A system and method for analyzing and repairing surface errors of a finished packaging box

Abstract

The present application relates to the technical field of packaging box production and manufacturing, and discloses a system and method for analyzing and repairing errors on the surface of a finished packaging box, which comprises a central control unit connected to a scrubbing and error-removing module, a visual positioning and deviation-correcting module, a special material pad printing module, a UV curing module and a customized hot stamping repair module; the scrubbing and error-removing module removes the error hot stamping graphics and text on the surface of the packaging box, cleans the surface of the base and outputs the cleaned packaging box; the visual positioning and deviation-correcting module collects images and performs position review, and the central control unit outputs displacement compensation instructions; the special material pad printing module receives the compensation instructions and adjusts the physical position of the packaging box, and under control, transfers special ink to the area to be repaired; the UV curing module performs light curing treatment on the special ink transferred to the surface; and the customized hot stamping repair module receives the packaging box after curing is completed, and performs hot stamping action on the surface according to the set parameters. The present application overcomes the traditional repair deviation phenomenon and reduces the loss cost.

Description

Technical Field

[0001] This invention relates to the field of packaging box manufacturing technology, specifically to a system and method for analyzing and repairing erroneous text on the surface of finished packaging boxes. Background Technology

[0002] Hot stamping is a core decorative technique in the production of finished packaging boxes. In practice, misprinting or omission of minute, complex text is a common problem. Current conventional repair methods often involve manually erasing the text and then directly applying hot stamping. During the positioning stage, alignment relies heavily on worker experience or is assisted by a single infrared photoelectric sensor. These conventional methods cannot dynamically compensate for minute spatial deviations that occur during product placement, leading to significant misalignment of the reprinted text and a disconnect between the repaired text and the original text on the packaging box.

[0003] In the surface hot stamping process, existing technologies lack specialized hot stamping molds adapted to the micro-complex text on packaging boxes, and cannot precisely control the pressure and temperature parameters of the hot pressing action. These hardware and process defects directly result in poor adhesion of the hot stamping, inconsistent metallic luster, and obvious processing marks left in the repair area. Furthermore, they lack the ability to adjust parameters when dealing with packaging boxes of different sizes and materials, making their adaptability very narrow.

[0004] Current conventional repair processes separate erasure, positioning, pad printing, and hot stamping cutting into independent processing steps, lacking data communication and motion linkage control between these steps. The entire repair operation relies heavily on manual workflow and intervention, which is not only cumbersome and prone to causing secondary scrapping of packaging boxes due to manual operation errors, but also increases material waste and overall repair costs, making it difficult to meet the actual needs of industrial continuous production. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an analysis and repair system and method for erroneous text on the surface of finished packaging boxes. It solves the problems of low positioning accuracy causing offset of reprinted text, lack of customized molds and precise parameter control resulting in poor hot stamping adhesion and obvious repair marks in existing packaging box erroneous text repair operations, and solves the problems of large material waste and high secondary scrap rate caused by the independent processing links and high dependence on manual flow.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of the present invention provides an analysis and repair system for erroneous text on the surface of a finished packaging box, including a central control unit, and a cleaning and error correction module, a visual positioning and correction module, a special material pad printing module, a UV curing module, and a customized hot stamping repair module, which are respectively communicatively connected to the central control unit.

[0007] The cleaning and error removal module is used to remove erroneous hot stamping graphics on the surface of the packaging box, clean the base surface of the area to be repaired on the packaging box, and output the cleaned packaging box. The visual positioning and correction module is used to acquire the reference feature image of the cleaned packaging box surface and perform position verification. The acquired image signal and position feedback signal are transmitted to the central control unit, and the central control unit outputs displacement compensation command according to the built-in algorithm. The special material pad printing module is used to carry the cleaned packaging box, receive the displacement compensation command and adjust the physical position of the cleaned packaging box. After the spatial position is locked, the special material pad printing module is controlled by the central control unit to transfer special ink to the area to be repaired, and generate a packaging box with special ink transferred on the surface. The UV curing module is used to receive the packaging box with special ink transferred to its surface. The UV curing module is controlled by the electrical signal of the central control unit to perform UV curing treatment on the transferred special ink to generate a cured packaging box. The customized hot stamping repair module is used to receive the cured packaging box and perform hot stamping on the surface of the special ink layer that has been photocured, according to the set pressure and temperature parameters.

[0008] This invention establishes a closed-loop repair mechanism for erroneous hot stamping graphics through the sequential integration of physical erasure, visually guided coordinate compensation, pad printing filling, photocuring, and hot stamping. The invention uses a central control unit as the data aggregation and execution hub, combines the wear resistance parameters of the underlying material to define the physical erasure boundary, calculates and outputs multi-degree-of-freedom position compensation parameters based on the spatial coordinate system, and simultaneously integrates a fluid pad printing deformation control mechanism and a multi-layer silicone mold's steady-state heat conduction control mechanism. This overcomes the substrate damage and secondary alignment deviation problems easily caused by conventional repair processes, achieving regionalized in-situ repair of erroneous graphics.

[0009] Preferably, the cleaning and error removal module includes a product clamping fixture and a solvent treatment assembly. The product clamping fixture physically limits and fixes the packaging box. The solvent treatment assembly includes a storage tank, a micro-drip valve, a wiping drive mechanism, and a physical wiping component. The micro-drip valve drips the wiping solvent stored in the storage tank onto the original hot stamping graphic surface. The physical wiping component is installed at the execution end of the wiping drive mechanism. The central control unit presets the maximum allowable wiping pressure based on the wear resistance parameters of the packaging box substrate film and adjusts the vertical downward pressure applied by the wiping drive mechanism to the physical wiping component to ensure that the wiping pressure generated within the contact area between the physical wiping component and the surface of the packaging box is less than the maximum allowable wiping pressure.

[0010] Preferably, the visual positioning and correction module includes an industrial vision camera, an infrared positioning photoelectric sensor, and a correction drive unit; the industrial vision camera acquires images of the area to be repaired, obtaining two-dimensional image data of the current packaging box surface; after the infrared positioning photoelectric sensor detects that the cleaned packaging box has entered a preset working plane, it sends a trigger level signal to the central control unit; the central control unit receives the trigger level signal and calculates the spatial pose difference between the reference features in the current image and the corresponding reference features in the reference template image through a template matching algorithm, thereby obtaining the position translation deviation of the packaging box in the X-axis direction, the position translation deviation of the packaging box in the Y-axis direction, and the rotation angle deviation of the packaging box around the Z-axis.

[0011] Preferably, the correction drive unit adopts a three-axis fine-tuning positioning platform, which includes an X-axis servo motor, a Y-axis servo motor, a rotary servo motor, and a transmission screw assembly. The central control unit receives the position translation deviation and the rotation angle deviation, calculates the reverse compensation motion parameters, analyzes the target position coordinates and converts them into motor drive pulse counts, and then synchronously sends the motor drive pulse counts to the X-axis servo motor, the Y-axis servo motor, and the rotary servo motor. Each servo motor drives the transmission screw assembly to move the cleaned packaging box to the target position coordinates.

[0012] Preferably, the special material pad printing module is equipped with a product support platform and a pad printing machine. The pad printing machine includes an ink supply component, an image carrier, and a pad printing transfer component. The product support platform supports the cleaned packaging box. The pad printing transfer component includes a pad printing head and a multi-axis displacement mechanism. The central control unit pre-determines the instantaneous contact area required for the area to be repaired based on the physical size parameters of the area to be repaired, and calculates the corresponding downward deformation depth by combining the original spherical radius of the working surface at the bottom of the pad printing head. The multi-axis displacement mechanism receives the position control command corresponding to the downward deformation depth and drives the pad printing head to press against the area to be repaired.

[0013] Preferably, the special material pad printing module is equipped with a constant pressure pad printing control mechanism, which includes a pad printing cylinder, an electro-proportional valve, and a pressure sensor. The pressure sensor detects the actual physical pressure applied to the pad printing head by the pad printing cylinder in real time and feeds back the collected analog pressure signal to the central control unit. The central control unit calculates the theoretical target driving force based on the set target contact pressure and the instantaneous contact area, and outputs an analog control signal to the electro-proportional valve. The electro-proportional valve adjusts the compressed air pressure entering the pad printing cylinder according to the received analog control signal, so that the actual contact pressure of the pad printing head on the contact plane is dynamically maintained within the set tolerance range of the target contact pressure value.

