JPH0933488A - Eddy current flaw detection probe and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a probe for eddy current flaw detection, which has uniform coil characteristics and can be mass-produced, and a manufacturing method thereof. [Structure] The eddy current flaw detection probe 1 has a coil as a printed coil 26. Also,
The manufacture is performed by forming the exciting coil 22 and the detection coil 23 by printed wiring on both sides of the film substrate 21, and sticking the film substrate 21 on the lower surface 10a of the probe body 10 to form the eddy current flaw detection probe 1. It

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an eddy current flaw detection probe and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, various coils such as a flow-through type coil, an insertion type coil, a probe coil, a mutual induction type coil and a self induction type coil have been used for an eddy current flaw detection probe.

However, at present, most of these coils are manually manufactured. For example,
In the case of a once-through type coil, a conductor wire is manually wound around a bobbin to produce the same coil, and in the case of a probe coil, a conductor wire is manually wound around a ferrite core to produce the same coil. Moreover, the small size of these coils generally requires great skill in their fabrication. For example, a probe coil having a core diameter of 1 mm is produced by winding a conductor wire having a wire diameter of 0.1 mm around the core for about 100 turns. Since the conducting wire to be wound is thus thin, the winding is performed using a microscope. As a result, it takes about 2 hours to produce one probe coil even by a skilled worker. Furthermore, if packaging is performed, the limit is that one probe is produced per day. FIG. 16 shows an example of an eddy current flaw detection probe manufactured by the conventional method according to FIG.

Further, in the probe having such a configuration, as shown in FIG. 17, when the exciting coil is wound in the shape of 8 in order to have a self-balancing function, if the winding method is not good, the winding intervals are not equal. A defect occurs that the flaw detection accuracy deteriorates. Of course, when the flaw detection accuracy becomes lower than a certain level, it cannot be used as a probe.

Further, in the case of a multi-channel eddy current flaw detector, a large number of probe coils with uniform characteristics are required, but since variations in coil characteristics are unavoidable in manual fabrication, characteristics such as balance and impedance are inevitable. Variation occurs. Therefore, when a multi-channel eddy current flaw detector is formed by using the coil manufactured by such a manual operation, a compensating circuit must be separately provided, which causes a problem that the configuration becomes complicated.

Furthermore, in order to detect a test material having a special shape, it is necessary to make the shape of the coil follow the surface shape of the test material. With difficulty.

In order to address the above-mentioned problems of the prior art, Japanese Patent Publication No. 57-11486 discloses that a conductive metal is formed on one surface of an insulating substrate and spirals in opposite directions are formed on the insulating substrate. Printed so that it becomes a continuous line segment, and the conductive portion is drawn out from the inner end of each spiral through the through hole to the other surface of the insulating substrate, and the conductive portion is used to generate an electromagnetic ultrasonic wave. There has been proposed an electromagnetic ultrasonic coil which is connected to a current generating power supply or a circuit for detecting an eddy current generated by an electromagnetic ultrasonic echo.

However, in the electromagnetic ultrasonic coil 130 according to the above proposal, as shown in FIG. 18, the exciting coil 132 and the detecting coil 133 have an insulating substrate 131.
Since they are formed on the same plane, the probe tip cannot be made compact.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and has a compact tip, uniform coil characteristics, and mass-producible eddy current flaw detection probe. Its purpose is to provide a manufacturing method thereof.

[0010]

A first aspect of the present invention is an eddy current flaw detection probe, characterized in that its coil is a printed coil, and an exciting coil and a detection coil are laminated. It is a thing.

In the first aspect of the present invention, it is preferable that the print coil is formed of a flexible member, and the print coil has a shape corresponding to the outer shape of the member to be inspected. It is preferable that a large number of print coils are arranged in a predetermined arrangement.

A second aspect of the present invention is a method for manufacturing an eddy current flaw detection probe, which comprises a procedure of forming a coil by a printed wiring on a flexible member, and a flexibility in which the printed wiring is formed. And a step of forming a member having the above at a predetermined position of the probe body to form an eddy current flaw detection probe.

