JPH06130042A - Nondestructive inspection apparatus for multilayer plastic tructure - Google Patents

Abstract

PURPOSE:To obtain an inspection apparatus wherein it can simultaneously confirm whether a gas barrier layer exists or not in a plurality of parts and it does not cause any inconvenience hygenically by arranging a plurality of ultrasonic probes on the flange circumference of a multilayer plastic structure. CONSTITUTION:For example, eight ultrasonic probes 30 are arranged on the flange circumference of a multilayer plastic structure (e.g. a food container). The probes 30 are changed over sequentially by a channel changeover device 23, and whenever a reflected signal is detected, it is judged by a gas barrier discrimination circuit 21 whether a gas barrier layer exists in its position. A control circuit part 22 repeatedly sends ultrasonic waves to the probes 30 through the changeover device 23, and the reflected signal from a molded product is received by the probes 30. A mechanism operating part 25 which holds an object under test and which brings the probes 30 into contact with the object under test is controlled through a sequencer 24. When the gas barrier layer exists in a container flange part, it can be judged that the gas barrier layer has been formed over the whole circumference of the container.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a multi-layer plastic structure including a gas barrier resin layer and having at least three synthetic resin layers in consideration of food use. It relates to a device to be inspected.

[0002]

2. Description of the Related Art Conventionally, in nondestructive inspection using an ultrasonic probe, only the position where the probe is applied can be inspected, and when inspecting a plurality of places, the place where the probe is applied is There is a problem that it is necessary to move each time and it is impossible to inspect a plurality of places at the same time.

Further, since it is difficult for the ultrasonic wave to directly enter from gas to solid due to its attenuation and reflection characteristics, generally, as shown in FIG. 8, is water or oil interposed between the tip of the probe and the object to be measured? As shown in FIG. 9, the entire object to be measured was immersed in water to propagate ultrasonic waves.

However, in containers for foods, which need to maintain hygiene in the manufacturing and inspection processes, the above liquids such as water or oil cannot be used at all from the viewpoint of hygiene, and nondestructive inspection by ultrasonic waves is effective. There was a problem that it was not used for.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to provide a plurality of locations on the flange periphery of a multilayer plastic structure including a gas barrier layer. At the same time, another object of the present invention is to provide a nondestructive inspection device for a multi-layered plastic structure which confirms the presence / absence of a gas barrier layer and has no problem in hygiene.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is characterized in that a plurality of ultrasonic probes are arranged on the circumference of a flange of a multilayer plastic structure. It is an inspection device, and further shown in FIG.
As shown in FIG. 3, the tip of the ultrasonic probe 10 is covered with silicone rubber 11 and brought into contact with the plastic surface in a dry state, and the contact and non-contact operations are performed by one ultrasonic probe with one air. It is a nondestructive inspection device for the above-mentioned multi-layered plastic structure, characterized in that it is performed using a cylinder.

[0007]

According to the present invention, the presence or absence of the barrier layer at each position can be inspected at the same time by disposing a plurality of ultrasonic probes on the circumference of the flange of the multilayer plastic structure.
In addition to coating the tip of the ultrasonic probe with silicon rubber, the ultrasonic probe uses one air cylinder for one ultrasonic probe for contact and non-contact with the plastic surface. Even if silicone rubber is used, stable pressing force and high adhesion can be obtained without interposing a liquid such as water or oil between the measurement object and the object to be measured, and it is possible to accurately propagate ultrasonic waves and receive reflected signals. Becomes

[0008]

The present invention will be described in detail below with reference to the drawings. The multilayer plastic structure to be inspected by the device of the present invention has, for example, a cross-sectional structure as shown in FIG. 10. For example, the base material layer 15 is a polypropylene layer and the adhesive layer 16 is a modified polypropylene layer. , Gas barrier layer 1
7 is a container in which a 5-layer structure is formed by a saponified product of an ethylene vinyl acetate alcohol copolymer having a gas barrier property.

If there is a gas barrier layer on the flange portion of the container, it can be judged that the gas barrier layer 17 is formed over the entire circumference of the container. As an example of an apparatus for implementing the inspection of the presence or absence of the flange gas barrier layer 17, a block diagram of a control apparatus is shown in FIG. 5, and a front view, a plane view, and a sectional explanatory view of a nondestructive inspection apparatus are shown in FIGS. 3 shows.

