JP2016112598A - Joint inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint inspection apparatus for a friction stirring point joint, which can determine whether or not a problem is present in a joint part, quantitatively and efficiently.SOLUTION: A control panel 5 includes: a pixel row extraction unit 6 for extracting multiple pixel rows linearly arranged in the radial direction of a joint at predetermined intervals around the center of the joint in a photographed image P1; a calculation unit 7 for calculating and processing the brightness of pixels in each pixel row, respectively; a line certification unit 8 for certifying a pixel row having a pixel being a brightness value of a predetermined value Zor more by a predetermined value Xor more as a light reflection line in each pixel row, and alternatively, certifying a pixel row having the pixel being a brightness value of a predetermined value Zor less by a predetermined value Xor more as a non-light reflection line; and a determination unit 9 for determining that the joining state of the joint has no problem when the light reflection line is a reference value Tor more and the non-light reflection line is a reference value Tor more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a joining inspection apparatus that inspects a joining state of a joint portion by friction stir spot joining.

  Conventionally, point joining by friction stirring is known as one method for joining superposed metal plates to each other. This joining is performed by rotating the rod-shaped rotating tool around its axis and moving the tip of the rotating tool into the stacked metal plates to pressurize the metal plates to each other. It is softened with frictional heat and solid-phase bonded.

  By the way, in the production line in which the friction stir spot welding is performed as described above, the joints are inspected so that the joints that are poorly bonded are not discharged to the subsequent process.

  For example, in Patent Document 1, the amount of heat applied to the metal plate at the time of joining is calculated using the load applied to the rotating tool at the time of joining and the dynamic friction coefficient of the metal plate, and the amount of pushing of the rotating tool against the metal plate at the time of joining is calculated. Is calculated from the movement amount of the rotary tool, and the calculated heat generation amount and push-in amount are compared with preset setting values to determine whether or not there is a problem in the joining state of the joint portion. Yes.

JP 2002-292478 A

  However, in Patent Document 1, it is not determined whether or not there is a problem with the joining state of the joined portion after joining, but by calculating the amount of movement and the amount of heat generated by the rotating tool during joining, Since the state of the joint is only predicted, for example, if wear occurs at the tip of the rotary tool, the calorific value to be calculated greatly deviates from the actual value, and consequently there is a problem with the joint state of the joint. There is a risk of erroneous determination of whether or not there is.

  In order to cope with this, it is conceivable that the joint is visually inspected by the operator after joining, but not only the joint cannot be quantitatively evaluated, but also the work load on the worker is increased.

  The present invention has been made in view of such points, and the object of the present invention is for friction stir spot joining that can quantitatively and efficiently determine whether or not there is a problem in the joint. It is to provide a bonding inspection apparatus.

  In order to achieve the above object, according to the present invention, when light is applied to the surface of the joint portion in which the joint state is good in the friction stir spot joining, the light extending along the radial direction of the joint portion and the light are reflected. Focusing on the occurrence of non-reflective parts, it is possible to determine whether there is a problem in the joint state of the joint part by extracting the light reflection part and the non-light reflection part from the photographed image. It is characterized by.

That is, in the first invention, a camera that photographs a circular joint portion applied to a workpiece by friction stir spot welding from the surface side, and a camera that is disposed on the side of the camera and irradiates light on the joint surface. A light source; and an inspection unit that is connected to the camera and inspects the joining state of the joint based on a photographed image of the surface of the joint taken by the camera. A pixel column extraction unit for extracting a plurality of pixel columns arranged in a line along the radial direction of the junction with a predetermined interval around the center of the junction; and a luminance value of each pixel in each pixel column, respectively a calculator for calculating process, in each pixel column, one having a predetermined value X ₁ or more pixels is a predetermined value Z ₁ or more luminance values while recognized as light reflection line at a predetermined value Z ₂ following luminance values A certain pixel has a predetermined value X ₂ or more A line certifying unit that recognizes a non-light reflecting line as a non-light reflecting line, a reference value T ₁ in which the number of light reflecting lines is equal to or greater than a predetermined reference value T ₁ , and a reference value T in which the number of non-light reflecting lines is predetermined. And a determination unit that determines that there is no problem in the bonding state of the bonding portion when the number is ₂ or more.

  According to a second invention, in the first invention, when the work is photographed by the camera, the work is moved from the camera to a predetermined distance so that a distance between each joint and the camera is constant every photographing. A work fixing means for fixing to a reference position separated by a distance is provided, and the camera is configured to shoot with a fixed focal length for each joint.

