System for automatically inspecting and sorting pellets

Abstract

The present invention relates to a system for automatically inspecting and sorting granular materials. The system obtains the colors and images of two surfaces of the granular materials while continuously conveying the granular materials at high speed to detect different colors, foreign objects, abnormal shapes, black spots, etc., and effectively removes the granular materials determined to be defective while conveying the granular materials, thereby improving the accuracy and efficiency of the granular material inspection and sorting operations. The system for automatically inspecting and sorting granular materials according to the present invention may include: a sorter configured to photograph and inspect the first surface and the second surface of each granular material while conveying a plurality of granular materials, separate and remove the granular materials determined to be defective, and convey and load the high-quality granular materials to a designated position; and a sample inspector configured to receive a plurality of granular materials determined to be good-quality among the granular materials sorted by the sorter, manufacture a plate-shaped sample of a molded product, and photograph the first surface and the second surface of the sample of the manufactured molded product, thereby inspecting whether the sample of the molded product is defective.

Description

Technical Field

[0001] The present invention relates to an apparatus for inspecting pellets for defects, and more particularly, to a system for automatically inspecting and sorting pellets, which detects the color of pellets while continuously conveying a large number of pellets to determine whether the pellets are defective, and removes the defective pellets from the conveying path, thereby collecting only good-quality pellets. Background Art

[0002] Pellets are solid particles of synthetic resin representing petrochemical products, which are widely used in various fields such as films, pipes, and automotive interior materials. Since the pellets as raw materials have an important influence on the quality of the final product, quality control and impurity control are very important. In particular, during the manufacturing process, defective pellets such as those having different colors such as black, yellow, red, or other colors that are not desired, or those having foreign substances attached or mixed therein, abnormal shapes with dimensions or shapes outside the dimensional range, and black spots caused by carbonization of raw materials or auxiliary materials or foreign substances appear, and thus, it is necessary to sort and remove foreign particles.

[0003] According to the related art, when producing pellets as raw materials for synthetic resin injection molding, a pellet sorting device capable of sorting only standardized pellets is used to manufacture synthetic resin injection molding products that require precision. The pellet sorting device according to the related art is designed such that pellets are formed from an extruder and supplied to a hopper through a discharge line, a screen is installed at the lower part of the hopper, and low-frequency vibration is applied to sort only standardized pellets.

[0004] However, in the sorting method using a screen, since the pellets are sorted according to the shape and size of the screen, the sorting accuracy deteriorates. In addition, pellets containing defects such as different colors, foreign substances, abnormal shapes, and black spots cannot be sorted, and thus, it is necessary to measure the pellets by an additional method. Further, since the size of each pellet is small, the processing amount to be processed per hour is 1,200 kg per hour, and about 4 million or more need to be inspected, and since the production speed of each pellet is 40 mm / sec, which is too fast, there are limitations in solving quality problems.

[0005] In addition, Korean Patent Registration No. 10-2009757 discloses a "material sorting device based on an artificial intelligence program", which, while conveying an object containing a plurality of pellets, uses a camera to acquire an original image, converts the original image into a preset size, and uses the converted image to distinguish normal pellets and abnormal pellets.

[0006] However, a pellet sorting device including a conventional foreign object sorting device is for large circular objects such as beans, rather than for a hexahedron shape such as a pellet color and foreign object sorting device. For circular objects, even if a camera is placed to view from two sides, there is an advantage in that the image mapping part is minimized, but due to depth problems, there is a minimized imaging range, which has limitations in detecting defects other than the innermost part. In addition, since color information cannot be obtained from both sides of the pellet, there are limitations in detecting defects. Summary of the Invention

[0007] Technical Problem

[0008] To solve the above problems, an object of the present invention is to provide a system for automatically inspecting and sorting pellets, which obtains the colors and images of two surfaces of the pellets while continuously conveying the pellets at high speed to detect different colors, foreign objects, abnormal shapes, black spots, etc., and effectively removes the pellets determined to be defective while conveying the pellets, thereby improving the accuracy and efficiency of the pellet inspection and sorting operations.

[0009] Another object of the present invention is to provide a system for automatically inspecting and sorting pellets, which manufactures the pellets classified as good products into samples of molded products to detect whether the samples are defective, thereby further improving the accuracy and efficiency of inspecting and sorting pellets.

[0010] Technical Solution

[0011] To achieve the above object, a system for automatically inspecting and sorting pellets according to the present invention includes: a pellet supply unit configured to supply a plurality of pellets; a first pellet conveying unit configured to convey the pellets supplied from the pellet supply unit forward from the rear side; a pellet transporting unit provided at the front end of the first pellet conveying unit to convey the pellets conveyed through the first pellet conveying unit downward; a second pellet conveying unit provided below the first pellet conveying unit to receive the pellets conveyed downward through the pellet transporting unit and invert the pellets at an angle of 180° so as to convey the pellets backward from the front side; a first vision inspection unit provided above the first pellet conveying unit to photograph a first surface of each pellet to inspect whether the pellet is defective; a first sorting unit provided in front of the first vision inspection unit to suck the pellets determined to be defective by the first vision inspection unit so as to separate the defective pellets from the first pellet conveying unit; a second vision inspection unit provided above the second pellet conveying unit to photograph a second surface of each pellet to inspect whether the pellet is defective; a second sorting unit provided behind the second vision inspection unit to suck the pellets determined to be defective by the second vision inspection unit so as to separate the defective pellets from the second pellet conveying unit; and an unloading unit provided at the rear end of the second pellet conveying unit to receive the pellets conveyed through the second pellet conveying unit so as to convey the pellets to a designated unloading position.

[0012] The first pellet conveying unit may include: a first conveying plate installed to be inclined downward at a predetermined angle from the rear side forward, and a plurality of channels along which the pellets move extending in the front-rear direction; and a first vibration generator configured to vibrate the first conveying plate at a predetermined frequency. The second pellet conveying unit may include: a second conveying plate installed to be inclined downward at a predetermined angle from the front side backward, and a plurality of channels accommodating the pellets extending in the front-rear direction; and a second vibration generator configured to vibrate the second conveying plate at a predetermined frequency.

