Extrusion molding apparatus for resin sheet and extrusion molding method for resin sheet

Abstract

An extrusion molding apparatus (100) for a resin sheet comprises a die (5), a pair of rolls (12), and a visible light imaging device (6). The die (5) extrudes a resin sheet (11). The resin sheet (11) is a sheet-shaped molten resin (10). The pair of rolls (12) press the resin sheet (11) from the die (5) below the die (5). The pair of rolls (12) include a first roll (1) and a second roll (2). The first roll (1) and the second roll (2) sandwich and press the resin sheet (11). The second roll (2) conveys the pressed resin sheet (11) in close contact therewith. The visible light imaging device (6) images the second roll (2) and the resin sheet (11) that is conveyed in close contact with the second roll (2).

Description

Resin sheet extrusion molding device and resin sheet extrusion molding method

[0001] The present invention relates to an extrusion molding apparatus and a method for extruding a resin sheet.

[0002] Japanese Patent Application Publication No. 2017-215277 is a publication relating to an extrusion molding apparatus and an extrusion molding method for a resin sheet. Hereinafter, Japanese Patent Application Publication No. 2017-215277 will be referred to as Patent Document 1.

[0003] Patent Document 1 describes a manufacturing apparatus for a film, which is a resin sheet. The film manufacturing apparatus described in Patent Document 1 includes a defect inspection system.

[0004] As shown in Fig. 1 of Patent Document 1, the defect inspection system photographs a film (resin sheet) as it is being conveyed and inspects the film for defects based on the photographed images. The film is photographed in a state where it is not attached to a roll or the like.

[0005] The device described in Patent Document 1 takes an image of the film when it is not attached to a roll or the like, so it is impossible to accurately inspect for defects such as missing touches, which will be described later. Therefore, the device described in Patent Document 1 cannot appropriately determine the state of the film (resin sheet).

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a resin sheet extrusion molding device and a resin sheet extrusion molding method that can appropriately determine the state of a resin sheet.

[0007] A resin sheet extrusion molding device according to a first aspect of the present invention includes a die, a pair of rolls, and a visible light imaging device. The die extrudes a resin sheet. The resin sheet is a sheet of molten resin. The pair of rolls presses the resin sheet from the die below the die. The pair of rolls includes a first roll and a second roll. The first roll and the second roll sandwich and press the resin sheet. The second roll transports the pressed resin sheet while keeping it in close contact with the second roll. The visible light imaging device photographs the second roll and the resin sheet being transported in close contact with the second roll.

[0008] A resin sheet extrusion molding device according to a second aspect of the present invention includes a die, a pair of rolls, and a visible light imaging device. The die extrudes a resin sheet. The resin sheet is a sheet of molten resin. The pair of rolls presses the resin sheet from the die below the die. The pair of rolls includes a first roll and a second roll. The first roll and the second roll sandwich and press the resin sheet. The second roll transports the pressed resin sheet while keeping it in close contact with the resin sheet. The visible light imaging device is oriented from below toward the second roll.

[0009] A resin sheet extrusion molding method according to a third aspect of the present invention includes the steps of extruding a resin sheet, sandwiching and pressing the resin sheet, transporting the resin sheet, and photographing the resin sheet. The resin sheet extruding step involves extruding a resin sheet, which is a sheet-shaped molten resin, using a die. The resin sheet sandwiching and pressing step involves sandwiching and pressing the resin sheet from the die below the die using a pair of rolls having a first roll and a second roll. The resin sheet transporting step involves transporting the pressed resin sheet while it is in close contact with the second roll. The resin sheet photographing step involves photographing the second roll and the resin sheet being transported in close contact with the second roll using a visible light imaging device.

[0010] A resin sheet extrusion molding method according to a fourth aspect of the present invention includes the steps of extruding a resin sheet, sandwiching and pressing the resin sheet, transporting the resin sheet, and photographing the resin sheet. The resin sheet extruding step involves extruding a resin sheet, which is a sheet-shaped molten resin, using a die. The resin sheet sandwiching and pressing step involves sandwiching and pressing the resin sheet from the die below a pair of rolls having a first roll and a second roll. The resin sheet transporting step involves transporting the pressed resin sheet while keeping it in close contact with the second roll. The resin sheet photographing step involves photographing the resin sheet pressed between the pair of rolls using a visible light imaging device pointing the imaging direction toward the second roll from below.

