JP2000187024A - Non-destructive inspection apparatus of composite foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently detect internal flaws of a composite foam and to facilitate inspection work reducing the inspection cost. SOLUTION: A non-destructive inspection apparatus for inspecting the internal flaw of a composite foam consisting of a foam 52 and the skin 51 covering the surface of the foam 52 consists of a transmitter 2 for transmitting inspecting horizontal waves 41 to the interior of the composite foam 5 from the outer surface 510 of the composite foam 5 and a detector 3 detecting the propagating waves 42 formed by the propagation of the inspecting horizontal waves 41 through the composite foam 5 on the outer surface 410 of the composite foam 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a nondestructive inspection device capable of nondestructively inspecting a composite foam comprising a skin and a foam.

[0002]

2. Description of the Related Art A composite foam comprising a foam and a skin covering the surface of the foam is known, and this material is applied to various plastic products. Conventional inspection methods for finding internal defects in the composite foam include
Inspection methods in which the above composite foam is cut directly have been adopted.

[0003]

However, the composite foam is relatively expensive. Therefore, the conventional inspection method involving destruction may further increase the price of the composite foam. On the other hand, a soft X-ray method, a CT scan method, and the like have been attempted as nondestructive inspection methods for composite foams. However, all of these inspection methods are very expensive and require safety measures for the human body. Therefore, the inspection work takes time. At present, it has not been put to practical use from this point.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and it is possible to efficiently detect internal defects of a composite foam, and to perform inspection work easily and at a low inspection cost. An object of the present invention is to provide a nondestructive inspection device for a foam.

[0005]

According to the first aspect of the present invention, there is provided a nondestructive inspection apparatus for inspecting internal defects in a composite foam comprising a foam and a skin covering the surface of the foam. A transmitter for transmitting a transverse wave for inspection from the outer surface of the composite foam to the inside of the composite foam, and a propagation wave formed by the transverse wave for inspection propagating through the inside of the composite foam; A non-destructive inspection apparatus for a composite foam, comprising: a receiver for detecting an outer surface of the composite foam.

Next, the operation of the present invention will be described. The nondestructive inspection apparatus according to the present invention is configured to apply a transverse wave for inspection to a composite foam and receive a propagation wave formed by the propagation of the transverse wave inside the composite foam. If the composite foam does not have any internal defects, there are no cavities or gaps in the interior where resonance phenomena are likely to occur. Waveform similar to a transverse wave).

If a test transverse wave is given to a composite foam having an internal defect such as a gap or a cavity, at least one of the waves including the fundamental frequency in the transverse wave has a fundamental frequency of It matches the natural frequency of the internal defect. Therefore, a resonance wave having a large amplitude derived from the resonance vibration generated by the internal defect is mixed with the propagation wave. In addition, the overtone vibration is reduced and the nodal vibration disappears as compared with the case where the natural frequency of the membrane vibration of the skin does not have an internal defect such as a gap.
It changes greatly. Therefore, the frequency of the propagating wave also changes greatly.

By observing the propagating wave in this way, it is possible to recognize a large change in amplitude and frequency that was not observed in the transmitted transverse wave for inspection. Therefore, in the device according to the present invention, the presence or absence of an internal defect of the composite foam can be known by receiving the propagating wave with the receiver and analyzing the amplitude and frequency thereof.

Further, the inspection apparatus according to the present invention can perform the inspection without damaging the target composite foam. Therefore, the inspection can be performed without wasting the expensive composite foam. Therefore, the inspection cost can be reduced. Further, the present invention is an apparatus for performing an inspection by applying an inspection transverse wave to a composite foam. Therefore, the structure is simple and the operation method is easy as compared with other devices conventionally considered. Furthermore, since an electric signal, a sound wave, and an elastic wave can be used as the transverse wave, the human body is safer than other devices.

As described above, according to the present invention, the internal defect of the composite foam can be efficiently detected, and the inspection work is easy.
It is possible to provide a nondestructive inspection device for a composite foam, which has a low inspection cost.

The electric signal is converted into a sound wave using an electroacoustic transducer or the like, and the sound wave is transmitted to the composite foam to propagate a transverse elastic wave to the composite elastic body.
The inspection device of the present invention can be configured to receive the propagation wave by the elastic wave (see Embodiment 1). Further, in the present invention, the transverse wave is transmitted from the transmitter to the composite foam so that the skin covering the surface of the foam vibrates.

