JP2003322622A - Defect inspection apparatus and defect inspection method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defect inspection apparatus and a defect inspection method using it which accurately find the number of defects on inspected materials when quality of the inspected materials is determined based on defect information of the inspected materials respectively detected by a plurality of defect detectors and determine the quality of the inspected materials based on the number of the defects. <P>SOLUTION: The defect inspection apparatus is provided with a plurality of the defect detectors and a discriminator for discriminating whether the defects respectively detected by the defect detectors are the same by comparing and verifying the defect information of the inspected materials sent from the defect detectors. The defect inspection method uses the defect inspection apparatus and discriminates whether the defects respectively detected by the defect detectors are the same by comparing and verifying the defect information of the inspected materials sent from defect detectors. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection apparatus having a plurality of defect detectors and a defect inspection method using the same.

[0002]

2. Description of the Related Art Defects in a material to be inspected can be classified into various types according to the quality required as a product. For example,
Defects existing in steel strips are roughly classified into hole defects, surface defects and internal defects, and defect detectors with various detection principles are used according to the defect types. For example, a transmitted light type hole defect detector is often used to detect a hole in a steel strip, and if it is a surface defect detector that detects a surface flaw in a steel strip,
As a CCD camera imaging method, a laser diffraction method, or the like, a leakage magnetic flux type, an ultrasonic type, or an overcurrent type is used as an internal defect detector for detecting an internal defect of a steel strip.

In recent years, quality requirements for products have become more and more stringent. For example, a plurality of defect detectors having different detection principles are installed on a steel strip inspection line according to the purpose, and each defect detector detects a defect. It is not unusual for defect inspection equipment to meet quality requirements. As a defect inspection device installed in a continuous galvanizing line that continuously galvanizes steel strip, there are transmitted light type hole defect detectors, CCD camera imaging type surface defect detectors, and leaks that can detect gouge defects. A magnetic flux type internal defect detector is installed in one line, each defect detector detects a defect independently, and the number of defects per inspection length of the inspected material is counted. It is used. Each of these defect detectors has a pass / fail determination function for independently performing pass / fail determination of whether the inspection target material passes or fails based on the number of defects of the inspection target inspection material.

Conventionally, the acceptance / rejection determination of the material to be inspected uses the acceptance / rejection determination function of each defect detector, and each defect detector makes its own acceptance / rejection determination of the material to be inspected.

[0005]

When the pass / fail judgment of the material to be inspected is performed in this manner, a defect of a defect type which should not be originally detected by the defect detector is detected depending on the detection principle of the defect detector. However, the defects are counted in duplicate, and one defect may be counted in duplicate in the number of defects independently counted by each defect detector.

For example, in a defect inspection apparatus for a continuous galvanizing line, when there are a plurality of relatively large hole defects (having a diameter of about 1 mm or more) per length of the material to be inspected, the hole defect detector of the transmitted light system is used. Although they are detected as hole defects, the surface defect detector of the CCD camera imaging method also detects the hole defect image and detects it as a surface defect. The magnetic flux leaked from the hole defect is detected as a gouge defect, so each defect detector detects it when making a pass / fail judgment as a product based on the total number of defects existing per inspection length of the inspected material. It was found that the total number of defects was larger than the actual total number of defects.

As described above, when the acceptance / rejection determination of the inspected material is made based on the defect information of the inspected material detected by each of the plurality of defect detectors, the same defect is redundantly detected and counted twice. In some cases, the total number of defects in the inspected material was erroneous, and as a result, the inspected material was determined to be rejected. The present invention is to solve the problems of the above-described conventional technology, based on the defect information of the inspected material detected by each of the plurality of defect detectors, when performing the pass / fail judgment of the inspected material, An object of the present invention is to provide a defect inspection device and a defect inspection method using the same, which can accurately determine the number of defects. Further, it is another object of the present invention to provide a defect inspection apparatus and a defect inspection method using the defect inspection apparatus, which determines whether the material to be inspected is acceptable or not based on the number of defects.

