view of two plate-shaped members welded by the laser welding apparatus according to the embodiment of the present disclosure. Front view of the laser welding apparatus according to the embodiment of the present disclosure. A side view of a head portion included in the laser welding apparatus according to the embodiment of the present disclosure. Cross-sectional view of a plate-shaped member when lap welding is performed using the laser welding apparatus according to the embodiment of the present disclosure. A cross-sectional view of a welding defect that occurs when lap welding is performed using the laser welding apparatus according to the embodiment of the present disclosure. Block diagram of a welding defect detecting device provided in the laser welding device according to the embodiment of the present disclosure. Hardware configuration diagram of welding defect detection device provided in the laser welding device according to the embodiment of the present disclosure. Flow chart of welding defect detection processing performed by the welding defect detecting apparatus provided in the laser welding apparatus according to the embodiment of the present disclosure. Cross-sectional view of a plate-shaped member showing a measurement range of a laser displacement sensor included in a welding defect detection device provided in the laser welding device according to the embodiment of the present disclosure. Cross-sectional view of a plate-shaped member showing a measurement range of a modified example of a laser displacement sensor included in a welding defect detection device provided in the laser welding device according to the embodiment of the present disclosure.

Hereinafter, the welding defect detection device, the welding device, and the welding defect detection method according to the embodiment of the present disclosure will be described in detail with reference to the drawings. In the figure, the same or equivalent parts are designated by the same reference numerals. In the orthogonal coordinate system XYZ shown in the figure, when the direction in which the welding defect detection device forms a linear welded portion on the object to be welded is the front-back direction, the front-back direction is the X direction, the vertical direction is the Z direction, and the Z-axis. The direction orthogonal to the X-axis is the Y-axis. Hereinafter, this coordinate system will be referred to and described as appropriate.

The welding device according to the embodiment is a laser welding device that irradiates one of the two stacked plate-shaped members with a laser beam to superimpose and weld the two plate-shaped members to be welded. This laser welding apparatus is provided with a welding defect detecting apparatus in order to detect the occurrence of lap welding defects at an early stage.

First, the configuration of the two plate-shaped members to be welded will be described with reference to FIG. Subsequently, the configuration of the welding apparatus will be described with reference to FIGS. 2 to 5, and subsequently, the configuration of the welding defect detecting apparatus will be described with reference to FIG.

FIG. 1 is a perspective view of two plate-

shaped members

110 and 120 to be welded by the laser welding apparatus according to the embodiment. In FIG. 1, the plate-

shaped members

110 and 120 are combined with the back side facing up.

Since the plate-shaped member 110 is used as a decorative panel of an elevator, as shown in FIG. 1, the plate-shaped member 110 is bent into a shape in which a rectangular frame portion 112 surrounds a rectangular plate portion 111. Although not shown, the surface of the plate-shaped member 110 is painted in order to enhance the design. The plate-shaped member 110 is an example of the first plate-shaped member as referred to in the present specification. The plate-shaped member 110 includes a member whose surface is painted and a member which is not painted, for example, a stainless steel material. The upper surface of the plate-shaped member 110 is an example of one plate surface as referred to in the present specification.

On the other hand, the plate-shaped member 120 is bent into a hat shape in cross section for use as a reinforcing member. As a result, the plate-shaped member 120 has arm portions 121 at both end portions having a hat-shaped cross section. The arm portions 121 are overlapped with the plate portion 111 of the plate-shaped member 110. Then, those arm portions 121 are joined to the plate portion 111 by welding. As a result, the plate-shaped member 120 reinforces the plate-shaped member 110. The plate-shaped member 120 is an example of the second plate-shaped member as referred to in the present specification. Further, the vertical direction, that is, the Z-axis direction, which is the direction in which the plate-shaped member 120 is overlapped with the plate-shaped member 110, is an example of the overlapping direction as referred to in the present specification.

The plate-

shaped members

110 and 120 are formed of a thin steel plate, for example, a thin galvanized steel plate. When the plate-shaped

members

110 and 120 formed of such thin steel plates are joined by resistance spot welding, high heat is applied to a region wider than the plate thickness by the welding, and the welding strain causes the plate-shaped

members

110 and 120 to be joined. 120 may be deformed. As a result, the design of the plate-shaped

members

110 and 120 may be deteriorated.

Therefore, in order to enhance the design, the laser welding apparatus according to the embodiment is used for welding the plate-shaped

members

110 and 120. This is because in the case of laser welding, heat can be applied to a local region to form a linear welded portion 130, and as a result, the plate-shaped

members

110 and 120 can be made difficult to deform. Next, the configuration of the laser welding apparatus will be described with reference to FIGS. 2 to 5.

FIG. 2 is a front view of the laser welding apparatus 1 according to the embodiment. FIG. 3 is a side view of the head portion 30 included in the laser welding device 1. FIG. 4 is a cross-sectional view of the plate-shaped

members

110 and 120 when lap welding is performed using the laser welding device 1. FIG. 5 is a cross-sectional view of a welding defect that occurs at that time. In addition, in FIG. 2 and FIG. 3, parts such as electric wires and screws are omitted for easy understanding. Further, in FIGS. 4 and 5, it is emphasized whether or not the penetration is formed from one plate-shaped member 120 to the other plate-shaped member 110.

