JP2013036894A - Non-destructive testing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve higher accuracy of fault detection than conventional apparatuses.SOLUTION: A non-destructive testing apparatus 10 comprises a transmitter 12 that outputs an electromagnetic wave, a receiver 14 that receives a reflected wave of the electromagnetic wave from a checked region 22, and displacing means 16 that alters an interval between the checked region 22 and the receiver 14. The apparatus further has a determining unit 44 that determines, with respect to the checked regions 22 different from each other, the presence or absence of any fault in the checked regions 22 at a plurality of intervals by using differences or ratios among the reflected waves received by the receiver 14.

Description

  The present invention relates to a nondestructive inspection apparatus.

  2. Description of the Related Art Conventionally, non-destructive inspection apparatuses that can detect defects in an inspection target without destroying the inspection target are known. For example, in Patent Documents 1 and 2, an eddy current is generated in a portion to be inspected of a conductive material, and a defect in the portion to be inspected is detected based on a change in the eddy current. Further, in Patent Document 3 and Non-Patent Document 1, microwaves are irradiated to a region to be inspected of a dielectric material, and a defect in the region to be inspected is detected based on a change in amplitude or phase of the reflected wave. .

  These non-destructive inspection devices are known to vary in receiving sensitivity of eddy currents and reflected waves due to variations in lift-off. The lift-off is an interval between the part to be inspected and the receiver that receives the reflected wave. In order to suppress fluctuations in reception sensitivity, calibration for adjusting lift-off may be performed before performing defect detection.

  For example, in patent document 3, a receiver is arrange | positioned on the reference | standard site | part without a crack and peeling. Further, the reflected wave is received while changing the lift-off. Next, as shown in FIG. 11, the minimum value is obtained from the amplitude of the reflected wave for each lift-off, and the lift-off d0 corresponding to the minimum value is set as the set value. When performing the defect detection, the lift-off is maintained at the set value d0 and the reflected wave from the inspection site is received. Based on the difference between the amplitude of the received reflected wave and the amplitude of the reflected wave at the lift-off d0 at the reference site, the presence / absence of a defect at the site to be inspected is determined.

Japanese Patent Laid-Open No. 9-274017 JP 2009-2945 A Japanese Patent Laid-Open No. 11-281590

Kyoyo, two others, “Non-Destructive Inspection Engineering Front Line”, First Edition, Kyoritsu Publishing Co., Ltd., July 25, 2009, p. 149-218

  By the way, in actual defect detection, there may be a lift-off with higher defect detection accuracy than the set value obtained by calibration. A point 100 in FIG. 12 indicates a difference between the amplitude of the reflected wave from the defect-free inspection site and the amplitude of the reflected wave from the reference site. A point 102 indicates the difference between the amplitude of the reflected wave from the inspected part including the defect and the amplitude of the reflected wave from the reference part. These are all reflected waves when lift-off is set to the set value d0.

  On the other hand, the point 104 indicates the difference between the amplitude of the reflected wave from the same site to be inspected as the point 100 and the amplitude of the reflected wave from the reference site. Point 106 indicates the difference between the amplitude of the reflected wave from the same part to be inspected as point 102 and the amplitude of the reflected wave from the reference part. These are all reflected waves when the lift-off d1 is different from the set value d0.

  As shown in FIG. 12, the difference between the points 104 and 106 is larger than the difference between the points 100 and 102. That is, in the latter, the difference between the defective portion and the non-defective portion is larger. Therefore, the latter is less likely to be erroneously determined in the defect determination than the former. As described above, there may be a lift-off with a defect detection accuracy higher than the lift-off determined by the calibration, and the conventional nondestructive inspection apparatus has room for improving the accuracy of defect detection.

  The present invention relates to a nondestructive inspection apparatus. The nondestructive inspection apparatus includes a transmitter that outputs an electromagnetic wave, a receiver that receives a reflected wave of the electromagnetic wave from a region to be inspected, and a displacement unit that changes a distance between the region to be inspected and the receiver. . Further, a determination unit is provided that determines the presence / absence of a defect in the inspected part using a difference or ratio of reflected waves received by the receiver at a plurality of intervals for different inspected parts.