[0011] According to the resin sheet extrusion molding device and resin sheet extrusion molding method of the present invention, the state of the resin sheet can be appropriately determined.

[0012] FIG. 1 is a side view of an extrusion molding device for a resin sheet according to embodiment 1. FIG. 2 is a side view of an extrusion molding device for a resin sheet according to embodiment 2. FIG. 3 is an image of a resin sheet with missing touch. FIG. 4 is an image of a resin sheet without missing touch. FIG. 5 is a side view of an extrusion molding device for a resin sheet according to embodiment 3. FIG. 6 is an enlarged perspective view of the vicinity of the first to third rolls as viewed from above and rear. FIG. 7 is a block diagram of an extrusion molding device for a resin sheet. FIG. 8 is a flowchart showing the operation of an extrusion molding device for a resin sheet.

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and description thereof will not be repeated.

[0014] In the following description, terms such as "front," "rear," "left," and "right" that indicate specific positions and directions may be used. However, these terms are used for convenience to facilitate understanding of the contents of the embodiments, and are not related to the directions in which the embodiments are actually implemented. <Embodiment 1>

[0015] An extrusion molding apparatus 100 and an extrusion molding method for a resin sheet according to the first embodiment will be described below with reference to Fig. 1. Fig. 1 is a side view of the extrusion molding apparatus 100 for a resin sheet according to the first embodiment.

[0016] 1, a resin sheet extrusion molding apparatus 100 according to the first embodiment includes a die 5, a pair of rolls 12, and a visible light imaging device 6. The resin sheet 11 is a sheet-shaped molten resin 10.

[0017] The die 5 extrudes a resin sheet 11. A pair of rolls 12 presses the resin sheet 11 from the die 5 below the die 5. The pair of rolls 12 has a first roll 1 and a second roll 2. The first roll 1 and the second roll 2 sandwich and press the resin sheet 11. The second roll 2 transports the pressed resin sheet 11 while keeping it in close contact with the resin sheet 11.

[0018] The visible light imaging device 6 captures an image of the second roll 2 and the resin sheet 11 that is transported in close contact with the second roll 2 (or is being transported in close contact with the second roll 2).

[0019] The objects photographed by the visible light photography device 6 are the second roll 2 and the resin sheet 11 pressed by the second roll 2. Therefore, the resin sheet 11 is photographed at a position that is preferable for determining the state of the resin sheet 11. As a result, the resin sheet extrusion molding device 100 can appropriately determine the state of the resin sheet 11.

[0020] The resin sheet extrusion molding device 100 further includes an upstream device 4 , a third roll 3 , and a personal computer 7 .

[0021] The upstream device 4 includes, for example, an extruder 40 and a gear pump (not shown). The extruder 40 melts and kneads the resin 10, which is the raw material of the resin sheet 11, while extruding the resin 10. The gear pump transports the melted and kneaded resin 10, i.e., the molten resin 10, to the die 5.

[0022] The third roll 3 sandwiches and presses the resin sheet 11 conveyed by the second roll 2 together with the second roll 2. The first roll 1, the second roll 2, and the third roll 3 are, for example, rolls of the same shape, and the surfaces in contact with the resin sheet 11 are mirror-finished. The axis 15 of the first roll 1, the axis 25 of the second roll 2, and the axis 35 of the third roll 3 are arranged parallel to each other. The first roll 1 and the second roll 2 are arranged at the same height. Hereinafter, the direction from the axis 15 of the first roll 1 to the axis 25 of the second roll 2 is referred to as the forward direction, and the opposite direction is referred to as the backward direction.

[0023] The surfaces of the first roll 1, the second roll 2, and the third roll 3 that come into contact with the resin sheet 11 are not limited to being mirror-finished, but may be embossed to transfer unevenness. The unevenness may be, for example, round, polygonal such as triangular, or hemispherical.

[0024] The personal computer 7 receives the image captured by the visible light imaging device 6 as data. The personal computer 7 judges the state of the resin sheet 11 from the received image. The judged state of the resin sheet 11 is good / bad in appearance, such as the presence or absence of a missed touch. A missed touch occurs when the adhesion between the resin sheet 11 and the second roll 2 is poor. Therefore, if there is a "missing touch," the adhesion between the resin sheet 11 and the second roll 2 is poor. Conversely, if there is no "missing touch," the adhesion between the resin sheet 11 and the second roll 2 is good.