  In the first invention, since a large number of protrusions extending in a circle around the center are formed on the surface of the bonded portion in which the bonding state is good in the friction stir spot bonding, A linear portion that irregularly reflects along the radial direction of the joint portion and a dark portion that does not diffusely reflect along the radial direction of the joint portion are generated by the protrusion. Therefore, when the joint portion is photographed from the surface side with a camera, the joining state of the joint portion can be quantitatively grasped by examining the number of irregular reflection portions or non-diffuse reflection portions in the photographed image. In addition, since it is not necessary for the operator to visually inspect the joined portion after joining, the joined portion can be efficiently inspected without increasing the operator's workload.

  In the second invention, since the pixel corresponding to the center position of the joint portion in each captured image captured by the camera always has the same coordinates, when extracting a pixel row for identifying a light reflection line or a non-light reflection line In addition, it is not necessary to set the center position of the joint part manually or by complicated image processing, and the inspection speed can be increased.

It is a schematic front view of the joining inspection apparatus concerning the embodiment of the present invention. It is a figure which shows the whole picked-up image of the workpiece | work by the camera of a joining inspection apparatus. FIG. 3 is an enlarged view of a part A in FIG. 2, and is an explanatory diagram illustrating a part of a specific procedure for a calculation process of a captured image by a pixel row extraction unit. It is the schematic which exaggerated each pixel of FIG. (A) is a figure which shows the picked-up image of the joint surface with a favorable joining state, (b) is the figure which respectively shows the result of having processed (a) by the line recognition part. (A) is a figure which shows the picked-up image of the surface of a junction part of poor joining, and (b) is a figure which shows the result of having carried out arithmetic processing of (a) by the line recognition part, respectively. It is a flowchart at the time of the junction inspection by the joining inspection apparatus which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiment is merely exemplary in nature.

  FIG. 1 shows a bonding inspection apparatus 1 according to the present invention. The joining inspection apparatus 1 is disposed on the downstream side of a joining step in which two aluminum plates are overlapped and joined to each other by friction stir spot joining to form a workpiece W in a vehicle production line. The joining state of the joining parts 10 having a plurality of circular shapes in the workpiece W is inspected.

  The joint inspection apparatus 1 includes a servo motor-controlled manipulator (work fixing means) 2, and the manipulator 2 is a reference in a posture in which the surface of the joint portion 10 faces the work W gripped by the arm tip 2 a of the manipulator 2. It is designed to be fixed at position B1.

  Above the workpiece W fixed at the reference position B1, the CCD camera 3 is disposed in a position facing a downward distance at a predetermined distance from the reference position B1, and the CCD camera 3 is referred to by the manipulator 2 as a reference. Each joint 10 is photographed from the surface side so that the focal length for each photographing with respect to each joint 10 of the workpiece W fixed at the position B1 is constant.

  A light source 4 for irradiating the workpiece W with light is disposed on the side of the CCD camera 3.

  Further, the CCD camera 3 takes in a photographed image P1 (see FIG. 2) of the workpiece W photographed by the CCD camera 3, and controls to inspect the joining state of each joint 10 based on the photographed image P1. A board (inspection means) 5 is connected.

  As shown in FIG. 3, the control panel 5 arranges the pixel rows 11 arranged in a line along the radial direction of the joint 10 in the captured image P <b> 1 around the center position C <b> 1 of the joint 10. A pixel column extraction unit 6 that extracts a plurality of pixels with a gap is provided.

  The pixel column extraction unit 6 will be described in detail with reference to FIGS. 3 and 4. From the center position C1 of the captured image P1 in the pixel group between the preset inner boundary circle 6a and the outer boundary circle 6b. A pixel row 11a composed of five pixels arranged along the direction toward the lower side of the paper (the radially outer side of the joint portion 10) is extracted, and then shifted from the pixel row 11a by 10 ° in the circumferential direction of the joint portion 10. The pixel row 11 at the position is extracted, and in this case, 36 pixel rows 11 are obtained in total.

  The photographed image P1 is obtained by photographing the workpiece W located at the reference position B1 with the CCD camera 3 at a constant focal length for each photographing. Therefore, the position of each joint portion 10 in the photographed image P1 is determined by photographing. It becomes substantially the same for each image P1. Therefore, when each calculation process is performed, values set in advance for each joint 10 are used for the coordinates of the center position C1, the inner boundary circle 6a, and the outer boundary circle 6b of the joint 10.

  In addition, the control panel 5 includes a calculation unit 7 that performs calculation processing on the luminance of each pixel in each pixel column 11 extracted by the pixel column extraction unit 6.

Furthermore, the control panel 5, while certified pixel array 11 having pixels is a predetermined value Z ₁ or more luminance values predetermined value X ₁ or the light reflection line 8a, a predetermined value Z ₂ following luminance value pixels the has a line discriminating section 8 to certify pixel rows 11 and the non-light-reflective line 8b having a predetermined value X ₂ or more.