[0013] The top surfaces of the first conveying plate and the second conveying plate may be coated with a light-absorbing resin to prevent diffuse reflection during the photographing processes of the first vision inspection unit and the second vision inspection unit.

[0014] The pellet supply unit may include: a hopper configured to have an input port for introducing pellets formed to be open; and at least one or more distribution plates provided below the hopper, in which a plurality of penetrating pellet distribution holes for the pellets to pass through are formed.

[0015] Each of the first distribution unit and the second distribution unit may include a plurality of vacuum nozzles arranged horizontally above the first pellet conveying unit and the second pellet conveying unit, respectively, such that the vacuum nozzles are configured to suck together the pellets determined to be defective and moving along the first pellet conveying unit and the second pellet conveying unit, as well as the pellets in the surrounding area of the defective pellets, so as to discharge the pellets to the outside.

[0016] A plurality of fine ventilation holes each having a size smaller than the size of each pellet may be formed to vertically penetrate the first pellet conveying unit and the second pellet conveying unit corresponding to the vacuum nozzles, and a discharge auxiliary fan may be installed below the first pellet conveying unit and the second pellet conveying unit, the discharge auxiliary fan being configured to blow air through the fine ventilation holes such that when discharging defective pellets through the vacuum nozzles, the discharge auxiliary fan operates to blow air upward through the fine ventilation holes, thereby assisting in discharging the pellets.

[0017] The pellet conveying unit may include: a first guide plate installed to extend downward from the front end of the first pellet conveying unit; a second guide plate installed at a specific distance greater than the thickness of the pellet spaced apart in front of the first guide plate; and a plurality of guide channels formed to vertically extend between the first guide plate and the second guide plate so as to guide the pellets downward.

[0018] The system may further include: an upper conveying auxiliary fan installed to blow air between the upper ends of the first guide plate and the second guide plate above the front end of the first pellet conveying unit; and a lower conveying auxiliary fan installed to blow air from the front side to the rear at the lower end of the second guide plate to push the pellets conveyed by the lower end of the second guide plate to the second pellet conveying unit.

[0019] The first guide plate and the second guide plate may be installed to be inclined at an angle of 2° to 4° with respect to an axis perpendicular to the ground.

[0020] The unloading portion may include: a non-defective product conveying conveyor configured to convey the pellets determined to be non-defective and discharged through the rear end of the second pellet conveying unit; an emergency discharge conveyor configured to convey the pellets determined to be defective and discharged through the rear end of the second conveying plate; and a conveyor moving unit configured to convey the non-defective product conveying conveyor and the emergency discharge conveyor to a position corresponding to the rear end of the second pellet conveying unit.

[0021] The system may further include a sample inspector configured to receive at regular intervals the pellets determined to be non-defective in the first visual inspection unit and the second visual inspection unit through the first distribution unit or the second distribution unit to manufacture a plate-shaped sample of a molded product, and configured to inspect whether the manufactured sample of the molded product is defective.

[0022] The sample checker may include: a pellet storage unit configured to receive pellets passing through the first dispensing unit or the second dispensing unit; a sample molding unit including a lower mold, an upper mold, and a heater, the lower mold being provided with a cavity in which a certain amount of pellets from the pellet storage unit are placed, the upper mold being configured to press the pellets placed in the cavity of the lower mold to manufacture a disk-shaped sample of a molded product, and the heater being configured to transfer heat to the pellets through the lower mold and the upper mold so as to melt the pellets; a cooling unit configured to cool the sample of the molded product manufactured in the sample molding unit; a sample transfer robot configured to transfer the sample of the molded product cooled by the cooling unit; a sample inspection unit configured to photograph the top surface and the bottom surface of the sample of the molded product transferred by the sample transfer robot so as to inspect whether the sample has defects; a marking unit configured to mark a predetermined mark on the surface of the sample of the molded product inspected by the sample inspection unit; and a sample unloading stacker configured to load the sample of the molded product marked in the marking unit.

[0023] The sample molding unit may include: an indexing table rotatably mounted at a predetermined angle with respect to an axis perpendicular to the ground, and a plurality of lower molds and upper molds being provided at regular intervals along the circumferential direction thereon; and an indexing vibration unit configured to vibrate the lower mold.

[0024] A system for automatically inspecting and sorting pellets according to another embodiment of the present invention includes: a sorter configured to photograph and inspect the first surface and the second surface of each pellet while conveying a plurality of pellets to separate and remove the pellets determined to be defective, and to convey and load the good-quality pellets P to a designated position; and a sample checker configured to receive a plurality of pellets determined to be good-quality among the pellets sorted by the sorter to manufacture a plate-shaped sample of a molded product and to photograph the first surface and the second surface of the manufactured sample of the molded product, thereby inspecting whether the sample of the molded product has defects.

[0025] The sorter may include: a pellet supply unit configured to supply a plurality of pellets; a first pellet conveying unit configured to convey the pellets supplied by the pellet supply unit from the rear side to the front; a pellet transporting unit provided at the front end of the first pellet conveying unit to convey the pellets conveyed through the first pellet conveying unit downward; a second pellet conveying unit provided below the first pellet conveying unit to receive the pellets conveyed downward through the pellet transporting unit and invert the pellets at an angle of 180° so as to convey the pellets from the front side to the rear; a first vision inspection unit provided above the first pellet conveying unit to photograph a first surface of each pellet to inspect whether the pellet is defective; a first dispensing unit provided in front of the first vision inspection unit to suck and discharge the pellets conveyed by the first vision inspection unit; a second vision inspection unit provided above the second pellet conveying unit to photograph a second surface of each pellet to inspect whether the pellet is defective; a second dispensing unit provided behind the second vision inspection unit to suck the pellets conveyed by the second pellet conveying unit; and an unloading unit provided at the rear end of the second pellet conveying unit to receive the pellets conveyed through the second pellet conveying unit so as to convey the pellets to a designated unloading position.