  In the above invention, it is preferable that the determination unit determines that there is a defect when a maximum value of the difference or the ratio exceeds a predetermined reference value.

  In the above invention, it is preferable that one of the different parts to be inspected is a defect-free part.

  In the above invention, it is preferable that the difference between the maximum value and the minimum value of the distance between the receiver and the site to be inspected is 0.25 times or more the center wavelength of the electromagnetic wave.

  Moreover, in the said invention, it is suitable that the maximum value of the space | interval of the said receiver and the said to-be-inspected site | part is 2 times or less of the center wavelength of the said electromagnetic wave.

  The present invention also relates to a nondestructive inspection apparatus. The non-destructive inspection apparatus includes an excitation unit that generates magnetic flux, a detector that detects eddy current generated in the inspection site by application of the magnetic flux, and a displacement unit that changes an interval between the inspection site and the detector. . Further, a determination unit is provided that determines the presence / absence of a defect in the inspected part using a difference or ratio of eddy currents detected by the detector at a plurality of intervals for different inspected parts.

  According to the present invention, it is possible to improve the accuracy of defect detection as compared with the prior art.

It is a figure which illustrates the nondestructive inspection device concerning this embodiment. It is a figure which illustrates an antenna. It is a figure explaining a defect detection process. It is a figure explaining a defect detection process. It is a figure explaining a defect detection process. It is a figure explaining a defect detection process. It is a figure which illustrates the nondestructive inspection device concerning other embodiments. It is a figure which illustrates the nondestructive inspection device concerning other embodiments. It is a figure which illustrates the nondestructive inspection device concerning other embodiments. It is a figure explaining a defect detection process. It is a figure explaining the conventional defect detection. It is a figure explaining the conventional defect detection.

  A nondestructive inspection apparatus according to this embodiment is illustrated in FIG. In FIG. 1, an axis extending in the left direction on the paper surface is an X axis, an axis extending in the upper direction on the paper surface is a Z axis, and an axis extending in the depth direction on the paper surface is a Y axis. The nondestructive inspection apparatus 10 includes a transmitter 12, a receiver 14, a three-dimensional movement mechanism 16, an arithmetic processing unit 18, and a signal source 20.

  The transmitter 12 is a device that outputs an electromagnetic wave to the inspection site 22 of the inspection object 21. For example, the transmitter 12 is connected to the signal source 20, and an electromagnetic wave transmitted from the signal source 20 to the transmitter 12 can be output from the transmitter 12.

  The receiver 14 is a device that receives an electromagnetic wave reflected from the inspected site 22. For example, the receiver 14 is connected to the arithmetic processing unit 18, and the reflected wave received by the receiver 14 is transmitted to the arithmetic processing unit 18.

  The transmitter 12 and the receiver 14 may be configured as separate devices or may be configured as an integrated device. For example, as shown in FIG. 2, both may be configured as an antenna 24 in which the transmitter 12 and the receiver 14 are integrated. The antenna 24 may have any shape as long as it can output an electromagnetic wave and receive a reflected wave thereof. For example, the antenna 24 can be a substantially conical horn antenna.

  Returning to FIG. 1, the signal source 20 is a device that outputs an electromagnetic wave having a desired frequency. For example, the signal source 20 is preferably capable of outputting an electromagnetic wave of 300 MHz to 300 GHz, which is a microwave frequency band.

  The three-dimensional moving mechanism 16 is a displacing means that can change the relative position between the antenna 24 and the inspection object 21. For example, the three-dimensional movement mechanism 16 includes a base 26, an X stage 28, a Y stage 30, a Z lift 32, and a fixed stage 41. The X stage 28 is a member that can move in the X-axis direction with respect to the base 26. Specifically, the X stage 28 is disposed on the base 26 and can be moved by an X stage moving motor 34. The Y stage 30 is a member that can move in the Y-axis direction with respect to the base 26. Specifically, the Y stage 30 is disposed on the X stage 28 and can be moved by a Y stage moving motor 36. The Z lift 32 is a member that can move in the Z-axis direction with respect to the base 26. Specifically, the Z lift 32 is held by an arm 38 extending from the Y stage 30 and can be moved by a Z lift moving motor 40. Further, a holding portion 39 is provided at the tip of the Z lift 32.