As the composite foam, a resin foam, a plastic, or the like, as described later, may be used. The internal defects of the composite foam include cavities generated during filling of expanded particles during production of the composite foam, cavities generated between expanded particles due to insufficient heating and melting of the expanded particles,
A gap generated at the interface between the skin and the foam is exemplified.

Next, as in the second aspect of the present invention, the transmitter has a transmitting contact having a contact end, and the transmitting contact is connected to a vibrator which generates a fundamental vibration of 1 to 10 kHz. The vibrator is connected to a frequency transmitter for generating a square wave electric signal of 0.4 to 4.0 kHz, while the receiver has a receiving contact having a contact end, Preferably, the receiving contact is connected to a receiving signal amplifier.

Since the transmitting contact is connected to a vibrator that generates a fundamental vibration of 1 to 10 kHz, a strong vibration energy in the audible sound range can be obtained. , Sufficient vibration energy can be transmitted. And the vibrator is 0.4 to 4.0 kHz.
Because it is connected to the frequency transmitter that generates a square wave electric signal of z, it can generate large vibration energy by stimulating the fundamental vibration of the vibrator and that the square wave electric signal contains many overtone vibrations Can be. Further, since the receiver is connected to the reception signal amplifier, the state of the propagation wave can be surely known.

If the fundamental vibration is lower than 1 kHz, the electro-acoustic conversion efficiency of the vibrator may be significantly reduced because the fundamental frequency is lower than the fundamental frequency of the vibrator. Also, 10k
When the frequency is higher than Hz, the vibrator is limited to the upper harmonic vibration, so that the film vibration efficiency may be reduced.

The square wave electric signal is 0.4 kHz.
If it is less than the upper limit, the upper limit of the upper-tone electrical signal included in the square wave may decrease, and the degree of resonance may be reduced.
On the other hand, if the frequency is higher than 40 kHz, the vibration is limited to the ultrasonic range, so that resonance may not easily occur.

A transverse wave is transmitted from the transmitter to the composite foam through the contact. And at the said contact end, the said contact is comprised so that a composite foam may be contacted. Preferably, the contact end and the composite foam are in point contact. Further, it is preferable that the surface of the contact end facing the composite foam has a shape such as a curved surface (such as a spherical surface) or an acute angle (such as a cone or a pyramid).

The above-mentioned vibrator is a portion for generating a vibration which is a transverse wave transmitted to the composite foam. As this vibrator, for example, a flexural vibrator can be used. Note that the flexural oscillator simply deforms the membrane vibration without the volume of the oscillator itself changing. Further, as the vibrator, a piezoelectric element, a slip type, a twist type, a low frequency thickness type, or the like can be used.

Further, it is preferable that an electroacoustic transducer for converting an electric signal in the vibrator into a sound wave is provided between the vibrator and the transmitting contact, and the sound wave is sent to the contact. Further, it is preferable that an electroacoustic transducer is provided between the receiving contact and the received signal amplifier to convert a propagation wave received as a sound wave into an electric signal.

The frequency transmitting section is a section which efficiently converts a predetermined electric signal mechanically and gives sufficient vibration energy to the foam. As the frequency transmitting section, for example, a buzzer sound generating section having the same structure as various alarm buzzers such as a station departure buzzer and an alarm sound for a fire alarm can be used.

Next, a signal control circuit configured to intermittently control a square wave electric signal in a range of 30 to 100 Hz is connected to the frequency transmitting section. preferable. Thus, when a resonance wave is generated by an internal defect existing in the composite foam, a sharper detection than continuous wave resonance can be performed by the action of the instantaneous force. In addition, noise radiation that is unpleasant to the surroundings can be reduced.

The range of the intermittent control is 30 Hz.
If it is less than the above, there is a possibility that the downtime becomes long and the internal defect detection becomes insufficient. On the other hand, when the frequency exceeds 100 Hz, the pause time becomes short, and the frequency becomes close to a continuous wave, so that the effect according to the present invention may be hardly obtained. The signal control circuit includes a C.MO.
S. Low power consumption devices such as ICs can be used.