Here, the line authorization work of the line authorization unit 8 will be described more specifically. For example, in FIG. 4, it is assumed that the luminance value of the color pixel in the region R ₁ is 20 and the luminance value of the color pixel in the region R ₂ is 200. Further, the pixel column 11 having three or more pixels having a luminance value of 100 or more is recognized as the light reflection line 8a, while the pixel column 11 having three or more pixels having a luminance value of 50 or less is regarded as the non-light reflection line 8b. Will be certified. Then, in FIG. 4, since the luminance value of all the five pixels in the pixel column 11a is 200, the line recognition unit 8 recognizes the light reflection line 8a. On the other hand, in the pixel row 11b arranged along the direction from the center position C1 of the photographed image P1 toward the right side of the drawing, the luminance value of three of the five pixels is 20, so that the line recognition unit 8 is the non-light reflection line 8b. It has come to be certified.

  When the line recognizing unit 8 recognizes the light reflecting line 8a and the non-light reflecting line 8b, as shown in FIGS. 5 (b) and 6 (b), the light is displayed on the screen displaying the photographed image P1. Auxiliary lines respectively corresponding to the reflection line 8a and the non-light reflection line 8b are displayed in an overlapping manner, so that the operator can visually recognize the light reflection line 8a and the non-light reflection line 8b. It has become.

Then, the control board 5 includes a determination unit 9 the presence or absence of a problem in the bonding state of the bonding portion 10, the determination section 9, the reference value above T ₁ of the light-reflecting line 8a is predetermined in, and adapted to determine the when the non-light-reflective line 8b is a predetermined reference value T ₂ or more problems in the bonding state of the bonding portion 10 is not provided.

  Here, when the determination operation of the bonded portion 10 in a good bonded state as shown in FIG. 5A is performed, and the determination operation of the bonded portion 10 as bonded as illustrated in FIG. 6A is performed. Each case will be specifically described. Here, when the number of the light reflection lines 8a is one or more and the number of the non-light reflection lines 8b is ten or more, it is determined that the joint portion 10 is good (no problem). Then, in the photographed image P1 shown in FIG. 5B, as a result of the arithmetic processing, three light reflection lines 8a and 29 non-light reflection lines 8b are generated. It is determined that the bonding portion 10 photographed at P1 is in a good bonding state. On the other hand, in the photographed image P1 shown in FIG. 6B, since there are no light reflection lines 8a and only five non-light reflection lines 8b are generated, the determination unit 9 uses this photographed image. It is determined that the joining portion 10 of P1 has a joining failure.

  Next, specific inspection control in the bonding inspection apparatus 1 will be described based on the flowchart shown in FIG.

  First, after the work W is formed in a joining process (not shown), the manipulator 2 takes out the work W from the joining process and fixes it to the reference position B1. Thereafter, an inspection start signal is output from the manipulator 2 to the control panel 5.

  When receiving the inspection start signal from the manipulator 2, the control panel 5 proceeds to step S1 in the flowchart of FIG. In this step S1, a photographed image P1 is obtained by photographing the work W fixed at the reference position B1 with the CCD camera 3. After obtaining the photographed image P1, the process proceeds to step S2, and one joint portion 10 to be inspected is selected from the seven joint portions 10 in the photographed image P1.

Next, in step S3, based on the photographed image P1, first, in the pixel group between the inner boundary circle 6a and the outer boundary circle 6b set in advance, the pixel row extraction unit 6 extends along the radial direction of the joint portion 10. A plurality of pixel rows 11 arranged in a line are extracted at a predetermined interval around the center position C1, and then the luminance values of the pixels in the extracted pixel rows 11 are calculated in the calculation unit 7. Then, the line discriminating section 8, in the respective pixel column 11, while certified as having pixel is a predetermined value Z ₁ or more luminance values predetermined value X ₁ or the light reflection line 8a, a predetermined value Z ₂ following luminance certified as having a pixel is a value predetermined value X ₂ or a non-light reflective line 8b.

Thereafter, the process proceeds to Step 4, whether or not the light reflection line 8a is a predetermined reference value above T ₁ determination unit 9 determines.

When the determination at step 4 is NO, that, when the determining unit 9 light reflection line 8a is not the predetermined reference value above T ₁ is determined, the process proceeds to step S9, the control panel 5, not shown production After outputting the production line stop signal to the main control unit of the line, the process proceeds to step S10 to display a warning on a display monitor (not shown).

On the other hand, when the determination in step S4 is YES, i.e., when the determination unit 9 light reflection line 8a is a predetermined reference value above T ₁ is determined, the process proceeds to step S5, the non-light-reflective line 8b is predetermined determination unit 9 determines whether a reference value T ₂ greater than or equal to a.