  The fixed stage 41 is provided within a movable range of the holding unit 39. One of the holding unit 39 and the fixed stage 41 holds the antenna 24, and the other holds the inspection object 21. Depending on the type and size of the inspection object 21, the weight may exceed the maximum weight that can be held by the holding unit 39. Therefore, it is preferable that the holding unit 39 holds the antenna 24.

  The arithmetic processing unit 18 is connected to the three-dimensional movement mechanism 16, the antenna 24, and the signal source 20. The arithmetic processing unit 18 is a device that performs arithmetic processing on signals sent from these devices and transmits control signals to these devices. The calculation processing unit 18 includes a storage unit 42 and a calculation unit 44. The storage unit 42 stores, for example, the movement path of the antenna 24 and the reflected wave data at a reference portion described later. The storage unit 42 may be any device capable of storing such information, and may be configured by one or a plurality of combinations such as a ROM, a RAM, an EPROM, and a hard disk device.

  The calculation unit 44 is a device that calculates a control signal for controlling the position of the antenna 24. For example, the amount of displacement in the X-axis direction, Y-axis direction, and Z-axis direction for moving the antenna 24 to a desired position is calculated, and the X-stage moving motor 34, the Y-stage moving motor 36, and the Z-lift moving A drive signal corresponding to each displacement amount can be transmitted to the motor 40. In addition, the calculation unit 44 also has a function of a determination unit that performs defect determination of the inspected part 22 described later. The calculation unit 44 may be any device that can perform these calculation processes and determination processes, and includes, for example, a microcomputer unit.

  Next, the defect detection process of the nondestructive inspection apparatus 10 in this Embodiment is demonstrated. As shown in FIGS. 3 to 5, the defect detection process is roughly divided into a reference reflected wave acquisition process S100, an inspection reflected wave acquisition process S200, and a defect determination process S300. In addition, you may replace the order of process S100 and process S200.

  As shown in FIG. 3, the calculating part 44 acquires the reference | standard reflected wave reflected from the reference | standard site | part in process S100. Here, the reference site is a site in which the presence or absence of defects on the surface or inside is known in advance by other non-destructive inspection means, inspection means with destruction, or the like. For example, the reference part is a part of a standard sample or the like having no defects on the surface or inside (no defect). The calculation unit 44 changes the lift-off with respect to the reference part and acquires the reference reflected wave for each lift-off. Here, the lift-off refers to the distance between the antenna 24 and the reflection part where the electromagnetic wave is reflected. The reference reflected wave may be acquired by the nondestructive inspection apparatus 10 or may be obtained by another apparatus or simulation that can change the lift-off between the antenna 24 and the reference portion.

First, the arithmetic unit 44 determines the position of the antenna 24 with respect to the reference site such that the initial value D _I lift-off is predetermined (S102). For example, the antenna 24 is brought into contact with the reference portion (lift-off = 0), and then the Z lift movement motor 40 is driven. In this case, to set the liftoff to the initial value D _I by calculating the lift-off from the rotational speed of the Z lift moving motor 40. For example, the initial value of lift-off is 0.5 mm. Thereafter, electromagnetic waves are irradiated from the antenna 24. At this time, the reflected wave from the reference part (reference reflected wave) is received by the antenna 24 (S104).

  Further, the calculation unit 44 determines whether or not the lift-off has reached a predetermined maximum lift-off (S106). If the maximum lift-off has not been reached, the lift-off is increased by a predetermined pitch, and the antenna 24 is separated from the reference portion (S108). For example, the lift-off is increased by driving the Z lift movement motor 40 by a predetermined number of revolutions. After the lift-off increases, the process returns to step S104, and the reference reflected wave in the lift-off after the increase is received. In this way, the reference reflected wave is received until the maximum lift-off is reached. The received reflected wave is stored in the storage unit 42 every lift-off.