[0026] The sample inspector may include: a pellet storage unit configured to receive the pellets from the sorter to store the pellets; a sample forming unit including a lower mold, an upper mold, and a heater, the lower mold having a cavity in which a certain amount of pellets from the pellet storage unit are placed, the upper mold configured to press the pellets placed in the cavity of the lower mold to manufacture a disk-shaped sample of a formed product, the heater configured to transfer heat to the pellets through the lower mold and the upper mold so as to melt the pellets; a cooling unit configured to cool the sample of the formed product manufactured in the sample forming unit; a sample conveying robot configured to convey the sample of the formed product cooled by the cooling unit; a sample inspection unit configured to inspect whether the sample is defective by photographing the top surface and the bottom surface of the sample of the formed product conveyed by the sample conveying robot; a marking unit configured to mark a predetermined mark on the surface of the sample of the formed product inspected by the sample inspection unit; and a sample unloading stacker configured to load the sample of the formed product marked in the marking unit.

[0027] The sample forming unit may include: an indexing table rotatably mounted at a predetermined angle with respect to an axis perpendicular to the ground, and a plurality of lower molds and upper molds are provided at regular intervals along the circumferential direction thereon; and an indexing vibration unit configured to vibrate the lower mold.

[0028] Beneficial effects

[0029] According to the present invention, while continuously conveying granular materials at high speed in a sorter, the colors and images of both surfaces of the granular materials can be obtained to detect defects such as different colors, foreign matters, abnormal shapes, black spots, etc., so as to remove the granular materials determined to be defective while conveying the granular materials. Therefore, it will have the effect of significantly improving the accuracy and efficiency of inspecting and sorting granular materials.

[0030] In addition, for the granular materials determined and classified as good products in the sorter, samples of molded products can be periodically manufactured to detect whether there are defects in the samples of the manufactured molded products, so as to predict and handle the sorting accuracy in the sorter and the possibility of defects in the final products. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a front view showing a system for automatically inspecting and sorting granular materials according to an embodiment of the present invention.

[0032] Figure 2 is a perspective view showing the configuration of a system for automatically inspecting and sorting granular materials according to an embodiment of the present invention.

[0033] Figure 3 is a perspective view showing the sorter shown in Figure 2 when viewed from different directions.

[0034] Figure 4 is Figure 2 a plan view of the sorter shown in

[0035] Figure 5 is Figure 2 a sectional view of the sorter shown in

[0036] Figure 6 is a front view showing the structure of a sample checker of a system for automatically inspecting and sorting granular materials according to an embodiment of the present invention.

[0037] Figure 7 is Figure 6 a plan view of the sample checker shown in

[0038] Figure 8 is Figure 6 a sectional view of the sample molding part of the sample checker shown in

[0039] Figure 9 is Figure 6 a perspective view of the structure of a part of the sample checker shown in

[0040] Figure 10 is Figure 6 a perspective view of the structure of another part of the sample checker shown in

[0041] Figure 11 Yes Figure 6 A diagram of an example of the operation of the sample checker shown in Detailed implementation mode

[0042] The system for automatically inspecting and sorting pellets according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Since the present invention can have various variations and various forms, specific embodiments are shown in the drawings and described in detail in the text. However, this is not to limit the present invention to the specific embodiments, and it should be understood that the present invention covers all modifications, equivalents, and substitutions within the scope of the idea and technology of the present invention. In the description of each drawing, the same reference numerals always represent the same elements. In the drawings, for the clarity of the present invention, the dimensions of the structure are enlarged compared to the actual structure, or reduced compared to the actual structure for understanding the schematic configuration.

[0043] Similarly, it should be understood that although terms such as "first" and "second" are used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one component from other components. For example, without departing from the scope of the appended claims, a first element that is referred to as the first element in one embodiment may be referred to as the second element in another embodiment. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Terms such as those commonly used and already in the dictionary should be understood to have a meaning that matches the context meaning in the art. In this description, unless clearly defined, terms are not ideally over-interpreted as formal meanings.

[0044] As Figure 1 described, the system for automatically inspecting and sorting pellets according to an embodiment of the present invention includes: a sorter 100 that takes pictures and inspects the first surface and the second surface of each pellet while conveying a plurality of pellets P, separates and removes the pellets P determined to be defective, and conveys and loads the pellets P with good quality to a designated position; and a sample checker 200 that receives at regular intervals a plurality of pellets determined to be good among the pellets sorted by the sorter 100 to manufacture a sample S of a molded product, and then takes pictures of the first surface and the second surface of the manufactured sample S of the molded product, thereby inspecting whether the sample S of the molded product is defective.

[0045] The sorting machine 100 is configured to obtain the size, shape, color, etc. of a plurality of pellets produced by cutting a thermoplastic resin into specific dimensions after extruding and molding the thermoplastic resin into a thin rod form, and to determine whether the plurality of pellets are defective, so as to sort the pellets into defective products and good products, and discharge the pellets determined to be defective products. The types of defects of the pellets inspected by the sorting machine 100 include: different colors deviating from the production quality standard, foreign substances attached or mixed with non-pellet substances, abnormal shapes with dimensions and shapes exceeding the size range to be produced, black spots caused by carbonization of raw materials or auxiliary materials or foreign substances, etc.

[0046] Referring to Figures 2 to 5 , the sorting machine 100 includes: a pellet supply unit 110 that supplies a plurality of pellets; a first pellet conveyor 120 that conveys the pellets P supplied from the pellet supply unit 110 forward from the rear side; a pellet transporter 140 that is provided at the front end of the first pellet conveyor 120 to convey the pellets conveyed by the first pellet conveyor 120 downward; a second pellet conveyor 130 that is provided below the first pellet conveyor 120 to receive the pellets P conveyed downward by the pellet transporter 140 and invert the pellets at an angle of 180° so as to convey the pellets from the front side to the rear side; a first vision inspection unit 150 that is provided above the first pellet conveyor 120 to photograph the first surface (top surface) of each pellet to inspect whether the pellet P is defective; a first dispensing unit 160 that is provided in front of the first vision inspection unit 150 to suck and discharge the pellet P inspected by the first vision inspection unit 150; a second vision inspection unit 170 that is provided above the second pellet conveyor 130 to photograph the second surface of each pellet to inspect whether the pellet is defective; a second dispensing unit 180 that is provided in front of the second vision inspection unit 170 to suck and discharge the pellet inspected by the second vision inspection unit 170; and an unloading unit that is provided at the rear end of the second pellet conveyor 130 to receive the pellet P conveyed by the second pellet conveyor 130 so as to convey the pellet P to a designated unloading position.

