JPH08332633A - Pellet inspection device - Google Patents

Abstract

PURPOSE: To provide a pellet inspection device which can relieve the burden from an inspector and judge whether pellets are good or not at high speed and with high accuracy. CONSTITUTION: Resin pellets stored in a hopper 201 are carried to the position of a rotating table 106 by linear feeders 104 and 105. An image signal for picking up the outer appearance and color of the resin pellets placed on the rotating table 106 by cameras 102 and 103 is issued, and whether the resin pellets are good or not is judged from the image signal by an image processing section 202. The good resin pellets and defective pellets are discriminated by the judgment result, and the defective pellets are taken out of defective pellet discharge sections 119 and 120, while the good pellets are taken out of good pellet discharge sections 117 and 118.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pellet inspection device for inspecting the appearance of resin pellets and classifying them into good pellets and defective pellets.

[0002]

2. Description of the Related Art There is known an apparatus for manufacturing a resin product such as a resin film by supplying a resin raw material in the form of a resin pellet to an extruder or an injection molding machine and melting it with a heating cylinder or the like. The shape and color of the resin pellet used in such an apparatus are the most important. The commercial value of such pellets is determined from a so-called "look", and it is particularly important that the pellets have a uniform color and shape by visual observation.

This is because when the pellet shape is non-uniform,
When transferring pellets to the heating cylinder through piping,
The friction between the pellets or between the pellets and the pipes increases, and the pellets cannot be transferred smoothly. As a result, there is a risk that the thickness of the molded resin film or the like may change, leading to product defects. Particularly in the case of a thermoplastic resin, if the particle diameters of the pellets are not uniform, plasticization becomes non-uniform at the stage of molding processing, resulting in deterioration of the quality of processed products. It is considered that such defective pellet shape is caused by abnormal manufacturing conditions in the manufacturing process of the pellets, and that the color unevenness of the pellets is caused by mixing of foreign matter or the like in the manufacturing process. .

Therefore, the shape and color of the pellets are often measured during the manufacturing process and shipping of the pellets, and if defective products are found, a large amount of defective pellets are produced by correcting the manufacturing conditions. Are prevented.

FIGS. 8A to 8C are diagrams showing examples of defective shapes of these pellets. FIG. 8A is a tailed pellet and FIG. 8B is a tailed pellet.
Inset pellets, and (C) shows the shape of headphone pellets. When the pellets having such a shape are mixed as the resin raw material, the pellets are caught with other pellets, and the pellets cannot be transferred smoothly as described above.

[0006]

The measurement of the shape of such pellets is currently performed manually. That is,
Each of the 10 to 1000 pellets is visually inspected to determine whether the shape is abnormal. Also,
The measurement of each dimension is performed using a caliper or the like. In addition, the color of pellets is measured in 30-1
The 00-gram pellets are visually observed to distinguish good products from defective products by the color.

However, in such an inspection, there are many differences among individuals depending on the measurer, and it is often the case that a defective product is erroneously determined to be a good product and vice versa. Further, in order to reduce such individual differences among the measurers, if the number of positions at which the pellets are measured is increased, the time required for the measurement is increased, the production capacity is lowered, and the measurer is burdened with a large burden. Will be called.

The present invention has been made in view of the above conventional example, and an object of the present invention is to provide a pellet inspection device capable of reducing a burden on a measurer and determining whether a pellet is good or defective at high speed and with high accuracy. And

[0009]

In order to achieve the above object, a pellet inspection apparatus of the present invention has the following configuration. That is, a supplying means for supplying resin pellets, a conveying means for conveying the resin pellets supplied from the supplying means to an inspection position, and an appearance of the resin pellets conveyed by the conveying means are read to generate a corresponding image signal. Read means, a judging means for judging whether the resin pellet is good or bad based on the image signal generated by the reading means, and at least a defective product of the resin pellet is classified according to the judgment result by the judging means. Separately, a separating means for taking out the resin pellets is provided.

[0010]

With the above construction, the resin pellets supplied from the supply means for supplying the resin pellets are conveyed to the inspection position, and the appearance of the conveyed resin pellets is read to generate the corresponding image signal. Based on the image signal thus generated, it is judged whether the resin pellet is good or bad, and at least the defective resin pellet is sorted and the resin pellet is taken out according to the judgment result.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the schematic arrangement of the pellet inspection apparatus of this embodiment.