As shown in FIG. 2, the laser welding apparatus 1 includes a surface plate 10 for mounting plate-shaped

members

110 and 120 to be welded, a moving mechanism 20 that moves relative to the surface plate 10. It includes a head unit 30 provided in the moving mechanism 20, and a control unit 40 that controls the operation of the moving mechanism 20 and the head unit 30.

The surface plate 10 has a rectangular parallelepiped outer shape, and as shown in FIG. 2, the upper surface of the surface plate 10 is formed horizontally and smoothly. The plate-shaped

members

110 and 120 of the work to be welded are placed on the upper surface in the above-mentioned superposed state. Further, a jig (not shown) is arranged on the upper surface of the surface plate 10. The jig determines the horizontal positions of the plate-shaped

members

110 and 120 placed on the surface plate 10.

On the other hand, the moving mechanism 20 includes a mechanism for moving the head portion 30 with respect to the surface plate 10 in the front-rear direction, the left-right direction, and the up-down direction, that is, in each axial direction of XYZ. Specifically, the moving mechanism 20 includes an X block 21, a Y block 22, and a Z block 23 that linearly move in the X-axis direction, the Y-axis direction, and the Z-axis direction. Since the X block 21, the Y block 22, and the Z block 23 move linearly in the X-axis direction, the Y-axis direction, and the Z-axis direction, the X-axis linear moving portion, the Y-axis linear moving portion, and the Z-axis Also called a linear moving part.

The X block 21 is formed in a gate shape having

columnar portions

211 and 212 and a beam portion 213 connecting the columnar portions 211 and the upper ends of 212. X rails 214 and 215 extending in the X direction are arranged on both sides of the surface plate 10 in the Y direction. The

columnar portions

211 and 212 are guided by the X rails 214 and 215 and move along the X rails 214 and 215 by a driving device (not shown). As a result, the

columnar portions

211 and 212 move in the X direction together with the beam portions 213. On the other hand, the beam portion 213 is provided with

Y rails

221 and 222 extending in the Y direction.

The Y block 22 is guided by the Y rails 221 and 222, and moves along the Y rails 221 and 222 by a drive device (not shown). As a result, the Y block 22 moves in the Y direction. Although not shown, the Y block 22 is provided with a Z rail extending in the Z direction.

The Z block 23 is guided by a Z rail (not shown) provided on the Y block 22 and moves along the Z rail by a drive device (not shown). As a result, the Z block 23 moves in the Z direction.

Further, the head portion 30 is fixed to the Z block 23. Therefore, the Z block 23 moves the head portion 30 in the Z direction by moving in the Z direction along a Z rail (not shown). The Z block 23 moves in the Y direction as well as the movement of the Y block 22 by moving the Y block 22 in the Y direction along the Y rails 221 and 222 of the X block 21. Further, the Z block 23 moves in the X direction as well as the movement of the X block 21 by moving the X block 21 along the X rails 214 and 215 extending in the X direction. As a result, the Z block 23 also moves the head portion 30 in the Y direction and the X direction.

In this way, the Z block 23 moves the head portion 30 together with the Y block 22 and the X block 21 in each axial direction of the XYZ. As a result of the X rails 214 and 215 being longer than the X direction of the surface plate 10 and the X block 21 being formed in a gate shape straddling the surface plate 10, the Y rails 221 and 222 are longer than the Y direction of the surface plate 10. The moving range of the Z block 23 is within the range on the surface plate 10. As a result, the Z block 23, together with the Y block 22 and the X block 21, can move the head portion 30 to a desired position on the plate-shaped

members

110 and 120 placed on the surface plate 10.

The head portion 30 is a portion for welding the plate-shaped

members

110 and 120 of the workpiece. As shown in FIG. 3, the head portion 30 includes a roller 31 that presses the plate-shaped

members

110 and 120 that are objects to be welded, and a laser welding head 32 that irradiates a laser beam.

The roller 31 is rotatably provided at the lower end of the support 311 extending downward from the Z block 23. Then, the roller 31 presses the work piece when the X block 21 and the Y block 22 move to a desired welded portion on the work piece and the Z block 23 descends. Specifically, the roller 31 presses the plate-shaped member 120 on the upper side of the plate-shaped

members

110 and 120 to be welded. As a result, the roller 31 brings the plate-shaped member 120 into close contact with the plate-shaped member 110 to minimize the gap between the plate-shaped

member

110 and 120. As a result, the roller 31 prevents the plate-shaped

members

110 and 120 from being displaced from each other.

Further, the roller 31 is arranged in front of the laser welding head 32, that is, on the + X side. As will be described later, the laser welding apparatus 1 irradiates the object to be welded with laser light only when the X block 21 moves to the + X side to perform welding. That is, when the X block 21 moves to the −X side, the laser welding device 1 does not irradiate the laser beam and does not perform welding. The roller 31 presses the plate-shaped member 120 to be welded on the + X side of the laser welding head 32, that is, on the upstream side which is the moving direction at the time of welding. Then, when the X block 21 moves to the + X side and the laser welding head 32 welds the workpiece, the roller 31 rotates the upper surface of the plate-shaped member 120 while pressing the plate-shaped member 120 of the workpiece. Move. As a result, the roller 31 presses the welded portion of the object to be welded in advance and presses the plate-shaped member 120 against the plate-shaped member 110. The roller 31 is an example of a pressing member as referred to in the present specification.