[0014] Preferably, the UV curing module includes a local UV light source, a light source focusing component, and a light source power controller; the central control unit reads the average irradiation intensity set by the local UV light source and calculates the target irradiation time by combining it with a preset radiation energy threshold; when the packaging box with special ink transferred on its surface reaches the working area of ​​the UV curing module, the central control unit sends a start electrical signal to the light source power controller, and the light source power controller drives the local UV light source to output ultraviolet radiation; after the total irradiation time of the local UV light source reaches the target irradiation time, the central control unit sends a power-off signal to stop the radiation operation.

[0015] Preferably, the customized hot stamping repair module includes a temperature-controlled pressing component and a multi-layer customized silicone mold; the multi-layer customized silicone mold is composed of an aluminum substrate layer, a base adhesive layer, a ramp connecting end, and a silicone hot stamping end stacked from top to bottom; the temperature-controlled pressing component is equipped with an electric heating element and a temperature sensor; the central control unit calculates the set compensation temperature of the heating plate based on a steady-state heat conduction model, combined with the target working temperature required by the bottom surface of the silicone hot stamping end, the downward output heat flow of the heating plate, and the comprehensive thermal resistance of the multi-layer customized silicone mold in the vertical direction; the central control unit compares the actual physical temperature read by the temperature sensor with the set compensation temperature, calculates the temperature deviation value at the current moment, adjusts the duty cycle of the pulse width modulation signal output to the external power execution element, and dynamically adjusts the heating power.

[0016] Preferably, the analysis and repair system further includes a finished product inspection module, which is located downstream of the customized hot stamping repair module. The finished product inspection module includes a back-end industrial camera, a high-brightness coaxial light source, and a mistake-proof sorting mechanism. The high-brightness coaxial light source illuminates a uniform parallel beam onto the repaired area of ​​the cured packaging box. The back-end industrial camera captures the inspection image of the packaging box surface and transmits the image data to the central control unit. The central control unit extracts the contour features and area parameters of the actual hot stamping pattern, calculates the hot stamping area deviation rate and the center position offset of the actual hot stamping pattern compared to the standard reference image. When the hot stamping area deviation rate or the center position offset exceeds the set maximum allowable threshold or maximum allowable tolerance, the central control unit sends an exclusive command to the mistake-proof sorting mechanism to execute a pneumatic rejection pusher action, pushing the unqualified packaging box out of the normal transmission route.

[0017] The second aspect of this invention provides a method for analyzing and repairing erroneous text on the surface of a finished packaging box, applied to the erroneous text analysis and repair system for the surface of a finished packaging box described in the first aspect of this invention, comprising the following steps: The packaging box to be repaired is fixed to the cleaning and error removal module, the erroneous hot stamping graphics on the surface of the packaging box are removed, the base surface of the area to be repaired of the packaging box is cleaned, and a cleaned packaging box is generated. The cleaned packaging box is transferred to the special material pad printing module. The visual positioning and correction module acquires the reference feature image of the surface of the cleaned packaging box. The central control unit calculates the coordinate deviation and drives the special material pad printing module to adjust the spatial position. The position is checked simultaneously to generate a packaging box with the spatial position locked. The central control unit triggers the mechanical action of the special material pad printing module to transfer the special ink to the repair area on the surface of the packaging box after the spatial position is locked, thereby generating a packaging box with the special ink transferred to its surface. The packaging box with special ink transferred to its surface is transferred to the working area of ​​the UV curing module. The central control unit turns on the UV light source to perform photocuring treatment on the transferred special ink to generate a cured packaging box. The cured packaging box enters the customized hot stamping repair module. The visual positioning and correction module performs secondary positioning and correction verification. The customized hot stamping repair module performs hot stamping on the surface of the cured packaging box repair area according to the set pressure and temperature parameters to generate a packaging box with completed hot stamping. The packaging box after the hot stamping operation is completed is output to the finished product inspection station. The inspection equipment verifies the graphic position tolerance and surface adhesion status of the repair area of ​​the packaging box after the hot stamping operation. The repair system analyzes and records the inspection data and performs the release of qualified products or the interception of unqualified products.

[0018] This invention provides a system and method for analyzing and repairing erroneous text on the surface of finished packaging boxes. It has the following beneficial effects: 1. This invention uses a visual positioning and correction module in conjunction with a correction drive unit to acquire image data using an industrial vision camera and perform position verification using an infrared positioning photoelectric eye. The central control unit calculates the deviation and drives the packaging box to adjust its spatial position. The above-mentioned dual positioning and dynamic correction mechanism can achieve high-precision alignment, overcome the text offset problem commonly found in traditional repair operations, and ensure that the repaired text and images are in consistent with the original text and images on the packaging box.

[0019] 2. This invention employs a customized hot stamping repair module and integrates a special material pad printing module in the early stages. The pressure and temperature parameters of the hot stamping action are controlled by a central control unit, and the surface hot stamping is performed with a multi-layer customized silicone mold. The above structure and process steps can meet the hot stamping requirements of micro-complex text on packaging boxes, ensuring that the surface hot stamping is tightly adhered and the metallic luster is uniform, avoiding obvious marks in the repair area. At the same time, it can fine-tune the visual and hot stamping parameters for packaging boxes of different sizes and materials, and has strong adaptability.

[0020] 3. This invention integrates various work units such as cleaning and error correction, visual positioning, special pad printing, light curing, and customized hot stamping repair. Through a central control unit, data communication and action linkage are achieved, creating a programmed control continuous workflow. The automated connection of each process reduces reliance on human experience and prevents secondary scrapping of packaging boxes due to manual repair errors. While maintaining the efficiency of continuous industrial production, it reduces material consumption and overall repair costs. Attached Figure Description

[0021] Figure 1 A structural block diagram of an analysis and repair system for erroneous text on the surface of a finished product packaging box provided in an embodiment of the present invention; Figure 2 A flowchart outlining the overall steps of a method for analyzing and repairing erroneous text on the surface of a finished product packaging box, as provided in an embodiment of the present invention. Figure 3 A flowchart illustrating the judgment and execution steps of the visual positioning correction process provided in this embodiment of the invention; Figure 4 This is a closed-loop control flowchart for pad printing and surface heat pressing of special materials provided in an embodiment of the present invention; Figure 5 A flowchart illustrating the judgment logic of the finished product inspection and error-proof sorting steps provided in this embodiment of the invention; Figure 6 A comparison diagram of center position offset provided for embodiments of the present invention; Figure 7This is a comparison chart of hot stamping area deviation rates provided in an embodiment of the present invention. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] See attached document Figure 1 This invention provides an analysis and repair system for erroneous text on the surface of finished packaging boxes, which includes a central control unit, and a cleaning and error correction module, a visual positioning and correction module, a special material pad printing module, a UV curing module, and a customized hot stamping repair module, all of which are respectively connected to the central control unit in communication.

[0024] The central control unit coordinates the operation cycle and data interaction of each module. The cleaning and error correction module, the visual positioning and correction module, the special material pad printing module, the UV curing module, and the customized hot stamping repair module are sequentially installed on the production line.

[0025] The cleaning and error correction module is located in the first section of the system and includes a product clamping fixture and a solvent treatment assembly. The product clamping fixture is used to physically limit and fix the packaging box. The solvent treatment assembly is equipped with wiping solvent and physical wiping components to perform the removal of local graphics and text on the surface of the packaging box.

[0026] The visual positioning and correction module includes an industrial vision camera, an infrared photoelectric sensor, and a correction drive unit. The industrial vision camera and infrared photoelectric sensor transmit the acquired image signals and position feedback signals to the central control unit. The central control unit outputs displacement compensation commands to the correction drive unit based on its built-in algorithm.

[0027] The special material pad printing module is equipped with a product support platform. The product support platform is mechanically connected to the correction drive unit and is used to receive and execute displacement compensation commands to adjust the physical position of the packaging box.

[0028] The UV curing module is located at the output end of the special material pad printing module, and the start / stop and operating power of its curing light source are controlled by the electrical signals of the central control unit.

[0029] The customized hot stamping repair module is located in the next process step after the UV curing module. It includes a temperature-controlled pressing assembly and a multi-layer customized silicone mold. The multi-layer customized silicone mold is installed at the execution end of the temperature-controlled pressing assembly, and it is composed of an aluminum substrate layer, a base adhesive layer, a ramped connecting end, and a silicone hot stamping end, stacked from top to bottom. The temperature and pressure sensors inside the temperature-controlled pressing assembly interact bidirectionally with the central control unit.