Next, it is preferable that, as in the fourth aspect of the invention, different display lamps be turned on according to the state of the propagation wave detected by the receiver. As a result, the inspection result can be displayed to the operator in an easy-to-understand manner, so that the efficiency of the inspection process can be improved and the inspection result can be prevented from being overlooked. The above-described mechanism for turning on the display lamp may be configured, for example, to convert a propagating wave into an electric signal and turn on the display lamp according to the voltage value of the electric signal.

Further, the state of the propagated wave can be sent to the visual recognition device as it is, and the inspection result can be known from this device. Specific examples of the visual recognition device include an oscilloscope having a CRT for displaying the waveform of a propagation wave, a printer and a plotter for printing the waveform of the propagation wave, and the like.

Next, it is preferable that the foam in the composite foam is made of resin.
When the foam is made of resin, the production of the composite foam is accompanied by poor filling of the resin and the occurrence of voids and gaps between the resins due to non-fusion of the resins when the heating is insufficient. Can be maximized.

The composite foam material made of resin is used for trucks, containers and pallets in the logistics field, bumpers and spoilers in the automobile field, floats and floating piers in the marine and fishery fields, and cutting boards in the household goods field. Since it is widely used in many fields such as a cooler box and a bathtub lid, the inspection apparatus of the present invention can greatly contribute to the efficiency and cost reduction of these manufacturing processes.

Further, specific examples of the composite foam include:
The skin is made of thermoplastic polyolefin resin (polypropylene resin, polyethylene resin, ABS resin, etc.),
Examples of the foam include a foamed thermoplastic polyolefin resin (foamed polypropylene, foamed polyethylene, foamed polystyrene, etc.) of the same system (for phase melting and easy recycling).

Others include thermoplastic polyolefin resins such as polycarbonate resins, polystyrene resins,
Vinyl chloride resin, a resin mixed with these resins,
Further, there may be mentioned a high-performance resin obtained by adding a filler, a stabilizer, a nucleating agent, a pigment and the like to the resin. On the other hand, as the thermoplastic polyolefin resin, expanded polystyrene copolymer resin,
Alternatively, a resin or the like obtained by mixing them may be used.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 A non-destructive inspection apparatus for a composite foam according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a nondestructive inspection device 1 (hereinafter, abbreviated as “inspection device 1”) of the present example is a composite foam 5 including a foam 52 and a skin 51 covering the surface of the foam 52. Void 5
5, a non-destructive inspection device for inspecting internal defects such as gaps 56;

The inspection apparatus 1 applies an inspection transverse wave 4 from the outer surface 510 of the composite foam 5 to the inside of the composite foam 5.
1 and a propagation wave 42 formed by the test transverse wave 41 propagating inside the composite foam.
On the outer surface 510 of the composite foam 5.

The transmitter 2 has a transmitting contact 21 having a contact end 215.
The oscillator 22 is connected to a vibrator 22 that generates a fundamental vibration of 10 kHz, and the vibrator 22 is connected to a frequency transmitting unit 23 that generates a square wave electric signal of 0.4 to 4.0 kHz. Further, the frequency transmitting section 23 outputs the square wave
It is connected to a signal control circuit 24 configured to perform intermittent control in the range of 0 to 100 Hz. On the other hand, the receiver 3 has a receiving contact 31 having a contact end 315,
The receiving contact 31 is connected to a received signal amplifier 32.

The details will be described below. As shown in FIG. 1, the inspection apparatus 1 has a transmitter 2 and a receiver 3. The transmitter 2 includes a transmitting contact 21 having a contact end 215, an electroacoustic transducer 210, a vibrator 22, a frequency transmitting unit 23,
And a signal control circuit 24. The receiver 3 is
It comprises a receiving contact 31 having a contact end 315, an electroacoustic transducer 310, and a received signal amplifier 32.

The inspection apparatus 1 also has a visual recognition device 16 and a printer 160 connected thereto, a synchronizing signal output unit 15 for transmitting a synchronizing signal to the visual recognition device 16 and the signal control circuit 24.

The transmitter 2 will be described. The signal control circuit 24 is configured so that the frequency
This is intermittently controlled to emit a square wave electric signal in the range of Hz. The square wave electric signal is transmitted from the frequency transmission unit 23 to the vibrator 22, and the square wave electric signal is intermittently transmitted to the vibrator 22 by the intermittent control.

