KR20150089242A - Detecting method for delamination defect in eva material and detecting device for thereof - Google Patents

Detecting method for delamination defect in eva material and detecting device for thereof Download PDF

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Publication number
KR20150089242A
KR20150089242A KR1020140009638A KR20140009638A KR20150089242A KR 20150089242 A KR20150089242 A KR 20150089242A KR 1020140009638 A KR1020140009638 A KR 1020140009638A KR 20140009638 A KR20140009638 A KR 20140009638A KR 20150089242 A KR20150089242 A KR 20150089242A
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South Korea
Prior art keywords
inspection target
target product
image
defect
eva
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KR1020140009638A
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Korean (ko)
Inventor
김재열
최승현
김성현
정나라
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조선대학교산학협력단
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Priority to KR1020140009638A priority Critical patent/KR20150089242A/en
Publication of KR20150089242A publication Critical patent/KR20150089242A/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/72—Investigating presence of flaws

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials Using Thermal Means (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Abstract

The present invention relates to a detection method for a delamination defect in an EVA material and a detection device thereof and, more specifically, to a detection method for a delamination defect in an EVA material and a detection device thereof, which can perform thermal non-destructive entire inspection and automate determination of a defect. According to the present invention, a detection method for a delamination defect in an EVA material comprises: a product heating step of heating a product to be inspected using heat; an IR image acquisition step of acquiring an IR image by photographing the object to be inspected which is heated by the heat with an infrared thermal camera; and a defect detection step of determining a delamination defect portion which is expressed with a lower temperature than a reference temperature which is set in the IR image.

Description

TECHNICAL FIELD [0001] The present invention relates to an EVA material detachment defect detection method and an EVA material detachment defect detection method,

More particularly, the present invention relates to an EVA material detachment defect detecting method and an EVA material detecting method, and more particularly, to a EVA material detachment defect detecting method and EVA material detachment detecting method, Heating the product to be inspected so as to be able to detect a peeling defect, which is a phenomenon to be lifted in a part of the joint surface, obtaining an IR image through an infrared thermal camera, and utilizing a phenomenon that heat conduction is not performed well in the peeling defect portion The present invention also relates to an apparatus and method for detecting defects in an EVA material, which is capable of performing thermal non-destructive inspection and automating defect discrimination by including a step of determining an exfoliation defect part through analysis of the obtained IR image.

The defects inspection system is a very important part in industrial production process and the non-destructive part of the inspection method is considerable progress.

As one of the non-destructive inspection methods, the infrared thermal imaging non-destructive inspection technology is a quality inspection and stability evaluation technology that diagnoses physical properties and occurrence of defects by detecting infrared rays emitted from the object without destroying the product. The application and importance are increasing with the development of semiconductors, nuclear power industry, defense industry, aerospace industry, automobile industry and so on.

It is very important to study the whole water inspection system applying this infrared imaging technique at the time when the defect detection is not automated or mechanized in the shoe inspection system.

The outsole (OUTSOLE) used as the sole of the shoe is different in structure, shape and material depending on the function of the shoe. In case of tennis file, the rubber is usually formed on the entire floor and the side wall.

Other shoes are functional and have a wear-resistant rubber compound used for the outsole tread to reduce the weight. The EVA shoes are made of EVA sponge, pylon, PU and other lightweight, (MIDSOLE) is bonded and used.

In addition, in order to lighten the shoe, rubber or EVA resin is foamed and used for outsole (OUTSOLE)

EVA resin is a copolymer produced by polymerizing ethylene monomer and vinyl acetate monomer (VAM) in a high-pressure reactor that produces low density polyethylene (LDPE) and produces EVA resin by injecting VAM as much as the desired VA content.

That is, if the VA content of any EVA resin is 15%, it means that it is a product obtained by polymerizing 85% of ethylene and 15% of VAM.

EVA resins are divided into high pressure polymerization, solution pressure and emulsion polymerization according to the production method, and their shapes are also changed according to the production method.