[0030] See attached document Figure 2 This invention provides a method for analyzing and repairing erroneous text on the surface of finished product packaging boxes, applied to the aforementioned system architecture, and includes the following steps: Step S1, cleaning and error removal. Fix the packaging box to be repaired onto the product clamping fixture of the cleaning and error removal module, use the solvent treatment component to remove the erroneous hot stamping graphics on the surface of the packaging box, and clean the base surface of the area of ​​the packaging box to be repaired.

[0031] Step S2, Positioning and Correction. The cleaned packaging box is transferred to the product support platform of the special material pad printing module. The industrial vision camera of the vision positioning and correction module acquires a reference feature image of the packaging box surface. The central control unit calculates the coordinate deviation between the current position of the packaging box and the standard reference position. The correction drive unit drives the product support platform to adjust its spatial position according to the deviation. The infrared photoelectric eye simultaneously verifies the position.

[0032] Step S3, Special Pad Printing. After the spatial position is locked, the central control unit triggers the mechanical action of the special material pad printing module. The pad printing head presses down along the set trajectory, transferring the special ink to the area to be repaired on the surface of the packaging box.

[0033] Step S4, UV curing. The packaging box is transferred to the working area of ​​the UV curing module. The central control unit turns on the UV light source and performs UV curing on the ink layer of the pad printing area according to the set radiation time and power parameters.

[0034] Step S5, surface hot stamping. The cured packaging box enters the customized hot stamping repair module. The visual positioning and correction module performs secondary positioning and correction verification. The temperature-controlled pressing component drives the multi-layer customized silicone mold downwards, performing hot stamping on the repair area surface according to the set pressure and temperature parameters.

[0035] Step S6, Finished Product Inspection. After the hot stamping process is completed, the packaging box is output to the finished product inspection station. The inspection equipment verifies the graphic position tolerances and surface adhesion of the repaired area. The system records the inspection data and accordingly releases qualified products or intercepts unqualified products.

[0036] The cleaning and error correction module is located at the first stage of the system and includes a product clamping fixture and a solvent treatment assembly. The product clamping fixture receives the packaging boxes entering the production line and physically limits and locks their position. The fixture includes a positioning base plate and a pneumatic side-push cylinder. The positioning base plate has several negative pressure suction holes on its surface. The packaging box is placed on the positioning base plate, and the pneumatic side-push cylinder drives a push plate to contact the side edge of the packaging box, pushing it to a preset mechanical zero position. A vacuum generator below the positioning base plate is activated, applying vacuum suction to the bottom of the packaging box through the negative pressure suction holes, ensuring the box is flat and fixed on the positioning base plate, preventing displacement during subsequent wiping processes.

[0037] The solvent treatment assembly is used to remove existing hot stamping designs from specific areas of the packaging box surface. The assembly includes a reservoir, a micro-drip valve, a wiping drive mechanism, and physical wiping components. The reservoir contains a removal solvent. This solvent is formulated as an organic mixture capable of dissolving the underlying resin adhesive of the hot stamping foil without damaging the packaging box's substrate film. The inlet of the micro-drip valve is connected to the reservoir, while the outlet faces the area to be repaired on the packaging box surface. The central control unit opens the micro-drip valve, dripping a measured amount of removal solvent onto the existing hot stamping design, causing the resin adhesive to swell.

[0038] The wiping drive mechanism employs a multi-degree-of-freedom robotic arm or a servo linear module. A physical wiping component, made of non-woven fabric or high-density sponge, is mounted at the end of the wiping drive mechanism. The wiping drive mechanism drives the physical wiping component downwards to press against the area to be repaired and performs a reciprocating wiping motion in the horizontal direction. The physical wiping component peels off the original metal layer and adhesive, softened by solvent, from the surface of the packaging box, exposing a clean base surface for subsequent pad printing.

[0039] The downward pressure applied by the physical wiping component to the packaging box surface needs to be controlled within a reasonable range to avoid excessive friction damaging the underlying cardboard fibers. The vertical downward pressure applied by the wiping drive mechanism to the physical wiping component should be set as follows: The contact area between the physical wiping component and the surface of the packaging box is The wiping pressure generated by the physical wiping element on the surface of the packaging box The calculation formula is expressed as: ; in, This indicates the wiping pressure exerted by the physical wiping element on the surface of the packaging box; This indicates the vertical downward pressure applied by the wiping drive mechanism to the physical wiping component; This indicates the contact area between the physical wiping component and the surface of the packaging box.

[0040] The central control unit presets the maximum permissible wiping pressure based on the wear resistance parameters of the packaging box substrate film. This maximum permissible wiping pressure can be calibrated by conducting a pre-destructive friction test on waste samples of the same batch of packaging box substrates.

[0041] The central control unit presets the maximum permissible wiping pressure based on the abrasion resistance parameters of the packaging box substrate film. This maximum permissible wiping pressure can be calibrated by conducting a pre-destructive friction test on waste samples of the same batch of packaging box substrates. The central control unit adjusts the vertical downward pressure output by the wiping drive mechanism. To ensure the actual wiping pressure generated The pressure is always kept below the maximum permissible wiping pressure. This control mechanism ensures thorough cleaning and the integrity of the substrate.

[0042] For the air path arrangement method of the vacuum generator in the product clamping fixture, the fluid pressure control principle of the micro-drip valve, and the reciprocating motion trajectory planning of the wiping drive mechanism, those skilled in the art can design them according to conventional automated assembly equipment standards. The mechanical and pneumatic structure and stepper motor motion control are well-known technologies in this field and will not be elaborated upon here. After wiping and cleaning, the packaging box is released from vacuum locking and transferred by conveyor belt to the next section where the visual positioning and correction module is located.

[0043] The hardware architecture of the visual positioning and correction module mainly includes a visual acquisition component and a position verification component. The visual acquisition component is used to acquire two-dimensional image information of the packaging box surface, while the position verification component is used to confirm the arrival status and reference height of the packaging box in physical space.

[0044] The vision acquisition component includes an industrial vision camera, an optical lens, and an illumination source. The industrial vision camera is fixedly mounted directly above the product support platform of the special material pad printing module, with its optical axis perpendicular to the platform's bearing surface. Specifically, the industrial vision camera is either a CCD area array camera or a CMOS area array camera. The optical lens is mounted on the photosensitive end of the industrial vision camera and is a telecentric lens. The telecentric lens is used to eliminate parallax caused by minor unevenness on the packaging box surface, ensuring that the acquired reference feature image does not suffer from perspective distortion. The illumination source is arranged around the bottom outer edge of the optical lens, using a shadowless ring light source or a coaxial light source, to provide uniform illumination to the area to be repaired on the packaging box surface, preventing reflective spots from appearing on the original hot stamping patterns.

[0045] The position verification component includes an infrared positioning photoelectric sensor. The infrared positioning photoelectric sensor is mounted at an angle above and to the side of the product support platform via a mounting bracket. The emitting end of the infrared positioning photoelectric sensor faces the positioning reference surface on the product support platform and emits an infrared detection beam. The infrared positioning photoelectric sensor is configured as either a diffuse reflection type photoelectric sensor or a specular reflection type photoelectric sensor. When the packaging box moves with the product support platform to the preset working plane by the correction drive unit, the receiving end of the infrared positioning photoelectric sensor receives the reflected light signal, generates a trigger level signal, and transmits it to the central control unit. This trigger level signal serves as the hardware trigger condition for the industrial vision camera to perform image capture.

[0046] The mounting height of an industrial vision camera depends on its set field of view and the focal length of its optical lens. The industrial vision camera's field of view, within the plane of the product support platform, covers the area of ​​the packaging box to be repaired and its surrounding reference features. The formula for calculating the system optical resolution of the vision acquisition component is: ; in, This indicates the system optical resolution of the vision acquisition components; Indicates the horizontal physical width of the field of view; This indicates the number of horizontal pixels in an industrial vision camera.

[0047] System optical resolution The accuracy must be less than a preset correction tolerance to provide sufficient image feature data support. This preset correction tolerance is determined based on the minimum accuracy requirements for physical alignment of the special material pad printing module, and is typically set between 0.05mm and 0.1mm. The relative position parameters of the industrial vision camera and the infrared positioning photoelectric eye in physical space are recorded in the register of the central control unit through the system initialization calibration program.

