KR100267614B1 - Cold rolled steel pinhole inspection device - Google Patents

Abstract

The present invention relates to a cold-rolled steel sheet pinhole inspection device, comprising: an infrared pulse LED (21) for forming light required for the cold-rolled pinhole inspection device; A light irradiator 22 irradiating light emitted from the infrared pulse LED 21 at various angles; An electric controller (23) for generating high energy infrared rays in the form of pulses from the infrared pulse LED (21); A condenser lens 24 condensing when passing through the infrared pinhole generated by the infrared pulse LED 21 and appearing on the rear surface of the cold rolled steel sheet 27; An infrared linear CCD sensor 25 which detects the infrared rays collected by the condenser lens 24 and converts the infrared rays into an electrical signal; The computer 26 is configured to evaluate and report the presence or absence of a pinhole using the electric signal converted by the infrared linear CCD sensor 25. The light is irradiated at various angles, and the light passing through the pinhole is collected to pinhole. Since the inspection is to have the advantage of improving the detection rate for the inclined pinhole based on the thickness direction of the cold rolled steel sheet.

Description

Cold rolled steel pinhole inspection device

The present invention relates to an inspection apparatus for inspecting pin-holes generated in a cold rolled steel sheet used as a steel can material steel sheet, and particularly, to improve the detection rate of pinholes inclined in the rolling direction with respect to the thickness direction of the steel sheet. The present invention relates to a cold-rolled steel sheet pinhole inspection apparatus using a multi-light source.

Common cold rolled steel sheet pinholes are caused by defects in materials, and the size of the pinholes is about 100 to 10 µm in diameter. Most of the pinholes have a characteristic parallel to the thickness direction of the steel sheet before cold rolling but inclined with the thickness direction of the steel sheet after rolling. When manufacturing a CAN product using such a pinhole material, the contents of the CAN leak out through the pinhole, forming a shape such as sweat droplets on the surface of the can, or rupturing during the process of making the can. . In order to eliminate the above problems and to supply the whole product to consumers, the cold rolled steel sheet production process is equipped with an inspection device for detecting pinholes.

The types and characteristics of the current pinhole inspection device are as follows.

First, a laser is used as a light source, and a detection sensor uses a photo multlpller tube, which has the configuration shown in FIG. As shown in FIG. 1, the light source reflects the He-Ne laser to the rotating mirror to irradiate the upper surface of the cold rolled steel sheet, and to place the optical distribution amplifier on the lower surface to receive the laser light passing through the pinhole to determine the presence of the pinhole. In this structure, a laser is generated in the laser light source 1 and reflected on the flipping mirror 3, and the reflected laser is reflected on the polygon mirror 4. The reflected laser is irradiated linearly to the deformation mirror 2 since the polygon mirror 4 rotates. Since the directionality of the laser reflected by the deformation mirror 2 is not irradiated directly to the steel sheet, it is changed to be irradiated perpendicular to the surface of the steel sheet by the concave mirror 5 and the tilt mirror 7. The laser, which is changed vertically, is received by the light tube 9 through the steel plate 15 in which the pinhole exists through the window 8. The laser is reflected by the internal micromirror and converted into an electrical signal in the photodistribution amplifier 10. The electrical signal is subjected to signal processing to evaluate the presence of pinholes.

The features of this pinhole inspection device are as follows.

end. In order to irradiate the light source composed of point sources in the width direction of the cold rolled steel sheet, the rotating mirror of the polygon must be rotated, and thus the light irradiation apparatus is very complicated.

I. The characteristics of the laser are difficult to irradiate the laser in various directions because the straightness of the light is strong. Therefore, the detection rate for the pinhole inclined in the rolling direction is low.

All. Since the short wavelength of 633mm is used, the permeability to micro holes is weak.

la. The cost of increasing the energy of the laser is high.

hemp. Although the light sensitivity of the optical receiver is high, it is influenced by the ambient light due to the reception of a wide wavelength.

bar. The optical system consists of several lenses, making lens maintenance difficult.

four. Large volume and weight of optics make installation difficult.

