A window pasting machine is used to solve the problem of bulging of window pasting film at the folding part

Abstract

The present application relates to a window pasting process method for solving the bulging problem of window pasting film at the folding part. The method forms a thinning belt by thinning along the folding line direction on the back side of the film, and sets an exhaust groove extending along the folding line in the thinning belt. The thinning belt reduces the stiffness of the film and improves its bending compliance, ensuring that the film can smoothly adapt to deformation during the folding process, avoiding the problems of bulging, wrinkling and lifting. The exhaust groove effectively provides a gas outlet channel, avoiding gas retention, ensuring the close fit of the film and paperboard, and reducing the generation of bubbles. By precisely controlling the application area of the adhesive layer, the adhesive layer is prevented from blocking the exhaust groove, ensuring smooth gas discharge. The process method can effectively solve the film deformation problem at the folding part in the subsequent folding box process, improve the window pasting effect, and ensure the appearance quality and production efficiency of the packaging product.

Description

Technical Field

[0001] This invention relates to the field of window film applicators, and more particularly to a window film applicator method for solving the problem of bulging at the folds of window film. Background Technology

[0002] With the development of modern packaging technology, the production processes of paper box packaging, paper card packaging, and other products have been widely applied. Especially for transparent lamination and window technology, which protects the paper material while showcasing superior visual appeal and product display, it has become a common form of packaging for many consumer and industrial products. However, despite the significant advantages of transparent lamination materials in terms of visual effect, problems such as bulging, wrinkling, and curling at the folds of the film material have consistently hampered production efficiency and product quality improvement during actual production. Particularly during the box folding process, the mechanical properties of the lamination material and the stress distribution in the fold line area often prevent the film from fully conforming to the cardboard fold, leading to poor appearance and structural problems.

[0003] 1. Thin film folding processing in existing technologies

[0004] Currently, in cardboard box production, folding lines and folding pretreatment technologies are used to improve the performance of the film during the folding process. For example, Chinese patent CN104118141A proposes a cardboard box window-sealing machine. This invention treats the film using techniques such as creasing, folding, and corner cutting to make it adaptable to deformation during subsequent folding and prevent wrinkles or bubbles from forming at the folds. However, these technical solutions have a limitation: simply adjusting the shape and rigidity of the folded area of ​​the film through simple physical pretreatment methods (such as creasing and corner cutting) cannot effectively solve the problem of gas retention within the film during folding. This leads to the formation of bubbles and uneven pressure distribution after folding, making it difficult to avoid bulging and warping.

[0005] 2. Combined application of exhaust grooves and thinning belts

[0006] To further address issues such as bulging and air bubbles during film folding, researchers have gradually realized that in addition to adjusting the film thickness and stress distribution, it is also necessary to provide gas venting channels to facilitate the removal of trapped gas within the film. This need has spurred the application of venting groove technology. For example, Chinese patent CN201002360Y discloses a packaging box windowing machine that incorporates venting grooves in the folding line area of ​​the film to guide gas out and prevent air bubbles during folding. However, existing venting groove solutions are often limited to the post-folding stage, i.e., gas venting is performed after the film has been bonded to the cardboard, failing to pre-plan venting channels during the windowing process, thus limiting their application in high-efficiency production.

[0007] 3. Current thin film scraping and thinning processes

[0008] Another common film processing method is thinning by scraping to alter the film's structure, thereby improving its bending performance and adaptability. Scraping thinning technology has been widely used in transparent lamination, especially in the fold lines of the film, where it has shown significant effectiveness. US Patent US20110245056A1 discloses a window lamination technique that effectively reduces stress generated during folding by scraping thin the fold lines on the back of the film, allowing it to adhere smoothly to the cardboard and avoiding air bubbles at the folds. Compared to the aforementioned techniques, this approach achieves a more significant effect by adjusting the film's folding performance by changing its physical properties (such as thickness and hardness). However, while scraping thinning can solve some stiffness issues, this technique also neglects the problem of gas retention within the film, requiring the handling of gas removal between the film and cardboard during the window lamination process. Summary of the Invention

[0009] The technical objective of this invention is to provide an improved window-applying process. By scraping and thinning the film on the back side and setting venting grooves, the problems of bulging, wrinkling, and lifting of the film at the folds are solved, thereby improving the film's adaptability during the window-applying process, ensuring a tight bond between the film and the cardboard, and improving the product's appearance and quality.

[0010] To achieve the objectives of this invention, the following technical solution is adopted:

[0011] A window laminating machine is used to solve the problem of bulging at the folds of window lamination. The method includes the following steps: S1: Feeding a cardboard, detecting and positioning the window area, fold line, and their relative positions to obtain the position to be processed corresponding to the fold line; S2: Conveying the transparent lamination to a scraping station, scraping and thinning the lamination along the fold line on the back side corresponding to the position to be processed, forming a thinning band in the area corresponding to the fold line, and forming at least one venting groove extending along the fold line within the thinning band to reduce the bending stiffness of the lamination in that area and provide gas outlet during lamination. S3: Apply an adhesive layer to the periphery of the window area, and control the adhesive layer to avoid at least one end outlet area of ​​the thinning strip and / or the venting groove; S4: Align and bond the transparent film with the cardboard window area, and press it from the thinning strip to both sides or from one side to the other side by a pressing member, so that the stagnant gas in the thinning strip and its adjacent area during the bonding process is discharged through the venting groove; S5: Output the cardboard with the window bonded, so that the thinning strip and the venting groove correspond to the folding line area in the subsequent box folding process, thereby reducing the bulging, wrinkling and curling of the transparent film at the fold.

[0012] As a further improvement, the positioning of the window area and fold line in S1 includes: reading at least one of the printed reference marks, die-cut positioning holes, crease lines or edge contours on the cardboard, and obtaining position data by at least one of the photoelectric sensor, vision camera, and laser displacement sensor to establish the relative coordinate relationship between the center line of the window area and the fold line; wherein, the fold line refers to the crease line, pre-fold line or structural turning line that bends during the subsequent folding process of the cardboard.

[0013] As a further improvement, in S2, the centerline of the thinning strip is either aligned with or offset parallel to the projection of the fold line; the width of the thinning strip is... The original thickness of the coating is The remaining thickness after thinning is The amount of thinning is And satisfy

[0014] ;

[0015] in, This indicates the width of the thinning strip in the direction perpendicular to the fold line. Indicates the thickness of the coating before scraping. This indicates the residual thickness at the thinned area after scraping. This indicates the thickness removed by scraping.

