JP2002156332A - Detection method and device of surface flaw or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of detecting the existence, kind, shape and direction of flaw or defect on the surface of a metal part or a metal product except a rolling trace, using one detection device. SOLUTION: Optical fiber bundles 3, 5 are arranged concentrically around spot light of a laser beam, and reflected scattered light is allowed to enter the inside optical fiber bundle 3, and diffracted light is allowed to enter the outside optical fiber bundle 5. Each optical fiber bundle 3, 5 is divided in numbers in the circumferential direction respectively, and photodetectors 8a, 8b...8l, 9a, 9b...9l are installed in each block, and light-receiving quantities are measured, and the mean value is determined from the total amount thereof by operation means 11a, 11b. A determination means 12 detects the existence and the kind of flaw in each block, by comparing the light receiving quantity in each block with the mean value, and the shape and the direction of the flaw from a light-receiving pattern in each block. The photodetector for detecting the rolling trace is determined, beforehand from a spot having no flaw, and the data of the photodetector is set excluded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting the presence or absence of a flaw or defect on the surface of a metal part or product and the type of flaw or defect.

[0002]

2. Description of the Related Art Methods for detecting surface scratches and defects (hereinafter simply referred to as "surface scratches") on metal parts and product surfaces include optical methods using laser light and image processing using a television camera. There is a law.

[0003] The former optical method using laser light,
The inspection is performed by irradiating the inspection surface with laser light and detecting the reflected light and the diffracted light with a photodetector. That is, when the inspection surface is irradiated with the laser beam, if there is a reflected scattered light corresponding to the reflectance of the surface from the inspection surface and a flaw, light having two different properties of diffracted light generated by the flaw is returned. Of these, the amount of the reflected scattered light changes depending on the reflectance of the surface, and if there are irregularities, the reflection angle also changes according to the inclination. Therefore, by installing the light source and the photodetector close to each other and monitoring the light amount of the photodetector, it is possible to detect irregularities such as dents and dents on the surface.

On the other hand, sharp scratches such as scratches (hereinafter referred to as "scratch scratches") generate diffracted light, so that minute scratches can be detected by detecting the diffracted light. Since the direction of the flaws varies and the direction of the diffracted light generated in the direction perpendicular to the flaws also varies, it is difficult to detect with a general photodetector, and it is necessary to use a specially shaped photodetector .

As described above, the conventional detection method requires two types of photodetectors, a photodetector for detecting reflected scattered light and a photodetector of a special shape for detecting diffracted light. And the diffracted light generated due to the scratches cannot be measured at the same time, and at present the skilled inspector visually inspects.

[0006] On the other hand, inspection methods based on image processing are widely used. However, in order to detect minute scratches, it is necessary to narrow down an area photographed by a television camera and enlarge the obtained image. There is a disadvantage that it takes time to inspect the entire inspection surface.

[0007]

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a method and an apparatus for inspecting an optical flaw using a laser beam, wherein both of reflected and scattered light caused by unevenness and diffracted light generated by the flaw are detected. Is to provide a detection method and apparatus capable of simultaneously detecting the presence or absence and type of a flaw or defect by simultaneously measuring the shape and the type of the flaw. It is an object of the present invention to provide a detection method and apparatus that can perform the detection.

[0008]

The invention according to claim 1 relates to a detection method for achieving the first object, and irradiates a spot surface of a laser beam to an inspection surface of a metal part or a product, and reflects the reflected scattered light. Among the double concentric optical fiber bundles centered on the spot light, the inner optical fiber bundle
The diffracted light generated by the scratch is incident on each of the outer optical fiber bundles, and the respective light amounts are measured with a photodetector.
It is characterized in that the presence or absence of a flaw or defect and the type thereof are detected by comparing the amount of light received from a normal surface without flaws or defects.