[0047] The pellet supply unit 110 includes: a hopper 111 configured such that an input port 111a for loading the pellet P is formed to be open at the upper end and has a wide upper portion and a narrow lower portion; and a plurality of distribution plates 112 that are spaced apart and provided below the hopper 111 and have a plurality of pellet distribution holes 113 through which the pellet P vertically passes. Thus, when a plurality of produced pellets P are added through the input port I11a of the hopper 111, the pellets P are evenly distributed to both sides through the pellet distribution holes 113 of the distribution plates 112 and fall onto the rear end of the first pellet conveyor 120 to be supplied.

[0048] The first pellet conveying unit 120 includes: a first conveying plate 121 installed to be inclined downward at an angle θ1 of about 2° to 4° from the rear side to the front side; and a first vibration generator 125 that vibrates the first conveying plate 121 at a predetermined frequency to convey the pellets P. A plurality of channels 122 along which the pellets P move are formed on the top surface of the first conveying plate 121 and extend in the front-rear direction. Each channel 122 has a groove extending in the front-rear direction of the first conveying plate 121, and the plurality of channels 122 are continuously arranged in the left-right width direction of the first conveying plate 121. Each channel 122 has a size slightly larger than that of each pellet P, so that the pellets P are conveyed in rows through the channels 122.

[0049] The first vibration generator 125 includes: a plurality of support rods 127 having an inverted "U" shape, which support the first conveying plate 121 at the lower part of the rear end of the first conveying plate 121; and a vibration module 126 that vibrates the support rods 127 in the Z-axis direction, that is, in the vertical direction, so that the first conveying plate 121 vibrates in the Z-axis direction at a frequency of 40 Hz to 440 Hz, so that the pellets P are conveyed along the channels 122 at a predetermined speed.

[0050] The second pellet conveying unit 130 includes: a second conveying plate 131 installed to be inclined downward at an angle θ2 of about 2° to 4° from the lower side of the first conveying plate 121 from the front side to the rear side, and provided with a plurality of channels 122 for accommodating the pellets P therein. In addition, the second pellet conveying unit 130 includes a second vibration generator 135 that vibrates the second conveying plate 131 at a predetermined frequency.

[0051] The number of channels 122 of the second conveying plate 131 is the same as the number of channels 122 of the first conveying plate 121, and the second vibration generator 135 is substantially the same as the first vibration generator 125. Therefore, the second conveying plate 131 vibrates in the Z-axis direction at a frequency of 40 Hz to 440 Hz, so that the pellets P are conveyed from the front side to the rear side along the channels 122 at a predetermined speed.

[0052] The top surfaces of each of the first conveying plate 121 and the second conveying plate 131 may be coated with a light-absorbing resin such as polytetrafluoroethylene to prevent diffuse reflection during the photographing process of the first visual inspection unit 150 and the second visual inspection unit 170.

[0053] The first vision inspection unit 150 and the second vision inspection unit 170 are respectively arranged above the first conveyor plate 121 and the second conveyor plate 131 at a predetermined distance to photograph the pellets P conveyed through the passage 122 of the first conveyor plate 121 and the second conveyor plate 131, so as to detect whether there are defects in the pellets P. The first vision inspection unit 150 and the second vision inspection unit 170, for example, use a 12M / 8Hz camera with R / G / B / W illumination to obtain the color, shape, size, etc. of the pellets P, to inspect defects such as different colors, foreign objects, abnormal shapes, black spots, etc., and to perform image tracking until the pellets P reach the first distribution unit 160 or the second distribution unit 180.

[0054] The first distribution unit 160 and the second distribution unit 180 are respectively arranged in front of the first vision inspection unit 150 and behind the second vision inspection unit 170. The first distribution unit 160 and the second distribution unit 180 include a plurality of vacuum nozzles 161 and 181 arranged horizontally left and right above the first conveyor plate 121 and the second conveyor plate 131. The vacuum nozzles 161 and 181 vacuum-extract the pellets P moving along the passage 122 of the first conveyor plate 121 and the second conveyor plate 131. The pellets P determined to be defective are discharged into a separate defective product collection container. A part of the pellets determined to be good products is discharged into the sample inspector 200. Here, since the vacuum nozzles 161 and 181 are each arranged across a plurality of passages 122, the pellets P determined to be defective products and the pellets P passing through the passages 122 around the defective pellets P are vacuum-extracted together and discharged. The vacuum nozzles 161 and 181 are connected to a vacuum generator such as a known vacuum pump to generate a suction force, and the pellets P sucked through the vacuum nozzles 161 and 181 are discharged to a defective product collection container (not shown) or the sample inspector 200 through a flow control valve (not shown) such as a three-way valve, and then collected.

[0055] When the first distribution unit 160 and the second distribution unit 180 suck the pellets P from the first conveyor plate 121 and the second conveyor plate 131, in order to prevent the pellets P from not separating from the passage 122, a plurality of fine ventilation holes 124 each having a size smaller than the size of each pellet P are formed to vertically penetrate the first conveyor plate 121 and the second conveyor plate 131 at positions corresponding to the vacuum nozzles 161 and 181 of the first distribution unit 160 and the second distribution unit 180, and a discharge auxiliary fan 162 for blowing air through the fine ventilation holes 124 is formed below the first conveyor plate 121 and the second conveyor plate 131, so that when the process of discharging defective pellets is performed through the vacuum nozzles 161 and 181, the discharge auxiliary fan 162 operates to blow air upward through the fine ventilation holes 124 to assist in discharging the pellets P.

[0056] The pellet conveying unit 140 is installed between the front ends of the first conveying plate 121 and the second conveying plate 131 substantially vertically with respect to the ground to convey the pellets P conveyed by the first conveying plate 121 downward, so as to invert the pellets by 180° while conveying the pellets to the front end of the second conveying plate 131.

