JP2008304336A - Inspection method of coated metal plate and inspection device of coated metal plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection method of a coated metal plate for certainly detecting the flaw of the insulating coating film, which is formed on the surface of a metal plate run continuously in its plate length direction without omission to specify a flaw occurring region without damaging the coating surface of the metal plate, and to provide an inspection device of the coated metal plate advantageously used in the inspection method of the coated metal plate. <P>SOLUTION: In a state that a plurality of conductive brushes 34, each of which is obtained by implanting a large number of amorphous metal fibers 44 in a longitudinal metal holder 46, are arranged in the plate width direction of a running metal plate 32 to be brought into contact with the whole width of a coating film formed region, DC voltage with below dielectric breakdown voltage is applied across a plurality of the conductive brushes 34 and the metal plate 32. On the basis of the obtained respective current values, the flaw of the coating film is detected while the conductive brush 34 which detects the flaw of the coating film is specified. Further, the flaw occurring region of the coating film is calculated from the arranging position of the specified conductive brush 34. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inspection method for a coated metal plate and a method for detecting the defect of an insulating coating film formed on the surface of a metal plate continuously running in the plate length direction using a conductive brush. The present invention relates to a coating metal plate inspection apparatus which is advantageously used.

  Conventionally, aluminum alloy plates (including aluminum plates) used for can end materials, fin materials, etc. are pre-coated with vinyl chloride, epoxy, acrylic, etc. The paint is applied and the insulating coating is pre-coated uniformly, but sometimes the insulating coating has scratches, pinholes, and parts that are thinner than the intended thickness. Minor coating film defects such as occurrence may occur.

  Such a defect causes corrosion even if it is minute, and causes a quality problem in products such as beverage cans and heat exchangers in which can end materials, fin materials, and the like are used. For this reason, before shipping a coated metal plate such as a can end material or a fin material, it is necessary to inspect a coating film defect in advance to identify a site where the defect occurs.

  However, it was difficult to inspect the entire width of the aluminum plate that can be continuously run in the plate length direction on the mass production line under the running state, that is, online. For can end materials, the enamellator method (ERV inspection) is performed offline. Such an enamellator method is a test in which an object to be a positive electrode is immersed in an electrolytic solution for inspection, and therefore, a sampling inspection in which a part of a coated metal plate is extracted and inspected, and coating film defects cannot be reliably detected. Such problems are inherent. In addition, a method (optical inspection) for optically inspecting the entire width of the aluminum plate by visual inspection or detecting reflected light reflected from the surface of the coated metal plate is also performed. With this method, it is difficult to detect minute coating film defects of several hundred μm or less depending on the coating color, and it is impossible to detect coating film defects on coated metal plates that run at high speed on the line. Met.

  As another method for inspecting coating film defects, a conductive brush is brought into contact with the painted surface, a high voltage is applied between the conductive brush and the subject, and the coating film defects are determined based on the current value. A method of inspection has been developed. For example, Patent Document 1 proposes a defect inspection apparatus for an inner surface organic coating layer of a seamless metal can coated with an organic coating layer so that a defect of an inner surface organic coating layer of a metal can can be automatically inspected at high speed. It has become. However, in this case, a conductive brush using a conductive short fiber in which a nylon-carbon composite film is combined with a nylon fiber (for example, φ: 0.15 mm) is used, so it can be said that it is flexible. In addition, the resistance of the brush element itself is high, and therefore, there is a drawback that the painted surface is easily scratched, and it is necessary to set the applied voltage high (usually 800 to 1000 V), which is safe. The above problem is also inherent.

  Furthermore, Patent Document 2 proposes a defect detection method for an inner surface coating of a metal container that detects a defect of an insulating coating applied to the inner peripheral surface of the metal container, in which a conductive liquid is used. Therefore, the voltage applied between the conductive brush and the metal container can be set to a low voltage (5 to 30 V). However, since such a method needs to supply a conductive liquid, it is difficult to apply it to a plate-like object traveling on a line.

  In addition, Patent Document 3 discloses a method in which a sealed container formed of a non-conductive material such as a resin and filled with contents is used as a subject, and the subject is inspected while being transported by a transporter. It has been revealed. There, a conductive brush is proposed in which an amorphous metal fiber having a wire diameter of several tens to 100 microns is densely fixed in a linear bundle brush shape as an electrode contact element on a metal holder. . By adopting such an amorphous metal fiber, the resistance of the brush element itself is lower and the applied voltage can be set lower than when using the conductive nylon fiber as described above, but the applied voltage can be reduced. There is still room for improvement from the viewpoint of preventing scratches and detecting defects in defects. Further, as in Patent Document 3, when inspecting a specimen such as an individually sealed container, it is possible to remove the specimen in which a coating film defect is detected by removing it as it is. However, when inspecting a long coated metal plate that can be continuously run in the plate length direction on a mass production line, even if a coating film defect is detected, it is substantially impossible to remove such a defect at any time. Therefore, it is necessary not only to detect the presence / absence of a coating film defect, but also to identify the site where the coating film defect occurs.

Japanese Patent Laid-Open No. 6-74941 JP 2000-46776 A Registered Utility Model No. 3047854

  Here, the present invention has been made in the background of such circumstances, and the problem to be solved is an insulation formed on the surface of a metal plate that is continuously run in the plate length direction. A method for inspecting a coated metal plate that does not damage the coated surface of the metal plate, and a method for inspecting the painted metal plate, as well as reliably detecting defects in the adhesive coating film without omission and specifying the defect occurrence site An object of the present invention is to provide an inspection apparatus for a coated metal plate that is advantageously used.

  And in order to solve this problem, the gist of the present invention is to inspect a coated metal plate that inspects an insulating coating film formed on the surface of a metal plate that is continuously run in the plate length direction. In this case, a plurality of amorphous metal fibers having a diameter of 10 to 100 μm are integrally implanted in a longitudinal metal holder as a conductive brush, and are closely positioned in the longitudinal direction of the metal holder. The extending rows of the amorphous metal fibers are arranged in parallel in 3 to 6 rows in the width direction of the metal holder, and the protruding length of each amorphous metal fiber constituting each row is 10 to 50 mm. A plurality of the conductive brushes are arranged in the plate width direction so that each longitudinal direction thereof is the plate width direction of the metal plate, and the coating film on which the insulating coating film of the metal plate is formed Of the formation site A DC voltage less than the dielectric breakdown voltage of the insulating coating film is applied between each of the plurality of conductive brushes and the metal plate in a state of contact with the width, and Based on the current value, the coating film defect of the metal plate is detected, the conductive brush that has detected the coating film defect is specified, and the coating on the metal plate is further determined from the location of the specified conductive brush. The present invention relates to a method for inspecting a coated metal plate, which is characterized by obtaining an occurrence site of a film defect.

  According to one of the preferred embodiments of the method for inspecting a coated metal plate according to the present invention, the amorphous metal fibers have a pitch of 10 to 100 μm in the width direction of the metal holder, and the amorphous metal fibers. It is planted at a pitch more than the diameter.

  According to another preferred embodiment of the method for inspecting a coated metal plate according to the present invention, the plate is formed so that an angle formed by the conductive brush and the painted surface of the metal plate is 30 to 80 °. The conductive brush is brought into contact with the coating surface in a posture in which the conductive brush is inclined backward with respect to the traveling direction of the metal plate that is caused to travel in the long direction.

  Furthermore, according to one of the desirable aspects in the inspection method of the coated metal plate according to the present invention, the length in the longitudinal direction of the conductive brush is 50 to 400 mm, and a plurality of such conductive brushes are the plate of the metal plate. It is arranged in a staggered pattern in the width direction.