In the second aspect of the present invention, it is preferable that a large number of members are formed in a predetermined arrangement on the flexible member on which the printed wiring is formed.

[0014]

In the present invention, since the coil is a printed coil, the characteristics of the coil are made uniform. Also,
In the flexible member having the printed coil formed thereon, the flaw detection surface of the eddy current flaw detection probe can be made to follow the outer shape of the test material.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described based on the embodiments, but the present invention is not limited to such embodiments.

An eddy current flaw detection probe of the present invention is shown in FIG. 1, and the probe 1 comprises a cylindrical ferrite core (probe main body) 10 and a detection portion 20 mounted on a lower surface 10a thereof. As shown in FIG. 2, the detection unit 20 is formed by forming an excitation coil 22 and a detection coil 23 on the upper surface 21a and the lower surface 21b of the film substrate 21, respectively. Here, as the film substrate 21, a polyester film substrate or a polyimide film substrate is used.

The excitation coil 22 and the detection coil 23 are formed on the substrate 21 by printed wiring using an etched foil method, an additive method, or the like.
The pattern of the coil (hereinafter, simply referred to as a print coil) 26 formed by the printed wiring is appropriately selected according to the flaw detection target. 3 to 6 are schematic diagrams showing pattern examples. Here, FIGS. 3 and 4 show the excitation coil 22, and FIGS. 5 and 6 show the detection coil 23. In addition,
The exciting coil 22 shown in FIGS. 3 and 4 has a pattern formed such that the magnetic force lines excited by the right half coil and the magnetic force lines excited by the left half coil strengthen each other.
The detection coil 23 shown in FIGS. 5 and 6 is formed with a pattern such that the magnetic force lines excited by the right half coil and the magnetic force lines excited by the left half coil cancel each other. The width of the conductive wire of the formed print coil is, for example, 0.1 mm, and the thickness is, for example, 1 mm.
8 μm.

As described above, since the coil is the printed coil in this embodiment, a large number of coils having uniform characteristics can be manufactured at low cost and in a short time. Further, since the exciting coil and the detecting coil are formed on both surfaces of the film substrate, that is, the exciting coil and the detecting coil are laminated, the probe tip can be made compact.

The eddy current flaw detection probe 1 having the detection portion formed of this printed coil is not limited to the one shown in FIG. 1, but may be one shown in FIGS. 7 to 12, for example.

In the eddy current flaw detection probe 1 shown in FIGS. 7 and 8, a conducting wire is wound around a side surface of a rectangular ferrite core 10 to form an exciting coil 22 and a lower surface 10a.
A plurality of film substrates 21 each having a detection coil 23 formed of a print coil 26 are attached in a column. By arranging a large number of detection coils 23, 23, 23, ... In a column shape, eddy current flaw detection over a wide range is performed at once, and flaw detection efficiency is improved.

The eddy current flaw detection probe 1 shown in FIGS. 9 and 10 comprises a ferrite substrate 10 having a cylindrical shape and a film substrate 21 having a large number of printed coils 26 arranged in a column. With such a configuration, eddy current flaw detection of a test material having a circular cross section is performed without rotating the probe 1, and flaw detection efficiency is improved.

The eddy current flaw detection probe 1 shown in FIGS. 11 and 12 has a shape corresponding to the shape of the flaw detection target while winding a conductor around the side surface of the rectangular parallelepiped ferrite core 10 to form the exciting coil 22. On the upper surface 10b,
A print coil 26 as shown in FIG. 12 is formed by adhering a film substrate 21 in a staggered arrangement. With such a configuration, it is possible to detect a flaw in a test material having a unique shape.

[0023]

EXAMPLES The present invention will be described in more detail below based on more specific examples.

Example of measurement On both sides of a 0.1 mm-thick polyimide film, as shown in FIG.
As shown in FIG. 3, a print coil (excitation coil 22 and detection coil 23) formed with a film thickness of 35 μm
The excitation coil 22 was attached to the lower surface of the ferrite core having a diameter of 5 mm so as to face it, and the eddy current flaw detection probe 1 was obtained. The main points of the exciting coil 22 and the detecting coil 23 are as shown in Table 1 below.