In this embodiment, eight ultrasonic probes are used on the circumference of the flange, and the ultrasonic probes arranged are sequentially switched by the channel switch 23. The gas barrier layer identifying circuit 21 determines whether the gas barrier layer exists at the position of the reflection signal of the signal. The control circuit unit 22 repeatedly sends an ultrasonic wave having a frequency of about 30 to 40 MHz to the ultrasonic probe 30 through the channel switch 23, and the ultrasonic probe 30 receives the reflected signal from the molded product again. Is.

The sequencer 24 holds the multi-layer plastic structure to be inspected and controls the mechanism operating unit 25 having a mechanism for contacting and non-contacting the ultrasonic probe with the multi-layer plastic structure.

In FIG. 1, reference numeral 41 is an apparatus mount, 50 is an ultrasonic probe mount, and 42 is a slide block for mounting multi-layer plastic structures 48, 49 to be inspected. In this embodiment, two slide blocks are mounted at the same time. I can do things. 43 and 44 are air cylinders 4 for moving the slide block 42.
The ultrasonic probe 3 is a stopper that limits the stroke of 5
The stop position of the slide block 42 is determined so that the flange portion 18 of the structure to be measured is correctly positioned at the zero position.

The air cylinders 46 (eight in total) serve to move the ultrasonic probe 30 up and down to make contact and non-contact with the container flange.

The device according to the present invention detects the gas barrier layer by the following operations. That is, the slide block 42 has multilayer plastic containers 48, 4 to be inspected.
When 9 is placed and the apparatus is started, the slide block 42 is moved by the air cylinder 45 and stopped by the stopper 43 or 44 in the correct positional relationship with respect to the ultrasonic probe 30.

Next, the ultrasonic probe 30 is pressed against the flange portion 18 by the individually mounted air cylinders 46. Next, ultrasonic waves are incident on the container flange portion 18 from the probe 30 from the control circuit portion 22 through the channel switch 23. If the gas barrier layer exists, the ultrasonic probe 30 again captures a reflection signal from the interface of the gas barrier layer 17 due to the difference in the densities of the resin forming the layer in addition to the front surface and the back surface of the flange portion. At the interface between the base material layer 15 and the adhesive layer 16, since both resins are made of the same polypropylene and have similar densities, clear reflection of ultrasonic waves does not occur.

The captured reflected signal passes through the control circuit section 22 and the gas barrier layer identification circuit 21 detects the presence or absence of the gas barrier layer from the reflected signal. Channel switch 2
Whether or not the gas barrier layer is formed on the entire circumference of the flange portion by repeating the above operation by sequentially switching the total of eight ultrasonic probes 30 by the timer having the built-in 3 You can check.

When a series of inspections is completed, the air cylinder 46
Rises to bring the ultrasonic probe 30 out of contact with the flange portion, the air cylinder 45 operates again and moves to the other container side placed on the slide block 42, and the inspection is performed in the same procedure. In the meantime, continuous inspection is possible by exchanging the container that has been inspected for the next uninspected container.

FIG. 6 and FIG. 7 are examples of the reflection signal obtained from one ultrasonic probe. The measured thickness of the flange portion of the multilayer plastic container is 1.0 mm, and the thickness of the gas barrier layer is 15 μm. FIG. 6 is a non-defective portion in which the gas barrier layer is correctly present as a layer, S is a reflection signal from the flange surface, B is a reflection signal from the flange back surface, and I is a reflection signal from the gas barrier layer.

FIG. 7 shows a defective portion in which the gas barrier layer does not exist. Only the reflection signals on the front surface S and the back surface B of the flange show no reflection signal from the gas barrier layer.

The gas barrier layer discrimination circuit 21 discriminates whether or not the reflection signal I from the gas barrier layer exists between the reflection signals S and B. As shown in the example of the reflected signal, the present device can clearly inspect and identify the presence or absence of the gas barrier layer.