  Next, as shown in FIG. 4, the calculation unit 44 acquires the reflected wave to be inspected reflected from the inspected site 22 in step S <b> 200. Next, the movement range of the antenna 24 in the X-axis direction and the Y-axis direction is input to the arithmetic processing unit 18 by an operator or the like (S202). Furthermore, the start point, end point, and movement path for the movement of the antenna 24 on the XY plane are determined based on this movement range.

Next, the calculation unit 44 moves the antenna 24 to the start point of the X coordinate and the Y coordinate (S204). Subsequently, the arithmetic unit 44 sets the lift-off of the antenna 24 with respect to the test region 22 to the initial value D _I (S206). Thereafter, an electromagnetic wave is irradiated from the antenna 24 and a reflected wave (inspected reflected wave) from the inspection site 22 is received by the antenna 24 (S208).

  Further, the calculation unit 44 determines whether or not the lift-off has reached a predetermined maximum lift-off (S210). If not reached, the calculation unit 44 drives the Z lift movement motor 40 to increase the lift-off by the same pitch as when the reference reflected wave is acquired, thereby separating the antenna 24 from the site 22 to be examined. (S212). Here, it is assumed that the same is not limited to completely the same, but includes a mechanical error. For example, it is assumed that an error of 10% or less with respect to a predetermined pitch is included. After increasing the lift-off, the process returns to step S208.

  If the lift-off reaches the maximum lift-off in step S210, the antenna 24 is moved to the next site to be examined. That is, the calculation unit 44 determines whether or not the antenna 24 has reached the end point coordinates of the X axis coordinate and the Y axis coordinate (S214). If not reached, the calculation unit 44 moves the antenna 24 by a predetermined pitch in at least one direction of the X-axis direction and the Y-axis direction (S216). Further, steps S206 to S214 are repeated in the inspected site after the movement. In this way, the reflected wave is acquired over all the parts to be inspected. The received reflected wave to be inspected is stored in the storage unit 42 for each X coordinate, Y coordinate, and lift-off.

  When the acquisition of the reference reflected wave and the reflected wave to be inspected is completed, the calculation unit 44 executes the defect determination step S300 (FIG. 5). The calculation unit 44 calls the inspection reflected wave data for each lift-off of the region to be inspected 22 at the start point of the X coordinate and the Y coordinate from the storage unit 42 (S302). Furthermore, the calculating part 44 calls the reference | standard reflected wave data for every lift-off from the memory | storage part 42 (S304). Next, the calculation unit 44 obtains the difference between the reference reflected wave and the reflected wave to be inspected for the same lift-off (S306). For example, the difference between the amplitudes of both reflected waves is obtained.

  FIG. 6 shows a graph in which the difference value between the amplitudes of the reference reflected wave and the reflected wave to be inspected is plotted. The horizontal axis of the graph is lift-off, and the vertical axis is the amplitude difference value. In FIG. 6, the difference value between the amplitudes of the reflected wave to be inspected and the reference reflected wave from the inspected site 22 that has been known to be defect-free in advance is shown as a filled square plot (■) for each lift-off. Further, the difference value between the amplitudes of the reflected wave to be inspected and the reference reflected wave from the inspected site 22 including the defect is indicated by a white circle plot (◯) for each lift-off. As shown in FIG. 6, compared to the difference in amplitude between the reflected wave to be inspected from the defect-free inspected part 22 and the reference reflected wave, the reflected wave to be inspected and the reference reflected wave from the inspected part 22 including the defect. The difference in amplitudes of these tends to vary greatly.