[0008]

The present invention is as follows. The invention according to claim 1 is a defect inspection apparatus having a plurality of defect detectors, wherein the defect information of a plurality of defect detectors and the inspection material sent from each defect detector are compared and collated. Thus, the defect inspection device is provided with a discriminator for discriminating whether or not the defects detected by the respective defect detectors are the same defect.

The invention according to claim 2 is the defect inspection apparatus according to claim 1, wherein the defect information of the material to be inspected is the position in the longitudinal direction of the defect. The invention according to claim 3 is the defect inspection apparatus according to claim 1 or 2, wherein the classifier is configured to determine a defect type. The invention according to claim 4 is configured such that the discriminator outputs the number of defects, and the pass / fail judgment is made based on the number of defects. apparatus.

According to a fifth aspect of the present invention, in the defect inspection method for making a pass / fail judgment of the inspected material based on defect information of the inspected material detected by each of the plurality of defect detectors, A defect inspection method characterized by determining whether or not the defects detected by the respective defect detectors are the same defect by comparing and collating the defect information of the inspected material that is sent. .

The invention according to claim 6 is the defect inspection method according to claim 5, wherein the defect information of the inspected material is the position in the longitudinal direction of the defect. The invention according to claim 7 is characterized in that the number of defects of the inspected material is obtained for each defect type, and the pass / fail judgment of the inspected material is performed according to the number of defects for each defect type. The defect inspection method described in 5 or 6.

The invention according to claim 8 is characterized in that the number of defects is obtained based on the result of the defect determination of the material to be inspected, and the pass / fail judgment is performed based on the number of defects. It is the defect inspection method described in any one.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, in a defect inspection apparatus having a plurality of defect detectors, the defect information of a plurality of defect detectors and the inspection material sent from each defect detector are compared and collated. As a result, a defect inspection apparatus equipped with a discriminator for discriminating whether or not the defects detected by the respective defect detectors are the same defect is sent from each defect detector when inspecting the inspected material. By comparing and collating the received defect information of the inspected material, it is possible to determine whether or not the defects detected by the respective defect detectors are the same defect. Furthermore, the number of defects of the inspected material is obtained based on the determination result, and the pass / fail judgment of the inspected material is performed according to the number of defects, whereby the number of defects of the inspected material can be accurately obtained. it can. Moreover, since the acceptance / rejection determination of the inspection material is performed according to the number of defects, the acceptance / rejection determination of the inspection material can be correctly performed. Alternatively, the discriminator can discriminate the defect type.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where the above invention is applied to an inspection of a galvanized steel strip will be described below with reference to FIGS. 1 and 2. FIG. 1 is a schematic layout of a defect inspection apparatus in a continuous galvanizing line to which the present invention is applied. In this continuous galvanizing line, defect detectors A, B and C are installed in this order from the upstream side. FIG. 2 is a schematic circuit diagram in the arithmetic unit 7 shown in FIG. 1, and reference numeral 7a is a discriminator. In this embodiment, the total number of defects per inspection length of the inspected material (also simply referred to as the number of defects) is obtained, and the pass / fail judgment of the inspected material is performed.

The continuous galvanizing line shown in FIG. 1 comprises an annealing furnace 3 and a galvanizing device 4 for immersing the steel strip S in a hot dip bath and then cooling it. The steel strip, which is the material S, is annealed and galvanized while being conveyed in the direction of the arrow 8, and is wound by the tension reel 6. Reference numeral 2 in the figure
Is a welding machine for welding the tail end of the preceding material and the leading end of the following material, and reference numeral 5 is a shearing machine for cutting the material S to be inspected connected by the welding machine 2.

Further, the detectors A, B and C are connected to the arithmetic unit 7 including the discriminator 7a as shown in FIG. 2, and the defect information AI, BI and CI are respectively sent and inspected. After the end, the shearing machine 5 sends cutting information 5I of the material to be inspected. N ₀ is the total number of allowable defects of the product used for the pass / fail judgment of the inspected material, and is sent from the host computer. Here, the defect detector A is a hole defect detector of a transmitted light system, the defect detector B is a surface defect detector of a CCD camera imaging system, and the defect detector C is a leakage flux type internal device capable of detecting a gouge defect. It is a defect detector.

