JPH0599858A - Attachment detection method - Google Patents

Abstract

PURPOSE:To facilitate detection of foreign materials firmly sticking on a material to be inspected of the size which is a specified value or more and also perform the qualitative analysis of the foreign materials in a serial process. CONSTITUTION:With a transparent adhesive tape 1 applied onto the surface of a material to be inspected, foreign materials on the surface of the material to be inspected is transferred onto the transparent adhesive tape and the transferred tape 1 and the other transparent film 2 are stuck each other, so secondary contamination is prevented and the state of the foreign materials adhering to the material to be inspected is held. The foreign materials A1, A2, A3 transferred onto the tape 1 are set below an optical instrument such as a microscope 6, through which an image of the foreign materials is supplied to an image processor 7. Within the image processor 7 the images of the foreign materials of a specified value or less are eliminated and only the objective foreign materials of the size which is the specified value or more are selected in that after an input image is reduced down to a certain quantity, it is returned to an original size.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is tolerant of adhering to the surface of the steel material or the mold of a molding machine for molding the material in the foreign matter inspection when the steel material is molded by the mold or the like. The present invention relates to a method for selecting, detecting, and evaluating foreign matter having the above size.

[0002]

2. Description of the Related Art When a steel material is molded into various shapes, if an unacceptable number of foreign particles of unacceptable size adhere to the material or the mold of a molding machine, it cannot be ignored in the product after molding. Since it will be scratched, it is necessary to quantitatively evaluate the size and the number of foreign substances that have adhered in advance.

Conventionally, as a method of knowing the size and the number of foreign substances on the surface of an object to be inspected, such as the above-mentioned steel materials, after cleaning the surface of the object to be inspected with a certain amount of cleaning liquid, the cleaning liquid is collected and the cleaning liquid is used. An evaluation method is known in which a certain amount of the foreign matter is vaporized and the foreign matter existing in a predetermined unit area is observed by an operator with an optical instrument such as a microscope to measure the size and the number of the foreign matter per measurement area. ..

There is also a method of irradiating the surface of the object to be inspected with light and comparing the intensity of the reflected light with the reflected light with respect to the standard plate and evaluating the presence rate of the foreign matter by the relative value thereof.

[0005]

However, in the method using the above-mentioned cleaning liquid, the cleaning liquid adheres to the outside of the measurement range or adheres (contacts) with the object to be inspected, so that the cleaning liquid is In the case of water, it may cause rust,
Further, in the case of a volatile solution, it causes discoloration, which significantly deteriorates the performance of the inspection object.

For this reason, in the former case, it is necessary to carry out a treatment to prevent the cleaning liquid from penetrating outside the measurement range, and it takes time. In the latter case, it is necessary to select a liquid which does not deteriorate the performance of the object to be inspected. However, there is a problem that it is difficult to select such a liquid. Furthermore, since it is necessary to rework the inspected object after cleaning, extra labor and time are required before and after the measurement.

Further, even if the amount of adhesion can be known by the above method, there is a problem that the qualitative analysis cannot be performed as a series of steps using the same sample because the state of the foreign matter changes due to the cleaning liquid. Further, the method using the reflected light has a problem that the roughness of the steel sheet is affected by the oiling or the like and the error factor is large.

The present invention has been made by paying attention to the above problems, and facilitates the detection of a foreign substance having a size larger than a predetermined value attached to an object to be inspected without using a cleaning liquid. At the same time, the purpose is to be able to perform qualitative analysis of adhering foreign matter in a series of steps.

[0009]

In order to achieve the above object, the method for detecting adhered matter according to the present invention is such that once adhered to the surface of an object to be inspected, foreign matter on the surface of the object to be inspected becomes a transparent adhesive tape. After transferring and attaching a transparent filter to the adhesive tape, the foreign matter transferred to the adhesive tape is projected by an optical device, and a foreign matter larger than a predetermined value is subjected to image processing of contraction / restoration operation on the projected image. The feature is that only images are selected.

[0010]

[Function] Once a transparent adhesive tape is attached to the surface of the object to be inspected, foreign matter on the surface of the object to be inspected is transferred to the transparent adhesive tape, and the transferred adhesive tape and another transparent film are attached to each other. By this, the foreign matter is transferred between the adhesive tape and the film, and the foreign matter is sandwiched between the adhesive tape and the film to be isolated from the outside world, so that the secondary contamination of the adhesive tape is prevented and the state of the foreign matter attached to the inspection object is maintained. To be done.

Thereafter, the foreign matter transferred to the adhesive tape is irradiated with light from one surface of the tape, and an image of the foreign matter is input from the other surface by an optical device such as a microscope, and an image signal of the image is obtained. Supply to processing equipment. In the image processing apparatus, the input image is shrunk by a predetermined amount and then returned to the original size to remove the image of the foreign matter having a predetermined value or less, and only the image of the foreign matter having a target size of the predetermined value or more is removed. Leave in the image.

After that, the number of images of the foreign matter is counted by an image processing apparatus, or the image is photographed or the like to be counted by an operator to quantitatively evaluate the foreign matter. It should be noted that air bubbles are generated when the adhesive tape and the transparent film are attached, but it has been experimentally found that the width of the outline of the air bubbles is about 2 μm, and it is known that the mainstream is the same. It is presumed that foreign matter of 5 μm or less in the inspection object is not a dimension unfavorable for molding, but there is no problem because the image of the bubbles disappears during the shrinking operation.

Further, the foreign matter adhered to the adhesive tape or the transparent film is directly subjected to the scanning electron microscope, so that the qualitative analysis of the foreign matter becomes possible as a series of steps.