According to the present invention, the presence or absence of a flaw or defect is detected by previously obtaining the amount of light received from a normal part having no flaw or defect, and comparing it with the amount of light received from another part.
By measuring the reflected scattered light and the diffracted light separately, it is possible to determine the type of the scratch, such as the difference between the unevenness such as a dent or a dent and the scratch.

[0010] The invention according to claim 2 relates to a detecting apparatus for achieving the first object, and comprises a laser light source for emitting laser light, a lens for narrowing the laser light from the laser light source, and a lens for narrowing the laser light. A central cylinder through which laser light passes;
An optical fiber bundle disposed at one end of the cylindrical body on a double concentric circle centering on the cylindrical body, and a photodetector that detects the amount of light guided from the optical fiber bundle, and detects laser light from a laser light source. It is characterized in that it is squeezed by a lens, passes through the axial hole of the central cylindrical body, irradiates the inspection surface, receives reflected light with the inner optical fiber bundle, and receives diffracted light with the outer optical fiber bundle.

According to the present invention, the detecting method according to the first aspect of the present invention can be carried out. In addition, the detecting device is constituted by a central cylindrical body and an optical fiber bundle concentrically arranged at one end thereof. Can be made small and compact, and by making it compact, it becomes possible to inspect the inner surface of a small-diameter cylindrical body such as a cylinder, or a flaw in a deep place.

The invention according to claim 3 relates to a detection method for achieving the second object. In the invention according to claim 1, the optical fiber bundle is divided into a plurality of blocks by dividing the bundle of optical fibers in a circumferential direction. After measuring the amount of received light in each block with the photodetectors provided independently, compare the amount of received light from a normal location with no flaws or defects for each block to detect the presence or absence of flaws or defects. Features.

According to the present invention, it is possible to determine at what angle and how much the reflected scattered light and the diffracted light from the surface of the inspection surface are returned from the amount of light received by each block measured by each photodetector. In other words, the form of irregularities on the surface, such as dents and dents, is evident from the light intensity distribution measured on the inner optical fiber bundle, and scratches are detected from the light intensity distribution measured on the outer optical fiber bundle. Is generated in a direction orthogonal to the direction of the scratch, the direction of the scratch can be detected from the block in which the scratch is detected.

The invention according to claim 4 relates to another detection method for achieving the second object, in which a spot light of a laser beam is irradiated on an inspection surface of a metal part or a product, and the reflected scattered light is spotted. Of the optical fiber bundles arranged concentrically around the light, the diffracted light generated by the flaw is made incident on the inner optical fiber bundle and the outer optical fiber bundle, respectively, and the respective light amounts are measured in the circumferential direction of the optical fiber bundle. It is characterized by detecting the presence or absence of a flaw or a defect by dividing into several blocks, measuring with a photodetector provided for each block, and comparing the measured light quantity with a threshold value.

The invention according to claim 5 relates to still another detection method which achieves the second object, and irradiates a spot light of a laser beam to an inspection surface of a metal part or a product and reflects its reflected scattered light. Of the double concentric optical fiber bundles centered on the spot light, the diffracted light generated by the flaw is incident on the inner optical fiber bundle and the outer optical fiber bundle, respectively, and the amount of each light is measured along the circumference of the optical fiber bundle. After dividing by several blocks in the direction and measuring with a photodetector provided for each block, the total amount of received light in each block is calculated, and then the ratio of the received light amount of each block to the calculated total amount of received light is calculated. Detecting the presence or absence of flaws or defects by calculating the average value of the received light amount of each block from the total amount of the received light amount and comparing it with the received light amount of each block And it features.