The computing unit 44 determines the presence / absence of a defect in the inspected part 22 using the variation tendency of the difference value (S308 in FIG. 5). For example, the calculation unit 44 obtains a difference value ΔS ₀₁ between the amplitude S _{1 of the} reflected wave to be inspected from the defect-free inspection site 22 and the amplitude S ₀ of the reference reflected wave for each lift-off. further. The maximum value ΔS _{01 # MAX} of the difference value ΔS ₀₁ is set as the reference value ΔS _Th0 . Subsequently, the calculation unit 44 obtains a difference value ΔS ₀₂ between the amplitude S _{2 of the} reflected wave to be inspected from the inspection target part 22 to be detected and the amplitude S ₀ of the reference reflected wave for each lift-off. Further, when any value of the difference value ΔS ₀₂ (for example, the maximum value ΔS _{02 # MAX} ) exceeds the reference value ΔS _Th0 , it is determined that the inspected site 22 includes a defect (S310, FIG. 5). S312). As shown in FIG. 6, the reference value ΔS _Th0 may be larger than the maximum value ΔS _{01 # MAX} . For example, the reference value ΔS _Th0 may be a value that is 1.2 times the maximum value ΔS _{01 # MAX} .

Alternatively, the difference between the maximum value and the minimum value of the difference value ΔS ₀₁ may be set as the reference value ΔS _Th1 . In this case, when the difference between the maximum value and the minimum value of the difference value ΔS ₀₂ exceeds the reference value ΔS _Th1 , the inspected part 22 is determined to include a defect.

Instead of performing defect determination using the difference in amplitude between the reference reflected wave and the reflected wave to be inspected, the difference between the phase difference between the reference reflected wave and the incident wave, and the phase difference between the reflected wave to be inspected and the incident wave. Defect determination may be used using For example, the inspection reflected waves from the examination site 22 of defect-free and the phase difference phi ₁ between the incident wave, obtains a difference [Delta] [phi ₀₁ of the phase difference phi ₀ reference reflected wave and the incident wave for each lift. Further, the maximum value of the difference Δφ ₀₁ or a value larger than the maximum value is set as the reference value Δφ _Th0 . Alternatively, the difference between the maximum value and the minimum value of the difference Δφ ₀₁ is set as the reference value Δφ _Th1 . In this case, the calculation unit 44 determines the difference Δφ ₀₂ between the phase difference φ ₂ between the reflected wave to be inspected from the inspection target part 22 to be detected and the incident wave, and the phase difference φ ₀ between the reference reflected wave and the incident wave. For each lift-off. Further, when any value of the difference Δφ ₀₂ exceeds the reference value Δφ _Th0 , it is determined that the inspected part 22 includes a defect. Or, if the difference between the maximum value and the minimum value of the difference [Delta] [phi ₀₂ exceeds the reference value [Delta] [phi _Th1, the examination site 22 determines that contain defects.

Furthermore, instead of using the difference between the reflected wave to be inspected and the reference reflected wave, the ratio of the reflected wave to be inspected and the reference reflected wave may be used. For example, the ratio S ₁ / S ₀ of the amplitude S _{1 of the} reflected wave to be inspected from the defect-free inspected site 22 and the amplitude S ₀ of the reference reflected wave is obtained for each lift-off. Further, the maximum value of the ratio S ₁ / S ₀ or a value larger than the maximum value is set as the reference value S _Th0 . Alternatively, the difference between the maximum value and the minimum value of the ratio S ₁ / S ₀ is set as the reference value S _Th1 . In this case, the calculation unit 44 obtains the ratio S ₂ / S ₀ between the amplitude S _{2 of the} reflected wave to be inspected and the amplitude S ₀ of the reference reflected wave from the inspection target part 22 to be detected for each lift-off. Further, when any value of the ratio S ₂ / S ₀ exceeds the reference value S _Th0 , it is determined that the inspected part 22 includes a defect. _{Alternatively} , when the difference between the maximum value and the minimum value of the ratio S ₂ / S ₀ exceeds the reference value S _Th1 , it is determined that the inspected part includes a defect.