The EVA resin produced through high pressure pressure is in the form of a solid pellet and the maximum VA content that can be produced varies depending on the conditions of the reactor but is less than about 40%.

Unlike LDPE resins, which are polymerized only with ethylene, EVA resins have unique properties other than LDPE resins by copolymerizing VAM.

Unlike LDPE, EVA resin is transparent and has excellent heat sealability and crosslinking properties, and is used as a raw material for shoe sponges, agricultural films, thermal films, and hot-melt adhesives.

Especially, EVA resin, which is applied to the sponge for footwear, is different from rubber and polyurethane materials, and is used as a raw material for impact shock absorbing material of footwear because of being light, easy to process, and relatively inexpensive.

The area where EVA resin is applied to the shoe is a shock-absorbing component called so-called midsole and insole, which is manufactured by secondary molding a crosslinked / foamed sponge of EVA.

One of the biggest defects in shoes is a defect in strength due to delamination in the bonding process.

The most serious defects are defects on the adhesive side of the midsole of shoes made of EVA material and the insole made of ordinary rubber material. So far, defective discrimination has relied on tensile testing, one of the destructive methods It was also common to be performed depending on the senses, such as the tester's vision.

However, there is a problem in that it is not possible to conduct a full inspection in the destructive method among the basic methods and only a sample inspection is required.

In addition, the method of discriminating defects through the tester's vision is not only difficult to accurately discriminate due to various variables of the surrounding environment such as the operator, ambient brightness and time, but also implements the repetition and reproducibility of the discrimination result There is a problem in that it is not possible to quantify data that can determine the peeling defect on the joint surface.

In the prior art, a "shoe inspecting apparatus using an X-ray" has been proposed in Japanese Patent Application Laid-Open No. 10-2004-0020988 (published on March 10, 2004) The present invention relates to a shoe inspecting apparatus for inspecting whether a staple temporarily applied during the assembling process remains on a floor surface of an assembled shoe or whether there is an assembling screw at a designated position. There has been a problem that it is difficult to apply it to the detection of peeling defects.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art as described above, and it is an object of the present invention to provide a method and apparatus for detecting a peeling defect of an EVA material, Is used to analyze the IR image of an object to be inspected heated by a heat source with an infrared camera to determine the part of the defect to be peeled, thereby enabling the inspection of the non-destructive whole number as well as the EVA material A method of detecting a separation defect, and a detection apparatus therefor.

In order to achieve the above object, an EVA material separation defect detection method according to the present invention is a method for detecting an EVA material separation defect, comprising the steps of: preparing an EVA (ethylene-vinyl acetate copolymer) A method for detecting a material separation defect, comprising: a product heating step of heating the inspection object product using a heat; An IR image acquiring step of acquiring an IR image by imaging an object to be inspected heated by the hot temperature with an infrared thermal imaging camera; A defect detection step of analyzing a temperature distribution of the inspection target product from the IR image and determining a portion indicated by a temperature lower than a reference temperature set in the IR image as a peeling defect portion; .

The EVA material separation defect detecting apparatus according to the present invention is an EVA material separation defect detecting apparatus for detecting an exfoliation defect on a joint surface of an EVA (ethylene-vinyl acetate copolymer) A heating source for heating the inspection target product; An infrared ray camera for picking up an inspection target product heated by the hot temperature to obtain an IR image of the inspection target product; Analyzing a temperature distribution of the inspection target product from an IR image acquired from the infrared radiographic camera and determining a portion indicated by a temperature lower than a reference temperature set in the IR image as a separation defect portion; .

Further, in the EVA material separating defect detecting apparatus according to the present invention, the hot temperature is a halogen lamp capable of adjusting the output.

Further, in the EVA material separation defect detection apparatus according to the present invention, the halogen lamp is arranged to irradiate light toward a surface parallel to the bonding surface of the inspection object product, and the infrared thermal imaging camera And is arranged in the same direction as the halogen lamp so as to be capable of obtaining an IR image with respect to the light reflected from the surface, and is arranged in a direction perpendicular to the junction surface of the inspection target product.