[0016] As a further improvement, the exhaust groove is disposed within the thinning zone, and the number of exhaust grooves is one, two, or more; the width of each exhaust groove is [missing information]. The depth of the trench is The spacing between the trenches is ;in, This indicates the width of the opening of the venting groove on the coated surface. This indicates the depth of the vent groove relative to the surface of the thinning zone. This indicates the distance between the centerlines of two adjacent exhaust channels; the exhaust channel is a continuous channel, a discontinuous channel, a corrugated channel, or a channel formed by connecting several short channels end to end.

[0017] As a further improvement, at least one end of the venting groove extends to the non-adhesive application area, the window edge area, or the outer edge area of ​​the coating to form an venting outlet communicating with the outside; in S3, a clearance distance is maintained between the adhesive layer and the edge of the thinning strip. ;in, This indicates the minimum spacing between the nearest boundary of the adhesive layer and the edge of the thinning strip, in order to prevent the adhesive layer from blocking the venting groove.

[0018] As a further improvement, the adhesive layer in S3 is a closed-loop adhesive frame, an intermittent adhesive frame, or segmented adhesive tape arranged around the window area, and the amount of adhesive is... The width of the adhesive layer is ;in, This indicates the amount of adhesive applied per unit length or per unit area. This indicates the width of the adhesive layer on the cardboard surface; the adhesive layer at least avoids the bulging sensitive areas on both sides of the fold line to reduce the degree of constraint on the lamination during subsequent box folding.

[0019] As a further improvement, the pressing component in S4 is a pressure roller, a pressure brush, a pressure plate, an elastic scraper, or a combination thereof; the pressing pressure is... The pressing speed is ;in, This indicates the pressure applied by the pressing component to the surface of the film. This indicates the relative running speed between the pressing component and the cardboard; the pressing component performs at least one directional pressing along a predetermined path from the area where the exhaust groove is located to the direction of the exhaust outlet, so as to promote the discharge of gas along the exhaust groove.

[0020] As a further improvement, the scraping and thinning in S2 and the forming of the venting groove are completed simultaneously, or the thinning strip is formed first and then the venting groove is formed; the scraping and thinning depth is a constant or gradually changing value in the width direction of the thinning strip, so that the thinning strip has a predetermined bending compliance in the subsequent box folding process.

[0021] Another aspect of the present invention provides a windowed cardboard box blank or a windowed cardboard card, wherein the transparent film has a thinning strip and an air vent groove disposed in the thinning strip in the area corresponding to the fold line of the cardboard, and the bending stiffness of the film at the thinning strip is lower than that of the unthinned areas on both sides, thereby reducing bulging, wrinkling or warping at the fold in the subsequent box folding process.

[0022] A third aspect of the present invention provides a window-applying machine for implementing the window-applying process method described herein, comprising: a paper feeding device for conveying paperboard and detecting the relative position of the window area on the paperboard with respect to the fold line; a scraping station for scraping the back side of the film along the fold line direction to form a thinning strip and an air venting groove within the thinning strip; an adhesive application device for applying an adhesive layer around the window area, avoiding the thinning strip and the air venting groove; a bonding and pressing device for aligning the film with the window area of ​​the paperboard and pressing it to ensure that gas is discharged through the air venting groove; and an output device for outputting the window-applying paperboard and sending it to a subsequent folding process, wherein the thinning strip and the air venting groove adapt to folding deformation in the subsequent process.

[0023] This invention significantly reduces the stiffness of the film at the fold line by scraping and thinning the transparent film along the fold line on the back side and setting venting grooves within the thinning strip. This improves the film's bending compliance, effectively preventing bulging, wrinkling, and lifting during the folding process. Simultaneously, the venting grooves provide an outlet channel for gas within the film, preventing gas stagnation and ensuring smooth venting during lamination. This avoids air bubbles or uneven pressure distribution caused by gas stagnation. Furthermore, the unobstructed flow of the venting grooves is further ensured through adhesive layer avoidance and directional pressing control, making the window lamination process more stable and improving product appearance quality and production efficiency. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall process of a window film application method for solving the problem of bulging at the folds of window film according to the present invention. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0026] I. Terminology Explanation

[0027] Windowing refers to a processing method in which a transparent viewing area is set on a cardboard box, cardboard, or other paper packaging blank, and a transparent film is used to cover the window area, so that the product inside the packaging can be displayed through the transparent area.

[0028] Paperboard refers to paper packaging substrates that have undergone printing, die-cutting, creasing, and other processing, including but not limited to color box blanks, folding paper box blanks, paper cards, and other paper materials that need to be folded to form a three-dimensional packaging structure.

[0029] The window area refers to the opening on the cardboard used for mounting the transparent laminating film. The window area is typically formed through a die-cutting process, and its edges serve as the bonding area between the transparent laminating film and the cardboard.

[0030] Transparent coating refers to transparent polymer film materials that cover the window area, including but not limited to polyethylene terephthalate film (PET), polyvinyl chloride film (PVC), and polypropylene film (PP).

[0031] Folding lines refer to the locations where cardboard bends during subsequent box folding processes, including die-cutting lines, pre-folding lines, or turning areas formed by the packaging structure design.

[0032] Thinning strips refer to the localized areas of reduced thickness formed on the back side of a transparent film at the fold line position through mechanical scraping, micro-cutting, or other material removal methods.

[0033] Venting grooves are microscale air-guiding structures set inside the thinning strip, used to provide a gas flow path during the transparent film lamination process, allowing air trapped between the transparent film and the cardboard to be discharged outwards.

[0034] Avoidance-based adhesive application refers to applying the adhesive layer to the window area while ensuring it avoids the thinning zone and the venting groove outlet area. This prevents the adhesive from blocking the air passage and reduces the restriction of the folded area by the adhesive layer.

[0035] II. System Structure and Overall Technical Route

[0036] This invention provides a window pasting machine for implementing the above-described window pasting process. The window pasting machine includes a paper feeding device, a detection and positioning module, a scraping station, an adhesive application device, a bonding and pressing device, and an output device.

[0037] The paper feeding device is used to carry and transport the paperboard to be processed, so that the paperboard passes through the detection area, the lamination area, the gluing area and the bonding area in a predetermined direction.

[0038] The detection and positioning module is used to acquire the positional relationship between the cardboard window area and the fold lines. The detection and positioning module can employ one or more of the following: a vision camera, a photoelectric sensor, and a laser displacement sensor.

[0039] The scraping station is used to perform local processing on the position of the corresponding fold line on the back side of the transparent film according to the detection and positioning results, forming a thinning strip and further forming an air venting groove.

[0040] The adhesive applicator is used to apply an adhesive layer around the window area and controls the adhesive layer to avoid the thinning strip and the vent outlet according to the position of the fold line.

