JP4974019B2 - Solder defect inspection device - Google Patents

Description

  The present invention relates to a solder failure detection device that detects a soldering failure of a printed circuit board on which components are soldered.

  Patent Document 1 discloses an illumination device that irradiates a proof in a direction intersecting with a longitudinal direction of a soldering portion of each pin of a surface mount component including a large number of pins mounted on a printed circuit board, and the printed circuit board. A camera for picking up an image of a soldering portion of each pin of the surface mount component that is disposed above and irradiated with the certification, and soldering of each pin of the surface mount component based on image data output from the camera Depending on the brightness of the image. A printed circuit board solder defect inspection apparatus including an arithmetic processing control apparatus for determining a soldering defect is disclosed.

Patent Document 2 is a printed circuit board inspection apparatus that inspects the surface state of each printed circuit board that is continuously carried in, a sensor head that is disposed opposite to the printed circuit board and detects the displacement amount of the protrusion on the printed circuit board, Disclosed is a statistical processing means for statistically processing a variation in the displacement amount of the protrusion relating to the same region output from the sensor head for a plurality of printed circuit boards to be inspected continuously. The sensor head detects and outputs the height of the solder protrusion on the printed circuit board as a displacement amount while moving and scanning in the vertical and horizontal directions on the printed circuit board by the X-axis moving unit and the Y-axis moving unit. is there. In addition, the statistical processing means calculates the average of the height of the solder for each area from the output of the sensor head position and displacement amount, and the average value of the height exceeds the preset setting range for each area The solder formation height is judged to be defective, and alarm data is output to the preceding solder printer.
Japanese Patent Laid-Open No. 11-6718 JP 2001-153646 A

  The printed circuit board solder defect inspection apparatus disclosed in Patent Document 1 illuminates a large number of soldering portions mounted on the printed circuit board, and images an image of the soldering portions irradiated with the illumination with a camera. Although it is for discriminating a soldering failure, since it is necessary to illuminate each one of the parts and take an image, not only the inspection work becomes very complicated, but also when there are high parts, There is a problem that the work becomes difficult due to the shadow of the lighting.

  In the printed circuit board inspection apparatus disclosed in Patent Document 2, since it is necessary to detect the height of the protrusion of the printed circuit board solder as a displacement amount by the sensor head, when inspecting the soldering of the lower surface of the printed circuit board, the solder bath It is necessary to inspect the printed circuit board sent out from the inside out. However, when the printed circuit board is turned upside down due to the height of the parts mounted on the upper surface of the printed circuit board, the bottom surface of the printed circuit board does not become a certain height. The problem that occurs.

  In addition, in an inspection apparatus that inspects a soldering failure of a printed circuit board after the solder tank, it is desirable that the printed circuit board is sent in the vicinity of the downstream side of the solder tank and immediately inspected in an image from below the printed circuit board. It is desirable to inspect without stopping the flow of the printed circuit board delivered from the solder bath.

  Therefore, the present invention provides a solder defect inspection apparatus that can be located in the vicinity of the downstream side of the solder bath and can perform a soldering defect inspection of a printed circuit board without stopping the flow of the printed circuit board. It is in.

  Therefore, the solder defect inspection apparatus according to the present invention is located on a carrying path where a printed board sent from a solder bath for performing a soldering process is carried, and extends perpendicularly to the carrying direction of the printed board, An imaging slit having a predetermined width in the transport direction of the printed circuit board, an imaging light source disposed near the imaging slit, and the print positioned below the imaging slit and passing over the imaging slit Reflecting means for reflecting an image of the soldered surface of the board in a predetermined direction, a camera for taking an image reflected by the reflecting means, and the printed board based on printed board image data output from the camera It comprises soldering failure detection means for detecting the soldering state of the lower surface.