Further, the phase difference between the reflected wave to be inspected and its incident wave and the ratio of the phase difference between the reference reflected wave and its incident wave may be used. For example, the phase difference φ ₁ between the reflected wave to be inspected from the defect-free inspection site 22 and its incident wave, and the ratio φ ₁ / φ ₀ between the reference reflected wave and the phase difference φ ₀ of the incident wave are obtained for each lift-off. . Further, the maximum value of the ratio φ ₁ / φ ₀ or a value larger than the maximum value is set as the reference value S _Th0 . Alternatively, the difference between the maximum value and the minimum value of the ratio φ ₁ / φ ₀ is set as the reference value S _Th1 . In this case, the calculation unit 44 has a ratio φ ₂ of the phase difference φ ₂ between the reflected wave to be inspected and the incident wave from the inspection target part 22 to be detected, and the phase difference φ ₀ between the reference reflected wave and the incident wave. / Φ _{0 is obtained} for each lift-off. Further, when any value of the ratio φ ₂ / φ ₀ exceeds the reference value S _Th0 , it is determined that the inspected site 22 includes a defect. _{Alternatively} , when the difference between the maximum value and the minimum value of the ratio φ ₂ / φ ₀ exceeds the reference value S _Th1 , it is determined that the inspection site includes a defect.

  Furthermore, the calculating part 44 memorize | stores the determination result in the memory | storage part 42 according to X coordinate and Y coordinate (S314 of FIG. 5). Further, the calculation unit 44 determines whether or not the X coordinate and Y axis coordinate of the reflected wave to be inspected have reached the end point coordinate (S316). If not, the calculation unit 44 changes at least one of the X coordinate and the Y axis coordinate (S318). After the change, that is, steps S306 to S316 are repeated for other parts to be examined. In this way, the presence or absence of a defect is determined over the entire inspection site.

  Note that, as shown in FIG. 6, fluctuations in the difference value of the amplitudes of the reflected wave to be inspected and the reference reflected wave from the region to be inspected 22 have periodicity. The fluctuation period substantially coincides with the half wavelength of the central wavelength of the electromagnetic wave emitted from the antenna 24. From this, it is difficult to obtain a local maximum value and a local minimum value in one cycle unless the difference between the minimum value (initial value) and the maximum value of lift-off is at least a quarter wavelength or more of the center wavelength of the electromagnetic wave. Therefore, the difference between the minimum value and the maximum value of lift-off is preferably 0.25 times or more the center wavelength of the electromagnetic wave emitted from the antenna 24.

  Further, as shown in FIG. 6, the amplitude of the difference value is attenuated as the lift-off increases, and the difference value (■) when the defect is included and the difference value (when the defect is not included) at the maximum value of the lift-off ( The difference in ○) becomes smaller. For this reason, it is preferable to determine the maximum value of lift-off within a range in which the difference between the two can be discriminated. In FIG. 6, the maximum value of lift-off is set to a value twice the center wavelength of the electromagnetic wave, and the difference between the difference value when there is a defect and the difference value without defect is relatively small around the maximum value. It has become. For this reason, it is preferable to set the maximum value of the lift-off so that the center wavelength of the electromagnetic wave irradiated from the antenna 24 is twice or less.

  In the above-described embodiment, the reference reflected wave and the reflected wave to be inspected are acquired separately, but may be acquired simultaneously. For example, as shown in FIG. 7, antennas 24a and 24b, Z lifts 32a and 32b, and Z lift drive motors 40a and 40b may be provided so that two inspected parts 22a and 22b can be inspected simultaneously. In this case, any one of the reflected waves may be a reference reflected wave, and the other may be a reflected wave to be inspected.

  Moreover, in embodiment mentioned above, although the defect of the to-be-inspected part 22 was detected by irradiating the to-be-inspected part 22 with an electromagnetic wave and acquiring a reflected wave, it is not restricted to this form. For example, defect detection may be performed using eddy current as shown in FIG.

  The nondestructive inspection apparatus 10 includes a coil 60, a detection circuit 62, and a power source 64. The coil 60 is an excitation unit that applies a magnetic flux to the part 22 to be inspected. The coil 60 is connected to a power source 64, and an alternating current having a predetermined frequency is sent from the power source 64. The detection circuit 62 is a circuit that can detect a change in eddy current at the site 22 to be inspected. For example, as shown in FIG. 9, the detection circuit 62 includes a bridge circuit including a coil 60, impedances Z <b> 1 to Z <b> 3, and an amplifier circuit 66.

