JPS5931437A - Foreign matter detecting method of hollow formed body - Google Patents

Abstract

PURPOSE:To check the presence or absence of foreign matter in a parison and the transparency easily by piking up image successively of the parison right after extrusion from a die head in an optional direction and processing the image pickup data electrically. CONSTITUTION:The example of the manufacture of a transparent bolt by the hollow forming method of a screw type extruder is exemplified in a figure. Polyvinyl chloride heated in a heating cylinder 1 is kneaded by the rotation of a screw 2 and passed through the head 3 to extrude the parison 4. At this time, the parison 4 is heated above its fusion point, so it has superior transparency. Then, a solid-state photographing camera 6 set right below the head 3 picks up images of the parison right before cutting successively and an electric signal from the camera 6 is monitored on a TV; data in the form of an electric signal obtained by judging the lightness of each picture element is inputted to a controller and compared with the reference value of a conforming parison.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting foreign matter generated or attached to a thermoplastic hollow molded article immediately before molding, thereby obtaining a bottle with a good appearance and free of foreign matter contamination.

The currently commonly used plastic blow molding method is as follows. f, that is, the heat stored in the hopper b] The plastic resin is sent forward by the rotation of the screw 'J A cylindrical parison with an inner and outer diameter of
Then, compressed air is blown from the upper end of the parison to bring the parison into close contact with the inner surface of the mold to obtain the bottle shape, and at the same time cool the parison.
This involves molding a hollow product.

According to the above-mentioned blow molding method, foreign matter may be generated or attached due to various defective conditions, such as heat or heat. 51'? Foreign matter that gets mixed into the plastic resin raw material even before molding, carbide that occurs due to inadequate heating conditions or structural problems of screws and cylinders during the plasticization stage, and adhesion to the head (also carbide and parison). During extrusion, foreign matter adhering from the outside is kneaded with the resin and extruded as a parison.Therefore, when compressed air is blown into this parison, it is natural that foreign matter or hollow bottles containing foreign matter may be removed. Molding tongue 7.). In this way, the molded product has a poor appearance and the product price is 11. , J P+9, even physical properties such as valence will be lost.

Here it is! - Bottles with foreign matter mixed in with glue are small defective products, so many molding manufacturers and bottle users have worked hard to develop methods for detecting foreign matter. For example, if you shine a light on a bottle, do you notice the reflected L? How to detect, or MOS type, CC[] type, etc. camera? use], image sensor Bottleke imaging 12,
Studies have been conducted on multiple evaluations of pixel brightness and darkness, and methods for determining whether a pixel is good or bad. However, these methods have the disadvantage that depending on the shape of the bottle, it may be impossible to distinguish between foreign objects and unevenness on the bottle due to the characteristics of the detection equipment, or it may be impossible to detect foreign objects that exist inside or at the bottom of the bottle. was there.

Therefore, in reality, foreign matter detection 2 is performed visually. (7 is 171) Visual inspection increases labor costs and has the disadvantage that complete detection of foreign objects is impossible due to the limitations of human ability.

Starting from the above point, the present invention uses a completely new method (2) to detect foreign substances present in Parsons using a detection power method based on two ideas.
-1 Is there an I-forming method to obtain a hot hole with no external defects?
Provided by J-romono.

As mentioned above, is compressed air used for plastic hollow molding? 1 fat before blowing? I pressed J7 with Parison and pushed it out 1°, but Bo!・Foreign matter generated on the surface or inside of the parison should be present in the parison. The present invention focuses on this point (also a method for detecting foreign substances).In other words, the liquid is extruded into a pipe shape in a state where it is melted in a bath and its transparency is increased. 1. If a foreign object is detected, the bottle formed by the parison is removed immediately after the parison is formed.

Hereinafter, the present invention will be explained in detail using specific examples.

Shown in the drawings (21) This example is an extruder with a complete set of screws.
Using the same blow molding method, this is a transparent bottle made of vinyl that measures 30% in length, 70% in width, and 180% in height. As shown in FIG. .The outer diameter is 239 and the inner diameter is 155.
Push out Ison (4). At this time, Nonorin (4) is heated above its melting point, so it is extremely transparent. In normal molding, this nokurison (4)
v 2002; The pitch is sandwiched with a ratio burr (5), and at the same time cutting is performed using a parison cutter (12), and the next step is blowing compressed air.In the present invention, a single solid-state camera ( 6) (hereinafter referred to as a CCD camera) continuously images the parison before it is cut. The electrical signal from the CCD camera (6) is monitored by the TV, and at the same time, the data from the electrical signal that determines the brightness of each pixel (7) is input to the controller. Pixel data is stored in advance in memory.If the parison that is continuously imaged is contaminated with foreign matter due to various factors, the pixel data of the imaged with a CCD camera (7) The pixel data will be different from the pixel data of a good product.In the case of a lever, the controller will output a defective signal?
Cut to the next step.

Here, in the foreign matter detection method of the present invention, the extruded parison is transparent (<1 is required, but even though many plastics are opaque at normal temperature, they become transparent when the temperature is above the melting point). is high, and in that sense, the scope of use of the present invention is considered to be extremely wide.

The camera used in the present invention is not only the above-mentioned CCI) camera, but also 1. TV (industrial camera), various cameras such as M'OS type imaging camera? In addition, it is also possible to use various optical sensors that detect the displacement of photovoltaic force or the Kuji effect. As shown in Figure 1, the CCD
It is preferable to set the camera (6) directly below the head1.
．． However, if this is not possible due to the structure of the molding machine, use parison (4) or prefectural assembly 2! i! ' Stop imaging the parison (4) at any point before it is (51Pi K).

The purpose of improving the foreign object detection accuracy or the parison's lack of transparency 1. It is also possible to move the camera not only in one direction but also in multiple directions.

The accuracy of detecting foreign objects depends on the degree of transparency, shape, etc. of the parison.According to the test results of the present inventor, it is possible to detect carbides with a diameter of 0.5 in the above-mentioned specific example. Ta.

Regarding the color of foreign substances, blackish ones are the most detectable (although it is possible to detect white foreign substances by using an illumination method).

According to the above embodiment, the foreign matter is detected using a CCD camera, and the parison is also molded in the normal process, but the molding machine? Electrical,
By mechanically improving it, it is also possible to eliminate defective parisons from the molding machine without molding them.

The above is an explanation of the present invention, but by using the present invention, conventional detection by weaving may not be accurate or may be completely inefficient depending on the shape of the product. It has now become possible to detect foreign objects in 7' plastic blow-molded bottles, which had been a major concern, using a very 111-year-old device.

Invention? Application J - Not only does the filter detect foreign substances, but it also controls the transparency of bottles, and in the case of colored materials, what color? It is also possible to control '1''.In addition, it is thought that it can be applied not only to the molding of bottles, but also to the molding of products other than bottles if it is a plastic blow molding.

[Brief explanation of drawings]

FIG. 1 is a simplified diagram of a filter device used in the foreign object detection method of the present invention. (1)...Heating/linda (2)...Scree (
3)...Head (4)...Parison (5)
・Split mold (6) ・Fixed imaging camera

Claims (1)

[Claims] The front ff was mixed up and the bath was drained due to the screw being sold once.
-J tl: Extrusion from a resin bed with a parison (
7. This parison Y l"Jf is cut to a certain length 17, and at the same time, it is mixed with a split mold, and then air is blown into the parison to obtain a desired hollow molded product. Immediately after being pushed out from the tie head, images are taken 17 continuously from any direction on Kahalin, and this imaging data Y!
Detecting the presence or absence of foreign matter in the parison through chemical processing. Featured foreign object detection method.