As shown in FIG. 1, the defect inspection apparatus includes defect detectors A, B and C and respective defect detectors A, B and C.
Defect information AI, BI, C of the inspected material sent from C
The arithmetic unit 7 is provided with a discriminator for discriminating whether or not the defects uniquely detected by the respective defect detectors A, B and C are the same by comparing and collating I. . In the arithmetic unit 7 having the discriminator 7a, the pulse generator (PLG) provided in each of the defect detectors A, B and C is used,
Steel strip longitudinal position X, Y, Z of the defect measured from the steel strip tip
(Mm) is used to calculate (X-Y), (Y-Z), and (X-Z), and the discriminator 7a abs (X-Y) ≤ γ (1) abs ( Y−Z) ≦ γ (2) abs (X−Z) ≦ γ (3) When (1), (2) and (3) are simultaneously satisfied, each defect The defects detected by the detectors A, B, and C are determined to be the same defect. Further, when any one of the expressions (1), (2) and (3) is satisfied, two detectors (A and B) selected from the defect detectors A, B and C, (B and The defects detected in C) or (A and C) are determined to be the same defect. Furthermore, when none of the expressions (1), (2) and (3) is satisfied, it is determined that the defects detected by the defect detectors A, B and C are not the same defect. However, γ was set to about 1000 mm. The reason why γ is about 1000 mm is that the resolution of the defect in the longitudinal direction is 1000 mm.

As a result of discriminating the defect, one defect marking information DI is sent from the discriminator 7a to the defect marker D for the defect detected by any of the defect detectors A, B and C, and the material to be inspected is sent. Defects that actually exist in the are marked. To perform such calculation / discrimination processing by the process computer, for example, it can be performed as shown in FIG.

FIG. 2 is a schematic circuit diagram in the arithmetic unit 7 shown in FIG. 1. In the arithmetic unit 7, each defect detector A, B, C is shown.
Discriminator 7a for discriminating whether or not the detected defects are the same defect, and three shift registers i, j, k which sequentially send signals to the discriminator 7a and various counters 7b, 7c1 to 7c3.
In addition, an adder 7d and a subtractor 7e are provided. Register i1
~ Il, j1-jm, and k1-k5, the defect detectors A, B,
The defect information AI, BI, and CI of the inspected material sent from C is stored. In this case, the defect information AI, BI, and CI stored in each register is re-stored after being shifted to the register located on the right side in the figure based on the line speed (that is, the transport speed of the material to be inspected) signal. In addition, the defective information AI, j1, and k1 are stored in the vacant registers i1, j1, and k1.
BI and CI are stored. At that time, the defect information stored in the rightmost registers il, jm, and k5 of the three shift registers i, j, and k in the figure is sequentially input to the discriminator 7a. In this case, if a defect is detected in each register within a predetermined length ΔX, ΔY, ΔZ (mm) of the steel strip, defect detection (marked with X in rectangle)
If no defect is detected within the range of the steel strip predetermined lengths ΔX, ΔY, and ΔZ (mm), the information of No defect (blank in rectangle) is stored. In addition, the prescribed length of steel strip Δ
X, ΔY, and ΔZ (mm) are set to the same value in order to simplify the calculation / discrimination processing, and correspond to the number of pulses of the pulse generator (PLG) provided in each defect detector.

The predetermined lengths of the steel strips ΔX, ΔY, ΔZ (m
m) should be set appropriately so that it can be determined whether or not the defects existing in the inspected material are the same defect according to the pitch of the defects existing in the inspected material and the required product quality. You can In galvanized steel strip inspection, the predetermined lengths of steel strip ΔX, ΔY, ΔZ (mm) are the same,
adopted m. Further, the defect information stored in each register is not limited to defect detection and defect non-detection 2-bit information, and by increasing the number of bits in the register, defect width position information and defect size It is also possible to store the feature amount.