The EVA material separation defect detecting device according to the present invention is characterized in that the inspection target product is a shoe in which a midsole made of an EVA material and an insole made of a general rubber material are bonded together with an adhesive.

According to the above-described structure, the EVA material separation defect detection method and the EVA material detection apparatus according to the present invention can detect a separation defect of an EVA material by utilizing a phenomenon that heat conduction is not performed well in the separation defect portion, The IR image obtained by imaging the object to be inspected by the heat source with the infrared ray camera is analyzed to determine the part to be peeled off, so that the non-destructive whole inspection can be performed and the defect identification can be automated with high reliability.

1 is a flow chart of a method of detecting a separation defect of an EVA material according to an embodiment of the present invention.
2 is a block diagram of an EVA material separation defect detection apparatus according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating an IR image of a first inspection target product according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating an IR image of a second inspection target product according to an embodiment of the present invention.
5 is a graph showing an average temperature change over time of a first inspection target product according to an embodiment of the present invention.
6 is a graph showing an average temperature change over time of a second inspection target product according to an embodiment of the present invention
FIG. 7 is a graph showing a change in temperature for each position of the first inspection target product according to an embodiment of the present invention
FIG. 8 is a graph showing a temperature change according to a position of a second inspection target product according to an embodiment of the present invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an EVA material separation defect detection method and a detection device thereof according to the present invention will be described in detail with reference to embodiments shown in the drawings.

FIG. 1 is a flowchart of an EVA material peeling defect detecting method according to an embodiment of the present invention, and FIG. 2 is a configuration diagram of an EVA material peeling defect detecting apparatus according to an embodiment of the present invention.

1, an EVA material separation defect detection method according to an embodiment of the present invention is a method for detecting a separation defect in an EVA material, which comprises the steps of: (a) bonding an EVA (ethylene-vinyl acetate copolymer) A product heating step S10, an IR image acquiring step S20, and a defect detecting step S30 for detecting the peeling defect on the surface (a).

The product heating step S10 is a step of heating the inspection target product A using the heating temperature 10 so that heat conduction can be performed on the bonding surface a of the inspection target product A.

A detailed description of the hot temperature 10 will be given later in the description of the EVA material peeling defect detecting apparatus according to an embodiment of the present invention.

The IR image acquiring step S20 is a step of acquiring an IR image by taking an image of the product A to be inspected heated by the heat 10 with the IR camera 20.

An example of the IR image is shown in FIGS. 3 and 4. FIG.

The defect detecting step S30 is a step of analyzing a temperature distribution of the inspection target product A from the IR image, and determining a portion indicated by a temperature lower than a reference temperature set in the IR image as a peeling defect portion.

The determination as the peeling defect portion is made in the computing unit 30, and a detailed description thereof will be given later in the description of the EVA material peeling defect detecting apparatus according to an embodiment of the present invention.

Hereinafter, a method of detecting a peeling defect of an EVA material according to an embodiment of the present invention has been described, and a method of detecting a peeling defect of an EVA material according to an embodiment of the present invention will be described in detail.

3 and 4 are IR images of a product to be inspected according to an embodiment of the present invention, and FIGS. 5 and 6 show the IR image of the product to be inspected according to an embodiment of the present invention. FIG. 7 and FIG. 8 are graphs showing temperature changes according to positions of a product to be inspected according to an embodiment of the present invention. FIG.

2 to 8, an EVA material separation defect detecting apparatus according to an embodiment of the present invention includes an EVA (Ethylene Vinyl Acetate Copolymer) material 1 and an A (10), an infrared ray camera (20), and an arithmetic unit (30) as an apparatus for detecting a delamination defect in a joint surface (a)

The heat source 10 is configured to heat the inspection object product A, and in an embodiment of the present invention, the control device is configured with a halogen lamp capable of controlling the output thereof.

Meanwhile, in one embodiment of the present invention, the halogen lamp as the heat source 10 is arranged to irradiate light toward a surface b parallel to the bonding surface a of the product A to be inspected.