The invention according to claim 6 relates to still another detection method for achieving the second object, in which a spot light of a laser beam is applied to an inspection surface of a metal part or a product, and the reflected scattered light is emitted. Of the double concentric optical fiber bundles centered on the spot light, the diffracted light generated by the flaw is incident on the inner optical fiber bundle and the outer optical fiber bundle, respectively, and the amount of each light is measured along the circumference of the optical fiber bundle. It was divided into several blocks in the direction, measured with a photodetector provided for each block, and the measured light amount was compared with a threshold value, and the total amount of received light in each block was calculated. By calculating the ratio of the received light amount of each block to the total amount of received light, or calculating the average value of the received light amount of each block from the total amount of received light, And detecting the presence or absence of scratches and defects by.

According to the fourth aspect of the present invention, it is determined that there is a flaw or defect in a block whose measured light receiving amount exceeds the threshold value. It is determined that a block having a high ratio to the amount of received light or a block exceeding the average value of the amount of received light has a scratch or a defect. In the invention according to claim 6, it is determined that the amount of received light in each block exceeds a threshold value, the ratio of the amount of received light is high, or a block exceeding the average value has a flaw or defect.

According to a seventh aspect of the present invention, in the third aspect of the present invention, a photodetector for detecting a rolling mark from light reception data from a normal portion having no flaws or defects is obtained in advance, and the light detector is used. It is characterized in that the presence or absence of a flaw or a defect is determined from the amount of light measured by the remaining photodetectors other than the detector.

Inevitably, rolling marks are formed on metal parts and products made of rolled material, and diffracted light is generated at the rolling marks, causing a problem that the rolling marks are erroneously recognized as scratches. However, according to the present invention, such a problem can be solved.

The invention according to claim 8 relates to an apparatus for performing the detection method according to claim 3 of the present invention. In the invention according to claim 2, the optical fiber bundle is divided into several blocks in the circumferential direction. In addition, a photodetector that measures the amount of received light is provided for each block, and the amount of received light measured by the photodetector is compared with the amount of received light from the surface of a normal part that has been determined in advance, and scratches and defects are detected. A determination means for determining the presence or absence of

According to a ninth aspect of the present invention, there is provided an apparatus for performing the detecting method according to the fourth aspect of the present invention. In the second aspect of the present invention, the optical fiber bundle is divided into a plurality of blocks by dividing the optical fiber bundle in a circumferential direction. A light detector that measures the amount of received light for each block, and a determination unit that determines the presence or absence of a flaw or defect by comparing the amount of received light measured by the light detector with a threshold. Features.

According to a tenth aspect of the present invention, there is provided an apparatus for performing the detecting method according to the fifth aspect of the present invention. In the second aspect of the present invention, the optical fiber bundle is divided into a plurality of blocks by dividing in a circumferential direction. Providing a photodetector for measuring the amount of received light for each block, and calculating the total amount of received light in each block and the ratio of the amount of received light in each block to the total amount of received light, or Calculating means for calculating the average value of the total amount of the light-emitting elements, and determining means for comparing the ratio with the threshold value or comparing the light receiving amount in each block with the average value to determine the presence or absence of a flaw or a defect. It is characterized by.

According to an eleventh aspect of the present invention, in the invention according to the tenth aspect, the determination means has a function of comparing a received light amount in each block with a threshold value.

[0024]

1 and 2 show a detection device according to the present invention. In a detection device according to the present invention, a center cylinder 2 having a shaft hole 2a and a portion around the center cylinder 2 are provided in an outer cylinder 1. FIG. An optical fiber bundle 3 bundled in a ring shape, a light-impermeable inner cylindrical body 4 put thereon, and an optical fiber bundle 5 further bundled in a ring shape around the inner cylindrical body 4 are fitted. Then, the laser light from the laser light source 6 is narrowed down by the lens 7 and passes through the axial hole 2a of the central cylindrical body 2, so that the inspection surface can be irradiated as spot light.