[0041] The laminating and pressing device is used to press the transparent film onto the window area of ​​the cardboard, and through the set pressing path, the air generated during the lamination process is discharged along the exhaust groove.

[0042] The output device is used to output the completed cardboard to the subsequent box folding process.

[0043] The overall technical approach of this invention is as follows:

[0044] First, the spatial relationship between the cardboard window area and the fold line is obtained through the detection and positioning module. Then, the scraping station is controlled to locally thin the transparent film according to the position of the fold line, so that the folded area has low bending stiffness. At the same time, an air vent is formed inside the thinned area to provide a gas outlet path for the bonding stage. After that, avoidance glue application is carried out around the window area to avoid the glue layer affecting the deformation of the thinned area and the air vent. After the transparent film and cardboard are aligned, the pressing component is used to press the film in the direction of air venting, so that the trapped air is discharged along the air vent. Finally, a window-mounted cardboard blank with folding adaptability is obtained.

[0045] III. Specific Implementation Methods of Window Mounting Process

[0046] 1. S1, Cardboard feeding and window area and folding line positioning

[0047] In this embodiment, the paperboard to be processed is first conveyed to the detection and positioning area by a paper feeding device. Since the transparent lamination requires local processing along the fold lines of the paperboard, the positional relationship between the window area and the fold lines needs to be accurately obtained before entering the lamination processing station.

[0048] The detection and positioning module is located above or to the side of the paper feeding path to collect positioning information on the surface of the cardboard.

[0049] In one implementation, the detection and positioning module employs an industrial vision camera.

[0050] The vision camera first acquires image information of the cardboard surface and identifies printing reference marks, die-cut positioning holes, creasing lines, and cardboard edge contours on the cardboard.

[0051] Among them, the printing reference mark can be a positioning pattern set in advance during the packaging printing process; the die-cut positioning hole can be a mechanical positioning structure formed during the cardboard processing; and the creasing line can be used as a folding line to directly identify the object.

[0052] The coordinates of the images obtained from visual acquisition need to be converted into the actual processing coordinates of the cardboard.

[0053] Let the position of the detection point in the image coordinate system be:

[0054] ;

[0055] in, This represents the pixel coordinates of the detection point in the horizontal direction of the image; This represents the pixel coordinates of the detection point in the vertical direction of the image.

[0056] The transformation relationship between the image coordinate system and the cardboard coordinate system is obtained through pre-calibration:

[0057] ;

[0058] in, and This indicates the actual position of the detection point in the cardboard coordinate system; and This indicates the pixel position of the detection point in the image coordinate system; The calibration matrix represents the transformation from image coordinates to cardboard coordinates.

[0059] Based on the converted coordinate data, the positional relationship between the center line of the window area and the fold line is established. Furthermore, the location for subsequent transparent coating processing is determined based on the detection results.

[0060] For example, when the cardboard has multiple window areas, the detection and positioning module acquires the boundary coordinates of each window area and matches them with the corresponding fold lines. When there is a slight conveying deviation in the cardboard, the control system adjusts the lateral position of the scraping station based on the real-time detection results, ensuring that the subsequent thinning belt accurately aligns with the fold lines. This positioning method avoids the processing deviations caused by traditional equipment that relies solely on the cardboard edge for positioning.

[0061] 2. S2, Formation of transparent film thinning strip and venting groove

[0062] After the fold line is positioned, the transparent film enters the scraping station. Based on the fold line position obtained in step S1, the scraping station performs localized thinning on the back side of the transparent film.

[0063] In this embodiment, the transparent lamination is applied to a transparent polymer film used to cover the window area of ​​the cardboard. Since the transparent lamination needs to bend along with the cardboard during the subsequent box folding process, if the transparent lamination maintains the same thickness overall, there will be no performance difference between the folded and unfolded areas. During folding, the lamination's own bending resistance can generate a restoring force, causing localized separation between the transparent lamination and the cardboard.

[0064] Therefore, the present invention adjusts the thickness of the transparent film locally according to the position of the cardboard folding line, so that the folded area forms a low-stiffness deformation area.

[0065] In the specific implementation process, the transparent coating is conveyed into the scraping station by a conveying mechanism. The scraping station includes a coating positioning component, a scraping execution component, and an venting groove forming component. The coating positioning component ensures the lateral stability of the transparent coating during conveying; the scraping execution component removes the material on the back side of the transparent coating according to a preset trajectory; and the venting groove forming component forms a continuous or intermittent air-guiding structure within the thinning area. The control system controls the position of the scraping execution component based on the fold line coordinates obtained in step S1, ensuring that the scraping path corresponds to the extension direction of the fold line.

[0066] In one embodiment, the centerline of the thinning strip coincides with the projection position of the fold line.

[0067] In another embodiment, considering the offset of the folded area in some packaging structures, the thinning strip can be offset parallel to the fold line. The thinning strip extends continuously along the fold line direction. Its width direction is perpendicular to the fold line direction. Let the width of the thinning strip be... The original thickness of the transparent coating is The remaining thickness of the thinned region is The thickness removed by scraping is ,but:

[0068] ;

[0069] in, Indicates the amount of thinning of the transparent coating; Indicates the original thickness of the untreated area of ​​the transparent coating; This indicates the remaining thickness after the thinning zone area has been treated.

[0070] Furthermore, the width of the thinning strip satisfies:

[0071] ;

[0072] in, Indicates the total width of the thinning strip; Indicates the width of the thinned area on one side of the fold line; This indicates the width of the thinned area on the other side of the fold line.

[0073] In actual processing, the width of the thinning strip is determined based on the cardboard thickness, folding angle, and properties of the transparent laminating material. For example, for a 0.08mm thick PET transparent laminating film, the thinning strip width can be set to 5mm to 15mm; for packaging structures with larger folding angles, the thinning strip width can be appropriately increased; and for packaging structures that need to maintain high tear resistance, the thinning range can be appropriately reduced.

[0074] In this embodiment, the original thickness of the transparent coating is 0.08 mm, the width of the thinning strip is set to 8 mm, and the remaining thickness after thinning is set to 0.05 mm. Through the above treatment, the bending stiffness of the thinned area is significantly reduced.

[0075] The flexural stiffness of a transparent coating is related to the material thickness, as follows:

[0076] ;

[0077] in, This indicates the bending stiffness per unit width of the transparent coating. Indicates the elastic modulus of the transparent coating material; Indicates the thickness of the transparent coating; This indicates the Poisson's ratio of the material.

[0078] As shown above, the bending stiffness of the transparent coating is related to the cube of its thickness. Therefore, by reducing the thickness of the region corresponding to the fold line, the bending stiffness in that region can be reduced rapidly.