[0025]

[Table 1]

Using this eddy current flaw detection probe, eddy current flaw detection was performed on a test material having a diameter of 20 mm and having artificial flaws (depth 0.3 mm) while rotating the test material as shown in FIG. The result is shown in FIG.

Comparative measurement example A ferrite core having a diameter of 5 mm was wound by a conventional manual method to form an exciting coil and a detecting coil, and used as an eddy current flaw detection probe. The main points of the exciting coil and the detecting coil are as shown in Table 2 below.

[0028]

[Table 2]

Using this eddy current flaw detection probe, eddy current flaw detection of the test material used in the measurement example was performed. The result is shown in FIG.

As is apparent from FIG. 15, it can be seen that in the measurement example, the same level of flaw detection accuracy as in the comparative measurement example can be obtained.

[0031]

As described above in detail, the eddy current flaw detection probe of the present invention has an excellent effect that it has uniform characteristics and can follow a special shape. As a result, the effect of facilitating the manufacture of the multi-channel eddy current flaw detector can be obtained. Further, since the printed coil is formed by laminating the exciting coil and the detecting coil, it is possible to obtain an excellent effect that the probe tip can be made compact.

On the other hand, according to the method for manufacturing an eddy current flaw detection probe of the present invention, it is excellent that the eddy current flaw detection probe which has uniform characteristics and can follow a special shape can be manufactured inexpensively in a large amount in a short time. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of an eddy current flaw detection probe of the present invention.

FIG. 2 is a schematic view of a detection unit used in the probe.

FIG. 3 is an explanatory diagram showing a pattern of a print coil.

FIG. 4 is an explanatory diagram showing another pattern of the print coil.

FIG. 5 is an explanatory diagram showing still another pattern of the print coil.

FIG. 6 is an explanatory diagram showing still another pattern of the print coil.

FIG. 7 is a schematic view of another embodiment of the eddy current flaw detection probe.

FIG. 8 is an explanatory diagram of a film substrate of the same embodiment.

FIG. 9 is a schematic view of still another embodiment of the eddy current flaw detection probe.

FIG. 10 is an explanatory diagram of a film substrate of the same embodiment.

FIG. 11 is a schematic view of still another embodiment of the eddy current flaw detection probe.

FIG. 12 is an explanatory diagram of a film substrate of the same embodiment.

FIG. 13 is an explanatory diagram of a detection unit used in a measurement example.

FIG. 14 is an explanatory diagram of an eddy current flaw detector used for measurement in Examples.

FIG. 15 is a graph of an eddy current flaw detection result, where (a) shows a measurement example and (b) shows a comparative measurement example.

FIG. 16 is a schematic view of a conventional eddy current flaw detection probe.

FIG. 17 is an explanatory diagram of a detection coil of the probe.

FIG. 18 is a schematic diagram of a coil pattern according to the proposal of Japanese Patent Publication No. 57-11486.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Eddy current flaw detection probe 10 Ferrite core, probe body 20 Detection part 21 Film substrate 22 Excitation coil 23 Detection coil 26 Print coil

Claims (6)

[Claims] 1. An eddy current flaw detection probe, wherein the coil is a printed coil, and an exciting coil and a detection coil are laminated. 2. The probe for eddy current flaw detection according to claim 1, wherein the printed coil is formed on a flexible member. 3. The eddy current flaw detection probe according to claim 1, wherein the printed coil has a shape corresponding to the outer shape of the flaw detection target member. 4. The eddy current flaw detection probe according to claim 1, wherein a large number of printed coils are arranged in a predetermined array. 5. A procedure for forming a coil with a printed wiring on a flexible member, and a flexible member on which the printed wiring is formed is mounted at a predetermined position of a probe main body for eddy current flaw detection probe. A method for manufacturing a probe for eddy current flaw detection, which comprises the following steps: 6. The method for manufacturing an eddy current flaw detection probe according to claim 5, wherein a large number of the printed wirings are formed in a flexible member in a predetermined arrangement.