In FIG. 1, 101 is a control unit for controlling the entire apparatus, which is a CPU 130 or C such as a microprocessor.
ROM 1 for storing PU control programs and various data
31 and a RAM 132, which is used when the CPU 130 executes control processing and temporarily stores various data. A timer 133 can set a plurality of times and measure a plurality of times at the same time. When the time instructed by the CPU 130 is counted, C
The PU 130 is notified. 134 is a FIFO
Then, a non-defective item flag or a defective item flag, which will be described later, is set, and these flags are read out in first-in first-out order in the set order. 102,1
Reference numeral 03 denotes a camera, which captures an image of the shape of the pellet placed on the rotary table 106 and outputs the captured image signal to the control unit 101 as described later. 104, 105
Both are linear feeders, and sequentially transfer pellets stored in a hopper 201 (FIG. 2) described later to the position of the rotary table 106.

Reference numerals 107 to 109 denote motor drivers, which rotate corresponding motors in accordance with instructions from the control unit 101. The motors 110 and 111 vibrate the corresponding linear feeders 104 and 105, respectively, and move the pellets placed on the linear feeders to the position of the rotary table 106. Motor 1
Reference numeral 12 is a motor for rotating the rotary table 106.

Each of 113 to 116 is a solenoid, and in response to a control signal from the control unit 101, pick-up members for the non-defective product ejection units 117 and 118 and the defective product ejection units 119 and 120 provided on the rotary table 106 are provided. By driving, the pellets are picked up from the rotary table 106, and good and defective pellets are taken out. The removal (discharging) of the pellets from the non-defective product discharging units 117 and 118 and the defective product discharging units 119 and 120 is not limited to the above-described configuration. For example, the rotary table 106 is provided with an opening, and the opening thereof is provided. The parts may be classified as good products or defective products and dropped.

FIG. 2 is a schematic view of the pellet inspection apparatus of this embodiment, and FIG. 3 is a top view of the pellet inspection apparatus of this embodiment.

The pellets 210 are accommodated in the hopper 201, and are sequentially fed by the linear feeder (vibration feeder) 104 in the direction of the linear feeder 105 (arrow A direction). Reference numeral 300 in FIG. 3 denotes the linear feeder 104.
Shows a side cross-sectional shape of the, and as shown, has a U-shaped groove,
The pellets transferred by vibration in the groove are fed to the linear feeder 1 from the portion 104a where the side wall is removed.
It drops on 05. The pellets thus sent to the linear feeder 105 are further sent to the position of the rotary table 106 by the vibration of the linear feeder 105, and fall into a groove (described later) provided on the table of the rotary table 106 to be stored. It In addition, 301 is a linear feeder 1.
05 shows a side cross-sectional shape of 05, and as shown in the drawing, the two grooves 105
The pellets a and 105b are arranged so that the pellets dropped from the linear feeder 104 first stay in the groove 105a, and when more pellets are supplied, they overflow into the next groove 105b and fall. Each of the linear feeders 104 and 105 is, for example, a metal SUS304.
It consists of.

As described above, the linear feeder 105 has the grooves 105a, 105b for maintaining the pellets falling from the linear feeder 104 in a desired direction and posture.
The pellets are aligned in one row by making the width of the column as narrow as the width of the pellets. Further, the pellets which are not shaped to fit in the groove or the pellets connected to other pellets are blown off or eliminated by, for example, air or the like, so that the pellets sent to the rotary table 106 are aligned in one row. It may be done.
Here, since the pellet feeding speed in the linear feeder 105 is set higher than the pellet feeding speed in the linear feeder 104, the pellets are sufficiently dispersed on the linear feeder 105 so that a sufficient interval is maintained between the pellets. be able to.

On the surface of the rotary table 106, as shown in FIG. 3, two grooves 105 of the linear feeder 105 are provided.
two grooves 106a in a concentric pattern corresponding to a and 105b,
106b is provided. Then, the pellets transferred from the groove 105a drop into the groove 106a,
The pellets transferred by are dropped into the groove 106b. By doing this, the pellets can be spaced apart, and the pellets can overlap or
Alternatively, it is possible to prevent the shapes from being in contact with each other and the shape cannot be accurately inspected. Further, there is an effect that it is possible to easily discharge the pellets by suction (pickup) after the inspection.
The grooves 106a and 106b are V-shaped grooves,
The inside has a rubber lining. The purpose of this lining is to make the pellet 210 turntable 106.
The purpose of this is to absorb the impact of falling to reduce the bound of the pellet and prevent the surface of the rotary table 106 from being worn. Nitrile rubber or the like is considered as the material of this rubber, and its thickness is about 1 mm. It should be noted that powdery dust adheres to the grooves on the surface of the rotary table 106, which may reduce the inspection accuracy of the pellets or dust may adhere to the pellets.
It is desirable to provide an air inlet or the like for sucking these dusts in front of the point where the pellets drop from the linear feeder 105b in the direction of rotation of 06.