[0048] For distortion correction methods of industrial vision cameras and the hand-eye calibration process between industrial vision cameras and product support platforms, those skilled in the art can use a standard checkerboard calibration board to solve the transformation matrix. The calibration calculation process and calibration model derivation are well-known technologies in the field and will not be elaborated here. The central control unit converts the image pixel coordinate system data acquired by the industrial vision camera into the physical space coordinate system data of the product support platform based on the transformation matrix.

[0049] See attached document Figure 3 Once the infrared positioning photoelectric eye detects that the packaging box has entered the preset working plane, it sends a trigger level signal to the central control unit. The central control unit receives this trigger level signal and controls the industrial vision camera to acquire images of the area to be repaired on the surface of the packaging box, obtaining two-dimensional image data of the current packaging box surface. The two-dimensional image data is transmitted to the memory of the central control unit in the form of a digital matrix.

[0050] The central control unit performs preprocessing operations on the received two-dimensional image data. These preprocessing operations specifically include image grayscale conversion, filtering and noise reduction, and contrast enhancement, aiming to eliminate ambient light interference and sensor noise. For the specific algorithm implementation of image preprocessing, those skilled in the art can use conventional digital image processing techniques such as Gaussian filtering or median filtering; the specific calculation process is well-known in the field and will not be elaborated here. The preprocessed image data is used to extract reference features from the surface of the packaging box.

[0051] The packaging box surface is pre-printed with regular geometric shapes, such as existing printed frames or borders. The system sets the edge segments or intersections of these existing printed frames as reference features for positioning. The central control unit uses an edge detection algorithm to extract the reference feature contours from the two-dimensional image data. The central control unit has a pre-stored reference template image of a standard packaging box, which contains standard coordinate data of the reference features at the ideal repair position.

[0052] The central control unit calculates the spatial pose difference between the reference features in the current image and the corresponding reference features in the reference template image using a template matching algorithm. The coordinates of the center point of the reference feature in the standard packaging box reference template image are set as follows: The reference angle for the standard baseline is The coordinates of the center point of the reference feature in the current packaging box image acquired and extracted by an industrial vision camera are: The current angle is The position translation deviation generated by the central control unit. Position translation deviation and rotation angle deviation The calculation formula is:

[0053] in, This indicates the amount of translational deviation of the packaging box along the X-axis. This indicates the amount of translational deviation of the packaging box in the Y-axis direction; This indicates the deviation of the packaging box's rotation angle around the Z-axis; This represents the X-axis coordinate of the center point of the reference feature in the reference template image; This represents the Y-axis coordinate of the center point of the reference feature in the reference template image; The reference angle representing the standard baseline; This represents the X-axis coordinate of the center point of the reference feature in the current packaging box image; This represents the Y-axis coordinate of the center point of the reference feature in the current packaging box image; This indicates the current angle of the reference feature in the current packaging box image.

[0054] The visual acquisition and positioning calculation process constitutes the system's initial positioning calibration. After the system completes the initial positioning calibration, the central control unit calculates the position translation deviation. Position translation deviation and rotation angle deviation It is converted into servo drive control data and output to the correction drive unit to perform physical position compensation and adjustment.

[0055] At the end of the correction drive unit's operation, the infrared positioning photoelectric eye re-detects the position of the packaging box edge, performing a secondary positioning verification. When both the translational and rotational angle deviations are within the system's set tolerance thresholds, the central control unit determines that the positioning calibration is complete and locks the current spatial coordinates of the product support platform. The system's set tolerance thresholds are determined based on the human eye's visual resolution limit for relative positional deviations of printed graphics and the physical alignment accuracy of the downstream pad printing head. Typically, the tolerance threshold for translational deviations is set between ±0.05mm and ±0.1mm, and the tolerance threshold for rotational angle deviations is set between ±0.1° and ±0.2°. The packaging box, along with the product support platform, maintains its current coordinates as it proceeds to the subsequent special pad printing process. If the position parameters exceed the set tolerances, the central control unit triggers an alarm feedback logic, interrupting the current process.

[0056] The web correction drive unit employs a three-axis fine-tuning positioning platform. This platform is located at the bottom of the product support platform of the special material pad printing module and is mechanically fixedly connected to it. The platform includes an X-axis servo motor, a Y-axis servo motor, a rotary servo motor, and a transmission lead screw assembly. The X-axis servo motor drives the product support platform to translate along the X-axis. The Y-axis servo motor drives the product support platform to translate along the Y-axis. The rotary servo motor drives the product support platform to rotate around the Z-axis.

[0057] The central control unit receives the position translation deviation output from the visual positioning calibration logic. Position translation deviation and rotation angle deviation The central control unit calculates the reverse compensation motion parameters that the product support platform needs to execute based on the aforementioned deviation. To ensure that the area to be repaired on the packaging box is precisely aligned with the working reference zero point of the special material pad printing module, the system establishes a spatial mapping relationship between the image pixel coordinate system and the physical motion coordinate system of the product support platform.

[0058] Let the initial coordinates of any target point on the packaging box to be repaired be set in the current industrial vision camera coordinate system as follows: After the correction drive unit performs the reverse compensation motion, the target position coordinates of the point to be repaired within the physical working plane are: The homogeneous transformation matrix relationship between the target position coordinates and the initial coordinates is expressed as:

[0059] in, This indicates the X-axis target position coordinates of the target point to be repaired after compensation; This indicates the Y-axis target position coordinates of the target point to be repaired after compensation; This indicates the initial X-axis coordinates of the target point to be repaired in the camera coordinate system; This indicates the initial Y-axis coordinate of the target point to be repaired in the camera coordinate system; This indicates the amount of translational deviation of the packaging box along the X-axis. This indicates the amount of translational deviation of the packaging box in the Y-axis direction; This indicates the deviation of the packaging box's rotation angle around the Z-axis.

[0060] The central control unit analyzes the target position coordinates and converts them into the corresponding number of motor drive pulses based on the mechanical transmission ratio. The central control unit then synchronously sends these motor drive pulses as control signals to the drivers of the X-axis servo motor, Y-axis servo motor, and rotary servo motor. Each servo motor drives the transmission screw assembly according to the received control signals, moving the product support platform along with the packaging box it carries to the target position coordinates.

[0061] Each servo motor is equipped with an absolute encoder at its end. The absolute encoder feeds back the actual operating position data of the motor to the central control unit, forming a closed-loop position control system to eliminate backlash errors caused by mechanical transmission backlash and ensure the final accuracy of physical displacement compensation. The pulse equivalent calculation method for the servo motor and the closed-loop position control logic can be calculated and tuned by those skilled in the art based on the motor specifications and lead screw pitch. The closed-loop control algorithm is well-known in the field and will not be elaborated upon here. After the product support platform stops moving, the system maintains the servo-locked state of the motor, preparing to execute subsequent actions.

[0062] The main hardware framework of the special material pad printing module includes a pad printing machine, which is positioned above the product support platform. The execution components of the pad printing machine include an ink supply assembly, an image carrier, and a pad printing transfer assembly.

[0063] The ink supply assembly includes an ink trough and a doctor blade assembly. The ink trough, fixed to the frame of the pad printing machine, holds a special ink, which is a resin-based ink with UV-sensitive crosslinking properties. The graphic carrier is a lettering mold, which is horizontally mounted on one side of the ink trough. The surface of the lettering mold has micro-grooves for holding the special ink, and the outline of the micro-grooves matches the target text pattern on the surface of the packaging box to be repaired. The doctor blade assembly includes a doctor blade and a doctor blade drive cylinder. The doctor blade drive cylinder is mechanically connected to the doctor blade, driving the doctor blade to adhere to and slide horizontally on the surface of the lettering mold. The doctor blade evenly coats the special ink into the micro-grooves and simultaneously scrapes away excess ink from non-patterned areas on the surface of the lettering mold.

[0064] The pad printing transfer assembly includes a pad printing head and a multi-axis displacement mechanism. The pad printing head is made of silicone material, and its bottom working surface has an outwardly convex spherical structure. This convex structure is used to squeeze air from the central area to the periphery when the pad printing head contacts the plane, preventing air bubbles from being trapped during the transfer of special inks. The multi-axis displacement mechanism is controlled by a central control unit, whose output end suspends and fixes the pad printing head, driving the pad printing head to perform spatial translation and vertical lifting movements between the lettering mold and the product support platform.