The optical fiber bundles 3 and 5 are provided so that the reflected scattered light is incident on the inner optical fiber bundle 3 and the diffracted light is incident on the outer optical fiber bundle 5. Each of the optical fiber bundles 3 and 5 is divided into several blocks in the circumferential direction, and divided into several blocks (FIG. 3 shows an example in which the optical fiber bundle 5 is divided into 12 blocks as an example in which the optical fiber bundle is divided into several blocks. ), And photodetectors 8a, 8b... 8l, 9a, 9b. Then, the calculating means 11a receives the light detector 8a,
8l and the average of the sums of the received light amounts determined by 8l are calculated, and the calculating means 11b calculates the light detectors 9a and 9b.
.. the sum of the received light amounts measured by 9l and the average value thereof are calculated, and the judgment means 12 calculates the individual received light amounts measured by the photodetectors 8a, 8b... 8l and 9a, 9b. The calculated average values are sequentially compared with each other, and if there is a measured value exceeding the average value, it is determined that the corresponding block of the measured value has a flaw, and the received optical fiber bundle is detected by the optical fiber bundle 3. It is determined whether it is an uneven fiber or a scratch based on whether the optical fiber bundle 5 is present or not, and the shape of the unevenness and the direction of the scratch are determined from the light receiving pattern. The result of the determination is output to a display means 10 comprising a display such as a CRT, and the presence or absence and type of the flaw, the form and direction of the flaw are displayed.

The detection device of this embodiment is configured as described above. When detecting the presence or absence of a scratch on the surface of the test object 13 made of a rolled material, only one diffracted light appears first, , For example, the photodetectors 9d and 9j in FIG. 3 are found, and the photodetectors 9d and 9j are detected.
The data measured by is excluded in advance. Similarly, for the photodetectors 8a, 8b,..., The data of the corresponding photodetectors are excluded.

Next, the apparatus is moved little by little in an arbitrary direction to change the irradiation position of the spot light on the surface to be inspected, and the judgment means 12 is damaged based on the amount of light received by the light detectors other than the light detectors excluded. Is determined. That is, the calculating means 11
a and 11b calculate the sum of the amounts of light received by the light detectors other than the light detectors whose data has been excluded and their average values, and determine means 12 sequentially calculates the average value and the light amounts measured by the respective light detectors. The corresponding block is obtained from the photodetector that has compared and measured the amount of light exceeding the average value, and it is determined that the block has a flaw. The pattern of the amount of light detected by the remaining light detectors 8a, 8b,... 8l excluding the light detector removed by the output removes the form of dents and dents on the surface of the subject in the same manner. The scratches and their directions are determined from the remaining light detectors 9a, 9b,. For example, when the light amounts of the photodetectors 9f and 9l exceed the average value, it is determined that a scratch is present in a direction orthogonal to the block corresponding to the detectors 9f and 9l.

According to the detection apparatus of this embodiment, the optical fiber bundle is arranged concentrically so that the reflection and scattering holes are received by the inner optical fiber bundle and the diffracted light is received by the outer optical fiber bundle. The device can determine the presence or absence of irregularities or scratches on the surface of the subject, and the type of the damage.Furthermore, each optical fiber bundle is divided into several blocks in the circumferential direction, and the amount of light received for each block is measured by the optical fiber. By comparing with the average value of the total received light amount of the entire bundle 3 or 5, it becomes possible to know in which block the reflected light or the diffracted light from the flaw was received, and thereby, it was possible to determine the shape of the unevenness and the direction of the scratch flaw. It is possible to judge it, and since the data of the rolling marks are excluded in advance in the measurement, the rolling marks are not erroneously recognized as scratches. The detection device is
Because it is housed in a cylindrical container and is small and compact, it can be inserted into a thin cylindrical body such as a cylinder or a deep place, and the presence or absence of scratches, its type, and its form and orientation It can be detected in the same manner.

In the above embodiment, the calculating means 11a, 11
b calculates the average value of the received light amount, and the determining means determines whether there is a flaw by comparing the average value with the received light amount of each block. In another embodiment, the calculating means 11a, 11b The ratio of the amount of light received by each block to the amount of light received by each of the optical fiber bundles is determined, and the determination means compares this ratio with a threshold to determine the presence or absence of a flaw.