  Defect detection using eddy current will be described. When an alternating current is sent from the power supply 64 to the coil 60, a variable magnetic field is generated in the coil 60. When the coil 60 is brought close to the part to be inspected 22 in this state, an eddy current is generated on the surface of the part to be inspected 22 due to the varying magnetic field generated in the coil 60. As a result, the current flowing through the coil 60 changes. The eddy current flows differently between the defect-free inspection region 22 and the inspection region 22 including the defect, and the current change of the coil 60 is also different. The current change is detected by the detection circuit 62, and the presence or absence of a defect is determined based on the detected current change.

  In the present embodiment, the reference current value flowing through the detection circuit 62 is detected for each lift-off by changing the lift-off between the reference region and the coil 60. Furthermore, the current value to be inspected flowing through the detection circuit 62 is detected for each lift-off by changing the lift-off between the part 22 to be inspected and the coil 60. Further, the difference or ratio between the reference current value and the current value to be inspected is calculated for each same lift-off.

  FIG. 10 shows a difference value 70 between the current value to be inspected and the reference current value in the inspected part 22 having no defect, and a difference value 72 between the current value to be inspected in the inspected part 22 including the defect and the reference current value. A graph is shown for each lift-off. As shown in this figure, the latter difference value tends to vary greatly compared to the former difference value. The computing unit 44 determines the presence / absence of a defect in the inspected site 22 using this variation tendency. For example, as in the above-described embodiment, the reference value may be set with respect to the maximum value of the difference value (or ratio) between the reference current value obtained every lift-off and the current value to be inspected. Alternatively, a reference value may be set for a difference between the maximum value and the minimum value of the difference value or ratio. In this case, the maximum value or difference between the maximum value and the minimum value of the difference value (or ratio) for each lift-off between the current value to be inspected and the reference current value generated from the inspection target part 22 to be detected exceeds the reference value. In this case, it is determined that the inspection site 22 includes a defect.

  DESCRIPTION OF SYMBOLS 10 Nondestructive inspection apparatus, 12 Transmitter, 14 Receiver, 16 Three-dimensional movement mechanism, 18 Computation processing part, 20 Signal source, 21 Inspection object, 22 Inspected part, 24 Antenna, 26 Base, 28 X stage, 30 Y stage, 32 Z lift, 34 X stage moving motor, 36 Y stage moving motor, 38 arm, 39 holding unit, 40 Z lift moving motor, 41 fixed stage, 42 storage unit, 44 computing unit, 60 coil, 62 detection circuit, 64 power supply, 66 amplification circuit.

Claims (6)

A transmitter that outputs electromagnetic waves;
A receiver for receiving the reflected wave of the electromagnetic wave from the site to be examined;
Displacement means for changing the distance between the inspected part and the receiver;
A determination unit that determines the presence or absence of a defect in the inspected part using a difference or ratio of reflected waves received by the receiver at a plurality of intervals for different inspected parts,
A nondestructive inspection apparatus comprising: The nondestructive inspection apparatus according to claim 1,
The nondestructive inspection apparatus, wherein the determination unit determines that there is a defect when a maximum value of the difference or the ratio exceeds a predetermined reference value. The nondestructive inspection device according to claim 1 or 2,
One of the different parts to be inspected is a non-destructive part. It is a nondestructive inspection device given in any 1 paragraph of Claims 1-3,
A non-destructive inspection apparatus, wherein a difference between a maximum value and a minimum value of a distance between the receiver and the site to be inspected is 0.25 times or more a center wavelength of the electromagnetic wave. The nondestructive inspection device according to any one of claims 1 to 4,
The nondestructive inspection apparatus, wherein the maximum value of the distance between the receiver and the part to be inspected is not more than twice the center wavelength of the electromagnetic wave. Excitation means for generating magnetic flux;
A detector for detecting an eddy current generated in a site to be inspected by application of the magnetic flux;
Displacement means for changing the distance between the region to be examined and the detector;
A determination unit that determines the presence or absence of a defect in the inspection site using a difference or ratio of eddy currents detected by the detector at a plurality of intervals for different inspection sites;
A nondestructive inspection apparatus comprising:

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