[0025] The visible light imaging device 6 may capture images from any direction as long as the object being imaged is the second roll 2 and the resin sheet 11 pressed by the second roll 2. Fig. 1 shows an example in which the visible light imaging device 6 captures images horizontally from the front to the rear. The example of Fig. 1 is not limited thereto, and the visible light imaging device 6 may capture images from below to above, or from above to below. <Embodiment 2>

[0026] The extrusion molding apparatus 100 and the extrusion molding method for a resin sheet according to the second embodiment will be described below with reference to Fig. 2. Fig. 2 is a side view of the extrusion molding apparatus 100 for a resin sheet according to the second embodiment.

[0027] 2, the resin sheet extrusion molding apparatus 100 according to the second embodiment differs from that according to the first embodiment in the arrangement of the visible light imaging device 6. Specifically, the visible light imaging device 6 included in the resin sheet extrusion molding apparatus 100 according to the second embodiment is oriented so as to take images from below toward the second roll 2.

[0028] The visible light imaging device 6 is prevented from receiving unnecessary light from above because light from above is blocked by at least the second roll 2. By preventing unnecessary light from entering the visible light imaging device 6 from above, the image showing "missing touch" and the image showing "no missing touch" are clearly different. As a result, the resin sheet extrusion molding device 100 can more appropriately determine the state of the resin sheet 11.

[0029] Furthermore, since the visible light imaging device 6 is directed from below toward the second roll 2, it images the resin sheet 11 on the upstream side. Therefore, feedback to the conditions for extrusion molding the resin sheet 11 is possible based on the state of the resin sheet 11 on the upstream side. As a result, the resin sheet extrusion molding device 100 can provide appropriate feedback based on the state of the resin sheet 11 that has been photographed.

[0030] The imaging direction of the visible light imaging device 6 is not limited to from rear to front and upward (see FIG. 2 ), but may be from front to rear and upward, or directly upward. As shown in FIG. 2 , the visible light imaging device 6 images the resin sheet 11 further upstream by imaging from rear to front and upward. Therefore, the resin sheet extrusion molding device 100 can provide more optimal feedback based on the state of the resin sheet 11 that has been photographed.

[0031] The visible light imaging device 6 is positioned so that the imaging optical axis 61 passes through the axial center 25 of the second roll 2. By having the imaging optical axis 61 pass through the axial center 25 of the second roll 2, the resin sheet 11 is imaged over a more appropriate range. Therefore, the resin sheet extrusion molding device 100 can more appropriately determine the state of the resin sheet 11.

[0032] The resin sheet extrusion molding apparatus 100 of embodiment 2 is not limited to an apparatus in a state in which the resin sheet 11 is being transported by the second roll 2, but also includes an apparatus in a state before the resin sheet 11 is transported by the second roll 2.

[0033] Next, with reference to Figures 3A and 3B, images captured by the visible light imaging device 6 of the resin sheet extrusion molding device 100 according to embodiment 2 will be described. Figure 3A is an image of the resin sheet 11 with "missing touches." Figure 3B is an image of the resin sheet 11 with "no missing touches."

[0034] In FIG. 3A, the color is lightened in vertical bands (stripe-like) as indicated by reference numeral 67. The vertical bands (stripe-like) where the color is lightened are missing touches. Therefore, missing touches can be seen in FIG. 3A as indicated by reference numeral 67. On the other hand, missing touches like those in FIG. 3A are not seen in FIG. 3B. As is clear from a comparison of FIG. 3A and FIG. 3B, there is a clear difference between the image with "missing touch" (FIG. 3A) and the image with "no missing touch" (FIG. 3B). Missing touches are caused by air, gas, bubbles, or the like that have entered between the resin sheet 11 and the second roll 2.

[0035] For comparison with the second embodiment, the resin sheet 11 pressed by the second roll 2 was photographed with an infrared photographing device (not shown) instead of the visible light photographing device 6. Even if a missing touch actually occurred, it was impossible to determine the missing touch in the image photographed with the infrared photographing device (not shown).