  In addition, according to one of the other preferable aspects of the method for inspecting a painted metal plate according to the present invention, a plurality of the conductive brushes arranged in the plate width direction of the metal plate are each a plate of the metal plate. The overlapping in the width direction is arranged to be 10 mm or less.

  According to another preferred aspect of the method for inspecting a coated metal plate according to the present invention, the applied voltage is set to 30 to 500 V, while the metal plate is run at a speed not exceeding 300 m / min. In this case, the inspection is performed.

  Furthermore, according to one of the other desirable embodiments in the method for inspecting a coated metal plate according to the present invention, the coating plate defect of the metal plate is detected and the conductive brush from which the coating film defect is detected is disposed. An alarm device that informs that there is a coating film defect and / or an output device that outputs position information of the coating film generation site is activated when the coating film defect occurrence site is obtained. Yes.

  In addition, according to another preferred aspect of the method for inspecting a coated metal plate according to the present invention, the insulative coating is continuously performed in the coating means provided on the upstream side in the traveling direction of the metal plate. The coating is performed on the painted surface of the metal plate on which the film has been coated and cured, and a plurality of the conductive brushes are arranged close to / separated from the metal plate based on the painting signal and the speed signal from the painting means. The conductive brush contacts only the coating film forming part of the metal plate, and the conductive brush does not contact the metal base part of the metal plate where the insulating coating film is not formed. Composed.

  And in this invention, (A) It is an inspection apparatus of the coated metal plate which inspects the insulating coating film formed on the surface of the metal plate continuously run in the plate length direction, and (B) the diameter is A row of amorphous metal fibers extending in close contact with the longitudinal direction of a metal holder, wherein the amorphous brush is integrally implanted with a plurality of amorphous metal fibers of 10 to 100 μm in a long metal holder. Are arranged in parallel in 3 to 6 rows in the width direction of the metal holder, and a plurality of conductive brushes in which the protruding length of each amorphous metal fiber constituting each row is 10 to 50 mm, and (C ) A plurality of such conductive brushes are arranged in the plate width direction such that the respective longitudinal directions are in the plate width direction of the metal plate, and the coating film is formed with the insulating coating film on the metal plate. Touch the full width of the part Or a conductive brush moving means for separating from the metal plate, and (D) a plurality of the conductive brushes in contact with the entire width of the coating film forming portion of the metal plate. Applying means for applying a DC voltage lower than the dielectric breakdown voltage of the insulating coating film between each of the conductive brushes and the metal plate, and (E) applying the voltage by the applying means, Based on each current value flowing between each and the metal plate, the coating plate defect of the metal plate is detected, the conductive brush that has detected the coating film defect is specified, and the specified conductivity is further determined. A coating metal plate inspection device characterized by comprising a coating film defect detecting means for determining a coating film defect occurrence site in the metal plate from the position where the conductive brush is disposed. It is.

  According to one of the preferred embodiments of the coated metal plate inspection apparatus according to the present invention, the amorphous metal fibers have a pitch of 10 to 100 μm in the width direction of the metal holder, and the amorphous metal fibers. It is planted at a pitch more than the diameter.

  Moreover, according to one of the other preferable aspects of the inspection apparatus of the coated metal plate according to this invention, the dimension of the longitudinal direction of the said electroconductive brush shall be 50-400 mm, and several of this electroconductive brush is the said metal plate. Are arranged in a staggered pattern in the plate width direction.

  Furthermore, according to one of the desirable aspects of the inspection apparatus of the coated metal plate according to the present invention, a plurality of the conductive brushes arranged in the plate width direction of the metal plate are respectively in the plate width direction of the metal plate. The overlapping is arranged to be 10 mm or less.

  In addition, according to one of the other preferable aspects of the inspection apparatus for a coated metal plate according to the present invention, a coating unit is provided on the upstream side in the traveling direction of the metal plate, and the conductive brush moving unit is provided with the coating unit. It is comprised so that it may act | operate based on the painting signal and speed signal from.

  Moreover, according to another preferable aspect of the inspection apparatus for a coated metal plate according to the present invention, limiter means for limiting application of the voltage is further provided.

  Furthermore, according to one of the other desirable modes of the coated metal sheet inspection device according to the present invention, the alarm device for notifying that there is a coating film defect and / or the position information of the occurrence site of the coating film defect is output. An output device is further provided.

  As described above, in the method for inspecting a coated metal plate according to the present invention, as a conductive brush, (1) a plurality of amorphous metal fibers having a diameter of 10 to 100 μm are integrally implanted in a long metal holder. (2) Three to six rows of amorphous metal fibers extending closely in the longitudinal direction of the metal holder are arranged in parallel in the width direction of the metal holder, and (3) each of them. From the place where the projection length of each amorphous metal fiber constituting the row is 10 to 50 mm, the waist or flexibility of the conductive brush becomes appropriate, and the plate length direction is continuously Even if it is brought into contact with the painted surface of the metal plate that is allowed to run, the tip of the conductive brush does not lift up from the painted surface and the tip of the conductive brush breaks effectively. result In addition, even a minute coating film defect can be reliably detected with high reproducibility and without leakage, and it can be advantageously prevented that the painted surface is damaged. It is.

  In addition, as described above, as the conductive fiber constituting the conductive brush, an amorphous metal fiber having a low electrical resistance compared to a conductive resin fiber to which a conventional conductive coating or the like has been applied is adopted, Since the protruding length of each amorphous metal fiber is a relatively short length (10 to 50 mm), the electrical resistance of the entire conductive brush can be reduced, and the applied voltage can be set low. As a result, safety for workers can be advantageously ensured.

  Furthermore, in the method of the present invention, a plurality of conductive brushes as described above are arranged in the plate width direction so as to cover the entire width of the coating film formation site, and the tips of the conductive brushes are formed on the coating film. In the state where it is in contact with the part, a direct current voltage less than the dielectric breakdown voltage of the insulating coating film is applied between each of the plurality of conductive brushes and the metal plate. The current value flowing between the metal plate and the metal plate can be measured, the current state of each conductive brush can be determined from each current value, and the coating film defect can be detected in the entire width of the coating film formation site. Is possible. Moreover, in the method of the present invention, the conductive brush in which the coating film defect is detected is specified, and the occurrence site of the coating film defect in the plate width direction of the metal plate is obtained from the specified conductive brush arrangement position. Can do.

  Therefore, according to the method of the present invention, the defect of the insulating coating film formed on the surface of the metal plate continuously running in the plate length direction is reliably detected without leakage, and the defect occurrence site is specified. It is possible to advantageously prevent damage to the painted surface of the metal plate.

  Further, even in the inspection apparatus for a coated metal plate according to the present invention, since the conductive brush as described above is used, it is brought into contact with the painted surface of the metal plate that is continuously run in the plate length direction. However, it is also effectively eliminated that the tip of the conductive brush does not float from the coating surface, and the tip of the conductive brush breaks. In addition to being able to reliably detect without reproducibility, it is also possible to advantageously prevent scratches on the painted surface. In addition, the electrical resistance of the entire conductive brush can be reduced, and the applied voltage can be set low, thereby ensuring safety for the operator.

  Furthermore, the inspection apparatus for a coated metal plate according to the present invention includes a plurality of conductive brushes arranged in the plate width direction so as to cover the entire width of the coating film forming portion by the conductive brush moving means, and the conductive brush With the hair tip in contact with the coating film formation site, a DC voltage less than the dielectric breakdown voltage of the insulating coating film was applied between each of the plurality of conductive brushes and the metal plate by the applying means. And, the coating film defect detection means detects the coating film defect based on the current value flowing between each of the conductive brushes and the metal plate, and the occurrence site of the coating film defect in the plate width direction of the metal plate Therefore, coating film defects can be automatically inspected on a mass production line.