The camera 102 images the color and shape of the pellets on the groove 106a transferred by the rotation of the rotary table 106, and the camera 103 also uses the groove 106a.
The color and shape of the pellet on b are imaged. The rotation speed of the rotary table 106 in this embodiment is about 1
10,000 revolutions / 38 minutes.

As a result of the inspection based on the picked-up image signal, the pellet on the inner groove 106b which is determined to be a non-defective product is rotated by the rotary table 106 and the non-defective product discharging section 1 is provided.
When it reaches the position 17, it is adsorbed (picked up) by the non-defective product ejecting section 117 and ejected as a non-defective product. Similarly, the pellets on the outer groove 106a which are determined to be non-defective are adsorbed (picked up) by the non-defective ejection section 118 and ejected. Further, the pellet determined to be a defective product on the inner groove 106b is adsorbed (picked up) by the defective product discharging unit 119 and discharged as a defective product at the timing when the rotary table 106 rotates to reach the position of the defective product discharging unit 119. To be done. Similarly, the outer groove 106
The defective pellets on a are discharged from the defective product discharge section 120. It should be noted that the camera 1 determines whether the pellet is good or bad.
The image signals captured by 02 and 103 are input to the image processing unit 202 in FIG. This image processing unit 202
May be configured by dedicated hardware, or may be executed by program processing by the control unit 101 in FIG. Hereinafter, in this embodiment, the image processing unit 20
The case where 2 is realized by the program of the control unit 101 will be described.

The pellet inspection apparatus of this embodiment extracts and takes out defective resin pellets, and grasps the frequency of occurrence of defective products or what causes the defective products. It is used as the main purpose. Therefore,
The main purpose is to extract defective resin pellets, but the present invention is not limited to this, and needless to say, may be used mainly for extracting good resin pellets.

Next, the process of determining whether the pellet is good or defective in the image processing unit 202 will be described.

4 to 6 are views for explaining the pellet shape inspection method in this embodiment. <External contact inspection> FIG. 4 is a diagram for explaining an inspection example based on the external contact. A point P4 having a maximum x-coordinate value and a point P3 having a minimum x-coordinate of the contour showing the imaged shape 400 of the let. And a point P2 having the smallest y coordinate and a point P1 having the largest y coordinate are determined. From the coordinates of these points, the distance in the y-axis direction (the number of Y circumscribing dots) determined by the points P1 and P2, and the point P3
And the distance in the x-axis direction (the number of X circumscribing dots) determined by the point P4. <Inner contact inspection> FIG. 5 is a diagram for explaining an inspection example based on the inner contact, and two straight lines parallel to the x-axis or the y-axis are drawn from the circumscribing center point 501 of the imaged pellet shape 500. Then, intersections (P1 to P4) between these two straight lines and the contour showing the shape 500 of the pellet are obtained. From the coordinates of these points, the distance in the y-axis direction (the number of dots inscribed in Y) determined by the points P1 and P2, and the distance in the x-axis direction determined by the points P3 and P4 (the X inscribed point Calculate the number of dots). <45 ° Inner Contact Inspection> FIG. 6 is a diagram for explaining an inspection example based on the inner contact in the 45 ° direction. From the circumscribed center point 601 of the imaged pellet shape 600, the x-axis or the y-axis is compared. And draw two straight lines that form an angle of 45 °, and intersect these two straight lines with the contour indicating the pellet shape 600 (P
1 to P4) is calculated. From the coordinates of these points, the distance in the y-axis direction determined by the points P1 and P2 (the number of Y tilt dots) and the distance in the x-axis direction determined by the points P3 and P4 (the number of X tilt dots) ). <Area Inspection> For example, the area of the pellet is obtained from the shape of the pellet as shown in FIGS. Here, the area is obtained by counting the number of dots included in the contour showing the shape of the pellet.