[0057] In this embodiment, the pellet conveying unit 140 includes: a first guide plate 141 installed to extend downward from the front end of the first conveying plate 121; a second guide plate 142 installed at a specific distance greater than the thickness of the pellet P in front of the first guide plate 141; and a plurality of guide channels 143 formed to vertically extend between the first guide plate 141 and the second guide plate 142 to guide the pellets P.

[0058] The guide channels 143 are formed to correspond one-to-one with the channels 122 of the first conveying plate 121 and the channels 122 of the second conveying plate 131, so as to convey the pellets P conveyed through the channels of the first conveying plate 121 to the channels of the second conveying plate 131.

[0059] When the pellets P are conveyed through the guide channels 143 to the channels 122 of the second conveying plate 131, in order to ensure that the pellets P are conveyed in a state of being inverted by 180°, the first guide plate 141 and the second guide plate 142 are preferably installed to be inclined at an angle θ3 of 2° to 4° with respect to the axis perpendicular to the ground.

[0060] In addition, in order to smoothly convey the pellets P from the front ends of the respective channels 122 of the first conveying plate 121 to the guide channels 143 and from the lower ends of the guide channels 143 to the channels 122 of the second guide plate 131, an upper conveying auxiliary fan 144 can be installed above the front end of the first guide plate 141, and the auxiliary fan 144 blows air between the upper ends of the first guide plate 141 and the second guide plate 142, and a lower conveying auxiliary fan 145 can be installed at the lower end of the second guide plate 143, and the auxiliary fan 145 blows air from the front side to the rear side to push the pellets conveyed from the lower end of the guide channels 143 to the channels of the second conveying plate 131.

[0061] The unloading unit is configured to receive the pellets P discharged from the rear end of the second conveying plate 141 of the second pellet conveying unit 130 to convey the pellets P to a designated unloading position. In this embodiment, the unloading unit includes: a good product conveying conveyor 191 that conveys the pellets determined to be good products discharged from the rear end of the second conveying plate 131; an emergency discharge conveyor 192 that conveys the pellets determined to be defective discharged from the rear end of the second conveying plate 131; and a conveyor moving unit 193 that conveys the good product conveying conveyor 191 and the emergency discharge conveyor 192 to positions corresponding to the rear end of the second conveying plate 131.

[0062] The transporter moving unit 193 includes: a movable plate 194 on which a good product conveyor 191 and an emergency discharge conveyor 192 are mounted; and an actuator that linearly moves the movable plate 194 by a specific distance, and the movable plate 194 is linearly moved by the actuator so that the good product conveyor 191 or the emergency discharge conveyor 192 is aligned with the lower side of the rear end of the second conveyor plate 131 to receive and convey the pellets discharged through the rear end of the second conveyor plate 131.

[0063] The emergency discharge conveyor 192 is configured to process and discharge all defective products in the event of an emergency, where the emergency is that the cumulative sum of the scores designated as defective as a result of inspections by the first vision inspection unit 150 and the second vision inspection unit 170 exceeds a specific value.

[0064] During the process of sorting defective pellets by the sorter 100, a certain number of high-quality pellets are periodically separated and conveyed to the sample inspector 200 to produce a sample S of a disk-shaped molded product, and then the sample S of the molded product is inspected for defects to minimize the possibility of defects in the final molded product using the pellets.

[0065] The sample inspector 200 includes: a pellet storage unit 210 that receives and stores high-quality pellets from the first distribution unit 160 or the second distribution unit 180 of the sorter 100; a sample molding unit 220 that manufactures a sample of a disk-shaped molded product by heating and pressing a certain amount of pellets supplied from the pellet storage unit 210; a cooling unit 230 that cools the sample S of the molded product manufactured in the sample molding unit 220; a sample inspection unit 250 that photographs the top and bottom surfaces of the sample S of the molded product conveyed by the sample transfer robot 240 after being cooled by the cooling unit 230 to inspect whether the sample S is defective; a marking unit 260 that marks a predetermined mark on the surface of the sample inspected by the sample inspection unit 250; and a sample unloading stacker 270 that loads the sample S of the molded product marked in the marking unit 260.

[0066] The pellet storage unit 210 is connected to the first distribution unit 160 or the second distribution unit 180 of the sorter 100 to receive and store pellets, and is configured such that a sensor is installed on one side thereof, so that when the pellets reach a certain amount (weight), the pellets are automatically supplied to the lower mold 221 of the sample molding unit 220.

[0067] The sample forming unit 220 includes: a lower mold 221 having a cavity for receiving a certain amount of pellets from the pellet storage unit 210; an upper mold 222 for manufacturing a sample of a disc-shaped formed product by extruding the pellets placed in the cavity of the lower mold 221; and a heater for transferring heat to the pellets through the lower mold 221 and the upper mold 222 to melt the pellets. The heater can be separately installed in each of the lower mold 221 and the upper mold 222.

[0068] Multiple lower molds 221 and upper molds 222 of the sample forming unit 220 can be provided respectively, so as to be arranged in a circle on a dividing table 225 that can rotate at a predetermined angle, thereby manufacturing samples S of multiple formed products at regular intervals.

[0069] The heaters provided in each of the lower mold 221 and the upper mold 222 can be configured by applying thin plate ceramic heaters finished with PTFE. The upper mold 222 is installed to rotate vertically around a hinge shaft 223 outside one side of the dividing table 225, and is rotated by an actuator such as a pneumatic cylinder or a hydraulic cylinder to press and form the pellets placed in the cavity of the lower mold 221.

[0070] A dividing vibration unit (not shown) for vibrating the lower mold 221 is installed, so that when the pellets are put into the lower mold 221 from the pellet storage unit 210, the pellets are evenly scattered throughout the cavity of the lower mold 221.

[0071] In addition, in order to improve the melting rate of the pellets by preheating the pellets when the pellets are put into the lower mold 221 from the pellet storage unit 210, a hot air supply machine (not shown) for supplying hot air to the lower mold 221 can be additionally installed on one side of the sample forming unit 220.

