JPH0815080A - Method for inspecting pinhole - Google Patents

Abstract

PURPOSE:To shorten the working time and, at the same time, to save the space and labor for inspecting pinholes by incorporating a pinhole inspecting process in a surfacetreating process and inspecting pinholes in the same process by using the same compressed air. CONSTITUTION:At time of performing, for example, pattern transfer, a pattern is transferred after supplying 10 compressed air to a plastic bottle A so that the bottle A cannot be bent and enclosing the compressed air in the bottle A. After completing the transfer, the supply of the compressed air is stopped 12 and the then internal pressure of the bottle A is measured with a pressure sensor. After about 0.3 second, the internal pressure of the bottle A is again measured with the pressure sensor and the propriety of the bottle A is decided by discriminating the presence/absence of pinholes from the difference between the previously measured and newly measured internal pressures. Therefore, it becomes unnecessary to separately provide a pinhole inspecting process and the space, labor, and facility required for separately inspecting the bottle A for pinhole can be saved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting pinholes of plastic bottles and the like, and particularly to a pin of a plastic bottle which is performed in the same step as the surface treatment step such as pattern transfer using compressed air Regarding hall inspection method.

[0002]

2. Description of the Related Art As a pinhole inspection method for plastic bottles, a method is widely known in which compressed air is enclosed in the bottle and the pressure difference over time is measured and obtained.
This method is a separate process called pinhole inspection, which is performed separately from the surface treatment process such as pattern transfer, and the bottle to be inspected is filled with compressed air, and after a certain period of time, before the passage of time. This is a method of inspecting the presence or absence of pinholes by detecting the internal pressure difference of the bottle after the passage with a pressure sensor. If there is no pinhole, there will be no pressure difference, and if there is a pinhole, the enclosed compressed air will escape, resulting in a reduced pressure and a pressure difference. In any case, the pinhole inspection is an independent process, so the jigs around the inspection machine must be adjusted each time the size and shape of the bottle changes.
The personnel, labor, etc. for that were needed.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the pinhole inspection process which is independently provided as one of the inspection processes for plastic bottles, and improves the pinhole inspection process. Incorporated into the surface treatment process such as pattern transfer and labeling, and using compressed air used during the surface treatment process such as pattern transfer and labeling,
An object of the present invention is to provide a pinhole inspection method for plastic bottles, which is performed in the same process as the surface treatment process.

[0004]

In order to achieve the above object in the present invention, compressed air is enclosed in a plastic bottle, and after a certain period of time, the difference in the internal pressure of the bottle between the time of encapsulation and the time after the passage of the compressed air is reduced. A method for inspecting the presence or absence of a pinhole in a bottle by detecting with a pressure sensor, the method being carried out by being incorporated in the same step as the surface treatment step of the plastic bottle. This is a pinhole inspection method.

[0005]

As described above, according to the present invention, the step of inspecting a plastic bottle for pinholes is incorporated in a surface treatment work line for pattern transfer, labeling, and the like.

[0006]

The present invention will be described in detail with reference to the following examples.
As shown in Fig. 1, we will describe the case where the pinhole inspection process is incorporated into the current picture transfer line, where the picture is transferred to a plastic bottle in a cycle of 2.1 seconds.

[0007] Compressed air of 1.2 kg / cm ² is supplied to the plastic bottle (A) so that the outer surface of the plastic bottle does not bend due to external pressure when transferring the pattern,
After enclosing (10), the pattern transfer process (11) starts while keeping the plastic bottle inflated. Immediately after the end of the pattern transfer step (11), the supply of compressed air is stopped (1
2) Do. The time from the start of compressed air supply to the stop of supply is 1.8 seconds. The internal pressure of the bottle when the supply of compressed air is stopped is measured with a pressure sensor. Then,
0.3 seconds after stopping the supply of compressed air, similarly measure the internal pressure of the bottle with a pressure sensor. The difference in the internal pressure of the bottle measured when the compressed air supply was stopped and 0.3 seconds after the stop was used to determine the presence or absence of a pinhole, and also to determine whether the pinhole was within the tolerance. (Pinhole inspection process (13)).

On the other hand, when a plastic bottle of the same product is subjected to a pinhole inspection using an independent pinhole inspection device of the same principle, 1.2 kg / cm ² of compressed air is supplied and enclosed in the plastic bottle. Then, the internal pressure of the bottle was measured after 0.3 seconds, and when it dropped to 0.8 kg / cm ² , it was found that there was a pinhole with an inner diameter of 0.2 to 0.3 mm. It is also known that if the internal pressure of the bottle is 0.8 kg / cm ² or more 0.3 seconds after stopping the supply of compressed air, there is no problem as a good product.

Therefore, as a result of the pinhole inspection using the above-mentioned process in which the pinhole inspection process is incorporated at the end of the pattern transfer work line, the internal pressure when the compressed air supply is stopped is 1.
For 2 kg / cm ^2, the internal pressure of the bottle after 0.3 seconds 0.8 kg /
If it is cm ² or more, it means that there is no problem as a good product,
Both the pattern transfer work and the pinhole inspection work can be performed in 2.1 seconds, which is the same as the conventional work time.

[0010]

According to the present invention, since the pinhole inspection is incorporated in the final step of the surface treatment work line such as pattern transfer and labeling, it is not necessary to newly provide a pinhole inspection step. Moreover, the space for it is not required. Therefore, an operator for pinhole inspection and various troubles are not required, which brings about an effect that the number of personnel and the price are not increased. Further, since the surface treatment process such as pattern transfer and label attachment and the pinhole inspection process are performed in the same process, there is an effect that one process can be omitted and time can be shortened.

[Brief description of drawings]

FIG. 1 is a partial process diagram of a pattern transfer work line incorporating a pinhole inspection process for a plastic bottle according to an embodiment of the present invention.

[Explanation of symbols] 10 ... compressed air supply 11 ... pattern transfer process 12 ... compressed air supply stop 13 ... pinhole inspection process A ... plastic bottle

Claims (1)

[Claims] 1. A method of inspecting for the presence or absence of pinholes in a bottle by enclosing compressed air in a plastic bottle, detecting a difference in internal pressure of the bottle after and after the elapse of a certain time with a pressure sensor. A method for inspecting a pinhole of a plastic bottle, wherein the method is incorporated in the same step as the surface treatment step of the plastic bottle.