[0079] For example, when the thickness of the transparent coating decreases from 0.08 mm to 0.05 mm, its theoretical bending stiffness ratio is:

[0080] ;

[0081] in, This indicates the bending stiffness of the folded region before thinning; This indicates the bending stiffness of the folded area after thinning.

[0082] This structure allows the transparent film to bend preferentially at the thinning zone during subsequent box folding, rather than forming random deformations near the fold line.

[0083] After forming the thinning strip, this invention further forms venting grooves inside the thinning strip. These venting grooves address the problem of air trapping during the transparent film lamination process. In traditional window lamination processes, when the transparent film covers the window area, a closed space gradually forms between the transparent film and the cardboard. When the lamination speed is high or the adhesive layer has high fluidity, some air cannot escape in time. This air forms localized air bubbles after lamination. When subsequent folding of the box causes bending, the air bubble area is compressed, further causing the transparent film to bulge or the edges to lift. Therefore, this invention provides venting grooves inside the thinning strip, so that the thinned area not only reduces stiffness but also has a gas guiding function.

[0084] The venting channels extend along the fold line. The number of venting channels can be determined based on the window size and the area covered by the film. In one embodiment, one venting channel is provided. This structure is suitable for packaging structures with small window areas and short air exhaust distances.

[0085] In another implementation, two or more exhaust channels are provided. Multiple exhaust channels can form parallel air guide channels, improving the exhaust capacity of large window areas.

[0086] The exhaust groove can adopt the following structures: (1) continuous straight groove; (2) intermittent groove; (3) corrugated groove; (4) air guiding channel formed by connecting multiple short grooves end to end.

[0087] Let the width of the exhaust groove opening be The depth of the exhaust groove is The center-to-center distance between adjacent exhaust channels is ,but:

[0088] ;

[0089] in, Indicates the structural parameters of the exhaust channel; This indicates the width of the opening of the venting groove on the transparent coating surface; This indicates the depth of the vent groove relative to the surface of the thinning zone; This indicates the distance between adjacent exhaust channels.

[0090] In this embodiment: number of venting grooves: 1; width of venting groove: 0.10mm; depth of venting groove: 0.02mm; the venting groove extends along the fold line. This size allows for airflow without disrupting the continuity of the transparent coating.

[0091] Furthermore, the exhaust duct has at least one outlet that connects to the outside.

[0092] One end of the venting groove extends to the edge of the window. In another embodiment, both ends of the venting groove extend to the outer edge of the transparent film. An outlet is provided to allow air to flow from the enclosed bonding area to the external environment. During bonding, when pressure is applied by the pressing member: the transparent film is compressed; the internal air is squeezed; the air enters the venting groove; moves along the direction of the venting groove; and is finally discharged from the venting outlet. Therefore, the "thinning strip + venting groove" composite structure formed by this invention simultaneously solves two technical problems: on the one hand, it reduces the stiffness of the folded area of ​​the transparent film by thinning; on the other hand, it releases the trapped air during the bonding process through the venting groove.

[0093] Compared to simply reducing the thickness of the transparent coating, this invention avoids bulging caused by residual air; compared to simply providing vent holes or vent grooves, this invention further improves the stress state of the coating during the folding process. Furthermore, the formation method of the thinning strip and vent groove can be adjusted according to production cycle requirements.

[0094] In one implementation, a simultaneous machining method is used. That is, the scraping tool completes both material removal and venting groove machining in a single movement. This method can reduce secondary positioning errors and improve the positional consistency between the thinning zone and the venting groove.

[0095] In another implementation: a thinning strip is first formed by a scraping mechanism; then an air venting groove is formed by a micro-embossing mechanism. This method is suitable for retrofitting existing window covering equipment.

[0096] 3. S3, Window area avoidance application of adhesive

[0097] After the thinning strip and venting grooves are processed in the transparent lamination, the film enters the gluing station. The gluing device is used to form an adhesive layer around the perimeter of the window area of ​​the cardboard. Traditional window-applying processes typically use a continuous closed glue frame structure to fix the transparent lamination to the cardboard as a whole. However, when the adhesive layer covers the fold-sensitive area, the transparent lamination is constrained by the adhesive layer during folding, causing the thinning structure to be unable to fully release deformation. Therefore, this invention adopts an avoidance-type gluing method. During the gluing process, the control system adjusts the gluing path according to the fold line position obtained in step S1 and the thinning strip position formed in step S2, so that the adhesive layer avoids the thinning strip area and the venting groove outlet.

[0098] The adhesive layer can be: a closed-loop adhesive frame; an intermittent adhesive frame; or segmented adhesive tape. The adhesive layer is primarily applied to the non-folded area of ​​the window region. Let the distance between the adhesive layer boundary and the edge of the thinning strip be... ,but:

[0099] ;

[0100] in, Indicates the actual avoidance distance; This indicates the minimum distance required to ensure that the exhaust channel outlet is not blocked by adhesive.

[0101] In this embodiment: Set to 2mm. This setting ensures that the adhesive layer does not enter the venting groove outlet area. Simultaneously, because sufficient adhesive area is maintained around the window perimeter, reliable bonding strength is achieved between the transparent film and the cardboard.

[0102] 4. S4, Transparent film alignment and bonding, directional pressing and venting.

[0103] After applying adhesive to avoid gaps in the window area, align and bond the transparent film to the window area of ​​the cardboard.

[0104] Traditional window-sealing equipment typically uses a unidirectional continuous pressing method with pressure rollers. While this method can bond the transparent film to the cardboard, the gradually increasing contact area between the film and cardboard means that air can easily become trapped between them if it cannot be released in time. This is especially problematic near the fold line, where the combined bending stress of the film and residual air pressure can easily cause localized bulging during subsequent box folding. Therefore, this invention employs a directional pressing method that aligns with the direction of the venting grooves during the bonding process.

[0105] In practice, the bonding and pressing device includes a pressing drive mechanism, a pressure adjustment mechanism, and a pressing component. The pressing component can be a pressure roller, a pressure brush, a pressure plate, an elastic scraper, or a combination of these structures. After the transparent film and the cardboard window area are initially positioned, the pressing component first acts on the vicinity of the thinning strip area. Due to the reduced thickness of the thinning strip area, this area can preferentially undergo bonding deformation, allowing the transparent film to gradually adhere to the cardboard surface. Subsequently, the pressing component moves in a predetermined direction, which is consistent with the extension direction of the venting groove.

[0106] For example, when the venting groove extends from the center of the window to the edge of the cardboard, the pressing member moves from the center area of ​​the window to the edge of the cardboard; when the venting groove is configured with multiple outlets, the pressing member moves in the direction of the nearest venting outlet.