[0072] A cooling unit 230 for cooling the lower mold 221 is arranged below one side of the dividing table 225 of the sample forming unit 220. The cooling unit 230 is configured to supply a cooling fluid such as air or cooling water to the bottom surface of the lower mold 221, so as to quickly cool the sample S of the formed product on the lower mold 221.

[0073] A sample transfer robot 240 is installed on one side of the sample forming unit 220 to vacuum suck the sample S of the formed product formed on the lower mold 221, so as to transfer the sample S to the sample inspection unit 250. The sample inspection unit 250 includes: an inspection table 251 having a circular opening 252 formed at its center, and the edge portion of the sample S of the formed product is located on the edge portion of the opening 252; and an upper vision inspection camera 253 and a lower vision inspection camera 254 provided above and below the opening 252 of the inspection table 251 to photograph the top surface and the bottom surface of the sample S of the formed product, so as to inspect whether the sample S has defects.

[0074] A marking unit 260 is installed on one side of the sample inspection unit 250, which marks specified marks, such as the defect position of the sample S of the molded product to be inspected, the lot number of the sample S of the molded product, and production data and time.

[0075] The sample unloading stacker 270 can be arranged below one side of the sample molding unit 220, but there is no particular limitation on its position. For example, the sample unloading stacker 270 is arranged as a cylindrical housing with an open top surface to load multiple samples S of the molded product. The conveyance of the sample S of the molded product from the marking unit 260 to the sample unloading stacker 270 can be carried out by the sample conveyance robot 240.

[0076] Hereinafter, the operation of the system for automatically inspecting and sorting pellets with the above configuration will be described.

[0077] First, when a plurality of pellets P produced by the hopper 111 of the pellet supply unit 110 of the sorter 100 are put in, the pellets P are uniformly distributed to both sides through the pellet distribution holes 113 of the distribution plate 112 to fall and are supplied to the rear end of the first conveying plate 121, and then are accommodated in the channel 122 of the first conveying plate 121.

[0078] Here, the first conveying plate 121 is vibrated at a predetermined frequency by the first vibration generator 125 to convey the pellets accommodated in the channel 122 of the first conveying plate 121 from the rear side forward along the channel 122 at a predetermined speed.

[0079] The first vision inspection unit 150 photographs the first surface (top surface) of the pellets conveyed along the channel 122 of the first conveying plate 121 to inspect defects such as different colors, foreign objects, abnormal shapes, black spots, etc., and performs image tracking until the pellets P reach the first distribution unit 160 or the second distribution unit 180.

[0080] When the pellets P after being inspected by the first vision inspection unit 150 reach below the vacuum suction nozzles 161 and 181 of the first distribution unit 160, a suction force is generated from the vacuum suction nozzles 161 and 181 on the channel 122 on which the pellets P determined to be defective are placed, so as to extract the defective pellets P and the pellets P around the defective pellets P together, so as to discharge the pellets into a defective product collection container (not shown).

[0081] The pellets P determined to be non-defective after passing through the first distribution unit 160 pass through the guiding channel 143 between the first guiding plate 141 and the second guiding plate 142 of the pellet conveying unit 140, and then are conveyed from the lower end of the guiding channel 143 to the channel 122 of the second conveying plate 131, and are inverted at an angle of 180 degrees to be placed on the second surface (bottom surface), that is, since the first conveying plate 121, the pellet conveying unit 140, and the second conveying plate 131 are arranged In this shape, the pellets P conveyed by the first conveyor plate 121 are inverted when being conveyed to the second conveyor plate 131.

[0082] The pellets P in each passage 122 conveyed to the second conveyor plate 131 travel from the front side to the rear along the passage 122 of the second conveyor plate 131 vibrated by the second vibration generator 135. Here, the second vision inspection unit 170 photographs the second surface of each pellet P from the upper side of the second conveyor plate 131 to inspect whether the pellets are defective, and the pellets determined to be defective are sucked by the vacuum nozzles 161 and 181 of the second distribution unit 180 and then discharged into a defective product collection container (not shown).

[0083] The high-quality pellets conveyed to the rear end of the second conveyor plate 131 are supplied and stored in a good product container (not shown) through the good product conveyor 191.

[0084] As described above, during the process of sorting defective pellets and high-quality pellets, the first vision inspection unit 150 and the second vision inspection unit 170 score the defective pellets. If the cumulative sum of the scores designated as defective exceeds a specific value, it is determined that the entire pellet product contains defective products. Therefore, the conveyor moving unit 193 operates to align the emergency discharge conveyor 192 with the lower side of the rear end of the second conveyor plate 131, so that all the pellets are emergently discharged to the outside through the emergency discharge conveyor 192.

[0085] As described above, during the process of sorting defective pellets and high-quality pellets, a part of the pellets determined to be good products by the first vision inspection unit 150 and the second vision inspection unit 170 are periodically sucked by the first distribution unit 160 or the second distribution unit 180 to be conveyed to the pellet storage unit 210 of the sample inspector 200.

[0086] In the sample inspector 200, when a predetermined amount of pellets (for example, 20 g) is stored in the pellet storage unit 210, the sensor checks the amount of the pellets to automatically supply the pellets in the pellet storage unit 210 to the cavity of the aligned lower mold 221 at the first position STAGE 1 (S1) of the indexing table 225 (see Figure 11 ). Here, the lower mold 221 is vibrated by an indexing vibration unit (not shown) to evenly spread the pellets P, and then high-temperature hot air is supplied to a hot air supplier (not shown) to preheat the pellets.

[0087] Subsequently, while closing the cavity of the lower mold 221, the upper mold 222 is rotated to heat and press the pellet P. Here, at the second position STAGE 2 (S2) and the third position STAGE 3 (S3), the indexing table 225 is rotated at a specific angle, and the pellet is heated and melted at a temperature of 260°C to 300°C by the heaters of the lower mold 221 and the upper mold 222. Then, at the fourth position STAGE 4 (S4) and the fifth position STAGE 5 (S5), the sample S of the molded product formed between the lower mold 221 and the upper mold 222 is cooled by blowing air through the cooling unit 230. Here, the sample S of the molded product is cooled to a room temperature of about 20°C.