The shape of the pellet is inspected by combining any one or all of the above-mentioned four kinds of inspection methods or an arbitrary inspection method. Then, for each inspection method, the measured pellet shape is normal (non-defective) or abnormal depending on whether or not the measured pellet shape (dot number) is within a predetermined range. It is possible to determine whether there is (defective product). In addition to the method described above, the pellet shape may be inspected by, for example, morphology treatment. <Color Inspection> Regarding the color of the resin pellet, whether or not the resin pellet is normal is determined by whether or not the color of the resin pellet read by the color cameras 102 and 103 is within a predetermined color range. It To determine this color, for example, R (red) G (green) from the color cameras 102 and 103
When each grayscale signal of B (blue) is input, each grayscale level is first sampled to obtain the shape of the pellet. Then, by the shape inspection of the pellets described above, the light and shade levels corresponding to the abnormal portion of the shape of the pellets are removed, and the respective light and shade levels of the resin pellets are determined. Depending on whether each of these color shade levels is within a predetermined range, it may be determined whether the resin pellet has a predetermined color,
Alternatively, the difference between the gray levels of these colors (color difference level) (R-
G: G-B: B-R), and whether or not the color of the resin pellet is normal may be determined depending on whether or not these color difference levels are within a predetermined range.

FIG. 7 is a flow chart showing the inspection processing in the pellet inspection apparatus of this embodiment. This processing is executed by the control unit 101.

The process of FIG. 7 is started when a large amount of pellets 201 are accommodated in the hopper 201 and the power of the apparatus is turned on. First, in step S1, the motor 110,
111 is rotated to vibrate the linear feeders 104 and 105, and the pellets 201 placed on the linear feeder 104 are transferred from the hopper 201 to the rotary table 106 via the linear feeder 105. At the same time, in step S2, the motor 112 is rotated at a constant speed and the rotary table 106 is rotated at a constant speed.

Next, in step S3, either the camera 102 or 103 receives the groove 10 on the rotary table 106.
When the pellet 201 on 6a or 106b is detected, the process proceeds to step S4, the image of the pellet 201 is imaged, and its shape and color can be obtained. Based on the shape and color of the imaged pellet 201, the inspection is performed by the method described above, and it is determined whether the read pellet is a good product or a defective product (step S5). If it is a non-defective product, the process proceeds to step S6, the non-defective product flag is written in the FIFO 134, and at the same time, the timer value a of the timer 133 (for example, the time required for the pellets to move from the camera 102 to the non-defective product discharging portion 118) is set, and the timer is set. 133
To start. On the other hand, if it is a defective product, the process proceeds to step S7, the defective product flag is written in the FIFO 134, and at the same time, the timer value b is stored in the timer 133 (for example, the camera 102).
The time required for the pellets to move to the defective product discharge section 120 is set, and the timer 133 is started.

Here, the distance from the camera 103 to the non-defective product discharging section 117 and the non-defective product discharging section 11 from the camera 102 are set.
Distances up to 8 are equal. Similarly, the camera 10
3 to the defective product discharge section 119, and the camera 102
It is assumed that the distance to the defective product discharging section 120 is equal.

Thus, the process proceeds to step S8, and the timer 13
3 is timed out, and when it is timed out, it indicates that the pellet imaged and inspected by the camera has arrived at either the non-defective product discharge portion or the defective product discharge portion. Go, FIF
The flag information is read from O134. If the flag is a non-defective item flag, the process proceeds to step S10, and the non-defective item ejecting section 117 or 118 ejects the pellets reaching that position. On the other hand, when the defective product flag is set, the process proceeds to step S11, and the defective product discharge unit 119 or 1
From 20, the pellet reaching that position is discharged. When the process of step S10 or step S11 is completed, the process proceeds to step S3 to execute the above-mentioned process.

Pellets that have not been inspected or need re-inspection are recovered from the rotary table 106, returned to the hopper 201, and inspected again.

In addition, in this embodiment, the non-defective product discharging section 117,
It was checked whether or not the pellets reached the position of 118, and at that time, the pellet take-out timing and the flag were checked, but it was determined that all the pellets that were not discharged by the defective product discharge units 119 and 120 were good products, Non-defective part 1
The pellets that have reached the positions 17 and 118 may be unconditionally discharged as non-defective products.

In this embodiment, the resin pellets are first stored in the hopper 201, but the present invention is not limited to this. For example, the resin pellets may be placed on a belt or the like and the linear feeder may be used. It may be conveyed to the position 104.

Further, in this embodiment, the rotary table 106 is used.
Although the resin pellets dropped onto the sheet are inspected, the present invention is not limited to this. For example, the resin pellets placed on the belt and conveyed may be inspected.