[0036] The extrusion molding apparatus 100 and the extrusion molding method for a resin sheet according to the third embodiment will be described below with reference to Fig. 4. Fig. 4 is a side view of the extrusion molding apparatus 100 for a resin sheet according to the third embodiment.

[0037] 4 , the resin sheet extrusion molding apparatus 100 according to the third embodiment differs from the second embodiment in that it further includes a light-reducing device (for example, a light-shielding device 8). The light-shielding device 8 blocks unnecessary light from entering the visible light imaging device 6.

[0038] The shading device 8 further reduces unnecessary light from entering the visible light imaging device 6. Therefore, the images captured by the visible light imaging device 6 show a clearer difference between the image with "missing touch" and the image with "no missing touch." As a result, the resin sheet extrusion molding device 100 can more appropriately determine the state of the resin sheet 11.

[0039] The shading equipment 8 is, for example, a shading member 81 (such as a shading film) that covers a window W of the building B. The upstream equipment 4, the die 5, and the first roll 1 to the third roll 3 are arranged inside the building B. Because the shading equipment 8 is the shading member 81 that covers the window W of the building B, unnecessary light entering the visible light imaging device 6 from the window W is suppressed with a simple configuration. Therefore, the resin sheet extrusion molding device 100 can appropriately determine the state of the resin sheet 11 with a simple configuration.

[0040] The light-shielding equipment 8 is, for example, a light-shielding enclosure 80. The light-shielding enclosure 80 encloses the upstream equipment 4, the die 5, and the first roll 1 to the third roll 3 from at least the top and side surfaces. Because the light-shielding equipment 8 is the light-shielding enclosure 80, unnecessary light entering the visible light imaging device 6 is sufficiently suppressed. Therefore, the resin sheet extrusion molding device 100 can more appropriately determine the state of the resin sheet 11.

[0041] The resin sheet extrusion molding device 100 may further include a disturbance presence / absence determination model 72. The disturbance presence / absence determination model 72 determines the presence or absence of disturbance in the image captured by the visible light imaging device 6. Disturbance occurs when unnecessary light enters the visible light imaging device 6. The disturbance presence / absence determination model 72 is generated by machine learning.

[0042] The presence or absence of disturbance in the captured image is determined by the disturbance presence / absence determination model 72. Therefore, if it is determined that there is a disturbance, the disturbance can be removed by processing the captured image, etc. Therefore, the resin sheet extrusion molding device 100 can more appropriately determine the state of the resin sheet 11.

[0043] The disturbance presence / absence determination model 72 is stored in the personal computer 7. The personal computer 7 not only determines the presence / absence of a disturbance using the disturbance presence / absence determination model 72, but also removes the disturbance by image processing or the like, and uses image data from which the disturbance has been removed. Note that the disturbance presence / absence determination model 72 is not an essential component. In other words, the presence / absence of a disturbance may be determined by a method other than machine learning. Furthermore, the disturbance may be removed by a method other than image processing.

[0044] The visible light imaging device 6 will now be described in detail with reference to Fig. 5. Fig. 5 is an enlarged perspective view of the vicinity of the first roll 1 to the third roll 3 as viewed from above and behind.

[0045] As shown in Fig. 5, multiple visible light imaging devices 6 may be arranged in the left-right direction, which is the direction along the axis 25 of the second roll 2. Fig. 5 shows an example in which there are two visible light imaging devices 6. The number of visible light imaging devices 6 is not limited to the example of Fig. 5, and may be three or more, or may be one. When there are multiple visible light imaging devices 6, the ranges captured by adjacent visible light imaging devices 6 may or may not overlap.

[0046] The multiple visible light imaging devices 6 are preferably arranged so as to capture the entire range in the left-right direction of the second roll 2. The multiple visible light imaging devices 6 may be arranged so as to capture only the range necessary to properly determine the state of the resin sheet 11. The range necessary to properly determine the state of the resin sheet 11 is, for example, only both ends of the second roll 2 or only the center of the second roll 2. The boundary between both ends and the center of the second roll 2 is any position from the left or right end to the center of the second roll 2.

[0047] When the visible light imaging device 6 is placed close to the second roll 2, it can capture clear images, but it cannot capture a sufficient range of images in the left-right direction of the second roll 2. Therefore, when multiple visible light imaging devices 6 are placed in the left-right direction, it can capture clear images and a sufficient range of images in the left-right direction of the second roll 2. As a result, the resin sheet extrusion molding apparatus 100 can more appropriately determine the state of the resin sheet 11 by using multiple visible light imaging devices 6 placed in the left-right direction.