Discrimination processing by the discriminator 7a shown in FIG. 2 will be described. The discriminator 7a includes three shift registers i,
The defect information AI, BI, CI stored in the registers il, jm, and k5 located at the rightmost position of j, k in the figure is input, and the defect information AI, BI, CI is input based on the defect information before the next information is input. Whether the detected defects are the same defect or not is determined, and the result is output. In this case, on the basis of the defect information AI, BI, and CI input to the discriminator 7a, discrimination is performed based on the table shown in Table 1, the duplicate count is output to the counter 7b, and the detected defect is defective. The defect marking information DI for marking the seed is output.

[0022]

[Table 1]

For example, the shift registers i and j shown in FIG.
According to the defect information AI, BI, and CI stored in the rightmost registers il, jm, and k5 of k, k, it is determined that the combination of the input information is 1 (the duplicate count is 2 and the hole defect). Two registers before the rightmost register
Defect information A stored in i (l-2), j (m-2) and k3
According to I, BI, and CI, it is determined that it is the combination 3 of the input information, and is further stored in the registers i (l-4), j (m-4), and k1 which are five registers before the rightmost register. According to the defect information AI, BI, and CI, the combination 4 of the input information is determined. Here, if no defect is detected by any of the defect detectors, it is determined that the combination of input information is 8 (the duplicate count is 0 and there is no defect).

Here, the signals of the shift registers i, j, k are also sent to the counters 7C1, 7C2, 7C3 at the same time, and in the counters 7C1, 7C2, 7C3, the defect detectors A, B, C are detected.
Counts the number of detected defects respectively detected, at the end of the inspection, the number of detected defects is summed by the adder 7d, and the total number of detected defects is sent to the subtractor 7e, while the counter 7b outputs the information from the discriminator 7a. The duplicate counts for each defect are added up, and when the inspection is completed, the added duplicate counts are sent to the subtractor 7e. The subtractor 7e subtracts the accumulated duplicate count number from the total detected defect number and outputs the total defect number N of the inspected material. In the arithmetic unit 7, the total number of defects N of this inspected material
And the total number N ₀ of permissible defects of the product sent from the host computer in advance are compared with each other to judge whether the material to be inspected is acceptable or not.

According to such an inspection method, the duplicate count numbers of the defects detected in duplicate are integrated, and the duplicate count number is removed from the total of the detected defects detected by the respective defect detectors, By determining the total number N of defects in the material to be inspected, the total number N of defects in the material to be inspected can be accurately obtained, and the pass / fail judgment of the material to be inspected can be correctly performed.

By the way, the longitudinal position X, Y, Z (mm) of the steel strip measured by using the pulse generator (PLG) provided in each of the defect detectors A, B and C is as long as one pulse is generated by the PLG. It can be calculated by the product of the length (mm) of the steel strip moving to the position / pulse (also called the length counter) and the cumulative pulse number of the PLG. At that time, at the steel strip longitudinal positions X, Y, Z (mm),
Generally, since there is an error of about 0.3%, for example, for a defect detected at a position of 1000 m from the tip of the inspected material, (X-
Y), (Y-Z), (X-Z) is approximately 3 m (1000 m x
There will be an error of 0.003). Therefore, in order to determine whether or not the defects detected by the defect detectors A, B, and C are the same defect depending on the position of the defect in the longitudinal direction,
Steel strip length (mm) / pulse (also called length counter) that moves while the PLG generates one pulse for each length of the inspected material
Is preferably corrected. PLG length counter (m
m) / pulse is corrected by, for example, P provided in the defect detector A.
Based on LG, the inspection data length L1 of the inspection material sent from the defect detector A after cutting the inspection material with the shearing machine 5 and the inspection data length L2 _B of the defect detector _B and Using the value of the inspection data length L2 _{c in} the defect detector C, the correction coefficients α _B and α _C can be obtained by the following equation. If α _B ≦ 0.95 or 1.05 ≦ α _B and α _C ≦ 0.95 or 1.05 ≦ α _C , no correction is performed.