  Further, the soldering failure detecting means includes an end face detecting means for detecting one end face in the traveling direction of the printed board, and a printed board within a range within a preset distance from the one end face detected by the end face detecting means. Recognition mark searching means for searching for a recognition mark provided on the correction mark, and correction means for calculating an error between the position of the recognition mark searched by the recognition mark searching means and the reference position of the recognition mark and correcting the printed circuit board image And an inspection unit that performs short determination of a soldering location based on the printed circuit board image corrected by the correction unit.

Further, the inspection means, inspection area setting means for setting a soldering inspection area of the corrected printed circuit board image, binarization means for binarizing the inspection area set by the inspection area setting means, The number of independent areas in the area is counted based on the image binarized by the binarization means, and this number is compared with a preset number, and the soldering state of this area is normal. And determining means for determining whether or not.

  Therefore, according to the present invention, when the printed circuit board sent out from the solder bath passes through the imaging slit, it is possible to sequentially take images of the lower surface of the printed circuit board through the camera and use the reflecting mirror. As a result, the position of the camera can be arranged at a position away from the solder bath and the printed circuit board heated by the solder bath, so that the thermal influence on the camera can be prevented. In addition, since the camera is not located directly under the printed circuit board, it is possible to prevent the lens from being contaminated by residues such as flux falling from the printed circuit board.

  For the input image, one end of the traveling direction, for example, the left end of the image is detected, and the recognition mark provided on the printed circuit board is searched for within a predetermined distance from this end. Therefore, the search for the recognition mark is facilitated, and the workability is improved.

  Furthermore, since the printed circuit board image is corrected by calculating the error between the position of the detected recognition mark and the reference position, it is possible to easily correct the front and back warpage, the left and right warpage, etc. of the printed circuit board. Therefore, it is easy to set a soldering inspection area (a group of parts to be soldered), and workability is improved.

Furthermore, binarizes the soldering inspection area, only counts the number of independent regions in the examination region, it is possible to identify the presence or absence of short locations, performing Ku efficiency good judgment work soldering defective portion Is possible.

  Embodiments of the present invention will be described below with reference to the drawings.

  For example, as shown in FIGS. 1A and 1B, the solder defect inspection apparatus 1 according to the present invention is located downstream of the solder bath 2 and is soldered in the solder bath 2 and guided by the guide rail 3. An imaging slit 5 extending perpendicularly to the passing direction of the printed board 4 and having a predetermined width in the passing direction of the printed board 4 and a pair of imaging slits disposed on both sides of the imaging slit 5 A light source (LED illumination) 6, a reflector 7 that is positioned below the imaging slit 5 and that solders the printed circuit board 4 that passes through the imaging slit 5 and reflects an image of the lower surface in a horizontal direction; A camera 8 that captures the lower surface image of the printed circuit board 4 reflected by the reflecting plate 7, and a control unit (C / U) 9 that processes a printed circuit board lower surface image signal that is captured and output by the camera 8. At least constituted by. 4a indicates the upper surface of the printed circuit board 4, and 10 indicates components disposed on the upper surface.

  An example of the soldering failure detection executed in the control unit 9 is shown in the flowchart of FIG. Hereinafter, description will be given along a flowchart of detection of defective soldering.

  In the soldering failure detection started from step 100, image data of the lower surface 4b of the printed circuit board 4 output from the camera 8 in step 110 is input. This image data is schematically shown in FIG.

In step 120, the front end (left end) 40 in the traveling direction is detected in the image data of the lower surface 4b of the printed circuit board 4. In step 130, areas 43 and 44 located at a predetermined distance from the end portion 40 are searched to detect the recognition marks 41 and 42. At this time, since the areas 41 and 42 set at predetermined positions from the left end 40 are searched, the search time for the recognition marks 41 and 42 can be shortened.