[0107] Through the aforementioned movement, the air between the transparent film and the cardboard is directionally compressed. The air first enters the exhaust groove inside the thinning belt, and then moves along the exhaust groove towards the outlet area.

[0108] The specific process is as follows: First stage: The pressing component contacts the surface of the transparent film and generates localized pressure; Second stage: The gap between the transparent film and the cardboard gradually decreases, and residual air is compressed; Third stage: Due to the low-resistance channel provided by the venting groove, air preferentially enters the venting groove; Fourth stage: The air moves along the extension direction of the venting groove and is discharged from the outlet; Fifth stage: The transparent film is completely adhered to the window area. To ensure effective venting without damaging the film during the pressing process, the pressing parameters need to be controlled. Let the pressing pressure be... The pressing speed is Then the pressing state parameters can be expressed as:

[0109] ;

[0110] in, This represents the set of parameters for the bonding status; This indicates the pressure per unit area exerted by the pressing component on the surface of the transparent film; This indicates the relative running speed between the bonding component and the cardboard.

[0111] In this embodiment: pressing pressure: 0.15MPa; pressing speed: 80mm / s. If the pressing pressure is too low, it will not be able to effectively push air into the venting groove; if the pressing pressure is too high, it may cause excessive diffusion of the adhesive layer, resulting in contamination of the venting outlet with adhesive.

[0112] Furthermore, this embodiment employs a two-stage lamination method. The first stage uses a wide-width pressure roller for overall pre-pressing, establishing initial contact between the transparent film and the cardboard. The second stage uses a narrow-width lamination component that moves along the venting groove direction to expel residual air. Compared to traditional overall lamination, this method reduces the formation of trapped air. In addition, the lamination component can employ an elastic structure. The elastic scraper or elastic pressure roller can generate adaptive pressure based on changes in the surface height of the transparent film. When the lamination component passes through the thinning zone, the elastic structure maintains continuous contact due to the reduced thickness in that area. When the lamination component passes through the non-thinning zone, the elastic structure prevents excessive local pressure. Therefore, this invention, through the coordination of lamination path control, pressure control, and venting structure, enables the transparent film to undergo an active venting process during lamination.

[0113] 5. S5. Complete the window patching output and adapt it to the subsequent box folding process.

[0114] like Figure 1 As shown, after the transparent film lamination is completed, the output device will output the cardboard with the windowed finish.

[0115] At this point, the cardboard window area is covered with a transparent film, and a thinning strip and venting groove are formed in the area corresponding to the fold line. The cardboard with the window attached then proceeds to the subsequent box-folding process. During box folding, the cardboard bends along the fold line. Because traditional transparent films have a uniform overall thickness, the folded and unfolded areas have the same bending stiffness, making it prone to generating significant restoring forces during folding. This invention, however, creates a thinning strip, forming a low-stiffness deformation area in the area corresponding to the fold line.

[0116] According to the thin film bending theory:

[0117] ;

[0118] in, Indicates the bending stiffness of the transparent coating; Indicates the elastic modulus of the transparent coating material; Indicates the thickness of the transparent coating; This indicates the Poisson's ratio of the material.

[0119] Since bending stiffness is related to the cube of thickness, reducing the local thickness can significantly reduce the bending resistance in that area. For example, the original thickness of the transparent coating is 0.08 mm; the thickness of the thinned area is 0.05 mm.

[0120] but:

[0121] ;

[0122] in, Indicates the bending stiffness of the transparent coating before thinning; This indicates the bending stiffness of the transparent coating after thinning.

[0123] As can be seen from the above relationships, the bending stiffness of the thinned area is significantly reduced. Therefore, during the folding process: the cardboard first deforms along the fold line; the thinned area bends simultaneously; the transparent film does not rebound due to excessive stiffness; and the film remains in close contact with the cardboard. Meanwhile, the venting grooves continue to provide cushioning during the folding process.

[0124] When folding causes localized stress changes, the venting grooves can provide space for minute deformations, allowing the internal stress of the transparent coating to be released.

[0125] IV. Implementation Method of Window Patching Machine Equipment

[0126] The present invention further provides a window pasting machine for implementing the above-mentioned window pasting process. The window pasting machine includes: a paper feeding device; a detection and positioning module; a scraping station; an adhesive application device; a bonding and pressing device; and an output device.

[0127] 1. Paper feeding device

[0128] The paper feeding device is used to continuously transport paperboard to be processed. The paper feeding device includes: a conveying mechanism; a positioning mechanism; and a driving mechanism. The conveying mechanism can be a conveyor belt, a chain conveyor, or a roller conveyor. The positioning mechanism is used to limit the lateral deviation of the paperboard, ensuring that the paperboard passes through each processing station in a preset direction. The driving mechanism is used to control the conveying speed.

[0129] In actual production, the paper feeding device and the detection and positioning module work together. When the paperboard enters the detection area, the control system triggers image acquisition. The subsequent processing position is adjusted based on the detection results.

[0130] 2. Detection and positioning module

[0131] The detection and positioning module is used to acquire the position of the window area and the fold line. This module includes: an image acquisition unit; a data processing unit; and a position output unit. The image acquisition unit acquires information about the cardboard surface. The data processing unit identifies the window boundaries, printing marks, and fold lines. The position output unit sends control parameters to the scraping station.

[0132] In one implementation, an industrial vision camera is used.

[0133] In another implementation, a laser displacement sensor is used to detect changes in the height of the indentation line.

[0134] By using real-time detection, the transparent lamination treatment location can be adapted to the errors of different batches of cardboard.

[0135] 3. Scraping station

[0136] The coating station is used to form the thinning strip and venting grooves. This station includes: a coating conveyor assembly; a scraping assembly; and a venting groove processing assembly. The coating conveyor assembly maintains stable movement of the transparent coating. The scraping assembly adjusts the processing depth according to control commands. The venting groove processing assembly forms microstructured air channels.

[0137] In one embodiment, the scraping assembly and the venting groove processing assembly are integrated into one unit. The thinning strip and venting groove are completed in a single processing step.

[0138] In another implementation, two independent processing modules are used. First, a thinning strip is formed, then an venting groove is formed. This structure facilitates the modification of existing window-applying machines.

[0139] 4. Adhesive application device

[0140] The adhesive application device is located after the scraping station and before the laminating and pressing device. It is used to form an adhesive layer around the window area of ​​the cardboard to achieve a fixed connection between the transparent film and the cardboard.

[0141] The adhesive application device includes an adhesive supply component, an adhesive quantity control component, a moving adhesive application component, and a position avoidance control component. The adhesive supply component is used to store and deliver the adhesive.