  Hereinafter, in order to clarify the present invention more specifically, a configuration of a coating metal plate inspection method and an inspection apparatus according to the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 schematically shows an example of a coating line for an aluminum alloy sheet material in which a coating metal sheet inspection apparatus according to the present invention is incorporated. As apparent from FIG. 1, the uncoiler is applied to the coating line 12 in which the inspection apparatus 10 for a coated metal plate is incorporated from the upstream side (left side in FIG. 1) to the downstream side (right side in FIG. 1). 14, the entrance-side accumulator 16, the pretreatment device 18, the coater 20, the oven 22, the cooling device 24, the inspection device 10, the exit-side accumulator 28, and the take-up reel 30 are arranged in this order.

  The unpainted aluminum alloy plate 32 wound in a coil shape is unwound by the uncoiler 14 and then continuously traveled between the inlet and outlet accumulators 16 and 28 at a constant speed. Thus, the pretreatment device 18, the coating device 26 (coater 20, oven 22, and cooling device 24) and the inspection device 10 can be run at the same speed. And by running and passing through each of these devices, the aluminum alloy plate 32 is pretreated (degreasing, chemical conversion film treatment, water washing, drying, etc.), painting treatment (painting, baking, cooling, etc.) and coating film defects. These inspections are performed on-line, and then are wound again in a coil shape on the take-up reel 30 provided on the downstream side of the output side accumulator 28.

  Accordingly, in the coated metal plate inspection apparatus 10, the aluminum alloy plate 32 on which the coating and curing of the insulating coating film are continuously performed by the coating apparatus 26 which is a coating means provided on the upstream side is provided as a plate length. It is introduced continuously in a state where the vehicle travels in the direction (right direction in FIG. 1).

  The coating line 12 is provided with two uncoilers 14. When the winding of the coil made of the aluminum alloy plate 32 supported by one of the uncoilers is finished, the end portion of the coil and the other end of the coil are finished. The start end portion of the coil supported by the uncoiler 14 is joined and connected by a stitcher. For this reason, in the inspection apparatus 10, an extremely long coated plate is inspected. Therefore, even if a coating film defect is detected by such an inspection apparatus 10, it is substantially impossible to remove the coating film defect by stopping the coating line 12 every time the detection is performed. is there.

  Incidentally, FIG. 2 schematically shows an example of a coating metal plate inspection apparatus 10 in a state where it is incorporated in the coating line 12 as described above. As apparent from FIG. In addition, the coated metal plate inspection apparatus 10 includes a plurality of conductive brushes 34, a moving device 36 that is a conductive brush moving means for bringing the conductive brushes 34 close to and / or away from the painted surface of the aluminum alloy plate 32, and Application device 38 as an application means for applying a DC voltage between the conductive brush 34 and the aluminum alloy plate 32, and a coating film defect of the insulating coating film formed on the surface (here, the upper surface) of the aluminum alloy plate 32 And a coating film defect detection device 40 which is a coating film defect detection means for detecting.

  The inspection apparatus 10 is configured such that a tension is applied between the rolls 41 and 42 such as a deflector roll and a bridle roll, which are inspection zones, and is flattened from the coating apparatus 26 side (upstream side). The coating film defects of the insulating coating film formed on the surface of the aluminum alloy plate 32 continuously run toward the 28th side (downstream side) are continuously inspected.

  More specifically, as shown in FIG. 3, a plurality of conductive brushes 34, each of which is connected to the + terminal of the application device 38, here, five conductive brushes 34, have a plate width of the aluminum alloy plate 32. 3 in the direction (left and right direction in FIG. 3), and with respect to the full width of the coating film forming portion where the insulating coating film of the aluminum alloy plate 32 is formed (here, the full width of the upper surface of the aluminum alloy plate 32). In the contacted state, the application device 38 applies a DC voltage between each of the plurality of conductive brushes 34 and the aluminum alloy plate 32 connected to the negative terminal, and the coating film The defect detection device 40 continuously detects the coating film defect from each current value obtained by the applied voltage, specifies the conductive brush 34 in which the coating film defect is detected, and From the arrangement position of the conductive brush 34, occurrence site of coating defects also than adapted to continuously detect.

  In the present embodiment, in particular, the conductive brush 34 has low electrical resistance, good conductivity, and even if it is brought into contact with the painted surface of the traveling aluminum alloy plate 32, it floats from the painted surface. As shown in FIGS. 4 and 5, the amorphous metal fiber 44 having a high degree of resilience that is supple and soft to the extent is removed from the opening of the metal holder 46 having a U-shaped cross section (downward in the figure). Those that are erected or planted so as to protrude toward the surface are employed. As a result, the electrical resistance value of the entire conductive brush 34 can be lowered as compared with the case of using conductive resin fibers to which a conventional conductive film or the like is applied, and the applied voltage is advantageously reduced. It is possible to improve safety.

  The electrical resistance value of the conductive brush 34 decreases as the amorphous metal fiber 44 becomes thicker. However, when the wire diameter of the amorphous metal fiber 44 is increased, the waist of the conductive brush 34 becomes stronger and the painted surface is damaged. It is feared to put on. For this reason, as the amorphous metal fiber 44 constituting the conductive brush 34, it is desirable to adopt a fiber having a diameter (fiber diameter) of 100 μm or less, preferably 50 μm or less. Further, when the amorphous metal fiber 44 is too thin, the conductive brush 34 loses its waist, and cracks, fatigue deformation, etc. occur, causing detection failure of the coating film defect. Those having a diameter of 20 μm or more are preferably employed.

  Furthermore, even if it is in the protruding length of the amorphous metal fiber 44 (L in FIGS. 4 and 5), if it is too long, the tip end portion of the conductive brush 34 is liable to be cracked, resulting in detection leakage. At the same time, it is desirable that the electrical resistance of the conductive brush 34 is high, so that it is 50 mm or less, preferably 30 mm or less. If the protrusion length (L) is too short, the surface of the aluminum alloy plate 32 is wavy. When there is unevenness such as, the metal holder 46 of the conductive brush 34 may come into contact with the painted surface and damage the painted surface, so it is desirable that the thickness be 10 mm or more, preferably 20 mm or more. In addition, as long as this protrusion length (L) satisfy | fills the said range, it can be made the same length in all the amorphous metal fibers 44, or length can be changed for every fiber row 48 mentioned later.

  Further, in the conductive brush 34 of the present embodiment, the fiber array 48 composed of a large number of amorphous metal fibers 44 extending closely in the longitudinal direction of the metal holder 46 (left and right direction in FIG. 4) is a metal. In the width direction (the left-right direction in FIG. 5) of the holder 46, the holders 46 are juxtaposed so as to form 3 to 6 rows (here, 4 rows). That is, 3 to 6 amorphous metal fibers 44 are arranged in the width direction of the metal holder 46. As a result, the conductive brush 34 made of the amorphous metal fiber 44 has an appropriate waist and softness as a whole, and prevents the painted surface of the aluminum alloy plate 32 from being scratched. The aluminum alloy plate 32 that is run in the plate length direction is fitted to the painted surface, follows the shape thereof, and detection failure of coating film defects can be advantageously prevented. If the number of rows of the amorphous metal fibers 44 in the width direction of the metal holder 46 is less than 3, the bristle portion of the conductive brush 34 becomes flexible as a whole, and the hair ends (of the amorphous metal fibers 44). The tip portion is likely to spread, and detection leakage may occur. In particular, when the surface of the aluminum alloy plate 32 has irregularities, detection leakage may occur remarkably. The bristle portion of the conductive brush 34 may become hard as a whole and may damage the painted surface of the aluminum alloy plate 32.