[0065] When the pad printing head picks up and transfers ink, its bottom working surface undergoes elastic deformation under pressure. The system controls the physical boundary range of the pad printing ink by limiting the downward pressure depth of the pad printing head. The bottom working surface of the pad printing head is assumed to be approximately a standard sphere, with an original spherical radius of [missing information]. The multi-axis displacement mechanism controls the downward vertical displacement of the printing pad, ensuring that the depth of downward deformation generated by the printing pad is... The instantaneous contact area between the pad printing die and the surface of the engraving mold or packaging box. The calculation formula is expressed as:

[0066] in, This indicates the instantaneous contact area when the pad printing nozzle undergoes elastic deformation; This represents the original spherical radius of the working surface at the bottom of the pad printing head; This indicates the depth of downward deformation generated by the printing pad controlled by the multi-axis displacement mechanism; This represents the constant value of pi.

[0067] The central control unit pre-determines the required instantaneous contact area for the area to be repaired based on the physical dimensions of the area. The corresponding compressive deformation depth is obtained based on the above formula. The central control unit will compress the deformation depth. The command is converted into a position control command and sent to the multi-axis displacement mechanism. The multi-axis displacement mechanism drives the moving printing head to press against the surface of the lettering die to obtain special ink, and then translates and descends to the same depth of pressure deformation. The special ink is pressed and transferred to the area of ​​the packaging box to be repaired on the product support platform according to the set area.

[0068] For the specific linear guide structure and drive element selection of multi-axis displacement mechanisms, those skilled in the art can use conventional servo modules or pneumatic slides for configuration. The mechanical combination method and basic electrical control are well-known technologies in this field and will not be elaborated here.

[0069] See attached document Figure 4 The special material pad printing module is equipped with a constant pressure pad printing control mechanism. This mechanism controls the physical pressure state of the pad printing head during the acquisition and transfer of special ink, ensuring the uniformity of the ink transfer thickness and preventing ink overflow or missing prints in the areas to be repaired on the packaging box surface.

[0070] The hardware components of the constant pressure pad printing control mechanism include a pad printing cylinder, an electro-proportional valve, and a pressure sensor. The pad printing cylinder is vertically mounted on the moving end of the multi-axis displacement mechanism. The pad printing head is fixed to the end of the piston rod of the pad printing cylinder via a connecting shaft. The electro-proportional valve is located in the air intake path of the pad printing cylinder, and its control terminal is electrically connected to the central control unit. The pressure sensor is connected in series on the connecting shaft between the pad printing cylinder and the pad printing head. The pressure sensor is used to detect the actual physical pressure applied by the pad printing cylinder to the pad printing head in real time and feeds back the collected analog pressure signal to the central control unit.

[0071] When the pad printing nozzle presses against the surface of the lettering mold or packaging box, an actual contact pressure is generated between the working surface of the bottom of the nozzle and the contact plane. The value of the actual contact pressure is affected by both the driving force output by the pad printing cylinder and the instantaneous contact area of ​​the pad printing nozzle. The formula for calculating the actual contact pressure is expressed as:

[0072] in, This indicates the actual contact pressure between the working surface at the bottom of the pad printing head and the contact plane; This indicates the driving force applied by the pad printing cylinder to the pad printing head; This indicates the instantaneous contact area when the pad printing nozzle undergoes elastic deformation.

[0073] The central control unit stores target contact pressure values ​​that match the viscosity and transfer characteristics of special inks. The central control unit then determines the target contact pressure and the pre-defined instantaneous contact area. The theoretical target driving force is calculated. The central control unit generates a corresponding analog control signal and outputs it to the electro-proportional valve. The electro-proportional valve adjusts the compressed air pressure entering the pad printing cylinder according to the received control signal, so that the pad printing cylinder outputs a physical thrust equal to the theoretical target driving force.

[0074] During the process of the pad printing head pressing down on the contact surface, the pressure sensor continuously collects the current actual driving force data and sends this data to the central control unit. The central control unit compares the actual driving force with the theoretical target driving force and calculates the driving force deviation between the two. Based on the driving force deviation, the central control unit adjusts the analog control signal output to the electro-proportional valve in real time, forming a closed-loop control circuit. The closed-loop control circuit ensures that the actual contact pressure of the pad printing head on the contact surface is dynamically maintained within the set tolerance range of the target contact pressure value, thus maintaining the physical force stability of the ink transfer process.

[0075] The PID pressure closed-loop control algorithm and the internal pneumatic pressure regulating structure of the electro-proportional valve involved in the constant pressure pad printing control mechanism can be configured by those skilled in the art according to conventional fluid transmission design specifications. The control operation logic and basic hardware operation principle are well-known technologies in this field and will not be elaborated here.

[0076] After the special material pad printing module completes the transfer of special inks, the packaging box is moved along with the product support platform to the operating area of ​​the UV curing module. The UV curing module includes a local UV light source, a light source focusing assembly, and a light source power controller. The local UV light source uses a UV LED array emitter, with its emission wavelength configured to match the absorption peak of the photoinitiator inside the special ink. The light source focusing assembly is installed on the emitting side of the local UV light source. The light source focusing assembly uses a quartz lens group structure to focus the ultraviolet beam onto the special ink area on the surface of the packaging box. The light source power controller is electrically connected to the local UV light source and receives command signals from the central control unit to adjust the operating status of the local UV light source.

[0077] A localized UV curing kinetic control mechanism is used to precisely adjust the UV radiation dose, causing cross-linking polymerization of resin molecules within the special ink layer, thus achieving adhesion and setting of the special ink on the packaging box surface. The degree of curing of the special ink layer depends on the cumulative radiation energy received per unit area. The instantaneous irradiation intensity of the localized UV light source is... The total irradiation time of the local UV light source is The cumulative radiant energy received by the special ink layer The integral calculation formula is expressed as:

[0078] in, This indicates the cumulative radiant energy received by the special ink layer; This represents the time from the start time 0 to the total irradiation time. Definite integral operations; This represents the instantaneous irradiation intensity of a localized UV light source as a function of time. This indicates the total irradiation time of a localized UV light source; Indicates the irradiation time variable; It represents the derivative of the time variable.

[0079] Under continuous illumination conditions where the light source power controller executes constant power output, the instantaneous irradiation intensity emitted by the local UV light source is considered a steady constant. The average irradiation intensity of the local UV light source is set as... Accumulated radiant energy The calculation formula is transformed into:

[0080] in, This represents the average irradiation intensity of a localized UV light source; This indicates the total irradiation time of a local UV light source.

[0081] The central control unit has a preset radiation energy threshold required for the special ink to complete the crosslinking reaction. This preset radiation energy threshold is obtained in advance through sample curing tests based on the absorption characteristics of the photoinitiator in the special ink and the thermodynamic requirements of the crosslinking reaction of the resin monomer. Its value range is usually set to 800 mJ / cm. 2 Up to 2500mJ / cm 2 The central control unit reads the average irradiation intensity set by the local UV light source. The target irradiation time is calculated based on a preset radiation energy threshold. The central control unit sends a start signal to the light source power controller when the packaging box reaches the operating area of ​​the UV curing module. The light source power controller drives the local UV light source to output the corresponding ultraviolet radiation. The total irradiation time of the local UV light source... Once the target irradiation time is reached, the central control unit sends a power-off signal to stop the radiation process. This control process limits the total energy of light radiation entering the special ink layer, preventing insufficient energy from causing ink peeling or energy overload from causing thermal damage to the bottom material of the packaging box.

[0082] For the specific semiconductor packaging structure of the UV LED array emitter, the piping configuration of the water-cooling heat dissipation component, and the constant current drive circuit design of the light source power controller, those skilled in the art can use standard components from conventional industrial-grade UV curing equipment for combination. The underlying hardware light-emitting principle and heat dissipation control are well-known technologies in the field and will not be elaborated upon here. After the photocuring process is completed, the packaging box is output by the transmission mechanism and enters the customized hot stamping repair module for the next surface layer processing operation.

[0083] The customized hot stamping repair module includes a temperature-controlled pressing component and a multi-layer customized silicone mold. The multi-layer customized silicone mold is installed at the actuator end of the temperature-controlled pressing component. The multi-layer customized silicone mold is used to heat-press the metal layer on the electroplated aluminum hot stamping foil to a special ink layer on the surface of the packaging box that has undergone photocuring treatment under preset temperature and pressure, thereby achieving surface metallization repair of graphics and text.