Here, the necessity of using one air cylinder for one ultrasonic probe to perform the contact / non-contact operation with the object to be measured will be described. In the non-destructive inspection using normal ultrasonic waves, as described above, the adhesion is enhanced between the ultrasonic probe tip and the object to be measured through a liquid such as water or oil. The apparatus of the present invention does not involve a liquid which is a hygienic problem in products such as food products, and enables ultrasonic waves to be propagated through the silicon rubber into the object to be measured, so that individual ultrasonic probes are used. To ensure that the ultrasonic probe has one air cylinder and one air cylinder, it is possible to align the adhesion and the pressure to the object to be measured, the pressing force, and the uniformity and stability of the pressing angle with high accuracy. The contacting and non-contacting operations are performed.

Since the attenuation and reflection characteristics of ultrasonic waves change depending on the adhesion and pressing force as described above, in order to perform accurate and stable ultrasonic wave incidence and capture of reflected signals, individual ultrasonic probe It is a very important requirement that the tentacles come into contact with the DUT under the same conditions. For example, when eight ultrasonic probes are attached to one fixing jig and one slightly large air cylinder is used to make contact or non-contact with the object to be measured, an unbalanced load or push It is easy to imagine that nonuniformity of the contact angle is likely to occur and adjustment for improvement cannot be performed.

[0023]

As described above, according to the present invention, it is possible to clearly determine whether or not the gas barrier layer is present in the flange portion of the multilayer plastic structure, and to check the liquid such as water or oil during the inspection. It is possible to provide a device that does not use the silicone rubber and solves the problems specific to non-destructive inspection by ultrasonic waves such as adhesion, and has no problem in hygiene management.

[0024]

[Brief description of drawings]

FIG. 1 is a front explanatory view of a nondestructive inspection device for a multilayer plastic structure according to an embodiment of the present invention.

FIG. 2 is a plan view of a nondestructive inspection device for a multilayer plastic structure according to an embodiment of the present invention.

FIG. 3 is an AA cross-sectional explanatory view of a nondestructive inspection device for a multilayer plastic structure according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram in which the tip of the ultrasonic probe is covered with silicon rubber.

FIG. 5 is a block diagram of a control device of the nondestructive inspection device for a multilayer plastic structure according to an embodiment of the present invention.

FIG. 6 shows an example of a reflected signal (when a gas barrier layer is provided).
It is a graph which shows.

FIG. 7: Example of reflection signal (without gas barrier layer)
It is a graph which shows.

FIG. 8 is a prior art illustration of a liquid-mediated method.

FIG. 9 is an explanatory diagram of a conventional technique of a method of submerging in water.

FIG. 10 is an explanatory diagram showing a configuration of a cross section of a container to be inspected by the present invention.

[Explanation of sign]

1, 10 ... Ultrasonic probe tip 2 ... Object to be measured 3 ... Liquid such as water or oil 4 ... Ultrasonic probe 5 ... Object to be measured 6
... water 7 ... water tank 11 ... silicon rubber 15 ... base material layer
16 ... Adhesive Layer 17 ... Gas Barrier Layer 18 ... Container Flange 19 ... Container Main Body 21 ... Gas Barrier Layer Identification Circuit 22 ... Control Circuit 23 ... Channel Switch 24 ... Sequencer 25 ... Mechanism Operating Unit 41 ... Device Stand 42 ... Slide block 43, 44 ... Stopper 45, 46 ... Air cylinder 48, 49 ... Multi-layer plastic container 50 ... Ultrasonic probe mount S ... Reflection signal from flange surface B ... Reflection signal from flange back surface
I ... Reflected signal from gas barrier layer

Claims (3)

[Claims] 1. A device for inspecting a multi-layer plastic structure including at least three synthetic resins including a gas barrier resin layer, which is a non-destructive inspection device for the presence or absence of the gas barrier resin layer. A non-destructive inspection device for a multilayer plastic structure, wherein a plurality of ultrasonic probes are arranged on the circumference of a flange of a plastic structure to inspect a plurality of locations at the same time. 2. The nondestructive inspection apparatus for a multilayer plastic structure according to claim 1, wherein the tip of said ultrasonic probe is covered with silicone rubber and brought into contact with the plastic surface in a dry state. 3. The ultrasonic probe according to claim 1 or 2, wherein the ultrasonic probe is brought into contact or non-contact with a plastic surface by using one air cylinder for each ultrasonic probe. Item 2. A nondestructive inspection device for a multilayer plastic structure according to item 2.