[0048] The visible light imaging device 6 selects an appropriate frame rate and exposure time for the speed at which the resin sheet 11 is transported by the second roll 2. For example, if the actual length of one pixel in the image is x [m], the speed at which the resin sheet 11 is transported by the second roll 2 is v [m / sec], and the exposure time of the visible light imaging device 6 is e [sec], it is desirable to satisfy the following formula (1). This is because the visible light imaging device 6 can capture images even more clearly: e≦x / v (1)

[0049] More specifically, when x = 0.00019 m (i.e., 0.19 mm) and v = 7 / 60 m / sec (i.e., 7 m / min or approximately 116 mm / sec), it is recommended to set e ≤ 0.0016 sec (i.e., 1.6 msec), as this allows the visible light imaging device 6 to capture images more clearly without causing blurring during imaging.

[0050] The second roll 2 is preferably a roll capable of conveying the resin sheet 11 at a speed of 0.5 m / min or more (more preferably 2 m / min or more) and 60 m / min or less. The first roll 1 and the third roll 3 each sandwich the resin sheet 11 together with the second roll 2. Therefore, the first roll 1 and the third roll 3 are also preferably rolls capable of conveying the resin sheet 11 at a speed of 0.5 m / min or more (more preferably 2 m / min or more) and 60 m / min or less.

[0051] The configuration for determining the state of the resin sheet 11 will be described in detail below with reference to Fig. 6. Fig. 6 is a block diagram of an extrusion molding device 100 for a resin sheet.

[0052] 6, the resin sheet extrusion molding device 100 further includes a state determination unit 73. The state determination unit 73 determines the state of the pressed resin sheet 11 from a machine-learned learning model 74. To determine the state, an image captured by the visible light imaging device 6 is input to the learning model 74.

[0053] The state determination unit 73 determines the state of the pressed resin sheet 11 from the machine-learned learning model 74, thereby improving the accuracy of the determination. Therefore, the resin sheet extrusion molding device 100 can more appropriately determine the state of the resin sheet 11.

[0054] The state determination unit 73 and the learning model 74 are stored in the personal computer 7. The personal computer 7 is capable of not only making a determination by the state determination unit 73 but also displaying the result of the determination. The personal computer 7 is also capable of transmitting the result of the determination to the outside.

[0055] Hereinafter, referring again to FIG. 6, a specific configuration for determining the state of the resin sheet 11 and automatic control based on the determination will be described in detail.

[0056] The resin sheet extrusion molding device 100 further includes an automatic control unit 90. The automatic control unit 90 automatically controls the equipment for extrusion molding the resin sheet 11. When the condition determination unit 73 determines that the condition is poor, the automatic control unit 90 automatically controls the equipment to resolve the poor condition.

[0057] The automatic control unit 90 automatically controls the equipment for extruding the resin sheet 11 based on the determination by the state determination unit 73. Therefore, the resin sheet extrusion molding device 100 can stably manufacture high-quality resin sheets 11.

[0058] The devices for extrusion molding the resin sheet 11 are devices related to the extrusion molding of the resin sheet 11, such as the upstream device 4, the die 5, and the first roll 1 to third roll 3. The devices related to the extrusion molding of the die 5 include, for example, an opening adjustment device (not shown) that adjusts the opening 50 of the outlet of the die 5 (hereinafter referred to as the die outlet).

[0059] The resin sheet extrusion molding apparatus 100 further includes a control panel 9. The control panel 9 includes a programmable logic controller (PLC), not shown. The automatic control unit 90 is stored in the control panel 9. In addition to the automatic control unit 90, the control panel 9 further includes an operation ON / OFF unit (not shown) and a judgment instruction unit 97.

[0060] The operation ON / OFF unit issues an instruction to start or stop extrusion molding (i.e., operation) of the resin sheet 11. The judgment instruction unit 97 issues an instruction to judge the state of the resin sheet 11. The operation ON / OFF unit and the judgment instruction unit 97 are operated by a touch panel or the like (not shown) of the control panel 9.