[0084] The main structure of the multi-layer customized silicone mold consists of, from top to bottom, an aluminum substrate layer, a base adhesive layer, a ramped connecting end, and a silicone hot stamping end, layered one on top. The aluminum substrate layer is made of high thermal conductivity aluminum alloy, and its top surface has mechanical mounting holes for fixed connection to the heating plate of the temperature-controlled pressing assembly. The aluminum substrate layer receives heat transferred from the heating plate and provides mechanical support strength for the lower structure. The base adhesive layer, coated on the bottom surface of the aluminum substrate layer, uses a high-temperature resistant silicone resin adhesive to achieve physical bonding between the different material layers.

[0085] The silicone hot stamping end is located at the bottom of a multi-layered custom silicone mold and is made of high-temperature resistant silicone material. The bottom surface of the silicone hot stamping end has an outwardly protruding graphic outline that matches the shape and size of the erroneous text or pattern to be repaired. A ramped connector connects the base layer and the silicone hot stamping end; its cross-section is trapezoidal, with the top width greater than the bottom width. The ramped connector smoothly transfers the mechanical pressure borne by the aluminum substrate layer to the bottom silicone hot stamping end, preventing stress concentration that could cause lateral bending or root breakage of the silicone hot stamping end under pressure.

[0086] During hot stamping, the temperature-controlled pressing assembly drives a multi-layered custom silicone mold to press vertically downwards. The silicone stamping tip contacts the electroplated aluminum foil and applies stamping pressure to the surface of the packaging box. Under pressure, the silicone stamping tip undergoes compression deformation in the vertical direction. This compression deformation determines the silicone stamping tip's ability to cover and adhere to the minute undulations of the underlying material. The initial thickness of the silicone stamping tip is set to... The Young's modulus of the silicone hot stamping end material is The actual hot stamping pressure applied per unit area to the silicone hot stamping end by the temperature-controlled pressing component is: The vertical compression deformation generated at the silicone hot stamping end The calculation formula is expressed as:

[0087] in, This indicates the vertical compression deformation generated at the silicone hot stamping end; This indicates the actual hot stamping pressure applied per unit area to the silicone hot stamping tip. Indicates the initial thickness of the silicone hot stamping end; This indicates the Young's modulus of the silicone hot stamping tip material.

[0088] The central control unit presets an appropriate vertical compression deformation value based on the physical hardness characteristics of the packaging box substrate material. Through the aforementioned mechanical calculation model, the central control unit calculates the actual hot stamping pressure required to achieve the preset deformation. Based on this actual hot stamping pressure parameter, it instructs the temperature control pressing component to output the corresponding mechanical driving force, ensuring balanced force during the hot stamping process and preventing excessive pressure from crushing the packaging box cardboard or insufficient pressure from causing the hot stamping to be weak.

[0089] For the CNC machine tool processing method of the aluminum substrate layer of the multi-layer customized silicone mold and the high-temperature vulcanization molding process of the silicone material, those skilled in the art can use conventional mold processing methods to make it. The specific machining tool path and vulcanization temperature and time curve settings are well known technologies in the field and will not be described in detail here.

[0090] The temperature-controlled pressing assembly of the custom hot stamping repair module incorporates an electric heating element and a temperature sensor. The electric heating element, embedded within the heating plate of the assembly, uses a resistance heating tube or ceramic heating element to convert electrical energy into heat. The temperature sensor, specifically a thermocouple or platinum resistance temperature probe, is mounted on the heating plate near the aluminum substrate layer of the multi-layer custom silicone mold. The temperature sensor continuously transmits the acquired real-time analog temperature signal to the central control unit.

[0091] In hot stamping, the heat generated by the heating plate needs to pass through a multi-layered custom silicone mold to reach the working interface. The heat is sequentially conducted from the heating plate to the aluminum substrate layer, the base adhesive layer, the ramped joint end, and finally to the silicone stamping end. Because the thermal conductivity of silicone is much lower than that of aluminum alloy, the multi-layered custom silicone mold has internal thermal resistance in the vertical thickness direction, resulting in the actual physical temperature of the bottom surface of the silicone stamping end being lower than the current temperature of the heating plate.

[0092] To ensure the resin film on the electroplated aluminum foil melts completely and adheres to the packaging box surface within a very short contact time, the bottom surface of the silicone hot stamping end needs to maintain a constant target operating temperature. This target operating temperature is determined based on the melting point characteristics of the resin film under the selected electroplated aluminum foil, and is typically set within the range of 100℃ to 150℃. The central control unit calculates the set compensation temperature of the heating plate based on a steady-state heat conduction model. The overall thermal resistance of the multi-layer customized silicone mold in the vertical direction is set as follows. The downward output heat flow of the heating plate is The target working temperature required for the bottom surface of the silicone hot stamping end is: The set compensation temperature of the heating plate The calculation formula is expressed as:

[0093] in, This indicates the set compensation temperature of the heating plate; This indicates the target operating temperature required for the bottom surface of the silicone hot stamping end; This indicates the downward output heat flow of the heating plate; This indicates that the multi-layer custom silicone mold has a combined thermal resistance in the vertical direction.

[0094] The central control unit will set the compensation temperature. This serves as the baseline control variable for the temperature control closed-loop mechanism. During operation, the temperature sensor continuously reads the actual physical temperature of the heating plate. The central control unit compares this actual physical temperature with the set compensation temperature. The central control unit calculates the temperature deviation at the current moment. Based on this temperature deviation, it adjusts the duty cycle of the pulse width modulation signal output to the external power actuator. The external power actuator receives this duty cycle signal and controls the on and off time ratio of the electric heating element, thereby dynamically adjusting the heating power.

[0095] When the actual physical temperature is lower than the set compensation temperature At this time, the central control unit increases the duty cycle of the pulse width modulation signal to enhance the heat output of the electric heating element. When the actual physical temperature exceeds the set compensation temperature... At this time, the central control unit reduces the duty cycle to reduce heat generation. This closed-loop control logic ensures a dynamic balance between heat output and heat loss, maintaining consistent heat-pressing parameters in the hot-stamping area on the packaging box surface.

[0096] For the solid-state relay drive circuit of the external power actuator in the temperature-controlled pressing assembly, the specific coding logic of the proportional-integral-derivative control algorithm for temperature deviation, and the mechanical transmission structure of the unwinding and rewinding machine for electroplated aluminum foil, those skilled in the art can configure them according to the standard of conventional industrial hot-pressing packaging equipment. The underlying hardware principles and conventional mathematical control models are well-known technologies in this field and will not be elaborated here.

[0097] See attached document Figure 5 The finished product inspection module is located downstream of the customized hot stamping repair module. This module inspects the surface quality of the packaging boxes after hot stamping repair, identifying any defects such as missed hot stamping, incomplete hot stamping, misalignment, or excess adhesive at the edges. The hardware configuration of the finished product inspection module includes a back-end industrial camera, a high-brightness coaxial light source, and a mistake-proof sorting mechanism.

[0098] The packaging box is transferred to the inspection station of the finished product inspection module via a transmission mechanism. A high-brightness coaxial light source illuminates a uniform parallel beam of light onto the repair area of ​​the packaging box. Due to the high reflectivity of the metal layer surface of the electroplated aluminum foil, while the surrounding unplated substrate surface exhibits diffuse reflection, the high-brightness coaxial light source enables the foil-plated areas in the image captured by the back-end industrial camera to appear bright, creating a clear grayscale contrast with the dark background. The back-end industrial camera captures the inspection image of the packaging box surface and transmits the inspection image data to the central control unit.

[0099] The central control unit performs threshold segmentation on the detected image data to extract the contour features and area parameters of the actual hot stamping pattern. The central control unit stores reference image data of the standard hot stamping effect. The system quantitatively evaluates the restoration quality by calculating the area deviation ratio and positional offset between the actual hot stamping pattern and the standard reference image. The actual extracted area value of the hot stamping pattern is set as... The standard hot stamping area value in the reference image is: Then the hot stamping area deviation rate The calculation formula is expressed as:

[0100] in, This indicates the deviation rate of the hot stamping area between the actual hot stamping image and the standard reference image. This indicates the actual area of ​​the hot stamping image extracted. This indicates the standard hot foil area value in the reference image.

[0101] At the same time, the geometric center coordinates of the actually extracted hot stamping image are set as follows: The geometric center coordinates of the standard hot stamping pattern in the reference image are: The actual offset of the center position of the hot stamping graphic. The calculation formula is expressed as:

[0102] in, This indicates the offset of the center position of the actual hot stamping image; The X-axis coordinates represent the geometric center of the actual extracted hot stamping graphic. The Y-axis coordinate representing the actual geometric center of the extracted hot stamping graphic; The X-axis coordinates represent the geometric center of the standard hot stamping pattern in the reference image; The Y-axis coordinate represents the geometric center of the standard hot stamping graphic in the reference image.