Although not shown, the laser welding head 32 has an optical fiber that transmits the laser light oscillated by the laser oscillator and a lens that collects the laser light emitted from the end of the optical fiber. Then, as shown in FIG. 2, the laser welding head 32 is fixed to the Z block 23. The laser welding head 32 is also simply referred to as a welding head.

Returning to FIG. 3, the laser welding head 32 collects the laser light on the plate-shaped member 120 when the Z block 23 is lowered and the distance from the lens to the plate-shaped member 120 of the workpiece matches the focal length. Let it shine to melt a part of the plate-shaped

members

110 and 120. Then, the laser welding head 32 separates from the melted part of the plate-shaped

members

110 and 120 by moving the X block 21 to the + X side. As a result, the melted portion is naturally cooled and solidified. As a result, the laser welding head 32 welds the plate-shaped

members

110 and 120. The laser welding head 32 is controlled by the control unit 40 and performs the above operation.

As shown in FIG. 2, the control unit 40 has a storage unit 41. The storage unit 41 stores in advance the coordinate data of the X block 21, the Y block 22, and the Z block 23 corresponding to the numerical data of the welded portion.

The control unit 40 reads the coordinate data, moves the X block 21 and the Y block 22 to the positions corresponding to the read coordinate data, and lasers the laser at the position of the XY coordinates of the welding start point shown in the coordinate data. The welding head 32 is moved. Then, the control unit 40 lowers the Z block 23 to bring the roller 31 into contact with the plate-shaped member 120 of the work piece. Further, the control unit 40 lowers the laser welding head 32 to a position separated from the plate-shaped member 120 by the focal length of the lens, and emits laser light from the optical fiber toward the lens.

The control unit 40 moves the laser welding head 32 in the + X direction while emitting the laser beam. That is, the control unit 40 moves the X block 21 to the + X side to form a linear welded portion 130 extending in the + X direction.
In order to weld the plate-shaped

members

110 and 120 pressed in advance by the roller 31, the control unit 40 moves the X block 21 only to the + X side when the laser beam is emitted to the laser welding head 32, and X Do not move block 21 to the -X side.

When the laser welding head 32 moves to the X coordinate of the welding end point, the control unit 40 stops the emission of the laser light from the laser welding head 32. Further, the control unit 40 raises the Z block 23 to raise the roller 31 and the laser welding head 32.

The control unit 40 forms a welded portion 130 on the plate-shaped

members

110 and 120 by a series of these operations. The control unit 40 forms the two welded portions 130 shown in FIG. 1 by repeating these series of operations. As a result, the control unit 40 welds the plate-shaped

members

110 and 120.

When the plate-shaped

members

110 and 120 are welded by the control unit 40, the bead 131 shown in FIG. 4 is formed in the welded portion 130. Here, in the present specification, the welded portion 130 is a portion including a weld metal melted and solidified during welding and a heat-affected zone affected by heat during welding. The bead 131 is a swelling of the weld metal surface that has been melted and solidified.

At the location where the bead 131 is formed, a penetration of the metal material extending from the upper surface of the plate-shaped member 120 to the plate-shaped member 110 is formed, and the penetration joins the plate-shaped member 120 and the plate-shaped member 110.

However, the above-mentioned penetration may not reach the plate-shaped member 110 because the lens (not shown) of the laser welding head 32 is dirty, the plate-shaped

members

110 and 120 are warped, and there is a thickness error or the like. As a result, as shown in FIG. 5, a welding defect may occur in which the plate-shaped

members

110 and 120 are not welded even though the bead 131 is formed. In addition, welding defects may occur in which the plate-shaped

members

110 and 120 are not welded with sufficient joint strength. In such a case, it is difficult to find a welding defect only by visually inspecting the bead 131. As a result, the operator of the laser welding apparatus 1 may not notice the occurrence of welding defects. In addition, the operator may operate the laser welding apparatus 1 as it is, causing a large number of welding defects.

Therefore, in order to detect welding defects at an early stage and prevent frequent occurrence of welding defects, the laser welding device 1 is equipped with a welding defect detecting device 2. Subsequently, in addition to FIGS. 2 to 4, the configuration of the welding defect detection device 2 will be described with reference to FIGS. 6 and 7.

FIG. 6 is a block diagram of the welding defect detection device 2. FIG. 7 is a hardware configuration diagram of the welding defect detection device 2. In addition to the welding defect detecting device 2, the configuration of the laser welding device 1 is also shown in FIG. 6 for easy understanding.

As shown in FIG. 6, the welding defect detection device 2 includes a laser displacement sensor 50, a determination unit 60 that determines the presence or absence of welding defects based on the output of the laser displacement sensor 50, and an alarm based on the determination of the determination unit 60. It is provided with an alarm unit 70 that emits an alarm.

The laser displacement sensor 50 irradiates an object with laser light, forms an image of the laser light reflected by the object on a light receiving element with a lens, and based on the fluctuation of the imaging position on the light receiving element from the reference position, the target. A sensor that measures the distance to an object or the displacement of an object. The laser displacement sensor 50 includes a light source that irradiates a band-shaped laser beam and a two-dimensional image sensor that receives the laser beam reflected by the object. The laser displacement sensor 50 measures the distance from the image formation position on the two-dimensional image sensor to the object or the displacement of the object by an angular distance measuring method. Then, the laser displacement sensor 50 measures the shape of the object on the plane formed by the band-shaped laser.