U _B = α _B × U _B '(α _B = L1 / L2 _B ) U _C = α _C × U _C ' (α _C = L1 / L2 _C ) However, U _B , U _C ; Length counter (mm) / pulse of PLG provided on the defect detectors B and C used when inspecting the inspected material, U _B 'and U _C '; respectively, the defect detector B when inspecting the inspected material , PLG provided in C
Length counter (mm) / pulse In the above description, it is determined whether the defects detected by the defect detectors are the same defect based on the defect information of the inspected material detected by the defect detectors. In determining whether or not it is, only the longitudinal position information of the defect is used for the determination, but in addition to the longitudinal position information of the defect, the defect width characteristic information and the defect feature amount such as the size of the defect. It is possible to further improve the discrimination accuracy by combining the above. Of course,
As can be seen from the determination results shown in Table 1, the defect number for each defect type per inspection length of the inspected material is calculated, and the pass / fail judgment of the inspected material is performed according to the defect number for each defect type. May be.

[0028]

According to the present invention, the number of defects of the material to be inspected can be accurately obtained. Further, since the pass / fail determination is made based on the number of defects, the pass / fail determination accuracy of the inspected material can be improved. As a result, it is less likely that the material to be inspected will be rejected, and the orthogonality of the products and the product manufacturing yield are improved.

[Brief description of drawings]

FIG. 1 is a schematic layout of a defect inspection apparatus in a galvanizing line for a steel strip to which the present invention is applied.

FIG. 2 is a schematic circuit diagram in an arithmetic unit including a discriminator.

[Explanation of symbols] S Inspected material 1 Payoff reel 2 Welding machine 3 Annealing furnace 4 Galvanizing device 5 Shearing machine 6 Tension reel 7 Computing device (process computer) 7a Discriminator 7b Counters 7C1, 7C2, 7C3 Counter 7d Adder 7e Subtractors A, B, C Defect detectors AI, BI, CI Defect information D Defect marker DI Defect marking information 5I Defect information of inspected material N Total number of defects of inspected material N ₀ Total allowable defects of product

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F069 AA02 AA60 BB19 BB34 CC06                       EE23 GG04 GG06 GG07 GG13                       GG59 GG68 HH11 QQ01                 2G047 AA07 AB04 AD11 BC07 GA18                       GA20 GA21 GG37 GG46                 2G051 AA37 AB07 CA04 DA15 EA12                       EB09 EC01                 2G053 AA11 AB22 BA02 BA15 BB03                       BB08 CB13 CB24 DA01 DB05                 4K027 AA02 AA05 AA22 AB42 AE21

Claims (8)

[Claims] 1. A defect inspection apparatus having a plurality of defect detectors, wherein the defect information is compared with the defect information of the material to be inspected sent from each of the defect detectors. 2. A defect inspection apparatus, comprising: a discriminator that discriminates whether or not the defects detected by the defect detector are the same defect. 2. The defect inspection apparatus according to claim 1, wherein the defect information of the inspected material is the position of the defect in the longitudinal direction. 3. The defect inspection apparatus according to claim 1, wherein the discriminator discriminates a defect type. 4. The defect inspection apparatus according to claim 1, wherein the discriminator outputs the number of defects and judges pass / fail based on the number of defects. 5. In a defect inspection method for judging whether a material to be inspected is acceptable or not based on defect information of the material to be inspected, which is detected by each of the plurality of defect detectors, the object to be inspected sent from each defect detector. A defect inspection method characterized by determining whether or not defects detected by respective defect detectors are the same defect by comparing and collating defect information of inspection materials. 6. The defect inspection method according to claim 5, wherein the defect information of the material to be inspected is the position of the defect in the longitudinal direction. 7. The defect number of the inspected material is determined for each defect type, and the acceptance / rejection determination of the inspected material is performed according to the defect number for each defect type. The defect inspection method described in. 8. The defect according to claim 5, wherein the defect number is obtained based on the result of the defect determination of the inspected material, and the pass / fail judgment is performed based on the defect number. Inspection method.