[0142] In one embodiment, the adhesive supply assembly includes an adhesive storage tank, an adhesive delivery line, and a pressure dispensing mechanism. The storage tank stores water-based adhesives, hot melt adhesives, or other adhesives suitable for bonding transparent films. The pressure dispensing mechanism provides a stable delivery pressure to the adhesive delivery line, enabling continuous delivery of the adhesive to the application assembly. An adhesive quantity control assembly regulates the amount of adhesive output during the application process. Since the required adhesive quantity varies at different locations within the window area, the adhesive quantity control assembly maintains a consistent adhesive layer thickness.

[0143] Specifically, the adhesive quantity control component can employ: a flow sensor; a pressure regulating valve; and a proportional control pump. The flow sensor detects the amount of adhesive output per unit time; the pressure regulating valve adjusts the adhesive supply pressure; and the proportional control pump adjusts the adhesive delivery speed according to control commands.

[0144] In actual processing, the control system calculates the target glue application amount based on the cardboard conveying speed and window size. Let the glue output per unit length be... The application speed is ,but:

[0145] ;

[0146] in, This indicates the amount of adhesive output per unit time. This indicates the amount of adhesive required per unit length. This indicates the moving speed of the adhesive application component.

[0147] A movable glue applicator is used to move along the periphery of the window area and form a glue layer. The movable glue applicator includes: a lateral movement mechanism; a longitudinal movement mechanism; and a glue nozzle. The lateral movement mechanism is used to adjust the position of the glue nozzle relative to the width direction of the cardboard; the longitudinal movement mechanism is used to control the movement of the glue nozzle along the window contour; the glue nozzle is used to uniformly apply the glue to the surface of the cardboard. In this invention, the glue application process does not simply form a closed glue frame, but rather adjusts the path according to the position of the fold line and the thinning strip.

[0148] Specifically, the detection and positioning module sends the coordinates of the fold line obtained in step S1 to the control system. The control system generates an avoidance zone based on the position of the thinning strip. When the adhesive nozzle moves to the vicinity of the thinning strip, the control system adjusts the nozzle's trajectory to maintain a preset distance between the adhesive layer and the thinning strip.

[0149] The adhesive layer avoids the venting groove outlet area. This ensures: first, that adhesive is prevented from entering the venting groove; second, that the venting channel remains continuous; and third, that the transparent overlay is less restricted by the adhesive layer during folding. In one embodiment, the adhesive layer employs a closed-loop avoidance structure. That is, the adhesive layer is positioned around the window area, but a local gap is formed at the venting groove outlet location.

[0150] In another embodiment, the adhesive layer employs a segmented structure. Multiple adhesive segments are respectively disposed in the non-folded area around the window perimeter. Compared to a continuous adhesive frame structure, this method can further reduce the constraint on the folded area of ​​the transparent overlay.

[0151] 5. Adhesive pressing device

[0152] The laminating and pressing device is located after the adhesive application device and is used to laminate the transparent film with the window area of ​​the cardboard. The laminating and pressing device includes a film positioning component, a pressing execution component, a pressure adjustment component, and a path control component.

[0153] (1) Film-coated positioning assembly

[0154] The lamination positioning assembly ensures that the transparent lamination is aligned with the window area of ​​the cardboard. This assembly includes: a positioning roller; an adsorption mechanism; and an edge correction mechanism. The positioning roller restricts the conveying direction of the transparent lamination; the adsorption mechanism keeps the transparent lamination flat; and the edge correction mechanism corrects lateral misalignment of the transparent lamination. Once the transparent lamination enters the lamination area, the positioning assembly first adjusts the lamination position according to the window area location, ensuring that the transparent lamination covers the window area.

[0155] (2) Pressing execution component

[0156] The lamination assembly is used to apply pressure to the surface of a transparent film. It can be: a pressure roller; a pressure plate; a flexible scraper; or a combined lamination structure.

[0157] In one embodiment, a multi-stage pressure roller structure is employed. The first-stage pressure roller is used to complete the initial contact between the transparent film and the cardboard; the second-stage pressure roller is used to directionally exhaust air along the exhaust direction; and the third-stage pressure roller is used to improve the overall bonding stability.

[0158] In another embodiment, an elastic scraper structure is employed. The elastic scraper has a certain degree of flexibility and deformation capability, which can adapt to local thickness variations in the transparent coating. When the pressing component passes through the thinning zone, the elastic scraper can maintain continuous pressure. When passing through non-thinning zones, it can prevent excessive local pressure.

[0159] (3) Pressure regulating component

[0160] The pressure regulating component is used to control the pressing pressure. It includes: a cylinder; a servo drive mechanism; and a pressure sensor. The pressure sensor collects the force applied during the pressing process in real time. The control system adjusts the cylinder pressure or the servo drive force based on the detected value. Let the detected pressure be... The target pressure is ,but:

[0161] ;

[0162] in, Indicates the pressure adjustment amount; This indicates the setting of target pressure; This indicates real-time pressure monitoring.

[0163] when:

[0164] ;

[0165] This indicates that the actual pressure is insufficient and the bonding pressure needs to be increased.

[0166] when:

[0167] ;

[0168] This indicates that the actual pressure is too high and the bonding pressure needs to be reduced.

[0169] The pressing process is kept stable by using a closed-loop adjustment method.

[0170] (4) Path control component

[0171] The path control component is used to control the movement direction of the pressing component. This invention differs from the traditional integral rolling method in that it controls the pressing path based on the direction of the venting groove. Specifically: the control system reads the position of the venting groove; generates the pressing movement path; and controls the pressing component to move from the thinning zone area towards the venting outlet.

[0172] For example, when the venting groove extends laterally along the cardboard, the pressing component moves laterally; when the venting groove extends longitudinally along the cardboard, the pressing component moves longitudinally. This control method ensures that the air has a clear discharge direction.

[0173] 6. Output device

[0174] The output device is located after the laminating and pressing device and is used to output the cardboard after the window-applied process. The output device includes: a conveying mechanism; a quality inspection mechanism; and a receiving mechanism.

[0175] (1) Conveying mechanism

[0176] The conveyor mechanism is used to carry the cardboard after windowing and transport it to the subsequent box folding process. The conveyor mechanism can be: belt conveyor; roller conveyor; chain conveyor.

[0177] In one implementation, the output delivery speed is synchronized with the front-end windowing speed.

[0178] Synchronous control prevents cardboard from piling up during the output process.

[0179] (2) Quality inspection agency

[0180] Quality inspection agencies use this equipment to conduct online inspections of cardboard after windowing. Inspection items include: the location of the transparent lamination; the integrity of the window coverage; the continuity of the adhesive layer; and the location of the thinning tape.