[0103] The central control unit is configured with a maximum permissible threshold for the hot stamping area deviation rate and a maximum permissible tolerance for the center position offset. These thresholds are entered during system initialization based on the acceptable quality limits for the production batch or customer-provided limit sample data. In this embodiment, the maximum permissible threshold for the hot stamping area deviation rate is typically set to 3% to 5%, and the maximum permissible tolerance for the center position offset is typically set to 0.1mm to 0.2mm. When the hot stamping area deviation rate... or center position offset When the corresponding set threshold is exceeded, the central control unit determines that the current packaging box is a defective product.

[0104] The error-proof sorting mechanism is located on the transmission path behind the inspection station. It includes a pneumatic rejection pusher and a waste collection trough. When the central control unit determines a package is defective, it sends an exclusion command to the error-proof sorting mechanism. The pneumatic rejection pusher then moves, pushing the defective package away from the normal transmission path and into the waste collection trough, achieving physical isolation and preventing defective products from flowing into subsequent packaging stages. If all parameters are within tolerance, the error-proof sorting mechanism remains stationary, and qualified packages flow out normally with the transmission mechanism.

[0105] For the image binarization segmentation algorithm of the back-end industrial camera, the delay control logic of the solenoid valve in the error prevention sorting mechanism, and the speed synchronization adjustment mechanism of the transmission mechanism, those skilled in the art can use conventional machine vision software libraries and programmable logic controllers for configuration. The underlying code of the algorithm and the control wiring method are well-known technologies in the field and will not be described in detail here.

[0106] Specific application examples: After mass production, some batches of high-end liquor packaging boxes exhibited printing defects in the special material pad printing and surface hot stamping. The system and method of this invention were used for automated repair. The repair process of this embodiment is described in detail below, combining specific formula calculations and system setting parameters: Step S1, Cleaning and Error Correction: The liquor packaging box to be repaired is fixed on a dust-free wiping worktable. The product clamping fixture activates the vacuum generator for limit locking. Based on the pressure formula... The contact area of ​​the customized pointed cotton swab (physical wiping component) used in this embodiment is... The central control unit presets the maximum permissible wiping pressure of the liquor box's base film to 0.2 MPa. The system adjusts the wiping drive mechanism to apply vertical downward pressure. Strictly controlled below 1.0N to ensure This ensures that the surrounding original graphics and substrate cardboard are not physically damaged when wiping away residual solvent.

[0107] Step S2, Visual Positioning and Correction: Activate the central control unit; the 2-megapixel industrial vision camera acquires images of the packaging box surface. Set the horizontal pixel count for the camera. Horizontal physical width According to the system optical resolution formula The system's optical resolution was calculated. This meets the accuracy tolerance requirements for correction. Through image template matching and calculation, the translational deviation of the current packaging box in the X-axis direction is obtained. Position translation deviation in the Y-axis direction The correction drive unit converts the above deviations into drive pulses for the servo motors based on the homogeneous transformation matrix, thereby completing the spatial position fine adjustment of the product support platform.

[0108] Step S3, Special Material Pad Printing: The central control unit sets the mechanical action parameters according to the 3x4mm micro-text to be repaired. The original spherical radius of the working surface of the pad printing silicone pad is known. Set the depth of compression deformation According to the formula The instantaneous contact area was calculated. To ensure uniform thickness transfer of the special ink, the actual contact pressure is set. From the formula The electric proportional valve needs to control the driving force output of the pad printing cylinder. Apply approximately 4.63N to precisely press the base ink onto the erasing area.

[0109] Step S4, UV curing: The packaging box is transferred to the UV curing module. The cumulative radiation energy of the special ink used in this embodiment is known. Average irradiation intensity of local UV light source According to the simplified integral formula The central control unit calculates the total irradiation time. After 10 seconds of local curing, the resin molecules inside the base ink are completely cross-linked and set.

[0110] Step S5, Surface Hot Stamping: The cured packaging box enters the customized hot stamping repair module. A customized hot stamping mold made of 70°C high-temperature resistant silicone is installed. This ensures that the silicone hot stamping end face meets the melting requirements of the electroplated aluminum resin film (target working temperature). ), combined with the comprehensive thermal resistance in the vertical direction of the multi-layered custom silicone mold From the heat conduction model formula The central control unit automatically adjusts the set compensation temperature of the heating plate of the temperature-controlled pressing assembly. Set the temperature to 135℃. Apply an actual hot stamping pressure of 0.3MPa and continue hot pressing for 4 seconds to complete the surface metallization repair of the hot stamping image.

[0111] A coaxial light source illuminates the repair area with a parallel beam, while a rear-end industrial camera captures the inspection image and transmits it to the central control unit. The central control unit performs threshold segmentation on the image to extract the actual hot stamping graphic features.

[0112] In the single repair calculation of this embodiment, the standard hot stamping area value in the reference image pre-stored by the system is set. The geometric center coordinates are .

[0113] The actual area value of the restored image extracted by the camera The actual geometric center coordinates are .

[0114] According to the area deviation formula The deviation rate of the hot stamping area of ​​the current packaging box is calculated. .

[0115] According to the position offset formula The offset of the center position is calculated. .

[0116] The central control unit compares the calculation results with the system-set thresholds: Currently ≤ Maximum allowable threshold (5%), and Maximum permissible tolerance (0.1mm). If the system determines the repaired box is acceptable, the error-proof sorting mechanism remains stationary, and the box is released for final packing. If any of the above indicators exceeds the limit, the pneumatic rejection rack will activate, pushing the defective product into the waste collection trough for physical isolation.

[0117] To verify the accuracy and stability of the system in batch repair operations, 100 high-end liquor boxes with printing defects from the same batch were selected for a comparative experiment. These boxes were randomly divided into two groups of 50 samples each. Control group (traditional repair system): The system uses manual visual alignment, ordinary constant pressure transfer printing and constant temperature heating plate blind hot stamping process.

[0118] Experimental group (system of this invention): The automated analysis and repair system with visual positioning correction, constant pressure transfer printing closed loop and temperature control closed loop as described in the above embodiments is used.

[0119] After the repair is completed, the industrial camera at the back end of the finished product inspection module captures images, which are then substituted into the following two core formulas for quantitative comparison and evaluation. The experimental results are shown in the appendix. Figure 6 With appendix Figure 7 As shown.

[0120] According to the formula Calculate the center position offset of the actual hot stamping pattern for each sample.

[0121] See attached document Figure 6 The horizontal axis represents the "sample number" participating in the test, with values ​​ranging from 1 to 50; the vertical axis represents the calculated "center position offset", in millimeters (mm).

[0122] The black solid line and circle mark represent the data distribution of 50 samples repaired using the system of this invention. It can be seen that, relying on machine vision and servo fine-tuning, the offset has always remained at an extremely low level (mainly concentrated between 0.02mm and 0.08mm).

[0123] The black dashed line and cross mark represent the data distribution of 50 samples restored using a traditional restoration system. Due to the cumulative error of manual alignment, the offset fluctuates drastically, with some samples even reaching 0.25 mm.

[0124] The black dotted line represents the preset "maximum allowable tolerance (0.1mm)" in the central control unit. When the data point is below the dotted line, it is judged as a qualified product. It can be seen that all data points generated by the system of this invention are within the qualified area.

[0125] The reason for the above differences lies in whether the system has closed-loop visual correction and mechanical compensation capabilities.

[0126] The shortcomings of traditional systems: Traditional methods mainly rely on manual alignment by visually observing the edges or remaining features of the packaging box. Due to visual fatigue of the human eye and random errors in manual placement, the initial position is not accurate enough; in addition, the lack of dynamic position correction during the repair process means that even slight mechanical vibrations can cause the final hot-pressed position to shift by tens or even hundreds of micrometers (more than 0.1mm).

[0127] Advantages of this invention: This invention introduces a high-precision visual positioning and correction module. Before each operation, the industrial camera captures images, and features are accurately extracted using a template matching algorithm, strictly following the pose difference formula (solved by...). , and The coordinate deviation is calculated. Then, the central control unit converts the deviation into drive pulses for the servo motors, directing the three-axis fine-tuning positioning platform to perform reverse physical compensation. Simultaneously, a secondary verification is performed using an infrared photoelectric sensor, constructing a closed-loop control chain of detection, calculation, compensation, and verification. This eliminates alignment errors and minimizes the center position offset. It remains within 0.1mm.