The laser displacement sensor 50 is provided on the head portion 30. Specifically, as shown in FIG. 3, the laser displacement sensor 50 is arranged behind the laser welding head 32, that is, on the downstream side opposite to the moving direction during welding. Although not shown, the laser displacement sensor 50 is fixed to the Z block 23 like the laser welding head 32. The laser displacement sensor 50 moves in synchronization with the laser welding head 32 by moving the X block 21, the Y block 22, and the Z block 23. That is, the laser displacement sensor 50 moves following the laser welding head 32. Then, the laser displacement sensor 50 measures the positions of the upper surfaces of the plate-shaped

members

110 and 120 below the laser welding head 32 on the downstream side. Specifically, the laser displacement sensor 50 measures the positions of the upper surfaces of the plate-shaped

members

110 and 120 on the YZ plane perpendicular to the moving direction of the laser welding head 32. As a result, the laser displacement sensor 50 measures the positions of the welded portion 130 formed by the laser welding head 32 and its periphery.

Returning to FIG. 6, the laser displacement sensor 50 transmits the measured position data to the determination unit 60 after the measurement. The laser displacement sensor 50 is an example of a position sensor as referred to in the present specification.

The determination unit 60 obtains the thickness T of the plate-shaped members 120 shown in FIG. 4 from the position data of the upper surfaces of the plate-shaped

members

110 and 120 measured by the laser displacement sensor 50.

Specifically, the storage unit 41 shown in FIG. 6 stores distance data from the vertical line extending directly below the laser displacement sensor 50 to the bead 131. The determination unit 60 reads out the distance data, and uses the distance data to obtain the thickness T of the plate-shaped member 120 at the position where the bead 131 shown in FIG. 4 is formed.

From the position data of the upper surfaces of the plate-shaped

members

110 and 120, the determination unit 60 determines the difference in height between the upper surface of the plate-shaped member 110 and the upper surface of the plate-shaped member 120 at the position where the end surface E of the plate-shaped member 120 is located. Ask. The determination unit 60 subtracts the obtained thickness T of the plate-shaped member 120 from the difference in height to obtain the vertical size of the gap G between the plate-shaped

members

110 and 120. In addition, the size of the gap G in the vertical direction is hereinafter simply referred to as the size of the gap G.

Here, the gap G is formed by plastically deforming the plate-shaped

members

110 and 120 due to heat during welding. That is, at the time of welding, the laser beam is irradiated only to the plate-shaped member 120 and not to the plate-shaped member 110, so that the plate-shaped member 120 is more easily deformed by heat than the plate-shaped member 110. The gap G is formed by the difference in the magnitude of this thermal deformation.

Since the gap G is formed by the heat during welding, it is formed regardless of the presence or absence of welding defects. Specifically, the gap G is formed by warping the plate-shaped member 120 under the influence of heat generated by irradiation with laser light. Then, when a welding defect occurs, that is, when the plate-shaped member 120 is not joined to the plate-shaped member 110, or when the plate-shaped member 120 is not joined with sufficient strength, the gap G tends to be large.

Therefore, the determination unit 60 determines the presence or absence of welding defects by utilizing this phenomenon of the gap G. More specifically, returning to FIG. 6, the storage unit 41 stores in advance the threshold data of the size of the gap G at the time of welding failure, which is obtained in the experiment. The determination unit 60 reads the threshold data and determines whether or not the size of the obtained gap G is larger than the read threshold. When the determination unit 60 determines that it is larger than the threshold value, it determines that a welding defect has occurred. Further, when the determination unit 60 determines that the value is equal to or less than the threshold value, the determination unit 60 determines that the welding is normally performed without any welding defect. When the determination unit 60 determines that a welding defect has occurred, the determination unit 60 transmits a welding defect signal to the alarm unit 70.

Although not shown, the alarm unit 70 has a buzzer. Upon receiving the welding failure signal, the alarm unit 70 generates an alarm sound from the buzzer. As a result, the alarm unit 70 notifies the operator of the laser welding apparatus 1 that a welding defect has occurred in the apparatus. As a result, the operator can recognize the occurrence of welding defects. Further, when the operator confirms the state of the laser welding device 1 and the plate-shaped

members

110 and 120, the laser welding device 1 can prevent an increase in welding defects. The alarm unit 70 is an example of the notification unit as referred to in the present specification.

As shown in FIG. 7, the laser welding device 1 has an I / O port (I / O port) connected to a CPU (Central Processing Unit) 200, a moving mechanism 20, a head unit 30, a laser displacement sensor 50, and an alarm unit 70. Input / Output Port) 300 and. Further, the storage unit 41 stores a control program and a welding defect detection program. The control unit 40 is realized by the CPU 200 executing a control program stored in the storage unit 41. Further, the determination unit 60 is realized by the CPU 200 executing the welding defect detection program stored in the storage unit 41.

Next, the operation of the welding defect detection device 2 will be described with reference to FIGS. 8 and 9. In the following description, it is assumed that the laser welding apparatus 1 is provided with a start button (not shown). Further, it is assumed that an abnormality confirmation button pressed by the operator when a welding defect occurs and the welding defect is confirmed is provided.