[0181] In one implementation, a visual inspection method is used. The visual inspection module acquires an image of the edge of the transparent coating and determines whether the transparent coating has shifted. If an anomaly is detected, the control system outputs a rejection signal.

[0182] (3) Receiving mechanism

[0183] The receiving mechanism is used to collect the processed cardboard. The receiving mechanism includes: a stacking platform; a lifting mechanism; and a limiting component. The stacking platform carries the cardboard; the lifting mechanism adjusts its height according to the number of cardboard sheets; and the limiting component keeps the cardboard sheets neatly arranged.

[0184] V. Specific Implementation Examples and Comparative Examples

[0185] To verify the effectiveness of the window-applying process provided by this invention in reducing bulging, wrinkling, and lifting of transparent film at folds, a laboratory simulation of a window-applying production line was used for verification.

[0186] The experimental equipment in this embodiment includes a paper feeding and conveying mechanism, a vision positioning module, a film coating and scraping module, a microgroove processing module, an adhesive application module, and a pressing module.

[0187] During the experiment, by adjusting the transparent film treatment method, folding tests were conducted on cardboard with windows applied under different process conditions, and the defects in the folded areas were statistically analyzed.

[0188] 1. Experimental materials and equipment conditions

[0189] The following materials were used in the experiment:

[0190] Cardboard: 350g / m² white cardboard; Window size: 80mm×50mm; Cardboard folding line type: die-cut creasing line; Transparent lamination: PET transparent film; Transparent lamination thickness: 0.08mm; Adhesive: water-based acrylic adhesive;

[0191] Adhesive application method: continuous adhesive application around the window perimeter; Pressing equipment: roller-type bonding and pressing mechanism.

[0192] The main performance parameters of the transparent coating are shown in Table 1 below.

[0193] Table 1 Parameters of Transparent Coating Materials

[0194]

[0195] During the experiment, the number of samples in each group was set to 1000. After the window was attached, the samples were sent to an automatic folding box device for folding test. The folding conditions were kept consistent: folding angle: 90°; folding speed: 40 pieces / min; ambient temperature: 25±2℃; ambient humidity: 50±10%RH.

[0196] 2. Evaluation Indicators and Testing Methods

[0197] To evaluate the folding stability of transparent coatings under different process conditions, the following evaluation indicators were set:

[0198] (1) Folding bulge rate

[0199] The fold bulge rate is used to evaluate the proportion of defects with obvious bulges in the folded area. Detection method:

[0200] After folding the box, visually inspect the area corresponding to the fold line and use a thickness gauge to confirm any local bulges.

[0201] The calculation formula is as follows:

[0202] ;

[0203] in: Indicates the folding bulge rate; This indicates the number of samples with bulging defects; This indicates the total number of samples tested.

[0204] (2) Length of film curling

[0205] The lamination lift-off length is used to evaluate the degree of separation between the transparent lamination edge and the cardboard. Testing method: The maximum lift-off length of the transparent lamination in the folded area is measured using a 0.01mm precision vernier caliper.

[0206] (3) Number of folds and wrinkles

[0207] The number of obvious wrinkles within a 20mm length of the folded area was counted using a 10x magnification observation method.

[0208] Example 1: This example uses the complete process method of the present invention. The specific processing procedure is as follows: First, the positional relationship between the cardboard window area and the folding line is obtained through the detection and positioning module. The detection module identifies the die-cutting positioning holes on the cardboard and establishes a cardboard coordinate system. Based on the detection results, the transparent lamination processing position is determined. Subsequently, the transparent PET film is conveyed to the scraping station. The back side of the transparent lamination is locally scraped along the folding line direction to form a thinning strip.

[0209] In this embodiment: the original thickness of the transparent coating is 0.08 mm; the width of the thinning strip is 8 mm; the remaining thickness after thinning is 0.05 mm. Subsequently, a continuous venting groove is formed at the center of the thinning strip. The parameters of the venting groove are as follows: groove width: 0.10 mm; groove depth: 0.02 mm; extension direction: along the fold line direction.

[0210] The venting grooves are located inside the thinning strip and extend to the non-adhesive area at the window edge. After lamination, an adhesive layer is applied around the window area. The adhesive layer maintains a 2mm clearance from the edge of the thinning strip. After adhesive application, the transparent film is aligned and bonded to the window area. During bonding, the pressure roller first acts on the area near the thinning strip and moves along the direction of the venting grooves. Bonding pressure: 0.15MPa; Bonding speed: 80mm / s. The processed cardboard undergoes folding and box testing. The test results are shown in Table 2 below.

[0211] Table 2 Test Results of Example 1

[0212]

[0213] Example 1, corresponding to the process conditions of this invention, exhibits a significantly lower folding bulge rate than the traditional window-applying process. The warping length of the transparent film after processing in Example 1 remains at a low level, indicating that the thinning strip and venting groove structure can improve the stability of the folded area.

[0214] Example 2: This example verifies the adaptability of increasing the number of venting grooves to a large window structure. The difference from Example 1 is that two venting grooves are provided. The two venting grooves are located on either side of the fold line. The spacing between the venting grooves is 3mm. The width of the thinning strip is 10mm. All other conditions remain the same. The test results are shown in Table 3 below.

[0215] Table 3 Test Results of Example 2

[0216]

[0217] As can be seen from Example 2, by increasing the number of exhaust grooves, the air release capacity can be further improved and the defects in the folding area can be reduced.

[0218] Example 3: This example verifies the adaptability of the gradient thinning structure. Transparent film: PET film; Original thickness: 0.10 mm. The thinning strip adopts a gradient structure. Specifically: Center area thickness: 0.055 mm; Edge area thickness: 0.075 mm. The venting groove adopts a corrugated structure. Pressing pressure: 0.18 MPa. The test results are shown in Table 4 below.

[0219] Table 4 Test Results of Example 3

[0220]

[0221] As shown in Table 4, the present invention can still maintain a low defect rate under different folding angle conditions.

[0222] Comparative Example 1: This comparative example uses the existing common window tiling process.

[0223] Specific conditions: The transparent film was not thinned; no ventilation grooves were provided; the adhesive layer covered the perimeter of the window; and a standard overall pressing method was used. The test results are shown in Table 5 below.

[0224] Table 5 Test Results of Comparative Example 1

[0225]

[0226] Comparative Example 1 showed the highest bulging rate. This indicates that traditional processes, lacking performance adjustment for the folded area and gas release pathways, are prone to folding defects.

[0227] Comparative Example 2: This comparative example only has an venting groove, without a thinning strip. Specific conditions: transparent film thickness: 0.08 mm; one venting groove; no reduction in film thickness. Test results are shown in Table 6 below.