[0088] When the lower mold 221 and the upper mold 222 reach the sixth position STAGE 6 (S6) by the rotation of the indexing table 225, the upper mold 222 is rotated to open the cavity, and the sample transfer robot 240 vacuum-sucks the sample S of the molded product on the lower mold 221 to distribute the sample S for placement on the inspection table 251 of the sample inspection unit 250. Subsequently, the upper vision inspection camera 253 and the lower vision inspection camera 254 capture the top and bottom surfaces of the sample S of the molded product to inspect for defects in the pellet.

[0089] When the defect inspection of the sample S of the molded product is completed, the sample transfer robot 240 vacuum-sucks the sample S of the molded product on the inspection table 251 to transfer the sample S to the marking unit 260. The marking unit 260 marks designated marks, such as the defect location on the surface of the sample S of the molded product, the lot number of the sample S of the molded product, and the production date and time.

[0090] When the marking is completed, the sample transfer robot 240 vacuum-sucks the sample S of the molded product of the marking unit 260 to transfer the sample S to the sample unloading stacker 270 for loading the sample.

[0091] As described above, in the system for automatically inspecting and sorting pellets according to the present invention, while continuously conveying pellets at high speed in the sorter, the colors and images of the two surfaces of the pellets can be acquired to detect defects such as different colors, foreign objects, abnormal shapes, and black spots, thereby removing the pellets determined to be defective while conveying the pellets. Therefore, the accuracy and efficiency of inspecting and sorting pellets can be greatly improved.

[0092] In addition, for the pellets determined and classified as good products in the sorter 100, samples S of molded products can be periodically manufactured to detect whether the manufactured samples S of molded products are defective, thereby predicting and handling the accuracy of sorting in the sorter and the possibility of defects in the final product.

[0093] As described above, the present invention has been described in detail with reference to the embodiments. However, those skilled in the art to which the present invention pertains can make various substitutions, additions, and modifications without departing from the above technical concept. Of course, it should be understood that such modified embodiments also fall within the protection scope of the present invention defined by the appended claims.

[0094] Industrial applicability

[0095] The present invention can be applied to a device for inspecting and sorting pellets for defects, where the pellets are solid particles of synthetic resin used in various fields such as films, pipes, automotive interior materials, etc.

Claims

1. A system for automatically inspecting and sorting granular materials, the system comprising: A pellet supply unit configured to supply a plurality of pellets; A first pellet conveying unit configured to convey the pellets supplied from the pellet supply unit forward from the rear side; A pellet transporting unit provided at the front end of the first pellet conveying unit to convey the pellets conveyed through the first pellet conveying unit downward; A second pellet conveying unit provided below the first pellet conveying unit to receive the pellets conveyed downward through the pellet transporting unit and invert the pellets at an angle of 180° so as to convey the pellets backward from the front side; A first vision inspection unit provided above the first pellet conveying unit to photograph a first surface of each pellet to inspect whether the pellet is defective; A first dispensing unit provided in front of the first vision inspection unit to suck the pellets determined to be defective by the first vision inspection unit so as to separate the defective pellets from the first pellet conveying unit; A second vision inspection unit provided above the second pellet conveying unit to photograph a second surface of each pellet to inspect whether the pellet is defective; A second dispensing unit provided behind the second vision inspection unit to suck the pellets determined to be defective by the second vision inspection unit so as to separate the defective pellets from the second pellet conveying unit; and An unloading unit provided at the rear end of the second pellet conveying unit to receive the pellets conveyed through the second pellet conveying unit so as to convey the pellets to a designated unloading position, wherein the pellet transporting unit includes: A first guide plate installed to extend downward from the front end of the first pellet conveying unit; A second guide plate installed at a specific distance greater than the thickness of the pellet spaced apart in front of the first guide plate; and A plurality of guide channels formed to vertically extend between the first guide plate and the second guide plate to guide the pellets downward.

2. The system according to claim 1, wherein, The first pellet conveying unit includes: A first conveying plate installed to be inclined downward at a predetermined angle forward from the rear side, and in the first conveying plate, a plurality of channels along which the pellets move extend in the front-rear direction; and A first vibration generator configured to vibrate the first conveying plate at a predetermined frequency, wherein the second pellet conveying unit includes: A second conveying plate installed to be inclined downward at a predetermined angle backward from the front side, and in the second conveying plate, a plurality of channels in which the pellets are accommodated extend in the front-rear direction; and A second vibration generator configured to vibrate the second conveying plate at a predetermined frequency.

3. The system according to claim 2, wherein, The top surfaces of each of the first conveying plate and the second conveying plate are coated with a light-absorbing resin to prevent diffuse reflection during the photographing processes of the first vision inspection unit and the second vision inspection unit.

4. The system according to claim 1 or 2, wherein, The pellet supply unit includes: A hopper configured such that an input port for inputting the pellets is formed to be open; and At least one or more distribution plates provided below the hopper, and a plurality of pellet distribution holes penetrating therethrough for the pellets to pass through are formed in the distribution plates.

5. The system according to claim 1, wherein, The first distribution unit and the second distribution unit each include a plurality of vacuum nozzles, and the plurality of vacuum nozzles are respectively arranged transversely above the first pellet conveying unit and the second pellet conveying unit, so that the vacuum nozzles are configured to suck together the pellets moving along the first pellet conveying unit and the second pellet conveying unit and determined to be defective and the pellets in the surrounding area of the defective pellet, so as to discharge the pellets to the outside.

6. The system according to claim 5, wherein, A plurality of fine ventilation holes are formed, each having a size smaller than the size of each pellet, and vertically penetrate the first pellet conveying unit and the second pellet conveying unit corresponding to the vacuum nozzles, and An exhaust assist fan configured to blow air through the fine ventilation holes is installed below the first pellet conveying unit and the second pellet conveying unit, so that when the process of discharging defective pellets is performed through the vacuum nozzles, the exhaust assist fan operates to blow air upward through the fine ventilation holes to assist in discharging the pellets.

