JPH02252524A - Inspecting, controlling method for foreign material in extrusion molding - Google Patents

Abstract

PURPOSE:To prevent an improper product from mixing in a product silo by detecting a foreign material content in a resin product, comparing the content with a specified value, and feeding a resin product to an improper product conveying route in case of specified value or more. CONSTITUTION:Part of resin pellets flowing in a conveying route 5 is sampled by an automatic sample collector 9, and supplied to a foreign material inspection unit 10. The unit 10 places the pellet on a turntable 102, sequentially passes it in a visual field of a photodetecting camera 106, inspects the foreign material by an optical method, and outputs foreign material data from a control computer 101 to a controller 11. The controller 11 compares a foreign material content with first, second specified values based on the data, sends a control signal to a switching member 8 if the content is more than the first value, communicates the route 5 with an improper product silo 7 to convey the pellet having large content to the silo 7, thereby eliminating the contamination of a product silo 6. If the content is more than the second value, it sends a control signal to an automatic screen changer 4 to replace a screen.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a method for controlling the foreign matter content of extruded resin products (including intermediate products such as resin pellets) in the process of molding resin materials using an extruder. The present invention relates to a foreign matter inspection and control method in extrusion molding that automatically inspects and automatically controls transfer route switching and extruder screen switching.

[Prior Art] In recent years, resin products have been used in various industrial fields such as food containers, optical instruments, and medical instruments, and the applications of resin products are expanding more and more. Along with this, there is a demand for high-quality resin pellets with low foreign matter content.For example, food containers are required to have a beautiful appearance.
Also, optical equipment requires improved light transmittance.

The resin base used for any molding must have a low foreign matter content.

Therefore, in the synthetic resin molding process using a conventional extruder, inspectors sample the resin pellets extruded from extrusion 1 (J machine) and check the foreign matter content through visual inspection, or Foreign matter content was inspected using a synthetic resin visual inspection machine installed separately from the production line.

[Issues to be solved] The conventional foreign matter content inspection described above was performed off-line, so it is difficult to prevent foreign matter from entering the specimen from the outside between the sampling of the resin pellet and the end of the inspection. This could not be prevented and accurate measurement results could not be expected. In particular, when the foreign matter to be inspected has a micron or submicron particle size, erroneous measurement results are often produced.

In addition, visual inspections and offline inspections by inspectors are
If it took time to obtain measurement results and defective products leaked out during that time, a large amount of defective products would mix with the good products in the production silo, leading to the risk of spreading contamination in the product silo. .

As a conventional technique to solve such problems, Japanese Patent Application Laid-open No. 6
There is a foreign matter inspection device for resin materials disclosed in Japanese Patent No. 0-54815. This device attempts to optically detect foreign substances contained in a resin sheet extruded from an extruder using a take-up means (transport path) L. According to this device, foreign matter in a resin sheet can be automatically detected online, and the location of foreign matter can be marked with a marker.

Foreign body inspection can be performed quickly.

However, even if a foreign object is detected by such a foreign object inspection device, human work and operation are required to remove the foreign object and eliminate the cause of the foreign object, so it is not possible to fully automate a resin material molding line. However, there were problems with workability.

The present invention was developed in view of these problems, and it is capable of quickly and highly accurately inspecting the foreign matter content of extruded synthetic resin products, and also automatically switches the conveyance route to remove defective products from product silos. The purpose is to provide a method for inspecting and controlling foreign matter in extrusion molding that can prevent foreign matter from entering the mold.

Furthermore, it is an object of the present invention to provide a foreign matter inspection and control method that can automatically switch the extruder screen to normalize the foreign matter removal function when defective products containing a large amount of foreign matter are produced.

[Means for Solving the Problems] In order to achieve the above object, the present invention continuously and automatically detects the foreign matter content in a resin product extruded from an extruder using a foreign matter inspection device, and based on this detection result, The foreign matter content is compared with a preset specified value, and if the foreign matter content is greater than the specified value, the resin product is transferred to the defective product conveyance route by controlling the route switching member (2). If necessary, the foreign matter content is compared with the first and second specified values set in advance (first specified value ≦ second specified value), and the foreign material content is determined to be the first specified value. In the second case, the route switching member on the conveyance route is controlled to transfer the resin product to the defective product conveyance route, and if the foreign matter content is more than the second specified value, the extruder screen is switched. be.

[Embodiment] Two embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of an apparatus for carrying out the method of the present invention, and FIG. 2 is a block diagram showing a foreign object inspection apparatus in the example of the apparatus.