FIG. 8 is a flowchart of the welding defect detection process performed by the welding defect detecting device 2. FIG. 9 is a cross-sectional view of the plate-shaped

members

110 and 120 showing the measurement range of the laser displacement sensor 50 included in the welding defect detection device 2. In FIG. 9, in order to facilitate understanding, the penetration of the plate-shaped

members

110 and 120 and the size of the gap G are emphasized. Further, the size of the roller 31 is emphasized more than that of the laser displacement sensor 50.

When the start button provided on the laser welding device 1 is pressed, the laser welding device 1 is started. As a result, the CPU 200 executes the welding defect detection program. As a result, the flow of welding defect detection processing is started.

When the flow of the welding defect detection process is started, the determination unit 60 first determines whether or not the laser welding head 32 is at the welded portion as shown in FIG. 8 (step S1). Specifically, the determination unit 60 reads the coordinate data of the X block 21, the Y block 22, and the Z block 23 corresponding to the numerical data of the welded portion described above from the storage unit 41, and uses the coordinate data as the X block 21, Y. It is determined whether or not the current coordinates of the block 22 and the Z block 23 are applicable.

When the determination unit 60 determines that the laser welding head 32 is not at the welding location (No in step S1), the determination unit 60 returns to the front of step S1.

On the other hand, when the determination unit 60 determines that the laser welding head 32 is at the welding location (Yes in step S1), the determination unit 60 tells the laser displacement sensor 50 that the positions of the upper surfaces of the plate-shaped

members

110 and 120 directly below the laser displacement sensor 50 and the plate shape. The position of the upper end of the end surface E of the member 120 is measured. The determination unit 60 acquires those positions measured by the laser displacement sensor 50 (step S2).

Specifically, the laser displacement sensor 50 irradiates the large area A3 shown in FIG. 9 with the above-mentioned laser light to measure the top surface shapes of the plate-shaped

members

110 and 120 in the large area A3. On the other hand, the storage unit 41 stores the XYZ coordinate data for the laser displacement sensor 50 in the areas A1 and A2 shown in FIG. Further, the storage unit 41 stores the XYZ coordinate data of the end surface E of the plate-shaped member 120 with respect to the laser displacement sensor 50.

Here, the laser welding head 32 moves forward, that is, moves toward the + X side so as to warp against the end surface E of the plate-shaped member 120, and the region A1 is located on the −Y side of the end surface E. It is a part of the upper surface of the shape member 110. The region A2 is a partial region of the upper surface of the plate-shaped member 120 located on the + Y side of the end face E and adjacent to the end face E. Further, the region A2 is a partial region where the bead 131 is predicted to be formed. The region A2 may be a region near a portion where the bead 131 is predicted to be formed, that is, a region near a welded portion, in addition to a partial region where the bead 131 is predicted to be formed.

The determination unit 60 reads out the XYZ coordinate data of the areas A1, A2 and the end face E, and acquires the height measured by the laser displacement sensor 50 at the position corresponding to these XYZ coordinate data from the laser displacement sensor 50. As a result, the determination unit 60 acquires the average height of the upper surfaces of the plate-shaped

members

110 and 120. Further, the determination unit 60 acquires the height of the upper end of the end surface E of the plate-shaped member 120. The step of measuring by the laser displacement sensor 50 is an example of the measuring step as referred to in the present specification. Further, the height measured by the laser displacement sensor 50 is an example of the position in the superposition direction as referred to in the present specification.

Next, the determination unit 60 obtains the thickness T of the plate-shaped member 120 (step S3). Specifically, the determination unit 60 subtracts the value of the average height of the upper surface of the plate-shaped member 110 from the value of the average height of the upper surface of the acquired plate-shaped member 120, and the thickness T of the plate-shaped member 120. Ask for.
The thickness T of the plate-shaped member 120 may be stored in the storage unit 41 in advance. In that case, the determination unit 60 may obtain the thickness T by reading the thickness T stored in the storage unit 41 in step S3.

Subsequently, the determination unit 60 obtains the size of the gap G (step S4). That is, the determination unit 60 subtracts the value of the thickness T of the plate-shaped member 120 obtained in step S3 from the value of the height of the upper end surface E of the plate-shaped member 120 acquired in step S2, thereby causing the gap G. Find the value of the magnitude of. The upper end of the end face E is an example of the end face portion of the plate surface as referred to in the present specification.

In step S4, since thermal deformation due to welding of the plate-shaped member 120 tends to be large at the end face E, the size of the gap G is obtained at the position where the end face E is located. Further, when the plate-shaped member 120 is in a floating state with respect to the plate-shaped member 110 due to poor welding, the floating tends to be large at the end face E, so that the gap G is formed at the position where the end face E is located. I'm looking for size. This makes it easier for the determination unit 60 to make a determination, which will be described later.

Next, the determination unit 60 reads the threshold data indicating whether the gap G is acceptable from the storage unit 41, and determines whether or not there is a welding defect. Therefore, whether or not the size of the obtained gap G is larger than the threshold value. Is determined (step S5). It should be noted that this step is an example of the determination step as referred to in the present specification.