Secondly, the light source is a halogen lamp, and the light is irradiated to the cold rolled steel sheet through the optical fiber bundle, and the pinhole inspection of the configuration as shown in FIG. 2 is used to determine the presence or absence of the hole through the pin diode. There is a device. This device irradiates the surface of the cold rolled steel sheet through the optical fiber bundle composed of the light generated from halogen in the width direction of the cold rolled steel sheet, and this device also does not show good performance for the inclined pinhole similar to the laser-based device. There is this. The optical receiver detects pinholes by linearly arranging pin diodes capable of detecting minute light. Unlike the laser, this device is characterized by the fact that the light is not composed of the point source light, but is linear in the width direction of the cold rolled steel sheet. However, the shape of the light irradiated in the rolling direction is also composed of dots, and in order to detect pinholes inclined in the rolling direction, a light source having excellent strong light and diffraction of light must be used, and light is generated in the halogen lamp 11. This light source is transmitted to the optical splitter 13 through the optical fiber bundle 12. The optical splitter 13 distributes the halogen light 14 evenly in the width direction of the steel plate, and the halogen light 14 passing through the strip 15 in which the pinhole exists is received by the pin diode sensor 16 and is pinned. Evaluate the presence of the hall.

The device features:

end. Since continuous halogen light is used, it is difficult to adjust the intensity of the halogen light.

I. The device is simpler than laser optics.

All. Maintenance is easy with the use of semiconductor sensors.

la. Low detection rate for inclined pinholes.

hemp. Sensitive to external light sources

A common feature of the device using a laser and the device using a halogen lamp in the above description is that the detection rate for pinholes that occur obliquely in the direction of movement of the strip (above 12 ° in the strip thickness direction) is low. In practice, the pinhole inclination after rolling is mostly 12 ° or more. A common feature of these two mentioned conventional devices is that the detection rate for slanted pinholes decreases drastically. The reason is that first, as shown in FIG. 3, the size of light entering the inclined pinhole is reduced by multiplying the vertically incoming light by COS (α) (α: inclination with the vertical pinhole). That is, when the light intensity incident to the vertical pinhole is I, the intensity I (α) = COS (α) × I of light incident to the pinhole inclined at the α angle is obtained.

Second, the general pinhole has a characteristic that the diameter of the hole is changed by roughness or narrowing, as shown in FIG. 4. Therefore, when the laser or halogen light having a straight line passes through the pinhole as shown in FIG. 4, the probability of light passing and receiving is significantly reduced. In this case, the light reduced by COS (α) flows into the pinhole, but since the reflection of the light increases due to the uneven surface existing on the inner wall of the pinhole, the light passing through the pinhole is significantly reduced.

The present invention was invented to solve the problems of the conventional cold-rolled steel sheet pinhole inspection apparatus currently used in view of the above situation, by constructing a new optical device using the LED pulse light to match the pinhole and thickness direction of the steel sheet thickness direction It is an object of the present invention to provide a cold-rolled steel sheet pinhole inspection apparatus using LED pulse light to improve the detection rate for the inclined pinhole.

1 is a block diagram of a cold-rolled steel sheet pinhole inspection device using a conventional laser.

2 is a configuration of the pinhole inspection device for cold rolled steel sheet using a conventional halogen lamp.

3 is a view showing the amount of light drawn in the inclined pinhole.

4 is a state diagram of the inner wall of the inclined pinhole.

5 is a block diagram of the cold-rolled steel sheet pinhole inspection device of the present invention.

6 is a view comparing the operation of the present invention pinhole inspection device and the pinhole inspection device,

(a) is the case of the present invention pinhole inspection device,

(b) is the case of the conventional pinhole inspection apparatus.

* Explanation of symbols for main parts of the drawings

1: laser 2: Deviation mirror

3: Flipping Mirror 4: Polygon Mirror

5: Concave Mirror 6: Cover

7: Tilt mirror 8: Window

9: optical tube (E.R.T) 10: optical distribution amplifier (P, M.T)

11 halogen lamp 12 optical fiber bundle

13: optical splitter 14: halogen light

15 strip 16 pin diode sensor

21: Pulsed Infra Red Light Emitted Doide

22: light irradiator 23: electric controller

24 condensing lens

25 Infra Red Linear CCD Sensor

26: signal processing computer 27: cold rolled steel sheet

The present invention for achieving the above object is an infrared pulse LED (21) for forming the light required for the cold rolling pin hole inspection device; A light irradiator 22 irradiating light emitted from the infrared pulse LED 21 at various angles; An electric controller (23) for generating high energy infrared rays in the form of pulses from the infrared pulse LED (21); A condenser lens 24 for condensing the infrared rays generated by the infrared pulse LED 21 when passing through the pinhole and appearing on the rear surface of the cold rolled steel sheet 27; An infrared linear CCD sensor 25 which detects the infrared rays collected by the condenser lens 24 and converts the infrared rays into an electrical signal; It is characterized in that it comprises a computer 26 for evaluating and reporting the presence or absence of pinholes using the electrical signal converted by the infrared linear CCD sensor 25.

Hereinafter, the operation of the cold-rolled steel sheet pinhole inspection device using the LED pulse of the present invention will be described in detail.