[0014]

Embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, the deposit detection method according to the present invention is carried out by using a steel plate as an object to be inspected, and a foreign substance of 5 μm or more attached to the surface of the steel plate is detected as an unacceptable foreign substance to be recognized, and An example of counting the number is shown.

First, in order to measure the amount of foreign matter adhering to the surface of the steel sheet to be inspected, the transparent adhesive tape 1 is attached to the measurement site of the steel sheet. Then, the adhesive tape is lightly adhered to the adhesive tape and the adhesive tape 1 is gently peeled off. As a result, the foreign matter attached to the surface of the steel sheet is transferred to the adhesive layer 1a of the transparent adhesive tape 1. Next, a relatively thick transparent film is bonded to the peeled transparent adhesive tape to form a sample S, and the sample S is placed on the mounting table 3 of the foreign matter observing instrument as shown in FIG. Here, the foreign matter observing instrument is composed of a visual field setting jig 4 having a predetermined amount of through holes 4a, and a transparent flat plate glass fixed on the visual field setting jig 4. A mounting table 3 on which the sample S is mounted, and the transparent adhesive tape 1 and the transparent film 2 mounted on the mounting table 3.
And a pressing jig 5 for pressing the sample S consisting of the above from above.

Next, a transmitted light 9 is emitted upward from below the visual field setting jig 4 of the foreign matter observing instrument, and the emitted light is an optical instrument installed above the sample S via a sample S. Input to 6. The microscope 6 has its light-receiving axis directed downward and is connected to an image processing apparatus, and supplies the input image to the image processing apparatus 7. The image is, for example, as shown in FIG. 3. In FIG. 3, three foreign object images A1 to A3 and one bubble B are drawn.
The contour width B1 of the bubble is about 2 μm.

In the image processing device 7, image analysis is performed on the input image. That is, after performing the edge enhancement processing on the observed image (original image), the density enhancement processing is performed on the processed image, and further, the image (binarization processed image) for the calculation is processed as shown in FIG. As shown in FIG. 2, the image of the small foreign matters A3 and bubbles B of 2 μm or less is removed by contracting by 2 μm from the edge portion ((b) in FIG. 2). After this process, the remaining foreign matter images A1, A2
Only the foreign matter to be measured is selected by returning only the original size ((a) in FIG. 2). Here, in the operation of restoring the contracted image, if the shape of the contracted image is deformed by expanding the contracted image, the original image before contraction is stored and the original image is used as the original image. Restore to.

Then, the image processing apparatus is caused to count the number of foreign matters remaining to be recognized in the image after the processing is completed, or the image is enlarged into a photograph or the like. Quantitative evaluation such as counting the number by the worker is carried out. As a result, it becomes possible to select a foreign substance that should be easily recognized without contaminating a portion outside the measurement range or equipment, and a quantitative evaluation of the foreign substance can be performed easily and efficiently.

In the above description, the size of the foreign matter to be recognized is set to 5 μm or more, but it may be 3 to 4 μm if necessary.
Set as above. In addition, focusing for displaying an image may be performed only for the first time when a plurality of samples S are present. This is because the total thickness of the transparent adhesive tape 1 and the transparent film 2 is almost constant, and therefore the microscope 6
This is because it can be covered by the depth of focus of the lens.

Further, when the white paper 8 which allows some light to pass through is arranged on the light source side, the unevenness of the light source can be eliminated by adding scattered light of the transmitted light 9. Furthermore, by subjecting this sample S to a scanning electron microscope or the like as it is, by performing a qualitative analysis,
Since the composition of the collected foreign matter can be known, qualitative analysis can be performed on the same sample S.

By the inspection as described above, it becomes possible to judge the presence of foreign matter and analyze at which stage in the process the foreign matter is mixed from the composition of the foreign matter, and various countermeasures can be taken. The foreign matter observing tool is an example, and other tools may be used as long as the sample S can be fixed.

[0022]

As described above, according to the deposit detection method of the present invention, a foreign substance is transferred using a transparent adhesive tape, so that a steel plate to be inspected, oil of a molding machine or the like is deposited. Even if the foreign matter is present, the foreign matter can be reliably transferred, the foreign matter can be collected very easily, and the foreign matter to be recognized can be easily detected.

Further, since no cleaning liquid is used, there is an effect that trouble such as corrosion can be prevented from occurring on the object to be inspected and the surrounding equipment. Further, by bonding the transferred transparent adhesive tape to another transparent film at the sampled location, it is possible to prevent secondary contamination and maintain the adhered state.

In addition to the quantitative evaluation of the amount of adhered foreign matter, the foreign matter on the transparent adhesive tape can be directly subjected to a scanning electron microscope or the like, and the qualitative analysis of the foreign matter can also be performed on the same sample. is there.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment according to the present invention.

FIG. 2 is a diagram showing an image before processing in an example according to the present invention.

FIG. 3 is a diagram showing a state of foreign matter and bubbles during processing in an example according to the present invention.

[Explanation of symbols]

 1 Adhesive tape 2 Transparent film 6 Microscope 7 Image processing device

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshiaki Shiraishi 1 Kawasaki-cho, Chiba-shi, Chiba Inside Kawasaki Steel Co., Ltd. (72) Inventor Tadao Shinohara 1 Kawasaki-cho, Chiba-shi Kawasaki Steel Co., Ltd. Chiba Inside the steel mill

Claims (1)

[Claims] 1. A foreign substance on the surface of the object to be inspected is transferred to a transparent adhesive tape by once adhering to the surface of the object to be inspected, a transparent filter is attached to the adhesive tape, and then transferred to the adhesive tape. And a foreign matter image larger than a predetermined value is selected by performing image processing of contraction / restoration operation on the projected image.