  By the way, the conductive brush 34 is manufactured by attaching and integrating the amorphous metal fibers 44 to the metal holder 46, and a conventionally known method can be adopted as the manufacturing method. Yes, for example, in the opening of the metal holder 46 having a U-shaped cross-section, each row of fiber rows 48 having a width substantially the same as the width of the metal holder 46, using a conductive adhesive (47), By sequentially laminating a plurality of amorphous metal fibers 44 at one end in the length direction, the metal holder 46 is tightened to firmly hold the amorphous metal fibers 44 between the metal holders 46, The amorphous metal fiber 44 and the metal holder 46 can be integrated. As another method, a plurality of amorphous metal fibers 44 are bundled so as to have predetermined longitudinal dimensions and width dimensions, and then solidified using a conductive adhesive (47). The conductive brush 34 in which the amorphous metal fiber 44 and the metal holder 46 are integrated can also be formed by inserting into the opening and tightening.

  At this time, the pitch of the amorphous metal fibers 44 in the width direction of the metal holder 46 (P in FIGS. 5 and 6) is not limited, but preferably 10 to 100 μm, and the amorphous metal fibers It is desirable that the diameter is 44 or more (10 to 100 μm). The reason is that when the pitch (P) exceeds 100 μm, there is a risk of detection omission, and in manufacturing, the lower limit of the pitch is 10 μm or more and the diameter of the amorphous metal fiber 44 or more. Because. When the distance between the fibers is different in the length direction of the amorphous metal fiber 44, the pitch (P) is not the hair tip side (tip side) but the portion sandwiched by the metal holder 46 (base side). The pitch at is indicated. In addition, in FIG. 6 and the like, it should be understood that the amorphous metal fiber 44 and the conductive adhesive layer 47 are shown extremely thick in order to facilitate understanding of the structure of the conductive brush 34. is there.

  In addition, the material of the amorphous metal fiber 44 constituting the conductive brush 34 is not particularly limited as long as it is made of an amorphous conductive metal conventionally known as an amorphous metal. For example, a Co—Fe—Cr—Si—B system, a Fe—Si—B system, a Co—Fe—Si—B system, and the like can be exemplified.

  Further, the dimension (α) in the longitudinal direction (left and right direction in FIG. 4) of the conductive brush 34 is appropriately set according to the width of the painted metal plate to be inspected, and is shorter than the width of the painted metal plate. Although a thing can be used, it is desirable that it is preferably about 50 to 400 mm. When such a dimension (α) is employed, an appropriate number of conductive brushes 34 are generally arranged in the plate width direction of the aluminum alloy plate 32 having a plate width of about 900 to 2000 mm. Thus, the site where the coating film defects are generated can be advantageously specified even in the width direction. However, if the dimension (α) in the longitudinal direction of the conductive brush 34 is less than 50 mm, the number of conductive brushes 34 arranged on the painted surface of the aluminum alloy plate 32 becomes too large, and the inspection data obtained as a result. On the other hand, when the data processing exceeds 400 mm, the number of conductive brushes 34 is reduced, and the specific range of the defect occurrence portion in the plate width direction of the aluminum alloy plate 32 is increased. As a result, the identification of the defect occurrence site becomes rough and the production of the conductive brush 34 becomes difficult. The plurality of conductive brushes 34 may all have the same dimension (α), and at least one or more may have different dimensions.

  A plurality of the conductive brushes 34 as described above are arranged in the plate width direction of the aluminum alloy plate 32 and are brought into contact with the entire width of the coating formation portion of the aluminum alloy plate 32. As shown in FIG. 7, the plurality of conductive brushes 34 are arranged such that the longitudinal direction thereof is the plate width direction of the aluminum alloy plate 32. In other words, the aluminum alloy plate 32 is disposed so as to be orthogonal to the plate length direction (traveling direction) rather than parallel. In addition, the plurality of conductive brushes 34 are not arranged in parallel in the plate length direction of the aluminum alloy plate 32, but rather cover the entire width of the coating film forming portion of the aluminum alloy plate 32. It is arranged in 32 plate width directions.

  In particular, in the present embodiment, the plurality of conductive brushes 34 are not arranged in a straight line in the plate width direction of the aluminum alloy plate 32, but the adjacent conductive brushes 34 are arranged in an aluminum alloy plate 32. Here, they are arranged in a staggered manner so as to be spaced apart in the plate length direction. For this reason, the amorphous metal fibers 44 of the conductive brush 34 can be brought into contact with the entire width of the paint forming portion without any gap, and at the boundary portion of the conductive brush 34 adjacent in the plate width direction of the aluminum alloy plate 32. It is possible to advantageously prevent the detection failure of the coating film defect. In addition to arranging the plurality of conductive brushes 34 in a staggered manner, it is possible to arrange them in a staircase pattern. In this case, the conductive brushes 34 are arranged in the plate length direction. Since the range is wide, a staggered shape having a narrow arrangement range is more preferable.

  As described above, when the adjacent conductive brushes 34 are arranged in a state shifted in the plate length direction, the metal fibers 44 can be brought into contact with the entire width of the coating formation portion without any gap as described above. The detection leakage can be effectively prevented. In FIG. 7, the conductive brush 34 (CH1) and the conductive brush 34 (CH2) are arranged in the plate length direction as indicated by a one-dot chain line. When the film is overlapped, the coating film defect 50 is detected by both the conductive brush 34 (CH1) and the conductive brush 34 (CH2) when the coating film defect 50 is caused to travel in the overlapped portion. As a result, the occurrence site of the coating film defect 50 in the plate width direction is specified in a wide range. That is, the arrangement | positioning site | part of the conductive brush 34 (CH1) and the conductive brush 34 (CH2) is specified as a generation | occurrence | production site | part of the coating-film defect 50, and it cannot specify to either one. For this reason, in order to obtain | require the generation | occurrence | production site | part of the coating-film defect 50 from the conductive brush 34 which detected the coating-film defect 50, the conductive brush 34 (part of the amorphous metal fiber 44) adjacent in a plate width direction is plate-length direction. In this case, it is desirable to avoid the overlap width (W), and ideally, the overlap width (W) is preferably 0, but in reality, it is difficult to set it to 0. There may be a gap between them, which may cause detection leakage. For this reason, even if the conductive brushes 34 overlap in the plate length direction, a plurality of the conductive brushes 34 are disposed so that the width (W) thereof is 10 mm or less, more preferably 5 mm or less. In this way, it is possible to ensure a relatively high degree of accuracy in identifying the site where the coating film defect 50 occurs.

  In the present embodiment, the conductive brush 34 as described above is fixedly held on the moving device 36 as shown in FIG. The conductive brush 34 inclines backward with respect to the traveling direction (traveling direction) of the aluminum alloy plate 32 that travels in the plate length direction so that the inclination angle (θ) is about 80 °, here, about 45 °. In the posture, it is brought into contact with the painted surface of the aluminum alloy plate 32.

  More specifically, an attachment arm portion 56 for holding the conductive brush 34 is provided on a support shaft 54 that is integrally provided so as to protrude downward from the lower surface of the main body 52 of the moving device 36. The front end side (lower end side) is positioned on the traveling direction side of the aluminum alloy plate 32, and the angle between the axis of the mounting arm portion 56 and the painted surface of the aluminum alloy plate 32 is 30 to 80 °. The metal holder 46 portion of the conductive brush 34 is clamped by a grip portion 58 that is integrally provided at the tip of the mounting arm portion 56 and is fixed by screwing or bolting. As a result, the conductive brush 34 is brought into contact with the painted surface of the aluminum alloy plate 32 at a predetermined inclination angle (θ) as described above.