Here, the threshold data should be data obtained by obtaining the threshold value at which welding failure occurs in advance in an experiment. It is preferable that the threshold data obtained in the experiment is stored in the storage unit 41 in advance. In an experiment conducted by the inventor under the condition that no strain is generated on the design surface in the lap welding of thin steel plates, when the size of the gap G exceeds 1/10 of the plate thickness of the plate-shaped member 120, the welding strength of the weld increases. It has been found to be unstable. Therefore, the value of the threshold data is preferably 1/10 of the design value of the plate thickness of the plate-shaped member 120 or the measured value in the experiment.

When the determination unit 60 determines that it is larger than the threshold value (Yes in step S5), it assumes that there is a welding defect and transmits a welding defect signal to the alarm unit 70. As a result, the determination unit 60 causes the alarm unit 70 to sound an alarm (step S6).

Here, the alarm sound continues to sound until the operator presses the above-mentioned abnormality confirmation button. As a result, the alarm unit 70 urges the operator to perform operations such as checking the state of the laser welding device 1 and stopping the operation.

After generating the alarm sound, the determination unit 60 returns to step S1 in order to detect a welding defect in the subsequent laser welding. Note that this step S6 is an example of the notification process as referred to in the present specification.

On the other hand, when the determination unit 60 determines that the value is equal to or less than the threshold value (No in step S5), it treats that there is no welding defect, and returns to step S1 to detect the welding defect in the subsequent laser welding.

The above flow continues until the user presses the start button provided on the laser welding device 1 again to stop the operation of the laser welding device 1. When the start button is pressed again and the operation of the laser welding apparatus 1 is stopped, the flow of the welding defect detection process is forcibly terminated.

As described above, the laser welding apparatus 1 according to the embodiment is provided with a welding defect detecting apparatus 2 that detects welding defects from the size of the gap G between the stacked plate-shaped

members

110 and 120. Therefore, the laser welding apparatus 1 can accurately detect the occurrence of welding defects in lap welding.

In the welding defect detection device 2, when the determination unit 60 determines that the size of the gap G is larger than the threshold value, the alarm unit 70 notifies that there is a welding defect. Therefore, the operator can easily know the presence or absence of welding defects without performing a visual inspection.

Laser welding has a smaller bead width than resistance welding and arc welding, and it is difficult to judge the presence or absence of welding defects by bead inspection. On the other hand, the welding defect detecting device 2 detects the welding defect from the size of the gap G between the plate-shaped

members

110 and 120, and therefore effectively detects the welding defect when performing lap welding by laser welding. be able to.

In addition, laser welding enables a large number of welding in a short time compared to resistance welding and arc welding. The welding defect detecting device 2 can detect welding defects at an early stage in laser welding capable of performing a large number of weldings, and can prevent a large number of welding defects from occurring.

The welding defect detection device 2 includes a laser displacement sensor 50 fixed to the head portion 30 of the laser welding device 1. Therefore, welding defects can be detected without providing a new moving mechanism. As a result, the welding defect detection device 2 can carry out from welding to inspection in the laser welding device 1. That is, it is possible to improve work efficiency by inspecting by so-called in-process.

The welding defect detection device 2, the laser welding device 1, and the welding defect detection method according to the embodiment of the present disclosure have been described above, but the welding defect detection device 2, the laser welding device 1, and the welding defect detection method are not limited thereto. .. For example, in the above embodiment, the determination unit 60 subtracts the value of the upper surface height of the plate-shaped member 110 from the value of the upper surface height of the plate-shaped member 120, and further subtracts the value of the upper surface height of the plate-shaped member 110 from the difference, and the thickness T of the plate-shaped member 120. The size of the gap G is obtained by subtracting. However, the determination unit 60 is not limited to this. The determination unit 60 determines the size of the gap G between the plate-shaped member 110 and the plate-shaped member 120 based on the vertical position of the plate-shaped member 110 and the vertical position of the plate-shaped member 120 measured by the laser displacement sensor 50. You just have to ask.

For example, the thickness data of the plate-shaped member 120 is stored in the storage unit 41 in advance, and the determination unit 60 reads the thickness data, and the value of the upper surface height of the plate-shaped member 120 and the upper surface height of the plate-shaped member 110. The size of the gap G may be obtained by subtracting the read-out thickness value from the difference from the value of. In this case, it is advisable to obtain the thickness T of the plate-shaped member 120 by experiment in advance. It is preferable that the thickness T obtained in the experiment is stored in the storage unit 41. In such a form, the laser displacement sensor 50 may measure two points, the upper end surface E of the plate-shaped member 120 and the upper surface of the plate-shaped member 110, and the measurement can be simplified.

Further, the determination unit 60 obtains the inclination angle of the portion of the upper surface of the plate-shaped member 120 from the position where the welded portion 130 is formed to the end surface E, and obtains the size of the gap G based on the obtained inclination angle. Is also good. Here, the inclination angle is an angle at which the portion of the upper surface of the plate-shaped member 120 is inclined with respect to the upper surface of the plate-shaped member 110.