In still another embodiment, the amount of received light of each block detected by the photodetector is omitted from the calculating means and compared with a threshold value in the judging means to judge the presence or absence of a flaw. In the embodiment, data of a portion that is not damaged is obtained in advance, and the determination unit determines the presence or absence of a damage by comparing the data with the received light amount data of each block. In any of the above-described embodiments, the same operation and effect as those of the above-described embodiment can be obtained.

[0031]

According to the first aspect of the present invention, the optical fiber bundle is arranged in a double concentric manner around the spot light, and the reflected scattered light is converted into the inner optical fiber bundle, and the diffracted light is changed into the outer optical fiber bundle. One detector detects the presence or absence of a flaw or defect, and determines the type of flaw such as unevenness or scratch by comparing each received light quantity and the received light quantity obtained in advance from a normal part without flaws. be able to.

According to the second aspect of the present invention, since the detection device can be made small and compact, the flaw inspection can be performed even in a narrow space such as the inner surface of a small cylindrical body such as a cylinder or a deep place. Becomes

According to the third to sixth and eighth to eleventh aspects of the present invention, when there are irregularities and scratches on the surface of the specimen, the form of the irregularities and the direction of the scratches can be detected. According to the invention according to claim 7, it is possible to prevent the rolling trace from being mistaken as a scratch.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a detection device according to the present invention.

FIG. 2 is a cross-sectional view of a detection device according to the present invention.

FIG. 3 is a schematic diagram of a system for detecting an amount of received light by dividing an optical fiber bundle into several blocks.

[Explanation of symbols]

 1, outer cylindrical body 2, central cylindrical body 2a, axial hole 3, 5, optical fiber 4, inner cylindrical body 6, laser light source 7, lens 8a, 8b, 8l, 9a, 9b 9l · ·· Photodetector 10 ··· Display means 11a, 11b ··· Calculation means 12 ··· Determining means 13 ··· Subject

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Saburo Okada 2-2-2 Hirosuehiro, Kure City, Hiroshima Prefecture Inside the Industrial Technology Research Institute of China (72) Inventor Masaaki Imade 2 Hirosuehiro, Kure City, Hiroshima Prefecture Chome No.2-2 Industrial Technology Institute, China Institute of Industrial Technology (72) Inventor Yu Iya 3-4-1, Ishio, Minami-ku, Hiroshima Japan System Design Co., Ltd. (72) Inventor Yuzo Shimatsutsu Higashihiroshima City High School No. 1-330, Stall, Tatsuei Kogyo Co., Ltd. F-term (reference) 2G051 AA82 AB07 AC17 BA10 BB17 CA07 CA08 CB01 CB05 CB06 EB01 EC01 EC03

Claims (11)