  Thereby, it is possible to more effectively prevent the painted surface of the aluminum alloy plate 32 from being scratched, and the conductive brush 34 can be brought into contact with the painted surface with a smaller pressure. Thus, the life of 34 can be extended. In short, when the conductive brush 34 is brought into perpendicular contact with the painted surface of the aluminum alloy plate 32, the tip portion (cut end portion) of the amorphous metal fiber 44 easily hits the painted surface, so There is a risk of scratching, and in order to more reliably prevent detection of coating film defects, the conductive brush 34 is placed on the painted surface in a state of being perpendicular to the painted surface of the aluminum alloy plate 32. When the contact length of the amorphous metal fiber 44 is increased, in other words, the tip of the conductive brush 34 is made to follow the running of the aluminum alloy plate 32, and only the tip end side of the amorphous metal fiber 44 of the conductive brush 34 is inclined. When the contact area is increased in a state where the conductive brush 34 is made, the conductive brush 34 is made larger than the case where the entire conductive brush 34 is inclined and brought into contact with the painted surface. In need of pressing the coated surface, as a result, with which may scratch the painted surface, the conductive brush 34 may become liable to fatigue deformation, its service life is likely to become shorter.

  If the inclination angle (θ) is smaller than 30 °, the contact area between the conductive brush 34 and the painted surface of the aluminum alloy plate 32 increases, but the distance between the metal holder 46 and the painted surface is short. The metal holder 46 may come into contact with the painted surface and damage the painted surface. On the other hand, when it exceeds 80 °, the above effect is reduced. For this reason, the conductive brush 34 is disposed so that the whole thereof has an inclination angle (θ) of 30 to 80 °, more preferably about 45 ° with respect to the painted surface of the aluminum alloy plate 32. It is desirable that

  Further, the contact length of the amorphous metal fiber 44 to the painted surface is not particularly limited, but in this embodiment, the contact length of the amorphous metal fiber 44 is preferably about 1 to 5 mm. The conductive brush 34 is positioned in the vertical direction so as to be about 2 to 3 mm. More specifically, a hydraulic cylinder 60 having a known structure is attached to the upper portion of the main body 52 of the moving device 36, and as the piston rod 61 projects or retracts from the hydraulic cylinder 60, FIG. As shown in FIG. 8, the conductive brush 34 can be moved downward or upward so that it can be brought into contact with or separated from the painted surface of the aluminum alloy plate 32. By adjusting the amount, the contact length of the amorphous metal fiber 44 can also be adjusted appropriately so as to be in the above range.

  Thus, even if the surface of the aluminum alloy plate 32 is undulated in the plate width direction, the amorphous metal fiber 44 is brought into contact with the painted surface with a predetermined contact length, so that the surface is even more reliable. A coating film defect can be detected.

  Incidentally, FIG. 9 schematically shows a signal system diagram in the painted metal plate inspection apparatus 10, in which the application apparatus 38 includes an AC power source 62, a rectifier 64, a booster 66, and a limiter 68. After the AC current fed from the AC power source 62 is converted into a DC current by the rectifier 64, the AC brush 62 is boosted by the booster 66 and connected to the + side. A predetermined DC voltage is applied between each of these and the aluminum alloy plate 32 connected to the negative side.

  Here, as the DC voltage applied between each conductive brush 34 and the aluminum alloy plate 32, the dielectric breakdown voltage of the normal thickness portion without the coating film defect (the minimum necessary for the dielectric breakdown of the insulating coating film). In other words, it is necessary to employ a DC voltage that can withstand the insulating coating film formed on the surface of the aluminum alloy plate 32 without being destroyed. The dielectric breakdown voltage varies depending on the type of paint, the film thickness of the coating film, the protruding length (L) of the conductive brush 34, and the like, and can be appropriately set according to them. Since the amorphous metal fiber 44 having a low electric resistance is used, a DC voltage within a range of 30 to 500 V can be applied.

  Further, the application device 38 is provided with a limiter 68 for each conductive brush 34, and when it is detected that a current exceeding a predetermined value flows between the conductive brush 34 and the aluminum alloy plate 32, The detection signal is transmitted to the booster 66 so that application of a voltage between the conductive brush 34 and the aluminum alloy plate 32 can be limited. Thereby, dielectric breakdown of the insulating coating film formed on the surface of the aluminum alloy plate 32 can be effectively prevented, damage to the product can be advantageously avoided, and safety for the operator is also advantageously secured. To be able to be. In the present embodiment, when the limiter 68 detects a current exceeding 100 to 300 μA, the booster 66 that has received the detection signal stops or temporarily applies the voltage and applies it again. ing.

  On the other hand, the coating film defect detection device 40 includes a comparator 70 and a data processing device 72. The comparator 70 measures the current value flowing between the conductive brush 34 and the aluminum alloy plate 32, and compares the current value with a reference value (threshold value for determining whether there is a coating film defect). When it is determined that there is a coating film defect, a defect signal (pulse signal in FIG. 9) indicating that there is a coating film defect is input to the data processing device 72. Such a comparator 70 is provided for each conductive brush 34, and the data processor 72 has the same number of signals (CH 1 to CHn) from the comparators 70 as the number (n) of conductive brushes 34 disposed. ) Is entered. The data processing device 72 receives a coating signal (coating roll opening / closing signal) indicating the presence or absence of coating from the coater 20 of the coating device 26 provided on the upstream side in the traveling direction of the aluminum alloy plate 32. A speed signal indicating the traveling speed of the aluminum alloy plate 32 is input from a speed detector (not shown) provided on the upstream side of the inspection apparatus 10.

  The data processing device 72 detects the coating film defect from the signals input from the plurality of comparators 70, identifies the conductive brush 34 that has detected the coating film defect, and identifies the identified conductive brush. From the position where 34 is disposed, the occurrence site of the coating film defect in the plate width direction of the aluminum alloy plate 32 is obtained. Then, when the coating film defect is detected and the generation site is obtained, the data processing device 72 sends the position information signal of the coating film generation site to the recording device 74 or the output device 76 connected to the data processing device 72. input. The recording device 74 records the position information of the coating film defect occurrence site for each conductive brush 34, and the output device 76 is directly applied to the end of the aluminum alloy plate 32 that is running in the plate length direction. The part where the coating film defect is generated is printed or marked in the form of a barcode.

  Further, the data processing device 72 introduces into the inspection device 10 a metal substrate portion where the coating film forming portion of the aluminum alloy plate 32 or the insulating coating film is not formed based on the input painting signal and speed signal. The timing to be squeezed is calculated. Then, based on the obtained calculation result, the moving device 36 connected to the data processing device 72 is operated. Specifically, when the conductive brush 34 comes into contact with the metal base portion, a large current flows between the conductive brush 34 and the aluminum alloy plate 32. The moving device 36 is operated to move the conductive brush 34 downward or upward so that the conductive brush 34 is in contact and the conductive brush 34 is not in contact with the metal base portion. The conductive brush 34 is brought into contact with or separated from the conductive brush 34.

  By the way, an aluminum alloy plate on which a coating and hardening (baking) of an insulating coating film are continuously performed on a continuous coating line 12 in which the inspection apparatus 10 for a coated metal plate having a structure as described above is incorporated. When inspecting 32 coating film defects, the operation proceeds as follows.