5 is a block diagram showing the overall configuration of the cold-rolled steel sheet pinhole inspection device using the LED pulse of the present invention, the infrared pulse LED 21 capable of generating infrared light, and the LED 21 arranged in a half cylinder form The light irradiator 22 irradiates at various angles in the rolling direction of the cold rolled steel sheet, and applies a voltage to generate infrared rays from the infrared pulse LED 21 in synchronization with the feed rate of the steel sheet, and adjusts the energy of the infrared rays. Infrared rays that pass through the pinhole of the cold rolled steel sheet 27 by adopting an optical condenser lens 24 and an infrared filter so that the infrared rays passing through the electric controller 23 having the function and the cold rolled steel sheet 27 can be concentrated in one place. The infrared linear CCD sensor 25 is received and the optical signal is converted into an electrical signal. In the infrared linear CCD sensor 25, the infrared ray passing through the pinhole generates a difference from an electrically normal signal, and provides the signal processing computer 26 with a basis signal of the presence or absence of the pinhole. The signal processing computer 26 analyzes the electrical signals received from the infrared linear CCD sensor 25 to evaluate the presence of the pinholes and to issue the necessary documents such as the movement distance of the cold rolled sheet and the widthwise position of the pinholes. Consists of.

6 is a view comparing the operation of the present invention pinhole inspection device and the conventional pinhole inspection device, (a) is the case of the present invention, (b) is a conventional case.

As shown in the light irradiator 22, all the infrared pulse LEDs 21 arranged in the light irradiator 22 generate infrared rays by the electric controller 23 at the same time. The time to generate infrared light is about 1kHz and the frequency can be controlled as 200KHz. The characteristics of the infrared pulse LED 21 can be controlled in a very short period of time, and the lens is configured at the end of the LED so that the infrared light emitted from the LED has a straightness as shown in FIG. 6 (a) within a certain distance. When arranged in the form as shown in (22), it can be detected even when the inclination of the pinhole generated in the cold rolled steel sheet is about 20 ° based on the thickness direction of the steel sheet. In addition, if the LED density is increased and the applied voltage is increased, the infrared energy is increased at the moment of being applied in the form of pulse, so that it is less affected by the environmental lighting of the surroundings than the conventional laser or halogen method and improves the infrared transmission efficiency of the pinhole. Can be.

Looking at the operating time and the output of the infrared pulse LED 21, when continuously driving the LED does not continuously output the maximum peak value that can be output from the LED as the temperature rises. However, in a short time, the peak can be output. Therefore, there is an advantage to obtain a high energy infrared ray by using the control of the pulse form. Since the straightness is strong and the high-energy light is irradiated at various angles, the probability of passage for small pinholes increases, and the detection rate for inclined pinholes increases as shown in FIG.

In the conventional case of the laser light having a strong straightness, the reflection of the laser occurs severely with respect to the inclined pinhole, which makes it difficult for the laser to reach the sensor portion as shown in FIG. However, the present invention configured to irradiate light of various angles is configured such that even when the angle of the pinhole is inclined, light of an angle suitable for the inclination can automatically pass through the pinhole to reach the opposite sensor. Conventional laser or halogen type detection is impossible when the pinhole inclination is ± 12 ° or more. However, in the case of the present invention as shown in FIG. 6 (a), when the light irradiator distribution has a degree of ± 20 ° based on the thickness direction of the cold rolled steel sheet, the same detection as the laser or halogen type is detected for the inclined pinhole within ± 34 °. Can be secured.

The cold-rolled steel sheet pinhole inspection device of the present invention, which acts as described above, irradiates light at various angles and collects the light passing through the pinhole, thereby inspecting the pinhole, thereby detecting a detection rate for the pinhole inclined based on the thickness direction of the cold-rolled steel sheet. There is an advantage that can be improved.

Claims (1)

An infrared pulse LED 21 for forming light required for a cold rolled pinhole inspection device; A light irradiator 22 irradiating light emitted from the infrared pulse LED 21 at various angles; An electric controller (23) for generating high energy infrared rays in the form of pulses from the infrared pulse LED (21); A condenser lens 24 condensing when passing through the infrared pinhole generated by the infrared pulse LED 21 and appearing on the rear surface of the cold rolled steel sheet 27; An infrared linear CCD sensor 25 which detects the infrared rays collected by the condenser lens 24 and converts the infrared rays into an electrical signal; Cold-rolled steel sheet pinhole inspection device, characterized in that it comprises a computer 26 for evaluating and reporting the presence or absence of the pinhole using the electrical signal converted by the infrared linear CCD sensor (25).