7. The system according to claim 1, further comprising: An upper conveying assist fan is installed to blow air between the upper ends of the first guide plate and the second guide plate above the front end of the first pellet conveying unit; and A lower conveying assist fan is installed to blow air from the front side to the rear side at the lower end of the second guide plate to push the pellets conveyed from the lower end of the second guide plate to the second pellet conveying unit.

8. The system according to claim 1, wherein, The first guide plate and the second guide plate are installed to be inclined at an angle of 2° to 4° with respect to an axis perpendicular to the ground.

9. The system according to claim 1, wherein, The unloading unit includes: A good product conveying conveyor configured to convey the pellets determined to be good products and discharged through the rear end of the second pellet conveying unit; An emergency discharge conveyor configured to convey the pellets determined to be defective and discharged from the rear end of the second pellet conveying unit; and A conveyor moving unit configured to convey the good product conveying conveyor and the emergency discharge conveyor to a position corresponding to the rear end of the second pellet conveying unit.

10. The system according to claim 1, further comprising a sample inspector configured to receive, at regular intervals through the first dispensing unit or the second dispensing unit, the pellets determined to be non-defective in the first visual inspection unit and the second visual inspection unit, so as to manufacture a plate-shaped sample of a molded product, and configured to inspect whether the manufactured sample of the molded product is defective.

11. The system according to claim 10, wherein, The sample inspector includes: A pellet storage unit configured to receive the pellets passing through the first distribution unit or the second distribution unit; A sample molding unit including a lower mold, an upper mold, and a heater. The lower mold is provided with a cavity, and a certain amount of pellets from the pellet storage unit are loaded into the cavity. The upper mold is configured to extrude the pellets placed in the cavity of the lower mold to manufacture a disc-shaped sample of a molded product. The heater is configured to transfer heat to the pellets through the lower mold and the upper mold so that the pellets melt; A cooling unit configured to cool the sample of the molded product manufactured in the sample molding unit; A sample conveying robot configured to convey the sample of the molded product cooled by the cooling unit; A sample inspection unit configured to photograph the top and bottom surfaces of the sample of the molded product conveyed by the sample conveying robot to check whether the sample is defective; A marking unit configured to mark a predetermined mark on the surface of the sample of the molded product inspected by the sample inspection unit; and A sample unloading stacker configured to load the sample of the molded product marked in the marking unit.

12. The system according to claim 11, wherein, The sample molding unit includes: Indexing table, which is rotatably mounted relative to an axis perpendicular to the ground at a predetermined angle, and on which a plurality of lower molds and upper molds are provided at regular intervals in the circumferential direction; and Indexing vibration unit, configured to vibrate the lower mold.

13. A system for automatically inspecting and sorting pellets, the system comprising: Sorting machine, configured to photograph and inspect the first surface and the second surface of each pellet while conveying a plurality of pellets, to separate and remove the pellets determined to be defective, and to convey and load the high-quality pellets to a designated position; and Sample inspector, configured to receive a plurality of pellets determined to be good products among the pellets sorted by the sorting machine, to manufacture a plate-shaped sample of a molded product, and to photograph the first surface and the second surface of the sample of the manufactured molded product, thereby inspecting whether the sample of the molded product is defective, wherein, the sorting machine includes: Pellet supply unit, configured to supply a plurality of pellets; First pellet conveying unit, configured to convey the pellets supplied from the pellet supply unit forward from the rear side; Pellet transporting unit, provided at the front end of the first pellet conveying unit to convey the pellets conveyed by the first pellet conveying unit downward; Second pellet conveying unit, provided below the first pellet conveying unit to receive the pellets conveyed downward by the pellet transporting unit, and to invert the pellets at an angle of 180°, so as to convey the pellets backward from the front side; First vision inspection unit, provided above the first pellet conveying unit to photograph the first surface of each pellet, so as to inspect whether the pellet is defective; First distribution unit, provided in front of the first vision inspection unit to suck and discharge the pellets conveyed by the first vision inspection unit; Second vision inspection unit, provided above the second pellet conveying unit to photograph the second surface of each pellet, so as to inspect whether the pellet is defective; Second distribution unit, provided behind the second vision inspection unit to suck the pellets conveyed by the second pellet conveying unit; and Unloading unit, provided at the rear end of the second pellet conveying unit to receive the pellets conveyed by the second pellet conveying unit, so as to convey the pellets to a designated unloading position, wherein, the pellet transporting unit includes: First guide plate, installed to extend downward from the front end of the first pellet conveying unit; Second guide plate, installed at a specific distance greater than the thickness of the pellet spaced apart in front of the first guide plate; and A plurality of guide channels, formed to vertically extend between the first guide plate and the second guide plate to guide the pellets downward.

14. The system according to claim 13, wherein, The sample inspector includes: Pellet storage unit, configured to receive the pellets from the sorting machine to store the pellets; Sample molding unit, including a lower mold, an upper mold and a heater, the lower mold is provided with a cavity, a certain amount of pellets from the pellet storage unit are loaded into the cavity, the upper mold is configured to extrude the pellets placed in the cavity of the lower mold to manufacture a disk-shaped sample of a molded product, the heater is configured to transfer heat to the pellets through the lower mold and the upper mold, so that the pellets melt; Cooling unit, configured to cool the sample of the molded product manufactured in the sample molding unit; A sample transfer robot configured to transfer samples of the molded products cooled by the cooling unit; A sample inspection unit configured to photograph the top and bottom surfaces of the samples of the molded products transferred by the sample transfer robot in order to inspect whether the samples are defective; A marking unit configured to mark a predetermined mark on the surface of the samples of the molded products inspected by the sample inspection unit; and A sample unloading stacker configured to load the samples of the molded products marked in the marking unit.

15. The system according to claim 14, wherein, The sample molding unit includes: An indexing table rotatably mounted at a predetermined angle with respect to an axis perpendicular to the ground, and having a plurality of lower molds and upper molds provided at regular intervals in the circumferential direction thereon; and An indexing vibration unit configured to vibrate the lower molds.

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