  In step 140, it is determined how much the distance L in the longitudinal direction and the distance W in the width direction between the recognition marks 41 and 42 are different from the actual distance (reference position). 4 is detected, and the image data is corrected. Specifically, when the distance L in the longitudinal direction is shorter than the actual distance L ′, it can be seen that warping has occurred in the longitudinal direction, so that the image data is enlarged by L ′ / L in the longitudinal direction. to correct. Similarly, if the distance W in the width direction is shorter than the actual distance W ′, it can be seen that a warp has occurred in the width direction, so that the image data is corrected to be expanded by W ′ / W in the width direction. .

  In step 150, an inspection area is set. In this embodiment, an area 50 is set as the first inspection area, and this area 50 is binarized in step 160. Thus, for example, when there is no short at the soldering location, as shown in FIG. 4A, the number of independent regions of the binarized video (in this case, 8) is set as the solder. Since the number of attachments (8) matches, it is determined in step 170 that the soldering is normally performed. On the other hand, as shown in FIG. 4B, when there is a short at the soldering location, the number of independent regions of the binarized video (in this case, there are 7 short locations 61; ) And the set number (8) of soldering are different, it is determined in step 170 that a short circuit exists.

  Then, in step 180, it is determined whether or not to continue, and if it is determined to continue (Y), the next inspection area 51 is set, and the inspection process 200 configured by steps 150 to 170 is performed in the same manner. In the determination of step 180, the inspection process 200 is continuously performed in succession with the inspection regions 52 and 53 until it is determined not to continue (N).

  The soldering information detected by the above soldering inspection is displayed on the screen, and it is possible to identify the abnormal part (short), and the defective part of the printed circuit board is corrected by the subsequent soldering correction work. It is. Also, by accumulating soldering information, it is possible to analyze the tendency of solder defects in the solder bath, etc., and further send the soldering information to the design department through a predetermined communication means. It can be used for design changes, component placement changes, and the like.

It is a schematic block diagram of the solder defect inspection apparatus which concerns on the Example of this invention, (a) is a side view, (b) is a top view. It is the flowchart figure which showed an example of the solder defect inspection which concerns on the Example of this invention. It is explanatory drawing which showed the example of the printed circuit board image. (A) is explanatory drawing of the binarized image which showed the normal soldering state, (b) is explanatory drawing of the binarized image containing a short circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solder defect inspection apparatus 2 Solder tank 3 Guide rail 4 Printed circuit board 4a Upper surface 4b Lower surface 5 Imaging slit 6 Illumination 7 Reflecting plate 8 Camera 9 Control unit

Claims (2)

An image pickup having a predetermined width in the transport direction of the printed circuit board, which is positioned on a transport path for transporting the printed circuit board sent from the solder tank for performing the soldering process, extends perpendicularly to the transport direction of the printed circuit board An image of a soldered surface of the printed circuit board that is positioned below the imaging slit and passes over the imaging slit, and is provided with a predetermined slit, an imaging light source disposed in the vicinity of the imaging slit, Reflection means that reflects in the direction, a camera that captures an image reflected by the reflection means, and soldering failure detection that detects the soldering state of the lower surface of the printed circuit board based on printed circuit board image data output from the camera In a solder defect inspection apparatus comprising means,
The soldering failure detection means is provided on the printed circuit board within a range within a preset distance from one end face detected by the end face detection means, and an end face detection means for detecting one end face in the printed board traveling direction. a recognition mark search means for probing the recognition mark, a correction means for an error between the actual distance and the distance between the recognition marks probed by the identification mark search means calculates, corrects the PCB image, the corrected An inspection device for inspecting a state of a soldering part based on a printed circuit board image corrected by the means, and a solder defect inspection device. The inspection means includes an inspection area setting means for setting a soldering inspection area of the corrected printed circuit board image, a binarization means for binarizing the inspection area set by the inspection area setting means, Based on the image binarized by the binarization means, the number of independent regions in the region is counted, and this number is compared with a preset number to determine whether the soldering state of this region is normal. determining means and solder defect inspection apparatus according to claim 1, characterized in that it is constituted by one.

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