[0061] Although not shown, the personal computer 7 and the control panel 9 each have a memory unit, a control unit, and another memory unit. The control unit includes a processor such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit). The memory unit includes a memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and a hard disk. The hard disk may be connected via a LAN (Local Area Network), i.e., a LANDISK 79. In the example shown in FIG. 6, the personal computer 7 has the LANDISK 79.

[0062] In addition to the disturbance presence / absence determination model 72, the state determination unit 73, and the learning model 74, the personal computer 7 further stores an input unit 70, a photography instruction unit 71, an image processing unit 77, and an output unit 76.

[0063] The input unit 70 receives instructions from the determination instruction unit 97 and images from the visible light imaging device 6. The imaging instruction unit 71 instructs the visible light imaging device 6 to capture an image. The disturbance presence / absence determination model 72 determines whether or not a disturbance exists in the image input to the input unit 70. If the presence / absence determination model 72 determines that a disturbance exists in the image, the image processing unit 77 performs processing to remove the disturbance from the image and transmits the image from which the disturbance has been removed to the state determination unit 73. If the personal computer 7 does not store the disturbance presence / absence determination model 72, it transmits the image input to the input unit 70 directly to the image processing unit 77 or the state determination unit 73.

[0064] The learning model 74 is generated by machine learning using images captured by the visible light imaging device 6 as learning data. The learning model 74 finds certain rules from the feature quantities of the input images through machine learning. The disturbance presence / absence determination model 72 is also generated in the same manner as the learning model 74.

[0065] The machine learning is not particularly limited as long as it is supervised learning. For example, the machine learning uses a decision tree, a nearest neighbor method, a naive Bayes classifier, a support vector machine, or a neural network. Therefore, the learning model 74 includes a decision tree, a nearest neighbor method, a naive Bayes classifier, a support vector machine, or a neural network.

[0066] For example, a neural network includes an input layer, one or more hidden layers, and an output layer. Specifically, the neural network is a deep neural network, a recurrent neural network, or a convolutional neural network, and performs deep learning. For example, a deep neural network includes an input layer, multiple hidden layers, and an output layer.

[0067] The state determination unit 73 not only determines whether there is "no missing touch" or "missing touch," but also determines the cause of the "missing touch" when there is "missing touch." Causes of the "missing touch" include, for example, "low roll pressure," "low roll temperature," "wide air gap," or "insufficient adjustment of the die exit." Therefore, the state determination unit 73 determines either (1) "no missing touch," (2) "missing touch" due to low roll pressure, (3) "missing touch" due to low roll temperature, (4) "missing touch" due to wide air gap AG, or (5) "missing touch" due to insufficient adjustment of the die exit.

[0068] When the state determination unit 73 determines that a “missing touch has occurred,” the output unit 76 transmits the cause of the “missing touch” to the automatic control unit 90 .

[0069] When the automatic control unit 90 receives the cause of the "missing touch" error, it automatically controls the device to eliminate the cause. Therefore, the automatic control unit 90 includes a roll pressure control unit 91, a roll temperature control unit 92, an air gap control unit 93, and a die exit control unit 94 for the automatic control.

[0070] When the roll pressure is low, which is a cause of the "missing touch," the roll pressure control unit 91 increases the roll pressure. Specifically, to increase the roll pressure, the roll pressure control unit 91 makes the first roll 1 and the second roll 2 strongly press the resin sheet 11.

[0071] When the roll temperature is low, which is a cause of the "missing touch," the roll temperature control unit 92 increases the roll temperature. Specifically, the roll temperature control unit 92 activates the heating unit (not shown) of the first roll 1 and / or the second roll 2 to increase the roll temperature.

[0072] When the air gap AG is wide, which is a cause of the occurrence of "missing touch," the air gap control unit 93 narrows the air gap AG. Specifically, the air gap control unit 93 lowers the die 5 and / or raises the first roll 1 and the second roll 2 to narrow the air gap AG.

[0073] If the cause of the "missing touch" is insufficient adjustment of the die outlet, the die outlet control unit 94 adjusts the die outlet sufficiently. Specifically, if the adjustment of the die outlet opening 50 is insufficient, the die outlet opening adjustment device (not shown) is operated to adjust the die outlet to an appropriate opening 50 so that the thickness of the resin sheet 11 is uniform. The adjusted die outlet opening 50 is, for example, in the front-to-rear direction.