The signal control circuit 24 is a C.MO.
S. It is composed of a circuit combining IC-4011B and 4528B.
5 and 2610. The vibrator 22 is a flexural vibrator having a fundamental frequency of 2.7 to 9.0 kHz.

The contact end 215 provided on the transmitting contact 21 is hemispherical, and is in a state of being in point contact with the composite foam 5 to be inspected. (Note that a conical contact can also be used as the contact.) The transmitting contact 21 is made of a hard resin or a metal material such as brass or copper. This is a receiving contact 3 described later.
Same as 1. The square wave electric signal is converted into a sound wave in the electroacoustic transducer 210 and transmitted to the composite foam 5 to be inspected through the contact end 215 of the transmitting contact 21.

Next, the receiver 3 will be described. The contact end 315 of the receiving contact 31 has a hemispherical shape and is in point contact with the composite foam to be inspected. The contact 31 is connected to a reception signal amplifier 32 via an electroacoustic transducer 310. Further, the electroacoustic transducer 2
Reference numerals 10, 310 denote a sliding plate made of a brass plate having a thickness of 0.5 to 1.0 mm and a protective metal case covering the sliding plate. In addition, from the receiver 3, the visual recognition device 16
Is received.

In the inspection apparatus 1, the receiving contact 31 and the electro-acoustic transducer 310, the transmitting contact 21 and the electro-acoustic transducer 210 are integrated to form the sensor section 11, and The sensor unit 11 is configured so that the distance between the center positions of the transmitting contact 21 and the receiving contact 31 is 50 mm.

Next, the composite foam 5 by the inspection apparatus 1 is used.
The detection of an internal defect will be described. The sound wave transmitted from the transmitter 2 propagates as a transverse elastic wave, causes a change in the shape of the skin 51 of the composite foam 5, and propagates through the composite foam 5. Cavity 55 and gap 56
Are present inside the composite foam 5, resonance waves 45 and 46 are generated from these portions by resonance. The propagation wave 42 is formed by combining all these waves,
The signal is detected by the receiving contact 31 as a received signal.

The received signal is amplified by the received signal amplifier 32 and sent to the visual recognition device 16. This visual recognition device 1
6 is an oscilloscope. The synchronization signal is sent from the synchronization signal output unit 15 to the visual recognition device 16 because the amplitude of the resonance wave can be constantly and stably observed as an image regardless of the magnitude of the resonance wave amplitude. The synchronizing signal from the synchronizing signal output unit 15 is supplied to a signal control circuit 2 for stabilizing intermittent oscillation.
4 has also been sent. Thus, the visual recognition device 16
The presence or absence of an internal defect is determined from the waveform obtained in step (1).
Further, the result obtained by the visual recognition device 16 can be output from the printer 160.

Next, a specific example of use of the inspection apparatus 1 of this embodiment will be described. As the composite foam 5 to be inspected, a foam having a skin 51 made of polypropylene and a foam 52 made of foamed polypropylene was used. This can be manufactured by filling the inside of a bag-like outer skin 51 with foamed particles made of polypropylene and foaming the inside of the outer skin. The composite foam 5 may have internal defects such as a cavity 55 and a gap 56 as shown in FIG.

The polypropylene foam particles for the foam 52 used in this example have a particle size of 2 to 6 mm. Also,
The density after foaming is 0.02 to 0.10 g / cm ³ .
The thickness of the skin 51 is 1.5 to 4 mm.

Further, in the above-described inspection apparatus 1, the transmitter 2
The frequency of the shear wave transmitted from is 800 Hz, the transmission intensity is 30 to 35 V, the sensitivity of the receiving amplifier is 30 to 35 dB,
The pressing strength of the contact ends 215 and 315 against the composite foam 5 is 1 to ² kg / cm ² .

When a plurality of composite foams were inspected under the above conditions, outputs as shown in FIGS. 2 and 3 were obtained from the visual recognition device 16 and the printer 160 shown in FIG. In addition, each of the composite foams that had been inspected by the inspection apparatus 1 was cut, and the state of internal defects was examined.

As a result, it was found that FIG. 2 shows the result of the composite foam 5 having no internal defect, and FIG. 3 shows the result of the composite foam having the internal defect. As can be seen from the figure, the amplitude of the waveform according to FIG. 2 was small and the amplitude according to FIG. 3 was very large. As described above, in the visual recognition device 1 of this example, the presence or absence of an internal defect in the composite foam 5 can be confirmed by observing the waveform of the received signal obtained from the receiver 3 with the visual recognition device 16 or the printer 160. Was.