  That is, first, a plurality of specific conductive brushes 34 using amorphous metal fibers as described above are prepared, and they are arranged in a staggered manner in the plate width direction of the aluminum alloy plate 32, for example, as described above. It is made to contact with respect to the full width of the coating-film formation site | part formed in the upper surface of the aluminum alloy plate 32. FIG. At this time, the conductive brushes 34 are arranged so that the longitudinal direction (left-right direction in FIG. 4) is substantially coincident with the plate width direction of the aluminum alloy plate 32, and the conductive brushes 34 are applied to the coating surface. It is made to contact so that it may incline with respect to a predetermined angle. In addition, the plurality of conductive brushes 34 are brought into contact with the entire width of the coating formation site. However, when the conductive brushes 34 overhang from both ends of the coating film formation site, the tips of the conductive brushes 34 are removed. In order to prevent erroneous detection of coating film defects by coming into contact with a metal base portion without a coating film, the conductive brush should be prevented from protruding from both ends of the coating film formation site. 34 is preferably provided.

  Then, in a state where a plurality of conductive brushes 34 are in contact with the coating film forming portion of the aluminum alloy plate 32, between each conductive brush 34 and the aluminum alloy plate 32 that is continuously run in the plate length direction. The application device 38 applies a DC voltage lower than the dielectric breakdown voltage in the normal thickness portion of the insulating coating film, preferably a DC voltage in the range of 30 to 500V.

  At this time, when there is no defect in the insulating coating film, current does not substantially flow between the conductive brush 34 and the aluminum alloy plate 32, but there is a coating film defect 50 in the insulating coating film 51. As schematically shown in FIG. 10, the tip end side of the amorphous metal fiber 44 constituting the conductive brush 34 enters a minute coating film defect 50, and is between the conductive brush 34 and the aluminum alloy plate 32. Current flows. Therefore, by continuously measuring this current value with the coating film defect detection device 40, a coating film defect can be detected based on the current value. Further, by identifying the conductive brush 34 (the conductive brush 34 in which a current exceeding a predetermined threshold value has flown) in which the coating film defect is detected, the arrangement position of the conductive brush 34 in the plate width direction is obtained. The occurrence position of the coating film defect in the plate width direction is also specified in a range corresponding to the dimension (α) in the longitudinal direction of the conductive brush 34. Further, the occurrence position of the coating film defect in the plate length direction of the aluminum alloy plate 32 can be easily obtained from the speed of the aluminum alloy plate 32 (specifically, tracking of the defect position by the line speed signal).

  Here, the speed of the aluminum alloy plate 32 (the line speed between the inlet / outlet accumulators 16 and 28 in the coating line 12) can be set as appropriate. Preferably, the aluminum alloy plate 32 is preferably 300 m / min. From the point that the leading end portion of the amorphous metal fiber 44 cannot enter and detection leakage occurs or the coating film is easily damaged by friction or the like. It is desirable to drive at a speed not exceeding min (0 to 300 m / min or less).

  Thus, when a coating film defect of the aluminum alloy plate 32 is detected and a site where the coating film defect is generated is obtained, a position information signal of the coating film defect generation site is connected to the data processing device 72. 74 and the output device 76. And the detection data which show the positional information on the site | part which a coating-film defect generate | occur | produces are recorded on the recording device 74. FIG. Further, the output device 76 is also actuated to print or mark the position information of the site where the coating film defect is generated directly on the end of the aluminum alloy plate 32 that is running in the plate length direction. As a result, every time a coating film defect is detected, even if the coating film defect cannot be removed at any time, the coating film defect detection data and aluminum recorded in the recording device 74 at the time of cutting the coated metal plate, etc. By confirming the mark 78 printed on the end portion of the alloy plate 32, the defect occurrence site can be easily grasped. The product can be manufactured.

  By the way, as described above, the aluminum alloy plate 32 to be inspected was wound in a part of the plate length direction in the coiled aluminum alloy plate 32 and another coil shape. Although there exists a connecting portion that joins and connects the starting end portion of the aluminum alloy plate 32, such a connecting portion is usually not coated in order to prevent damage to the coater roll of the coater 20. For this reason, when the conductive brush 34 is held in contact with the coating film forming part of the aluminum alloy plate 32, the conductive brush 34 comes into contact with the metal base part where the insulating coating film is not formed. It will end up. Therefore, in the present embodiment, the timing at which the metal base portion such as the connecting portion passes through the inspection apparatus 10 based on the painting signal and the speed signal from the upstream side of the line is the data processing apparatus of the coating film defect detection apparatus 40. 72 is calculated. Then, the moving device 36 is operated according to the calculation result, and the plurality of conductive brushes 34 are separated from the aluminum alloy plate 32. Then, when the metal substrate portion passes, the moving device 36 is activated again, and a plurality of conductive brushes 34 are brought into contact with the painted surface of the aluminum alloy plate 32.

  As described above, in the present embodiment, a plurality of the conductive brushes 34 are brought close to / separated from the aluminum alloy plate 32 based on the painting signal or the line signal, and the insulating coating film of the aluminum alloy plate 32 is formed. The conductive brush 34 is brought into contact only with the formed portion, and the conductive brush 34 is prevented from coming into contact with the metal base portion of the aluminum alloy plate 32 where the insulating coating film is not formed.

  The inspection of the coated metal plate as described above is continuously performed until the coating line 12 is stopped. In addition, when the inspection is continuously performed for a long time in this way, the tip of the conductive brush 34 (the tip of the amorphous metal fiber 44) brought into contact with the aluminum alloy plate 32 becomes wax. It may become dirty by etc. This dirt lowers the conductivity of the conductive brush 34, destabilizes the output, and may further contaminate the coating film. Therefore, when the coating line 12 is stopped, the conductive brush 34 is regularly provided. Is preferably washed with a solvent such as hexane.

  The exemplary embodiments of the present invention have been described in detail above. However, the embodiments are merely examples, and the present invention is limited in any way by specific descriptions according to such embodiments. It should be understood that it is not interpreted.

  For example, in the above example, an aluminum alloy plate is exemplified as the metal plate. However, the material is not limited to the aluminum alloy as long as it is a plate material made of a conductive metal material. The present invention can be applied to plate materials made of various metals such as steel.

  In the above example, the five conductive brushes 34 are installed in the width direction of the aluminum alloy plate 32. However, the number of the conductive brushes 34 is not limited in any way. It can be appropriately set according to the dimension (α) in the longitudinal direction, the width dimension of the coating film forming site in the aluminum alloy plate 32, and the like.

  Moreover, in the said embodiment, in order to make an understanding of the process of applying a voltage between the aluminum alloy plate 32 and the electroconductive brush 34 easy, the insulating coating film 51 is formed only in the upper surface as a coating metal plate. An aluminum alloy plate 32 is illustrated, in which one electrode (conductive brush) is brought into contact with the painted surface (upper surface) and the other electrode is brought into contact with the non-painted surface (lower surface), Although a voltage is applied between the conductive brush 34 and the aluminum alloy plate 32, the coating may be performed on both surfaces of the aluminum alloy plate 32. When an insulating coating film is formed on both surfaces of the aluminum alloy plate 32, the conductive brush 34 connected to the + terminal or the − terminal of the application device 38 is brought into contact with the painted surface to be inspected. The other electrode can be electrically connected directly to an unpainted portion of the aluminum alloy plate 32 extending continuously in the longitudinal direction (for example, a portion of the bare coil upstream in the traveling direction) or to the aluminum alloy plate 32. If the contact is made indirectly with a metal frame or the like that is in contact with each other, a voltage can be applied between the conductive brush 34 and the aluminum alloy plate 32, and coating film defects can be inspected. it can. In addition, when inspecting the coating film defects of the insulating coating film applied on both surfaces, a plurality of conductive brushes 34 are arranged on each surface to detect the coating film defects separately. That's fine.