[0074] The control by the automatic control unit 90 is preferably not so drastic as to eliminate the cause of the problem all at once, but rather so gradual as to gradually eliminate the cause of the problem. For example, if the roll temperature is low, which is the cause of the "missing touch," the roll temperature control unit 92 raises the temperatures of the first roll 1 and the second roll 2 by 2°C. A predetermined time (e.g., several minutes) is then set as the time for the status determination unit 73 to make a second judgment. If the status determination unit 73 determines after the predetermined time that the roll temperature is still low, which is the cause of the "missing touch," the roll temperature control unit 92 further raises the temperatures of the first roll 1 and the second roll 2 by 2°C. A predetermined time is then set as the time for the status determination unit 73 to make a second judgment. In this way, the 2°C increase in the temperatures of the first roll 1 and the second roll 2 and the judgment by the status determination unit 73 after the predetermined time are repeated until the status determination unit 73 determines that "missing touch does not exist." <Experimental Example>

[0075] Here, an experimental example of the resin sheet extrusion molding device 100 will be described, focusing on the state determination unit 73 and the learning model 74.

[0076] First, the learning model 74 was trained on 1,000 images captured by the visible light imaging device 6. Next, the state of the resin sheet 11 in each of 250 separate images captured by the visible light imaging device 6 was determined by the state determination unit 73. The actual state of the resin sheet 11 in the separate 250 images is known. The relationship between the actual state (known) and the state determined by the state determination unit 73 is as shown in Table 1 below. In Table 1, (1) is "no touch omission", (2) is "touch omission" due to low roll pressure, (3) is "touch omission" due to low roll temperature, (4) is "touch omission" due to wide air gap AG, and (5) is "touch omission" due to insufficient adjustment of the die outlet.

[0077]

[0078] As shown in Table 1, when the actual state was "(1) no touch-off" it was correctly judged in all 47 cases. When the actual state was "(2) touch-off due to low roll pressure" it was correctly judged in 51 cases out of 52 cases, with one incorrect judgement being "(4) touch-off due to wide air gap AG". When the actual state was "(3) touch-off due to low roll temperature" it was correctly judged in all 49 cases. When the actual state was "(4) touch-off due to wide air gap AG" it was correctly judged in 48 cases out of 49 cases, with one incorrect judgement being "(3) touch-off due to low roll temperature". When the actual state was "(5) touch-off due to insufficient adjustment of the die exit" it was correctly judged in all 53 cases.

[0079] Therefore, in the resin sheet extrusion molding device 100, extremely high-accuracy judgments were obtained from the experimental results of the learning model 74 and the state judgment unit 73. Specifically, 248 out of 250 images were accurately judged, resulting in a judgment rate of 99.2%. Even when a similar experiment was performed under different shooting environments, the judgment rate was still 90% or higher. This experimental example also demonstrates that the resin sheet extrusion molding device 100 can appropriately judge the state of the resin sheet 11.

[0080] The operation of the extrusion molding apparatus 100 for a resin sheet (extrusion molding method) will be described in detail below with reference to Fig. 7. Fig. 7 is a flowchart showing the operation of the extrusion molding apparatus 100 for a resin sheet.

[0081] 7 , in step S1, conditions for extrusion molding the resin sheet 11 are set in a device for extrusion molding the resin sheet 11. In step S2, the die 5 extrudes the resin sheet 11 downward. In step S3, the first roll 1 and the second roll 2 clamp the resin sheet 11 from the die 5.

[0082] In step S4, the visible light imaging device 6 captures an image of the resin sheet 11 pressed by the second roll 2. In step S5, the state determination unit 73 determines the state of the resin sheet 11 from the captured image.

[0083] In step S6, it is determined whether the state of the resin sheet 11 is determined to be poor by the state determination unit 73. If the state of the resin sheet 11 is determined to be poor (Yes in step S6), the process proceeds to step S7. If the state of the resin sheet 11 is not determined to be poor (No in step S6), the automatic control ends but operation continues.

[0084] In step S7, the automatic control unit 90 automatically controls the equipment for extrusion molding the resin sheet 11 so as to eliminate the defective condition of the resin sheet 11. Then, the process returns to step S4.

[0085] The embodiments of the present invention have been described above with reference to the drawings. However, the embodiments are illustrative in all respects and are not limiting. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims. Of the configurations described in the embodiments, those other than those described as the invention of the first and second aspects in the "Means for Solving the Problems" are optional configurations and may be deleted or modified as appropriate.