The infrared radiographic camera 20 is configured to pick up an inspection target product A heated by the heating temperature 10 so as to obtain an IR image of the inspection target product A.

Meanwhile, in an embodiment of the present invention, the infrared ray camera 20 may be configured to allow the IR image to be acquired for light reflected on one surface (b) of the product to be inspected (A) by a reflection method The object to be inspected A is disposed in the same direction as the halogen lamp as the light source 10 so as to obtain an accurate IR image of the whole on the joint surface a of the product to be inspected A, (a).

The operation unit 30 analyzes the temperature distribution of the inspection target product A from the IR image acquired from the infrared thermal imaging camera 20 and removes a portion displayed at a temperature lower than the reference temperature set in the IR image It is determined as a defective portion.

That is, the calculation unit 30 calculates the reference temperature (temperature) in the IR image using the phenomenon that heat conduction is not performed well due to lifting of the EVA material 1 and the other material 2 in the peeling defect portion of the bonding surface (a) And a portion which is displayed at a lower temperature is determined as a peeling defect portion.

In the experiment according to an embodiment of the present invention, the heat source 10 uses one 1 Kw halogen lamp.

In the experiment according to an embodiment of the present invention, the infrared radiographic camera 20 uses a P620 product manufactured by FLIR.

The technical functions of the infrared radiographic camera 20 used in the experiment according to the embodiment of the present invention are as shown in the following Table 1.

Imaging and optical data Field of view / Minimum focus distance 24 ° x18 ° / 0.3m Spatial resolution 0.65 mrad Thermal sensitivity 40 mK @ + 30 ° C Image frequency 30 Hz Focal Plane Array / Spectral range Uncooled microbolometer / 7.5-13 ㎛ IR resolution 640 x 480 pixels Temperature range -40 ° C to + 500 ° C Accuracy ± 2 ° C or ± 2% of reading

The product to be inspected (A) used in the experiment according to an embodiment of the present invention is a product to be inspected, which is a rubber to be bonded to a general rubber used in shoes, and an EVA material And the second test object to which the second test object was bonded.

Since the test object A according to the embodiment of the present invention is a shoe in which a midsole made of an EVA material and an insole made of a general rubber material are bonded together with an adhesive, it is necessary to pay attention to the experimental result on the second test object product .

The infrared ray camera 20 and the heat source 10 were supplied with a light source and a heat source for two minutes by the same reflection method to obtain temperature data for each hour. The results are shown in FIGS. 3 to 8.

3 is an IR image of a first inspection target product captured by the infrared thermal imaging camera 20, and Fig. 4 is an IR image of a second inspection target product.

On the other hand, the inspection target product disposed on each of FIGS. 3 and 4 is a normal product, and the inspection target product disposed below is an abnormal product having a separation defect.

In FIG. 3 and FIG. 4, Li1 represents a position on a certain line of a normal product, Ar1 represents a certain area (area) of a normal product, Li2 represents a position on a certain line of an abnormal product, Ar2 represents an abnormal product (Area) of the area.

5 and 6 show the average temperature change over time of the product to be inspected according to an embodiment of the present invention. The first product to be inspected and the second product to be inspected are both abnormal products (Ar2 ), It can be confirmed that the average temperature is low in a certain area (area).

7 and 8 illustrate the temperature change of each inspection target product on a certain line according to an embodiment of the present invention. In the case of the normal product Li1 in both the first inspection target product and the second inspection target product There is no temperature change by position, but in case of abnormal product (Li2), it can be confirmed that the temperature is lower than the ambient temperature in the peeling defect part.

As a result of the above-described experiment, it was found that the apparatus according to the embodiment of the present invention is capable of detecting the peeling defect of the EVA material.

The halogen lamp was able to confirm that the temperature rise rate was good because it directly applied the heat source to the product to be tested (A) and that the product to be tested (A) was not damaged by the heat applied directly.

Thus, the possibility of developing a full inspection system for shoe using the EVA material through the infrared thermal imager 20 can be seen.