Next, the operation and effect of this embodiment will be described.
The inspection apparatus 1 of the present embodiment is configured to give an inspection transverse wave 41 to the composite foam 5 and receive a propagation wave 42 formed by the propagation of the transverse wave 41 inside the composite foam 5.
By transmitting a test shear wave to the composite foam 5, the skin 5
1, when the composite foam 5 has an internal defect, the propagation wave 41 is very affected by the resonance waves 45 and 46 because the cavity 55 and the gap 56 exist inside. It has a large amplitude. The inspection apparatus 1 of the present embodiment can inspect the presence or absence of an internal defect of the composite foam 5 by receiving the propagation wave 41 at the receiver 3.

In this example, the inspection device 1 is a composite foam 5
The inspection can be performed without impairing the cost and wasting the expensive composite foam 5. Therefore, the inspection cost can be reduced. Further, in this example, since a sound wave converted from an electric signal is used for the composite foam 5, the device structure is simple and the operation method is easy. Furthermore, it is safe for the human body.

As described above, according to this embodiment, there is provided a non-destructive composite foam inspection apparatus capable of efficiently detecting an internal defect of a composite foam, easily performing an inspection work, and reducing the inspection cost. Can be.

Embodiment 2 As shown in FIG. 4, the inspection apparatus of this embodiment comprises a transmitter and a receiver, and is provided with a judgment circuit and a display unit connected to the receiver. As shown in FIG. 4, the transmitter 2 has a transmitting contact 21 having a contact end 215. The transmitting contact 21 generates a fundamental vibration of 1 to 10 kHz.
2 and the vibrator 22 is 0.4 to 4.0 k
It is connected to a frequency transmitting unit 23 that generates a square wave electric signal of Hz. Further, the frequency transmitting section 23 is connected to a signal control circuit 24 configured to intermittently control the square wave electric signal in a range of 30 to 100 Hz.

On the other hand, the receiver 3 has a receiving contact 31 having a contact end 315, and the receiving contact 31 is connected to a received signal amplifier 32. An electric circuit for measuring the voltage of the signal sent from the reception signal amplifier 32 and lighting the three-color display lamps 631, 632, 633 on the display unit 63 in accordance with the voltage value is provided in the judgment circuit 61. is there. Further, the frequency of the signal sent from the reception signal amplifier 32 measured by the judgment circuit 61 is measured,
A frequency display section 62 for displaying is provided. Other configurations are the same as those of the first embodiment.

As in the first embodiment, the inspection apparatus 1 of the present embodiment
Also, the transverse wave 41 for inspection transmitted from the transmitter 2 propagates through the composite foam 5 and reaches the contact 31 of the receiver 3. Electroacoustic transducer 310 connected to contact 31
Is converted into an electric signal, and the electric signal is further amplified by the reception signal amplifier 32.

The voltage of the electric signal amplified by the reception signal amplifier 32 is measured by a judgment circuit 61. If the voltage is high, it means that the amplitude of the propagation wave 42 is large.

Therefore, the judgment circuit 31 determines whether the voltage is high,
The display lamp 631, the display lamp 631,
632 and 633 are turned on. This correspondence is as follows. Indicator lamp 631, red. . . High voltage. That is, the cavity (approximate: vertical, horizontal, height 10 mm or more)
Or a gap (approximately 1.0 mm or more).

Indicator lamp 632, yellow. . . Medium voltage. Cavity (standard: vertical, horizontal, height less than 10 mm)
And the size of the gap portion (approximate: less than 1.0 mm) is medium. Indicator lamp 633, green. . . low voltage. No cavities or gaps. In other words, it is a good composite foam. Therefore, an operator observing the inspection apparatus 1 can observe the display unit 63 and know whether the composite foam 5 is good or not based on which display lamps 631 to 633 are turned on.

Further, by using the display of the frequency of the frequency display section 62, it is possible to determine whether or not the bonding state between the foam and the skin covering the surface of the foam is good. Others are the same as the first embodiment.