[0086] In the embodiment, the state determination unit 73 is described as determining the cause of "missing touch" as any one of (2) low roll pressure, (3) low roll temperature, (4) wide air gap AG, and (5) insufficient adjustment of the die outlet. The state determination unit 73 is not limited to the above-described (2) to (5), and may determine causes other than the above-described (2) to (5).

[0087] Although the resin sheet 11 has not been described in detail in the embodiment, it may be any sheet that can be molded by extruding the molten resin 10 through the die 5. The resin sheet 11 is, for example, a transparent or opaque sheet.

[0088] 7, steps S1 to S7 including the initial setting have been described, but after the initial setting is complete, steps S4 to S7 (i.e., within the range of step S10) may be repeated at predetermined time intervals. Alternatively, steps S1 to S3 may be manually controlled in advance by an operator, and automatic control may begin from steps S4 to S7 (i.e., within the range of step S10).

[0089] In the embodiment, the light blocking equipment 8 has been described as an example of light entrance suppression equipment, but any equipment that suppresses unnecessary entrance of light into the visible light imaging device 6 may be used. Another example of light entrance suppression equipment may be a light projecting equipment. The light projecting equipment projects light to suppress unnecessary entrance of light into the visible light imaging device 6.

[0090] INDUSTRIAL APPLICABILITY The present invention provides an extrusion molding device for a resin sheet and an extrusion molding method for a resin sheet, and has industrial applicability.

Claims

1. A resin sheet extrusion molding device comprising: a die that extrudes a resin sheet, which is a sheet-shaped molten resin; a pair of rolls that press the resin sheet from the die below the die; and a visible light imaging device that photographs the resin sheet pressed by the pair of rolls, wherein the pair of rolls has a first roll and a second roll, the first roll and the second roll sandwich and press the resin sheet, the second roll transports the pressed resin sheet while keeping it in close contact with the second roll, and the visible light imaging device photographs the second roll and the resin sheet that is transported in close contact with the second roll.

2. A resin sheet extrusion molding device comprising: a die that extrudes a resin sheet, which is a sheet-shaped molten resin; a pair of rolls that press the resin sheet from the die below the die; and a visible light imaging device that photographs the resin sheet pressed by the pair of rolls, wherein the pair of rolls has a first roll and a second roll, the first roll and the second roll sandwich and press the resin sheet, the second roll transports the pressed resin sheet while keeping it in close contact with the resin sheet, and the visible light imaging device takes images from below toward the second roll.

3. A resin sheet extrusion molding device as described in claim 1 or claim 2, further comprising a light-receiving suppression device for suppressing unnecessary light from entering the visible light imaging device.

4. A resin sheet extrusion molding device as described in claim 1 or claim 2, further comprising a disturbance presence / absence determination model that determines the presence or absence of disturbance in an image captured by the visible light imaging device, wherein the disturbance presence / absence determination model is generated by machine learning.

5. A resin sheet extrusion molding device as described in claim 1 or claim 2, further comprising a state determination unit that determines the state of the pressed resin sheet, wherein the state determination unit inputs an image captured by the visible light imaging device into a machine-learned learning model to determine the state, and determines the state from the learning model.

6. A resin sheet extrusion molding device as described in claim 5, further comprising an automatic control unit that automatically controls equipment for extruding the resin sheet, wherein when the condition determination unit determines that the condition is poor, the automatic control unit automatically controls the equipment to eliminate the poor condition.

7. A resin sheet extrusion molding method comprising: extruding a resin sheet, which is a sheet-shaped molten resin, through a die; sandwiching and pressing the resin sheet from the die between a pair of rolls having a first roll and a second roll below the die; transporting the pressed resin sheet while in close contact with the second roll; and photographing the second roll and the resin sheet being transported in close contact with the second roll with a visible light imaging device.

8. A method for extruding a resin sheet, which is a sheet-shaped molten resin, using a die; a pair of rolls having a first roll and a second roll sandwiching and pressing the resin sheet from the die below the die; the pressed resin sheet being transported while being tightly adhered by the second roll; and an image of the resin sheet pressed by the pair of rolls being taken with a visible light imaging device pointing the imaging direction toward the second roll from below.

Images