[Claims] 1. An inner optical fiber bundle among a plurality of double concentric optical fiber bundles in which a spot light of a laser beam is irradiated on an inspection surface of a metal part or a product, and the reflected and scattered light is arranged concentrically around the spot light. Then, the diffracted light generated by the flaw is incident on the outer optical fiber bundle, and the amount of each light is measured with a photodetector and compared with the amount of light received from a normal surface with no flaws or defects. And a method for detecting surface flaws or the like, characterized by detecting the type thereof. 2. A laser light source for emitting laser light, a lens for narrowing the laser light from the laser light source, a central cylindrical body for passing the laser light narrowed by the lens, and a cylindrical body at one end of the cylindrical body. An optical fiber bundle arranged on a double concentric circle, and a photodetector for detecting the amount of light guided from the optical fiber bundle, and a laser beam from a laser light source is squeezed by a lens to form an axial hole in a central cylindrical body. A surface flaw or the like, wherein the reflected light is received by an inner optical fiber bundle and the diffracted light is received by an outer optical fiber bundle. 3. The optical fiber bundle is divided in the circumferential direction into several blocks, and the amount of light received in each block is measured by a photodetector provided independently for each block. 2. The method for detecting a surface flaw according to claim 1, wherein the presence or absence of a flaw or a defect is detected by comparing the amount of light received from a normal part without a flaw. 4. An inner optical fiber bundle among optical fiber bundles arranged by irradiating a spot light of a laser beam onto an inspection surface of a metal part or a product, and reflecting and scattering the reflected light in a double concentric circle centering on the spot light. Then, the diffracted light generated by the scratch is incident on each of the outer optical fiber bundles, and each light amount is divided into several blocks in the circumferential direction of the optical fiber bundle and measured by a photodetector provided for each block. A method of detecting surface flaws or the like, characterized in that the presence or absence of flaws or defects is detected by comparing the detected light quantity with a threshold value. 5. An inner optical fiber bundle among a plurality of optical fiber bundles arranged by irradiating a spot light of a laser beam to an inspection surface of a metal part or a product and reflecting and scattering the reflected light in a double concentric circle centering on the spot light. Then, the diffracted light generated by the scratch is incident on each of the outer optical fiber bundles, and the respective light amounts are divided into several blocks in a circumferential direction of the optical fiber bundle, and measured by a photodetector provided for each block. Calculate the total amount of received light in each block, and then calculate the ratio of the amount of received light in each block to the calculated total amount of received light, or calculate the average value of the amount of received light in each block from the total amount of received light A method for detecting the presence or absence of a flaw or the like by comparing the amount of light received by each block with the amount of light received. 6. An inner optical fiber bundle among optical fiber bundles arranged by irradiating a spot light of a laser beam to an inspection surface of a metal part or a product, and reflecting and scattering the reflected light in a double concentric circle centering on the spot light. Then, the diffracted light generated by the scratch is incident on each of the outer optical fiber bundles, and the amount of each light is measured by a photodetector provided for each block divided into several blocks in the circumferential direction of the optical fiber bundle. By comparing the measured light amount with the threshold value, calculating the total amount of received light in each block, and then calculating the ratio of the received light amount of each block to the calculated total amount of received light, or A method for detecting the presence or absence of a flaw or a defect by calculating an average value of the amount of received light of each block from the total amount of the data and comparing the amount of received light with the amount of received light of each block. 7. A photodetector for detecting a rolling mark based on received light data from a normal portion having no scratches or defects is obtained in advance,
The method for detecting a surface flaw or the like according to any one of claims 3 to 6, wherein the presence or absence of a flaw or defect is determined from the amount of light measured by the remaining photodetectors other than the photodetector. 8. The optical fiber bundle is divided in the circumferential direction into several blocks, and a photodetector for measuring the amount of received light is provided for each block, and the amount of received light measured by the photodetector is obtained in advance. 3. The apparatus for detecting a surface flaw according to claim 2, further comprising a judging means for judging the presence or absence of a flaw or a defect by comparing the amount of light received from the surface of the normal place. 9. An optical fiber bundle is divided in a circumferential direction into several blocks, and a photodetector for measuring the amount of received light is provided for each block. 3. The detection device for surface flaws or the like according to claim 2, further comprising a judgment means for comparing the results to determine the presence or absence of a flaw or defect. 10. An optical fiber bundle is divided in a circumferential direction into several blocks, and a photodetector for measuring the amount of received light is provided for each block, and the total amount of received light and the amount of received light in each block are provided. Either calculate the ratio of the amount of received light in each block to the total amount, or compare the ratio and a threshold with a calculating unit that calculates the average value of the total amount of received light,
3. The surface flaw / defect detection device according to claim 2, further comprising a judgment unit for comparing the amount of light received in each block with the average value to determine the presence / absence of a flaw or defect. 11. An apparatus according to claim 10, wherein said determination means has a function of comparing the amount of light received in each block with a threshold value.