FIG. 10 is a cross-sectional view of the plate-shaped

members

110 and 120 showing the measurement range of the modified example of the laser displacement sensor 50.
As shown in FIG. 10, the determination unit 60 measures the surface shape of a part of the upper surface of the plate-shaped member 120 included in the region A4 from the vicinity of the bead 131 to the end face E, and the surface shape of the part obtained by the measurement. The inclination angle θ of the plate-shaped member 120 may be obtained from. Here, the inclination angle θ is an angle at which the upper surface of the plate-shaped member 120 is inclined on a plane perpendicular to the moving direction, that is, a YZ plane when the laser displacement sensor 50 moves in the X direction. In this case, the storage unit 41 stores the design-time distance L from the center of the welded portion 130 to the end face E shown in FIG. 10, and the determination unit 60 reads the distance data from the storage unit 41 and reads the distance. It is preferable to obtain the size of the gap G based on the value of L and the inclination angle θ. With such a form, the size of the gap G can be obtained only by measuring a narrow region.

In the above embodiment, in order to obtain the thickness of the plate-shaped member 120, the laser displacement sensor 50 measures the height of the upper surface of the plate-shaped member 110 in the region A2 where the bead 131 is formed. However, the laser displacement sensor 50 is not limited to this. The laser displacement sensor 50 may measure the vertical position of the region or portion where the welded portion 130 is formed in order to obtain data for obtaining the thickness of the plate-shaped member 120. Alternatively, the vertical position of the region or portion on the side opposite to the end surface E of the plate-shaped member 120 from the position where the welded portion 130 is formed may be measured.

For example, the laser displacement sensor 50 may measure the height of the upper surface of the plate-shaped member 120 in the region on the right side of the bead 131, that is, on the side opposite to the end surface E with respect to the bead 131 in FIG. .. The location where the plate-shaped

members

110 and 120 are closest to each other by welding is often the bead 131. Therefore, it is desirable that the laser displacement sensor 50 measures the bead 131 or the welded portion 130. Even so, the laser displacement sensor 50 can obtain data for approximately determining the thickness of the plate-shaped member 120.

In the above embodiment, the laser displacement sensor 50 measures the vertical position of the plate-shaped

members

110, 120, that is, the height of the plate-shaped

members

110, 120, but the laser displacement sensor 50 is not limited to this. .. The laser displacement sensor 50 may be another sensor as long as it is a position sensor capable of measuring the heights of the plate-shaped

members

110 and 120. For example, a displacement sensor such as an eddy current type, a capacitance type, or an ultrasonic type, or a position sensor may be used. When the position sensor is the laser displacement sensor 50, the laser displacement sensor 50 may use a spot beam method for irradiating the laser light. Further, the distance measuring method of the laser displacement sensor 50 may be a confocal method, a spectral interference method, or the like, in addition to the triangular distance measuring method.

Further, in the above embodiment, the laser displacement sensor 50 measures the heights of the plate-shaped

members

110 and 120. This is because the plate-shaped

members

110 and 120 are overlapped in the vertical direction, so that the position in the overlapping direction is measured. However, the laser displacement sensor 50 and the plate-shaped

members

110 and 120 are not limited to this. That is, the welding defect detection device 2 is not limited to the fact that the plate-shaped

members

110 and 120 are superposed in the vertical direction and that the laser displacement sensor 50 measures the heights of the plate-shaped

members

110 and 120. The plate-shaped member 120 may be superposed on one plate surface of the plate-shaped member 110 with the end surface E arranged on one plate surface of the plate-shaped member 110. In that case, the laser The displacement sensor 50 may measure the positions of the plate-shaped

members

110 and 120 in the overlapping direction.

In the above embodiment, the alarm unit 70 has a buzzer, and when the determination unit 60 determines that welding is defective, the alarm unit 70 generates an alarm sound from the buzzer. However, the welding defect detection device 2 is not limited to this. The welding defect detection device 2 may include a notification unit that notifies that there is a welding defect when the determination unit 60 determines that the linear welding portion 130 has a welding defect. Therefore, the alarm unit 70 may notify that there is a welding defect, and in that case, it may be referred to as a notification unit. For example, the alarm unit 70 may include a display device and display welding defect information on the display device to notify that there is a welding defect. Further, the alarm unit 70 may be provided with a lamp, and the lamp may be turned on and blinked to notify that there is a welding defect. In such a case, the alarm unit 70 may be referred to as a notification unit.

In the above embodiment, the welding defect detection device 2 is provided in the laser welding device 1. However, the welding defect detection device 2 is not limited to this. In the laser welding apparatus 1, the bead 131 is smaller than when formed by other types of welding, and it is difficult to determine welding defects. Therefore, it is desirable that the welding defect detecting device 2 is provided in the laser welding device 1. However, the welding defect detection device 2 may be provided in another type of welding device. For example, it may be provided in a resistance welding device or an arc welding device.

In the above embodiment, the welding defect detection device 2 is incorporated in the laser welding device 1. However, the welding defect detection device 2 is not limited to this. The welding defect detection device 2 may be a device separate from the laser welding device 1. Even in such a form, welding defects can be easily detected without inspecting the beads.

In the above embodiment, the laser welding device 1 includes a roller 31 that presses the plate-shaped member 120 and presses the plate-shaped member 120 against the plate-shaped member 110. However, the laser welding apparatus 1 is not limited to this. As described above, the laser welding apparatus 1 may be a laser welding apparatus or another welding apparatus, but in the welding apparatus, the presence or absence of the roller 31, that is, the presence or absence of the pressing member is arbitrary. In the welding apparatus, the plate-shaped member 120 and the plate-shaped member 110 may be welded in a state where the plate-shaped member 120 is pressed and not pressed against the plate-shaped member 110. Although the roller 31 is described above as an example of the pressing member, the pressing member may be a rod member urged by an elastic member in addition to the roller 31.