  Furthermore, in the above example, the coated metal sheet inspection apparatus 10 according to the present invention is applied to the painting line 12 in detail. However, the coated metal sheet is continuously run in the sheet length direction. For example, the present invention can of course be applied to another mass production line.

  In the above embodiment, the output device 76 directly prints information indicating a coating film defect on the end portion of the aluminum alloy plate 32, but instead of the output device 76 or the output device. 76, a known alarm device that informs that there is a coating film defect is installed, for example, an alarm lamp or alarm buzzer is installed for each conductive brush 34, and whether or not a coating film defect is detected and the coating film defect is detected. It is also possible to inform the operator of the position where the conductive brush 34 is detected.

  In addition, in the above-described embodiment, all the conductive brushes 34 are moved downward or upward at the same time as the piston rod 61 projects or retracts from the hydraulic cylinder 60. It is also possible to configure each brush 34 to move.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art. It goes without saying that any one of them falls within the scope of the present invention without departing from the spirit of the present invention.

  Some examples of the present invention will be shown below to clarify the present invention more specifically. However, the present invention is not limited by the description of such examples. Needless to say.

−Relationship between breakdown voltage and film thickness−
First, a plurality of aluminum alloy plates are used as metal plates, and different thicknesses are applied by applying different amounts of epoxy / acrylic paint (LW1541A manufactured by Kansai Paint) to one surface of each of the metal plates. Several painted metal plates were prepared. In addition, a conductive brush was prepared by implanting conductive fibers in a metal holder (46) made of aluminum alloy. Specifically, four types of conductive brushes (a) to (d) shown in Table 1 below were prepared.

  Then, the prepared four types of conductive brushes are used as one electrode and brought into contact with the painted surface of the painted metal plate, while the other electrode is brought into contact with the surface where no coating film is formed, and the dielectric breakdown voltage is measured. The results obtained are shown in Table 2 below. In addition, the measurement of the dielectric breakdown voltage is performed by using “dielectric breakdown test (short-time breakdown test)” in “Testing method of dielectric strength of solid electrical insulating material” defined in JIS C 2110, except that a conductive brush is used as the + electrode. Was carried out in accordance with.

As is clear from the results of Table 2, it can be seen that the dielectric breakdown voltage (V) increases as the film thickness of the insulating coating film increases. For example, in the case of the conductive brush (a), 5 to It is necessary to apply a DC voltage of about 30 to 500 V to a coated metal plate having a coating weight of 125 mg / m ² . In addition, among the four types of conductive brushes, it can be seen that the conductive brush (a) using the amorphous metal fiber and having a protrusion length (L) of 15 mm has a low dielectric breakdown voltage and excellent conductivity.

−Relationship between breakdown voltage and coating type−
Next, as the metal plate, three aluminum alloy plates were used, and on one surface of the metal plate, as shown in Table 3 below, a vinyl chloride paint (VALSPAR 4963C), an epoxy / acrylic paint ( Three types of coated metal plates were prepared by applying 1) (KW Kansai Paint LW1541A) or epoxy / acrylic paint (2) (Kansai Paint 04LW1581C) to a predetermined film thickness. Moreover, the conductive brush (a) shown by the said Table 1 was prepared as a conductive brush. And as mentioned above, the dielectric breakdown voltage was measured, and the obtained results are also shown in Table 3 below.

  As is clear from the results in Table 3, it can be seen that the dielectric breakdown voltage (V) varies depending on the type of the insulating coating film. Therefore, it is understood that the applied voltage needs to be adjusted depending on the type of the insulating coating film.

-Inspection of coating film defects-
As the conductive brush (34), two types of the four types of conductive brushes (a) to (d) shown in Table 1 above are prepared, and the painted metal having the structure shown in FIG. 2 or FIG. It attached to the board | substrate inspection apparatus (10). Moreover, this test | inspection apparatus (10) was installed in the middle of the well-known coating line (the delivery side of a coating apparatus) which performs the coating with respect to a metal plate continuously, as FIG. 1 shows.

Also, an aluminum alloy (A5182-H19) plate having a length of 5000 m, a width of 1500 mm, and a thickness of 0.28 mm was prepared, and the epoxy / acrylic paint (LW1541A manufactured by Kansai Paint Co., Ltd.) was formed on one surface of the aluminum alloy plate. The coating weight was 20 mg / dm ² and the film thickness was about 2 μm. 1 to 7 coating film defects (paint missing defects) were artificially prepared.

  The coated metal plate on which the coating film defects are formed is passed at a line speed of 250 m / min, while the two conductive brushes are overlapped in the plate length direction so that the width is 5 mm or less. After being disposed and brought into contact with the coating film forming site so that the inclination angle (θ) is 45 ° and the contact length of the hair tip is about 2 to 3 mm, a predetermined amount is provided between the metal plate and the conductive brush. The voltage of was applied. And the value of the current flowing between the metal plate and the conductive brush was measured, and the obtained results are shown in Table 4 below. The painted metal plate was grounded by grounding it through a metal uncoiler in contact with an unpainted bare coil in a conductive state.

  As is apparent from the results of Table 4, when the conductive brush (a) having a protrusion length (L) made of amorphous metal fibers of 15 mm is used as the conductive brush, the applied voltage is 300 V, No. All the coating film defects 1 to 7 could be detected, and minute coating film defects that were difficult to detect by conventional visual inspection or optical inspection could be reliably detected without omission. In addition, although not clarified in Table 4 above, such a coating film defect is detected by either one of the two conductive brushes, and it is possible to specify the defect occurrence site in the plate width direction, I understood.

  On the other hand, although it consists of an amorphous metal fiber, in the comparative example 1 using the electroconductive brush whose protrusion length (L) exceeds 50 mm, it is No. Although the coating defects of 1, 3, and 4 were detected, because the amorphous metal fibers were too long, the tips of the hairs expanded (the spacing between the amorphous metal fibers increased), and the detection of minute coating film defects was unstable. Thus, it is understood that a detection omission occurs. Further, in Comparative Example 2 in which a conductive brush made of conductive acrylic fiber (projection length: 55 mm) was applied and 300 V was applied, the applied voltage was considerably lower than the dielectric breakdown voltage. Only the defect (No. 1) could be detected. Furthermore, in Comparative Example 3 in which a conductive brush made of conductive acrylic fiber (projection length: 55 mm) was used and the applied voltage was 600 V close to the dielectric breakdown voltage, No. 1 and no. Although the coating film defects of No. 4 were detected, it can be seen that the fiber spacing is widened, the detection of minute defects becomes unstable, and detection omission occurs. In addition, in Comparative Example 4 in which a conductive brush made of conductive nylon fiber (projection length: 55 mm) was used and the applied voltage was 400 V close to the dielectric breakdown voltage, No. Although the coating film defects of 1, 2, and 4 could be detected, it was found that the fiber interval was widened, the detection of minute defects became unstable, and detection omission occurred.

-Scratch occurrence-
Moreover, in the inspection of the coating film defect, when the painted surface contacted with the conductive brush was observed with a scanning electron microscope (SEM), no scratches were observed on the painted surface due to the conductive brush. It was.