In the inspection apparatus 1 according to the present embodiment, the quality of the composite foam 5 is indicated by three display lamps 631, 632, 633 in a very easy-to-understand manner. Therefore, the inspection result can be presented to the worker in an easy-to-understand manner, so that the efficiency of the inspection process can be improved and the inspection result can be prevented from being overlooked.

Embodiment 3 In this embodiment, as shown in FIG. 5, an inspection of the degree of fusion of expanded particles in a composite foam using an inspection apparatus according to the present invention will be described. The inspection apparatus 1 used in this example has the same configuration as that of the second embodiment.

By the way, as described above, the composite foam can be produced by filling the foam with the foam particles, heating the foam to expand the foam particles, and shaping the foam with the foam. . However, if this foaming does not occur sufficiently due to some problem, a composite foam having a low degree of fusion may be obtained. In the composite foam having a low degree of fusion, the filled foam particles are not fused to each other and are not sufficiently foamed, so that cavities and gaps are generated between the foam particles, and the strength is reduced. In addition, it is a defective product that causes "sink" on the epidermis.

It is known that the lower the degree of fusion, the larger the voids and gaps are formed inside the composite foam. Therefore, as shown in FIG. 5, it is considered that there is a correlation between the degree of fusion and the voltage of the electric signal obtained by converting the propagation wave. Therefore, by using this correlation diagram, the degree of fusion inside the composite foam can be measured using the inspection device according to the present invention.

[0060]

As described above, according to the present invention, there is provided a nondestructive inspection apparatus for a composite foam which can efficiently detect internal defects of the composite foam, and can easily perform the inspection work and have a low inspection cost. can do.

[Brief description of the drawings]

FIG. 1 is a block diagram of an inspection apparatus according to a first embodiment.

FIG. 2 is a diagram showing an inspection result of a composite foam having no internal defect in the first embodiment.

FIG. 3 is a diagram showing an inspection result of a composite foam having an internal defect in the first embodiment.

FIG. 4 is a block diagram of an inspection device according to a second embodiment.

FIG. 5 is a diagram showing a relationship between a voltage of an electric signal and a degree of fusion in an inspection device according to a third embodiment.

[Explanation of symbols]

 1. . . Inspection equipment, 2. . . Transmitter, 21. . . Outgoing contact, 215, 315. . . Contact end, 22. . . Vibrator, 23. . . Frequency transmitting section, 24. . . 2. signal control circuit; . . Receiver, 31. . . 32. receiving side vibrator . . Receiving signal amplifier, 41. . . Transverse wave for inspection, 42. . . 4. propagating wave, . . Composite foam, 51. . . Epidermis, 52. . . Foam, 61. . . Determination circuit, 63. . . Display, 631-633. . . Indicator lamp,

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuyuki Akika 4384-2 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term in Totsuka Electronic Measurement Laboratory (reference) 2G047 AA08 AB05 BC03 BC04 BC09 CB02 GB11 GF06 GF11 GH01 GH13

Claims (5)

[Claims] 1. A non-destructive inspection device for inspecting internal defects in a composite foam comprising a foam and a skin covering the surface of the foam, comprising: A transmitter that transmits a transverse wave for inspection to the inside of the body, and a receiver that detects a propagation wave formed by the propagation of the transverse wave for inspection inside the composite foam on an outer surface of the composite foam. A non-destructive inspection device for a composite foam, comprising: 2. The transmitting device according to claim 1, wherein the transmitting device has a transmitting contact having a contact end, wherein the transmitting contact has 1 to 10 contacts.
connected to a vibrator that generates a fundamental vibration of kHz.
The vibrator is connected to a frequency transmitter for generating a square wave electric signal of 0.4 to 4.0 kHz, while the receiver has a receiving contact having a contact end, A non-destructive inspection apparatus for a composite foam, wherein the child is connected to a reception signal amplifier. 3. The composite foaming apparatus according to claim 2, wherein a signal control circuit configured to intermittently control a square wave electric signal in a range of 30 to 100 Hz is connected to the frequency transmission unit. Non-destructive body inspection equipment. 4. The method according to claim 1, wherein:
A non-destructive inspection apparatus for a composite foam, wherein different display lamps are turned on in accordance with the state of a propagation wave detected in the receiver. 5. The method according to claim 1, wherein:
A non-destructive inspection apparatus for a composite foam, wherein the foam in the composite foam is made of a resin.