[0228] Table 6 Test Results of Comparative Example 2

[0229]

[0230] As shown in Comparative Example 2, setting up an exhaust structure can reduce some residual air, but it cannot solve the problem of excessive stiffness in the transparent film folding.

[0231] Comparative Example 3: This comparative example only includes a thinning strip, without an exhaust groove. Specific conditions: Thinning area thickness: 0.05 mm; Thinning width: 8 mm. Test results are shown in Table 7 below.

[0232] Table 7 Test Results of Comparative Example 3

[0233]

[0234] As shown in Comparative Example 3, reducing the thickness of the transparent coating can improve folding deformation, but there are still defects caused by residual air in the bonding.

[0235] VI. Analysis of Experimental Results

[0236] Based on the above embodiments and comparative test results, the following results can be obtained:

[0237]

[0238] After adopting the combined structure of the thinning strip and exhaust groove of the present invention, the folding bulge rate is reduced from 12.6% in the traditional process to 0.5% to 0.8%.

[0239] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A window film applicator for solving the problem of bulging at the folds of window film during the application process, characterized in that, The process includes the following steps: S1: Feeding paperboard, detecting and locating the window area, fold line, and relative position of the paperboard to obtain the position to be processed corresponding to the fold line; S2: The transparent film is conveyed to the scraping station, where it is scraped and thinned along the fold line on the back side of the film corresponding to the position to be processed, forming a thinning strip in the area corresponding to the fold line. At least one venting groove extending along the fold line is formed in the thinning strip to reduce the bending stiffness of the film in this area and provide a gas outlet channel during bonding. S3: An adhesive layer is applied to the periphery of the window area, and the adhesive layer is controlled to avoid at least one end outlet area of ​​the thinning strip and / or the venting groove. S4: The transparent film is aligned and bonded to the window area of ​​the cardboard, and the bonding is performed from the thinning strip to both sides or from one side to the other by a pressing member, so that the gas trapped in the thinning strip and its adjacent area during the bonding process is discharged through the venting groove. S5: The cardboard with the window bonded is output so that the thinning strip and the venting groove correspond to the fold line area in the subsequent box folding process, thereby reducing the bulging, wrinkling and curling of the transparent film at the fold.

2. The process for windowing as claimed in claim 1, wherein, The positioning of the window area and fold line in S1 includes: reading at least one of the printed reference marks, die-cut positioning holes, crease lines or edge contours on the cardboard, and obtaining position data by at least one of the photoelectric sensor, vision camera, and laser displacement sensor to establish the relative coordinate relationship between the center line of the window area and the fold line; wherein, the fold line refers to the crease line, pre-fold line or structural turning line that bends during the subsequent folding process of the cardboard.

3. The window-applying process according to claim 1, characterized in that, The center line of the thinning band in S2 is coincident with the projection of the folding line or is arranged in parallel offset; the thinning band width is , the original thickness of the film is , the residual thickness after thinning is , the thinning amount is , and the following conditions are met ； wherein, represents the width of the thinned tape in the direction perpendicular to the folding line, represents the thickness of the coating film before scraping, represents the residual thickness at the thinned tape after scraping, represents the thickness removed by scraping.

4. The window-applying process according to claim 3, characterized in that, The exhaust grooves are located within the thinning zone, and there may be one, two, or more exhaust grooves; the width of each exhaust groove is... The depth of the trench is The spacing between the trenches is ;in, This indicates the width of the opening of the venting groove on the coated surface. This indicates the depth of the vent groove relative to the surface of the thinning zone. This indicates the distance between the centerlines of two adjacent exhaust channels; the exhaust channel is a continuous channel, a discontinuous channel, a corrugated channel, or a channel formed by connecting several short channels end to end.

5. The window-applying process according to claim 4, characterized in that, At least one end of the venting groove extends to the non-adhesive application area, the window edge area, or the outer edge area of ​​the coating to form an venting outlet communicating with the outside; in S3, a clearance distance is maintained between the adhesive layer and the edge of the thinning strip. ;in, This indicates the minimum spacing between the nearest boundary of the adhesive layer and the edge of the thinning zone, in order to prevent the adhesive layer from blocking the venting groove.

6. The window-applying process according to claim 1, characterized in that, The adhesive layer in S3 is a closed-loop adhesive frame, an intermittent adhesive frame, or segmented adhesive tape arranged around the window area, and the amount of adhesive is... The width of the adhesive layer is ;in, This indicates the amount of adhesive applied per unit length or per unit area. This indicates the width of the adhesive layer on the cardboard surface; the adhesive layer at least avoids the bulging sensitive areas on both sides of the fold line to reduce the degree of constraint on the lamination during subsequent box folding.

7. The window-applying process according to claim 1, characterized in that, The pressing component in S4 is a pressure roller, a pressure brush, a pressure plate, an elastic scraper, or a combination thereof; the pressing pressure is... The pressing speed is ;in, This indicates the pressure applied by the pressing component to the surface of the film. This indicates the relative running speed between the pressing component and the cardboard; the pressing component performs at least one directional pressing along a predetermined path from the area where the exhaust groove is located to the direction of the exhaust outlet, so as to promote the discharge of gas along the exhaust groove.

8. The window-applying process according to claim 1, characterized in that, The scraping and thinning in S2 and the forming of the venting groove are completed simultaneously, or the thinning strip is formed first and the venting groove is formed later; the scraping and thinning depth is a constant or gradually changing value in the width direction of the thinning strip, so that the thinning strip has a predetermined bending compliance in the subsequent folding process.

9. A windowed cardboard box blank or windowed cardboard card prepared using the windowing process described in any one of claims 1 to 8, characterized in that, The transparent film has a thinning strip and an air vent groove in the area corresponding to the fold line of the cardboard. The bending stiffness of the film at the thinning strip is lower than that of the unthinned areas on both sides, thereby reducing bulging, wrinkling or warping at the fold in the subsequent box folding process.

10. A window-applying machine for implementing the window-applying process method according to any one of claims 1 to 8, characterized in that, include: A paper feeding device is used to convey paperboard and detect the relative position of the window area on the paperboard with the fold line; a scraping station is used to scrape the back side of the film along the fold line to form a thinning strip and form an air venting groove in the thinning strip. An adhesive applicator is used to apply an adhesive layer around the perimeter of the window area, avoiding the thinning strip and venting groove; The laminating and pressing device is used to align and press the film with the window area of ​​the cardboard, ensuring that gas is discharged through the venting groove; An output device is used to output the cardboard with the window attached and send it to the subsequent folding box process, wherein the thinning strip and the venting groove adapt to the folding deformation in the subsequent process.

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