In FIG. 1, 1 is an extruder that melts and kneads the polymer supplied into a cylinder 2, and a die 3 provided at the tip.
A screen is provided at the end of the cylinder 2 to remove foreign matter, and the cylinder 2 is formed into a desired cross-sectional shape and continuously extruded. Auto screen changer 4 to automatically change the screen if it changes
is installed. These extruder 1 and auto screen changer 4 may be appropriately selected from known ones depending on the material of the supplied polymer, the shape of the product to be molded, etc. Other peripheral equipment 7, such as a cooling unit 7 for cooling molded products and a pelletizer for molding pellet-shaped products, are also installed as necessary.

Reference numeral 5 denotes a product conveyance path consisting of piping and the like, through which the resin product extruded from the outlet of the die 3 (hereinafter referred to as a resin pellet in this embodiment) is conveyed by air flow or the like. Near the end of the transport path 5, it branches into two, one branch path 5a
A product silo 6 for accommodating non-defective products is provided at the branch path 5b, and a defective product silo 7 for accommodating defective products is provided at the other branch path 5b. Further, a switching member 8 is provided at one branch point in order to send the transported resin pellets to either the silo 6 or 7. As the switching member 8, the branch path 5
An on-off valve, an on-off door, etc. that selectively closes either a or 5b can be used.

9 is an automatic sample collection machine, 10 is a foreign substance inspection device, and 11 is a control device. The automatic sample collection machine 9 is connected to the transport path 5
A part of the resin pellet being transported is sampled and used as a foreign object inspection device! 110 continuously.

Examples of the foreign matter inspection device 1O include the "Automatic Pellet Appearance Inspection Machine" manufactured by Seizang Co., Ltd., and the
rF&F sample test 9 manufactured by Toshiba Co., Ltd. and NY-520 manufactured by Toshiku Co., Ltd. can be used.

FIG. 2 shows a schematic configuration of an rF&F sample inspection device manufactured by Nippon Aluminum Industry Co., Ltd. In the figure, 101 is a control computer, ! 02 is a glass turntable, and 103 is a feeder for supplying samples. The turntable 102 is connected to the control computer 10
It rotates at a constant speed according to the drive signal from 1. Feeder 103 has automatic sample collection of 4m! Samples of resin pellets continuously sent from 9 are supplied in fixed amounts to the upper surface of the turntable 102.

Further, 104 and 105 are strobes, lo6 is a light receiving camera, and 107 is an inspection unit. The strobe 1o4° 105 emits light in response to a control signal from the strobe body 10B, and irradiates the upper and lower surfaces of the turntable 102 with light beams. The light receiving camera 106 receives the light beam transmitted or reflected by the sample on the turntable 102, and sends it to the inspection unit 107 as inspection information. The inspection unit 107 detects the amount of foreign matter contained in the sample based on the inspection information from the light receiving camera 106, and outputs foreign matter data to the control computer 101.

A control device 11 controls the auto screen changer 4 and the switching member 8 based on the amount of foreign matter detected by the foreign matter inspection device 1o. That is, the control device 111
The first and second specified values (first specified value ≦
A second specified value) is set, and if the foreign matter content is greater than or equal to the first specified value, the switching member 8 is controlled so that the resin pellet is transported to the defective product silo 7. . Further, when the foreign matter content is at the second specified deviation, the auto screen changer 4 is controlled to automatically replace the screen.

Next, a specific example of the method of the present invention performed using the above-mentioned apparatus will be described.

Resin pellets extruded from the die 3 of the extruder 1 and cut into granules by a not-shown beletizer are pneumatically transported within the transport path 5.

The switching member 8 always communicates the transport path 5 with the product silo 6.

A part of the resin pellet flowing through the conveyance path 5 is sampled by an automatic sample collector 9 and supplied to a foreign matter inspection device 10. In the foreign matter inspection device 110, the sampled resin pellet is placed on a turntable 102-Lf, 1. The inspection unit 107 inspects the foreign matter content based on the inspection information input from the light receiving camera 106, and sends it to the control computer 1o1 as foreign matter data.
from the control computer 101 to the control bag fi
Foreign object data is output to l.

The control bag 2111 compares the foreign material content with the first and second specified values based on the foreign material data, and if the foreign material content is equal to or higher than the first specified value, it sends a control signal to the switching member 8 to stop the conveyance. Route 5 is communicated with defective product silo 7. Therefore, the resin pellets containing a large amount of foreign matter are transported to the defective product silo 7 and do not contaminate the defective product silo 7.