As a result of the test results, it was confirmed that the non-destructive inspection for the adhesion efficiency evaluation using the infrared thermography camera 20 in the field production line was possible. When the halogen lamp was applied to the heat source 10, In the case of a good place, the heat conduction was good, and the temperature was high. In the defective part where the joint part was excited, the heat conduction was not performed well and the temperature was low. When the halogen lamp was used as the defect detecting heat source, The temperature rise rate due to the difference in the heat transfer rate of the heat exchanger was high.

The EVA material separation defect detection method and detection apparatus described above and shown in the drawings are only one embodiment for carrying out the present invention and should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is defined only by the matters set forth in the following claims, and the embodiments improved and changed without departing from the gist of the present invention are obvious to those having ordinary skill in the art to which the present invention belongs It will be understood that the invention is not limited thereto.

S10 Product heating stage
S20 IR image acquisition step
S30 defect detection step
A Product to be inspected
1 EVA material
2 other materials
a joint surface
b day surface
10 heat source
20 Infrared thermal camera
30 operation unit

Claims (5)

An EVA material separation defect detection method for detecting a separation defect on a joint surface of a product to be inspected in which EVA (ethylene-vinyl acetate copolymer) material and other materials are mutually bonded,
A product heating step of heating the inspection target product by using a hot temperature;
An IR image acquiring step of acquiring an IR image by imaging an object to be inspected heated by the hot temperature with an infrared thermal imaging camera;
A defect detection step of analyzing a temperature distribution of the inspection target product from the IR image and determining a portion indicated by a temperature lower than a reference temperature set in the IR image as a peeling defect portion; And removing the EVA material. An EVA material separation defect detecting apparatus for detecting a separation defect on a joint surface of an inspection target product in which EVA (ethylene-vinyl acetate copolymer) material and other materials are mutually bonded,
A heat source for heating the inspection target product;
An infrared ray camera for picking up an inspection target product heated by the hot temperature to obtain an IR image of the inspection target product;
Analyzing a temperature distribution of the inspection target product from an IR image acquired from the infrared radiographic camera and determining a portion indicated by a temperature lower than a reference temperature set in the IR image as a separation defect portion; And a peeling defect detecting device for detecting the peeling defect of the EVA material. 3. The method of claim 2,
Wherein the hot temperature is a halogen lamp capable of controlling the output. The method of claim 3,
Wherein the halogen lamp is arranged to irradiate light toward a surface parallel to the bonding surface of the inspection target product,
Wherein the infrared ray camera is disposed in the same direction as the halogen lamp so as to enable acquisition of an IR image for light reflected from one surface of the inspection target product and is arranged in a direction perpendicular to the bonding surface of the inspection target product Wherein the EVA material is a PET film. The method according to any one of claims 2 to 4,
Wherein the inspection target product is a shoe in which a midsole made of an EVA material and an insole made of an ordinary rubber material are bonded together with an adhesive.
KR1020140009638A 2014-01-27 2014-01-27 Detecting method for delamination defect in eva material and detecting device for thereof KR20150089242A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110031511A (en) * 2019-04-19 2019-07-19 清华大学深圳研究生院 Defect detecting device, defect detecting system and defect inspection method
KR102020518B1 (en) * 2018-09-27 2019-09-10 (주)케이디솔루션즈 Device And Method for Position Estimation for Measuring Temperature of Out Sole on Changing Shoes Size in Sole-Bonding Pressure of Shoe

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102020518B1 (en) * 2018-09-27 2019-09-10 (주)케이디솔루션즈 Device And Method for Position Estimation for Measuring Temperature of Out Sole on Changing Shoes Size in Sole-Bonding Pressure of Shoe
CN110031511A (en) * 2019-04-19 2019-07-19 清华大学深圳研究生院 Defect detecting device, defect detecting system and defect inspection method
CN110031511B (en) * 2019-04-19 2022-02-25 清华大学深圳研究生院 Defect detection device, defect detection system and defect detection method

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