The present disclosure allows for various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Moreover, the above-described embodiment is for explaining the present disclosure, and does not limit the scope of the present disclosure. That is, the scope of the present disclosure is indicated by the claims, not the embodiments. And various modifications made within the scope of the claims and within the equivalent meaning of disclosure are considered to be within the scope of the present disclosure.

This application is based on Japanese Patent Application No. 2019-178823 filed on September 30, 2019. The specification of Japanese Patent Application No. 2019-178823, the scope of claims, and the entire drawing shall be incorporated into this specification as a reference.

1 laser welding device, 2 welding defect detection device, 10 platen, 20 moving mechanism, 21 X block, 22 Y block, 23 Z block, 30 head part, 31 roller, 32 laser welding head, 40 control unit, 41 storage unit , 50 laser displacement sensor, 60 judgment part, 70 alarm part, 110 plate-shaped member, 111 plate part, 112 square frame part, 120 plate-shaped member, 121 arm part, 130 welded part, 131 bead, 200 CPU, 211,212 Columnar part, 213 beam part, 214,215 X rail, 221,222 Y rail, 300 I / O port, 311 support, A1, A2, A4 area, A3 large area, E end face, G gap, L distance, T Thickness, θ tilt angle.

Claims

It is superposed on one plate surface of the first plate-shaped member, and the end surface of the second plate-shaped member arranged on the one plate surface is located at a position separated from the end surface by a certain distance. It is a welding defect detection device that detects welding defects in the formed welded portion.
A position sensor that measures the position of the plate surface of the first plate-shaped member and the plate surface of the second plate-shaped member in the superposition direction, and
Based on the position of the plate surface of the first plate-shaped member and the plate surface of the second plate-shaped member in the overlapping direction measured by the position sensor, the first plate-shaped member and the second plate-shaped member A determination unit that obtains the size of the gap and determines that the welded portion has a welding defect when the obtained gap size exceeds the threshold value.
When the determination unit determines that the welded portion has a welding defect, a notification unit for notifying that there is a welding defect, and a notification unit.
Welding defect detection device equipped with.
The position sensor is based on the position in the overlapping direction of the end faces of the second plate-shaped member and the position on the plate surface of the second plate-shaped member where the welded portion is formed or the welded portion is formed. Also measured the position of a part on the opposite side of the end face in the superposition direction,
The determination unit obtains the plate thickness of the second plate-shaped member from the position of the plate surface of the first plate-shaped member in the stacking direction and the position of the part of the second plate-shaped member in the stacking direction. The obtained plate thickness is subtracted from the difference between the position of the plate surface of the first plate-shaped member in the overlapping direction and the position of the end surface of the second plate-shaped member in the overlapping direction, and the gap is obtained. Find the size of
The welding defect detection device according to claim 1.
The determination unit is the first in a plane perpendicular to the moving direction in which the position sensor moves from the positions of the plate surface of the first plate-shaped member and the plate surface of the second plate-shaped member measured by the position sensor. The inclination angle at which the portion of the plate surface of the two-plate-shaped member from the position where the welded portion is formed to the end surface is inclined with respect to the plate surface of the first plate-shaped member is obtained, and the determined inclination angle is obtained. Find the size of the gap based on
The welding defect detection device according to claim 1 or 2.
The position sensor faces one surface of the second plate-shaped member, welds the second plate-shaped member at a position separated from the end surface by a certain distance, and welds the second plate-shaped member to the second plate-shaped member. Follows the weld head behind the weld head that moves relative to and along the end face to form the weld, and moves relative to the second plate-like member together with the weld head. To do,
The welding defect detection device according to any one of claims 1 to 3.
The welding head irradiates the second plate-shaped member with a laser beam to weld the second plate-shaped member to the first plate-shaped member.
The welding defect detection device according to claim 4.
The welding defect detection device according to any one of claims 1 to 5,
The second plate-shaped member is welded at a position facing one surface of the second plate-shaped member and separated from the end surface by a certain distance, and the second plate-shaped member is welded relative to the second plate-shaped member. And a welding head that moves along the end face to form the weld.
Welding equipment equipped with.
A pressing member that presses the second plate-shaped member and presses against the first plate-shaped member is further provided.
The welding apparatus according to claim 6.
It is superposed on one plate surface of the first plate-shaped member, and the end surface of the second plate-shaped member arranged on the one plate surface is located at a position separated from the end surface by a certain distance. It is a welding defect detection method for detecting welding defects in the formed welded portion.
A measurement step of measuring the position of the plate surface of the first plate-shaped member and the plate surface of the second plate-shaped member in the superposition direction, and
Based on the position of the plate surface of the first plate-shaped member and the plate surface of the second plate-shaped member in the overlapping direction measured in the measuring step, the first plate-shaped member and the second plate-shaped member on the end face. A determination step of determining the size of the gap between the plate-shaped member and determining that the welded portion has a welding defect when the obtained gap size exceeds the threshold value.
When it is determined in the determination step that the welded portion has a welding defect, a notification step for notifying the welding defect and a notification step
Welding defect detection method.