Furthermore, if the foreign matter content is north of the second specified value, a control signal is sent to the auto screen changer 4,
Replace the screen. As a result, a clogged screen or a screen that cannot cope with changes in raw material supply amount, operating temperature, etc. is replaced with a normal and appropriate screen, and the foreign matter removal function is restored.

Note that the present invention is not limited to the one embodiment described above, and various modifications can be made without changing the gist.

For example, the method of the present invention can be applied to extrusion molding of resin products other than resin pellets, and can also be applied to cases where a conveyance path is formed by various known conveyance means such as a belt conveyor.

[Experiment Example 1] Hereinafter, the results of an experiment conducted using the method for inspecting and controlling foreign matter in extrusion molding of the present invention will be compared with Comparative Example 1. I will explain.

In the following experimental examples and comparative examples, an rF&F sample inspection device manufactured by Nippon Aluminum Industry Co., Ltd. is used as a foreign matter inspection device.

Experimental Example 1 The extruder 1410 has an auto screen changer,
Using an extruder that produces high-density polyethylene (equivalent to Idemitsu 110J (trade name)) at a production rate of 150 kg in 7 hours, 1 g of iron powder with a particle size of 40 to 70 pm is added to the raw material at approximately 20 minute intervals as colored foreign matter. did.

Resin pellets extruded from an extruder (contains colored foreign matter)
had a size of 2 to 5 φ.

The frequency of monitoring by the foreign object inspection device was set to I kg/15 minutes, and when the number of colored foreign objects of 507 zm or more reached 50 pieces/I kg or more, the conveyance route was switched to the defective product silo side. Furthermore, when the number of colored foreign particles of 50 g, m or more reached 90 pieces/1 kg or more, the auto screen changer was activated to replace the screen. I used something.

The product silo has a capacity that can receive lOl of high-density polyethylene, and in order to make the properties of the resin pellets uniform within the product silo, the IOT silo is
Blending operation was carried out on the resin bed 1/1 in the product silo for 1 hour.

FIG. 3 shows the change in the number of foreign particles at the extruder outlet in Experimental Example 1 above.

Comparative Example 1-1 High-density polyethylene was produced in the same manner as in Experimental Example 1, and colored foreign matter was also introduced in the same manner. The pellets containing colored foreign matter extruded from the extruder were resin pellets with a size of 2 to 5 gmmφ.

A portion of the produced pel/foot was sampled and visually inspected by eight inspectors. The speed of visual inspection is 1 person.
The processing speed was Kg/2 hours.

Then, when the number of colored foreign substances (more than 50g2m) reached 50 pieces/Ikg or more, the transport route was switched to the defective product silo side.Additionally, 50μml;
The screen of the extruder was manually switched when the number of ino-colored foreign substances in -h reached 90 pieces/I kg or more. A 200 mesh screen was used17. The capacity of the product silo was the same as in the example, and after receiving 10 tons of high-density polyethylene, the resin pellet was blended for 1 hour.

Comparative Example 1-2 High-density polyethylene was produced in the same manner as in Experimental Example 1 and Comparative Examples J and -1, and colored foreign matter was also introduced in the same manner.

A portion of the produced pellets was collected, and the samples were inspected every 15 minutes by patch processing using an automatic pellet appearance inspection machine. And the number of colored foreign particles of 50 uLm or more is 50 pieces/I
When the condition exceeded K, the transport route was switched to the defective product silo. Further, when the number of colored foreign substances of 50 pLm or more became 70 pieces/IKg or more, the screen of the extruder was manually switched. 20 screens
0 mesh was used. In addition, after adding IOT's high-density polyethylene l/l,
・Performed the blending operation.

Experimental example 1. Comparative example 1-1. Table 1 shows the results of measuring the physical properties of the resin pellets obtained from the product silo in Comparative Example 1-2. The physical properties were measured by creating test pieces in accordance with JISK-7113 (tensile elongation at break).

Table 1 Experimental example 2 High-density polyethylene (equivalent to Idemitsu 110J (trade name)) with an auto screen changer at the extruder outlet
Using an extruder capable of producing 750 kg/hour, resin pellets with 2 to 51 layers and a diameter of φ were produced.

Colored foreign matter is randomly contained in the produced resin pellets due to variations in the production process.