It is a schematic explanatory drawing which shows an example of the coating line in which the inspection apparatus of the coating metal plate according to this invention was integrated, Comprising: The flowchart which shows a work process is shown together. It is a schematic explanatory drawing which shows one Embodiment of the inspection apparatus of the coating metal plate according to this invention, Comprising: The state which made the some electroconductive brush contact the coating surface of a metal plate is shown. FIG. 3 is an explanatory view taken along the line III-III in FIG. 2. It is a schematic explanatory drawing which shows one Embodiment of the electroconductive brush used for the inspection apparatus of the coating metal plate according to this invention. FIG. 5 is a VV cross-sectional explanatory diagram in FIG. 4. It is a figure which shows the lower surface of the electroconductive brush shown by FIG. It is a figure for demonstrating the arrangement | positioning position of several electroconductive brush shown by FIG. 2, Comprising: It is the figure which observed the coating metal plate in which the electroconductive brush was arrange | positioned from upper direction. It is a figure for demonstrating another state of the test | inspection apparatus of the coated metal plate shown by FIG. 3, Comprising: The state which separated the some electroconductive brush from the coating surface of the metal plate is shown. It is a signal system diagram in the inspection apparatus of the coating metal plate according to this invention. It is a partial expanded explanatory view which shows the state by which the conductive brush was made to contact the metal plate in which the insulating coating film was formed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Coating metal plate inspection apparatus 12 Coating line 14 Uncoiler 16, 28 Accumulator 18 Pretreatment device 20 Coater 22 Oven 24 Cooling device 26 Coating device 30 Take-up reel 32 Aluminum alloy plate 34 Conductive brush 36 Moving device 38 Application device 40 Coating Membrane Defect Detection Device 44 Amorphous Metal Fiber 46 Metal Holder 47 Conductive Adhesive Layer 48 Row 50 Coating Film Defect 52 Main Body 54 Support Shaft 56 Mounting Arm 58 Holding Port 60 Hydraulic Cylinder 61 Piston Rod 62 AC Power Supply 64 Rectifier 66 Booster 68 Limiter 70 Comparator 72 Data processing device 74 Recording device 76 Output device 78 Mark

Claims (16)

In the inspection method of the coated metal plate that inspects the insulating coating film formed on the surface of the metal plate that is continuously run in the plate length direction,
As the conductive brush, a plurality of amorphous metal fibers having a diameter of 10 to 100 μm are integrally planted in a long metal holder, and extend close to the longitudinal direction of the metal holder. A row of amorphous metal fibers is arranged in parallel in 3 to 6 rows in the width direction of the metal holder, and the projection length of each amorphous metal fiber constituting each row is 10 to 50 mm, A plurality of the conductive brushes are arranged in the plate width direction so that the respective longitudinal directions thereof are in the plate width direction of the metal plate, and the coating film forming site where the insulating coating film is formed on the metal plate In a state where it is in contact with the full width of each of the plurality of conductive brushes, a DC voltage lower than the dielectric breakdown voltage of the insulating coating is applied between each of the plurality of conductive brushes and the metal plate, and Power of Based on the value, a coating film defect of the metal plate is detected, a conductive brush that has detected the coating film defect is specified, and a coating film on the metal plate is further determined from the position of the specified conductive brush. A method for inspecting a coated metal plate, characterized in that a defect occurrence site is obtained.   2. The amorphous metal fiber is planted at a pitch of 10 to 100 [mu] m in the width direction of the metal holder and at a pitch equal to or larger than the diameter of the amorphous metal fiber. Inspection method for painted metal plates.   The conductive brush is tilted backward with respect to the traveling direction of the metal plate that is run in the plate length direction so that the angle formed by the conductive brush and the painted surface of the metal plate is 30 to 80 °. 3. The method for inspecting a coated metal plate according to claim 1, wherein the conductive brush is brought into contact with the painted surface in a posture to perform.   The dimension in the longitudinal direction of the conductive brush is 50 to 400 mm, and a plurality of the conductive brushes are arranged in a staggered manner in the plate width direction of the metal plate. The inspection method of the painted metal plate of any one of these.   The plurality of the conductive brushes arranged in the plate width direction of the metal plate are respectively arranged so that the overlap in the plate length direction of the metal plate is 10 mm or less. Item 5. The method for inspecting a coated metal plate according to any one of Items4.   The said applied voltage shall be 30-500V, The inspection method of the coated metal plate of any one of Claim 1 thru | or 5 characterized by the above-mentioned.   The inspection of the coated metal plate according to any one of claims 1 to 6, wherein the inspection is performed under a state in which the metal plate is caused to travel at a speed not exceeding 300 m / min. Method.   An alarm notifying that there is a coating film defect when detecting the coating film defect of the metal plate and determining the generation site of the coating film defect from the position of the conductive brush that has detected the coating film defect. The method for inspecting a coated metal plate according to any one of claims 1 to 7, wherein an apparatus and / or an output device that outputs position information of a position where the coating film defect occurs are operated.   The inspection is performed on the painted surface of the metal plate on which the insulating coating film has been applied and cured continuously in the coating means provided on the upstream side in the running direction of the metal plate, and from the coating means. Based on the coating signal and the speed signal, the plurality of the conductive brushes are brought close to / separated from the metal plate, and the conductive brush is brought into contact with only the coating film forming portion of the metal plate, thereby the insulating coating. The inspection of the coated metal plate according to any one of claims 1 to 8, wherein the conductive brush does not contact a metal base portion of the metal plate on which no film is formed. Method. A coating metal plate inspection device that inspects an insulating coating film formed on the surface of a metal plate that is continuously run in the plate length direction,
A conductive brush in which a plurality of amorphous metal fibers having a diameter of 10 to 100 μm are integrally planted in a long metal holder, and the amorphous metal fibers extend in close proximity to each other in the longitudinal direction of the metal holder Are arranged in parallel in 3 to 6 rows in the width direction of the metal holder, and the plurality of conductive brushes each having a protruding length of 10 to 50 mm of each amorphous metal fiber constituting each row,
A plurality of such conductive brushes are arranged in the plate width direction so that the respective longitudinal directions thereof are in the plate width direction of the metal plate, and the coating film forming site on which the insulating coating film is formed on the metal plate Conductive brush moving means for contacting the full width of the metal plate or separating the metal plate from the metal plate,
In a state where a plurality of the conductive brushes are in contact with the full width of the coating film forming portion of the metal plate, the insulating coating film is interposed between each of the plurality of conductive brushes and the metal plate. Applying means for applying a DC voltage lower than the dielectric breakdown voltage;
The application of voltage by the application means detects the coating film defect of the metal plate and the coating film defect based on the respective current values flowing between the conductive brush and the metal plate. A coating film defect detecting means for specifying the conductive brush, and further determining a coating film defect occurrence site in the metal plate from the arrangement position of the specified conductive brush;
A device for inspecting a painted metal plate, characterized in that it comprises   The said amorphous metal fiber is planted in the pitch of 10-100 micrometers in the width direction of the said metal holder, and the pitch more than the diameter of this amorphous metal fiber, It is characterized by the above-mentioned. Inspection equipment for painted metal sheets.   The dimension in the longitudinal direction of the conductive brush is 50 to 400 mm, and a plurality of the conductive brushes are arranged in a staggered manner in the plate width direction of the metal plate. 11. Inspection apparatus of the coated metal plate of 11.   The plurality of the conductive brushes arranged in the plate width direction of the metal plate are respectively arranged so that the overlap in the plate width direction of the metal plate is 10 mm or less. The inspection apparatus of the coated metal plate of any one of Claim 12.   The coating means is provided upstream in the traveling direction of the metal plate, and the conductive brush moving means is operated based on a painting signal and a speed signal from the painting means. 14. The inspection apparatus for a coated metal plate according to any one of items 13.   15. The painted metal plate inspection apparatus according to claim 10, further comprising limiter means for restricting application of the voltage. 16. An alarm device for notifying that there is a coating film defect and / or an output device for outputting position information of a site where the coating film defect is generated is further provided. The inspection apparatus of the coated metal plate of Claim 1.

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