[0035]

As described above, according to the present invention, it is possible to reduce the burden on the measurer and distinguish a good pellet from a defective pellet at high speed.

Further, according to the present invention, there is an effect that the quality of the pellet can be judged with high accuracy. Further, according to the present invention, overlapping of pellets can be eliminated, and good or defective pellets can be accurately identified based on the shape or color of individual pellets.

[0037]

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a pellet inspection apparatus of this embodiment.

FIG. 2 is a schematic view of a pellet inspection apparatus of this embodiment.

FIG. 3 is a top view of the pellet inspection apparatus of this embodiment.

FIG. 4 is a diagram for explaining a shape inspection method in the inspection apparatus of this embodiment.

FIG. 5 is a diagram for explaining a shape inspection method in the inspection apparatus of this embodiment.

FIG. 6 is a diagram for explaining a shape inspection method in the inspection apparatus of this embodiment.

FIG. 7 is a flowchart showing an inspection process in the inspection apparatus of this embodiment.

FIG. 8 is a diagram showing an example of defective pellet shape.

[Explanation of symbols]

 101 control unit 102, 103 color camera 104, 105 linear feeder 106 rotary table 117, 118 non-defective product discharging unit 119, 120 defective product discharging unit 130 CPU 131 ROM 132 RAM 133 timer 134 FIFO

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tadashi Hashimoto 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Co., Ltd. Yokkaichi Plant (72) Inventor Yoshitaka Hikami 1-5, Kamitoba Oyanagi-cho, Minami-ku, Kyoto-shi, Kyoto Duck Engineering Co., Ltd. (72) Inventor Takashi Ono 1-5 Oyanagi-cho, Kami Toba, Minami-ku, Kyoto-shi, Kyoto Prefecture Duck Engineering Co., Ltd. (72) Hiromi Okamoto, Kamitaba, Minami-ku, Kyoto-shi, Kyoto Prefecture 1-5 Oyanagicho, Duck Engineering Co., Ltd. (72) Inventor Shigeo Takai 1-5, Oyanagicho, Minami-ku, Kyoto-shi, Kyoto Prefecture Duck Engineering Co., Ltd.

Claims (11)

[Claims] 1. A supply unit for supplying resin pellets, a transfer unit for transferring the resin pellets supplied from the supply unit to an inspection position, and a corresponding image obtained by reading the appearance of the resin pellets transferred by the transfer unit. A reading means for generating a signal, a judging means for judging whether the resin pellet is good or bad based on the image signal generated by the reading means, and at least a failure of the resin pellet depending on the judgment result by the judging means. A pellet inspecting apparatus, comprising: a sorting unit that sorts good products and takes out resin pellets. 2. The pellet inspection apparatus according to claim 1, wherein the carrying means has a linear feeder on which the resin pellets discharged from the supplying means are placed and conveyed by vibration. 3. The pellet inspection apparatus according to claim 1, wherein the reading unit reads the shape and / or color of the resin pellet and generates a corresponding image signal. 4. The reading means reads the resin pellets placed on a rotary table, and the rotary table rotates in a predetermined direction at a constant speed. The pellet inspection apparatus according to item 1. 5. The pellet inspection apparatus according to claim 4, wherein the rotary table has grooves concentrically provided on the surface thereof, and the resin pellets are accommodated in the grooves. . 6. The reading means has an image pickup device for reading the appearance of the resin pellets at a predetermined position on the rotary table, and the sorting means is a non-defective product by the judging means on the downstream side in the rotating direction of the rotary table. The pellet inspection device according to claim 4, further comprising a take-out member for taking out the resin pellets determined to be defective. 7. The supply means has a hopper for storing resin pellets.
The pellet inspection device according to any one of 1. 8. The pellet inspection apparatus according to claim 4, wherein the resin pellets conveyed by the linear feeder are dropped onto the rotary table. 9. The linear feeder according to claim 2, wherein the linear feeder has a groove extending along the extending direction of the linear feeder with a width that can accommodate substantially one resin pellet having a normal shape. Pellet inspection device. 10. The pellet inspection apparatus according to claim 2, further comprising an excluding means for excluding resin pellets that cannot be accommodated in the groove of the linear feeder from above the linear feeder. 11. The image signal input from the reading means includes each color component data obtained by reading the pellet,
The pellet inspection apparatus according to claim 3, further comprising a detection unit that removes color data of a portion other than the original shape of the pellet from the color component data to detect the color of the pellet.