The frequency of monitoring by the foreign substance inspection device is 500 g/l 0 minutes, and the number of colored foreign substances of 50 gm or more is 1500 g.
When the product reaches the top, the transport route is switched to the defective product silo side. Furthermore, when the number of colored foreign particles of 50 ILm or more reached 50 pieces and weighed 7500 g or more, the auto screen changer was operated to replace the screen. Note that two 200-mesh screens were used in a stacked manner. What is this effective area? It was 30 cm'.

The product silo has a capacity that can receive 30 tons of high-density polyethylene, and in order to make the properties of the resin pellets in the product silo uniform, after receiving 30 tons of high-density polyethylene,
The resin pellets in the product silo were blended for 3 hours.

FIG. 4 shows the change in the number of foreign particles at the extruder outlet in Experimental Example 2 described above.

Comparative Example 2-1 In the same manner as in Experimental Example 2, a resin pellet of high-density polyethylene (bullet size 2 to 5 squares, 1φ) was produced.

A portion of the produced pellets was collected and visually inspected by an inspector. Visual inspection speed is 1 person I kg7
The number of inspectors for 2 hours was 8, which is the same as in Comparative Example 1-1.

Switching to the defective product silo was performed in the same manner as in Experimental Example 2, and the product silo was the same as in Experimental Example 2, with a capacity of 30 tons. The screen of the extruder was switched in Comparative Example 1-1 when the number of colored foreign substances of 50 ILm or more reached 50 pieces and 7500 g or more.
I did the same thing manually.

Two 200-mesh screens were stacked together. In addition, in the same manner as in Experimental Example 2, after receiving 30 tons of products, the resin pellets in the product silo were blended for 3 hours.

Comparative Example 2-2 High-density polyethylene was produced in the same manner as Experimental Example 2 and Comparative Example 2-1.

A portion of the produced pellets was collected, and the samples were inspected every 10 minutes in batch processing using an automatic pellet appearance inspection machine. And the number of colored foreign objects of 50μ2m or more was 20/
500. When this occurred, the transport route was switched to the defective product silo side. In general, the extruder screen was manually switched as in Comparative Example 2-1 when the number of colored foreign substances of 50 pm or more was 50 pieces and 1,500 g or more. 2 screens with 200 mesh
I used a sheet. Also, in the same way as Comparative Example 2-1,
After receiving 30 tons of high-density polyethylene, the resin pellets in the product silo were blended for 3 hours.

Experimental example 2. Comparative example 2-1. Table 2 shows the results of measuring the physical properties of the resin pellet obtained from the product silo in Comparative Example 2-2. The physical properties were measured by creating test pieces in accordance with JISK-7113 (tensile elongation at break).

Table 2 [Effects of the Invention] As explained above, according to the foreign matter inspection and control method in extrusion molding of the present invention, the foreign matter content of extruded synthetic resin products can be inspected quickly and with high precision, and moreover, it can be done automatically. It is possible to prevent defective products from entering the product bin by switching the conveyance route.

Furthermore, when defective products containing a large amount of foreign matter are produced, the screen of the extruder can be automatically switched to normalize the foreign matter removal function, thereby improving yield.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of an apparatus for carrying out the method of the present invention, Fig. 2 is a structural diagram showing a foreign object inspection apparatus in the same example, and Figs. 3 and 4 are experimental examples 1 and 2, respectively. FIG. 3 is a diagram showing changes in the amount of foreign matter at the extruder outlet in FIG. 1: Extruder 4 Niote screen changer 5: Product transport route 6: Product silo 7: Defective product silo 8: Switching member 9: Automatic sample collection machine 10 2 Foreign material inspection device 11: Control device

Claims (2)

[Claims] (1) The foreign matter content in the resin product extruded from the extruder is continuously and automatically detected by a foreign matter inspection device, and based on this detection result, the foreign matter content is compared with a preset standard value, and the foreign matter content is A foreign matter inspection and control method in extrusion molding, characterized in that when the content exceeds a specified value, a path switching member on the conveyance path is controlled to transfer the resin product to a defective product conveyance path. (2) First and second regulations in which the foreign matter content in the resin product extruded from the extruder is continuously and automatically detected by a foreign matter inspection device, and the foreign matter content is preset based on the detection results. value (first specified value ≦ second specified value), and if the foreign matter content is greater than or equal to the first specified value, the path switching member on the conveyance path is controlled and the resin product is transferred to the defective product conveyance path. A foreign matter inspection and control method in extrusion molding, characterized in that the foreign matter inspection and control method in extrusion molding is further characterized in that the screen of the extruder is switched if the foreign matter content exceeds a second specified value.