When the determination in step S5 is NO, that is, when the determination unit 9 non-light-reflecting line 8b is not the predetermined reference value T ₂ or more is determined, the process proceeds to step S9, the control panel 5, not shown After outputting the production line stop signal to the main control unit of the production line, the process proceeds to step S10 to display a warning on a display monitor (not shown).

On the other hand, when the determination in step S5 is YES, i.e., when the determination unit 9 and the non-light-reflective line 8b is a predetermined reference value T ₂ or more is determined, the process proceeds to step S6, inspection judging unit 9 is other It is determined whether or not there is a joint 10 that has not been performed.

  When the determination in step S6 is NO, that is, when the determination unit 9 determines that there is no other joint 10 that has not been inspected, the process proceeds to step S7, and the control panel 5 controls the main control unit of the production line (not shown). After outputting a signal for continuing the production line, the process proceeds to step S8 to display on the display monitor (not shown) that there is no problem with the workpiece W.

  On the other hand, when the determination in step S6 is YES, that is, when the determination unit 9 determines that there is another joint 10 that has not been inspected, the process returns to step S2 to select the joint 10 to be inspected next.

  As described above, according to the embodiment of the present invention, a large number of protrusions extending in a circular shape around the center position C1 are formed on the surface of the joint 10 that is well joined in the friction stir spot joining. 10 When the surface is irradiated with light, a linear portion (light reflection line 8a) that irregularly reflects along the radial direction of the joint portion 10 by each of the projections, and a dark portion (non-reflective) along the radial direction of the joint portion. A light reflection line 8b) is generated respectively. Therefore, when the junction 10 is photographed from the surface side by the CCD camera 3, the junction state of the junction 10 is quantitatively grasped by examining the number of light reflection lines 8a or non-light reflection lines 8b in the photographed image P1. be able to. Moreover, since it is not necessary for the operator to visually inspect the bonded portion 10 after bonding, the bonded portion 10 can be efficiently inspected without increasing the operator's work load.

  In addition, since the pixels corresponding to the center position C1 of the joint portion 10 in each captured image P1 captured by the CCD camera 3 always have the same coordinates, the pixel row 11 for identifying the light reflection line 8a or the non-light reflection line 8b. Is extracted, it is not necessary to set the center position C1 of the joint 10 manually or with complicated image processing, and the inspection speed can be increased.

  In the embodiment of the present invention, the CCD camera 3 is used for shooting an area including a plurality of joints 10 of the workpiece W. However, a CMOS camera may be used for shooting.

  In the embodiment of the present invention, one light source 4 is arranged around the CCD camera 3, but the present invention is not limited to this, and two or more light sources 4 may be arranged.

  INDUSTRIAL APPLICABILITY The present invention is suitable for a joining inspection apparatus that inspects a joining state of a joint portion by friction stir spot joining.

1 Bonding inspection device 2 Manipulator (work fixing means)
3 CCD camera 4 Light source 5 Control panel (inspection means)
6 Pixel column extraction unit 7 Calculation unit 8 Line recognition unit 9 Judgment unit 10 Joint unit 11 Pixel row B1 Work reference position P1 Captured image C1 Center position of joint W Work

Claims (2)

A camera that shoots a circular joint applied to the workpiece by friction stir spot welding from the surface side;
A light source disposed on the side of the camera and irradiating the joint surface with light;
An inspection unit that is connected to the camera and inspects the bonding state of the bonding portion based on a photographed image of the bonding portion surface photographed by the camera;
The inspection means includes a pixel column extraction unit that extracts a plurality of pixel columns arranged in a line along the radial direction of the joint in the photographed image at a predetermined interval around the center of the joint; a calculation unit for respectively processing the luminance value of each pixel in the pixel column in each pixel column, while recognized as light reflection line which has a predetermined value X ₁ or more pixels is a predetermined value Z ₁ or more luminance values , a line discriminating section that identified as non-light reflecting line having a pixel is a predetermined value Z ₂ following luminance values predetermined value X ₂ or more, in the number of the light-reflecting lines predetermined reference value above T ₁ and, joining the inspection, characterized by comprising a said non-light-reflecting determination section that there is no problem in the bonding state number is located when the joint with a predetermined reference value T ₂ or more lines apparatus. In the joining inspection apparatus according to claim 1,
A workpiece fixing means for fixing the workpiece to a reference position separated from the camera by a predetermined distance so that a distance between each joint and the camera is constant for each imaging when the workpiece is photographed by the camera; Prepared,
The bonding inspection apparatus, wherein the camera is configured to shoot with a fixed focal length for each bonding portion for each shooting.