[0128] According to the formula Calculate the deviation rate of the hot foil area for each sample's actual hot foil design.

[0129] See attached document Figure 7 The horizontal axis represents the "sample number" participating in the test, with values ​​ranging from 1 to 50; the vertical axis represents the calculated "hot foil area deviation rate", in percentage (%).

[0130] The solid black lines and circled markings represent sample data repaired using the system of this invention. Thanks to the constant pressure pad printing control mechanism and dynamic temperature control compensation, the transfer of special inks and the adhesion of electroplated aluminum are relatively uniform, and the hot stamping area deviation rate is stably controlled between 1.0% and 4.5%.

[0131] The black dashed lines and crosses represent sample data restored using traditional restoration systems. Due to limitations in mechanical initial pressure and heat dissipation, glue overflow or incomplete printing often occurs, resulting in significant fluctuations in the hot stamping area deviation rate, with most samples ranging from 5% to 12%.

[0132] The black dotted line represents the preset "maximum allowable threshold (5%)" in the central control unit. As shown in the figure, the traditional repair system has a large number of unqualified intercepted items that exceed this threshold, while most samples in the system of this invention are controlled within the threshold.

[0133] The area deviation rate directly depends on the uniformity of pad printing ink coating and the consistency of temperature and pressure during hot stamping.

[0134] The shortcomings of traditional systems: Traditional equipment mostly adopts a blind pressure mode with a constant thrust output from a cylinder. On the one hand, when the pad printing head presses down, if it encounters a slight tolerance in the thickness of the packaging cardboard, the actual contact pressure will change, resulting in inconsistent ink transfer. On the other hand, there is thermal resistance when the temperature of the heating plate is conducted to the mold surface. Traditional equipment does not have dynamic temperature compensation, which causes the mold surface temperature to drop during continuous operation, resulting in uneven melting of the electroplated aluminum resin film. Ultimately, this manifests as rough edges, overflow, or defects in the repaired graphics.

[0135] Advantages of this invention: This invention employs a dual closed-loop protection mechanism. First, a constant-pressure pad printing control mechanism is introduced in the pad printing section. A pressure sensor monitors the actual thrust in real time, and an electric proportional valve dynamically adjusts the air pressure to ensure that the contact pressure between the pad printing head and the surface of the packaging box is always maintained at the target value, guaranteeing the consistency of the special base ink transfer area. Second, a multi-layer customized silicone mold and a steady-state thermal conduction compensation model are used in the hot stamping section. The system not only utilizes the elastic deformation of the silicone bottom end to cover the unevenness of the cardboard, but also considers the overall thermal resistance... A set compensation temperature higher than the target temperature was set. This ensures sufficient transient heat at the contact surface during continuous hot pressing. Precise control of pressure and temperature solves the problems of excessive extrusion or insufficient fusion of the resin film, thereby reducing the deviation rate of the hot stamping area. Keep it below 5%.

[0136] From the appendix Figure 6 and attached Figure 7 It can be seen that a large number of samples using the traditional repair system exceeded the standard. In contrast, the system of this invention showed higher stability and yield in continuous operation (48 out of 50 samples met the standard, with a front-end repair yield of 96%).

[0137] It is worth noting that the data points of samples No. 17 and No. 42 slightly exceeded the preset maximum allowable tolerance (0.1 mm) and maximum allowable threshold (5%). Further analysis revealed that this was due to occasional physical deformation caused by a severe localized change in the thickness of the base cardboard. However, thanks to the closed-loop visual verification mechanism of the finished product inspection module in step S6 of this invention, these two occasional non-conforming products were accurately identified at the end of the production line and physically isolated to the waste bin by a pneumatic rejection pusher, preventing them from entering the next packing process. This demonstrates that the systematic design of high-precision closed-loop control at the front end and visual error-tolerant interception at the end, proposed in this invention, not only improves the initial repair yield but also ensures the final pass rate of the finished products, possessing significant industrial practical value.

Claims

1. A system for analyzing and repairing erroneous text on the surface of finished packaging boxes, characterized in that, include: The cleaning and error removal module is used to remove erroneous hot stamping graphics from the surface of the packaging box, clean the base surface of the area to be repaired on the packaging box, and output the cleaned packaging box. The visual positioning and correction module is used to acquire reference feature images of the cleaned packaging box surface and perform position verification. It transmits the acquired image signals and position feedback signals to the central control unit, which outputs displacement compensation commands according to the built-in algorithm. A special material pad printing module is used to carry the cleaned packaging box, receive the displacement compensation command and adjust the physical position of the cleaned packaging box. After the spatial position is locked, the special material pad printing module is controlled by the central control unit to transfer special ink to the area to be repaired, and generate a packaging box with special ink transferred on its surface. A UV curing module is used to receive the packaging box with special ink transferred to its surface. The UV curing module is controlled by the electrical signal of the central control unit to perform UV curing treatment on the transferred special ink to generate a cured packaging box. A customized hot stamping repair module is used to receive the cured packaging box and perform hot stamping on the surface of a special ink layer that has undergone light curing, according to the set pressure and temperature parameters.

2. The system for analyzing and repairing erroneous text on the surface of a finished packaging box according to claim 1, characterized in that, The cleaning and error removal module includes a product clamping fixture and a solvent treatment component. The product clamping fixture physically limits and fixes the packaging box. The solvent treatment assembly includes a storage tank, a micro-drip valve, a wiping drive mechanism, and a physical wiping component; The micro-drip valve drips the erasing solvent stored in the reservoir onto the original hot stamping pattern surface; The physical wiping element is installed at the end of the wiping drive mechanism; The central control unit presets the maximum permissible wiping pressure based on the wear resistance parameters of the packaging box base film. The central control unit adjusts the vertical downward pressure applied to the physical wiping component by the wiping drive mechanism to ensure that the wiping pressure generated in the contact area between the physical wiping component and the surface of the packaging box is less than the maximum permissible wiping pressure.

3. The system for analyzing and repairing erroneous text on the surface of a finished packaging box according to claim 1, characterized in that, The visual positioning and correction module includes an industrial vision camera, an infrared positioning photoelectric sensor, and a correction drive unit. The industrial vision camera acquires images of the area to be repaired, obtaining two-dimensional image data of the current packaging box surface; After the infrared positioning photoelectric eye detects that the cleaned packaging box has entered the preset working plane, it sends a trigger level signal to the central control unit. The central control unit receives the trigger level signal and calculates the spatial pose difference between the reference features in the current image and the corresponding reference features in the reference template image through a template matching algorithm, thereby obtaining the position translation deviation of the packaging box in the X-axis direction, the position translation deviation of the packaging box in the Y-axis direction, and the rotation angle deviation of the packaging box around the Z-axis.

4. The system for analyzing and repairing erroneous text on the surface of a finished packaging box according to claim 3, characterized in that, The correction drive unit adopts a three-axis fine-tuning positioning platform, which includes an X-axis servo motor, a Y-axis servo motor, a rotary servo motor, and a transmission screw assembly. The central control unit receives the position translation deviation and the rotation angle deviation, calculates the inverse compensation motion parameters, parses the target position coordinates and converts them into motor drive pulse counts, and then synchronously sends the motor drive pulse counts to the X-axis servo motor, the Y-axis servo motor and the rotary servo motor. Each servo motor drives the transmission screw assembly to move the cleaned packaging box to the target position coordinates.

5. The system for analyzing and repairing erroneous text on the surface of a finished packaging box according to claim 1, characterized in that, The special material pad printing module is equipped with a product support platform and a pad printing machine, and the pad printing machine includes an ink supply component, an image carrier, and a pad printing transfer component. The product support platform carries the cleaned packaging box; The pad printing transfer assembly includes a pad printing head and a multi-axis displacement mechanism; The central control unit pre-determines the instantaneous contact area required for the area to be repaired based on the physical size parameters of the area to be repaired, and calculates the corresponding downward deformation depth by combining the original spherical radius of the working surface at the bottom of the pad printing head. The multi-axis displacement mechanism receives the position control command corresponding to the downward deformation depth and drives the pad printing head to press against the area to be repaired.

6. The system for analyzing and repairing erroneous text on the surface of a finished packaging box according to claim 5, characterized in that, The special material pad printing module is equipped with a constant pressure pad printing control mechanism, which includes a pad printing cylinder, an electric proportional valve, and a pressure sensor. The pressure sensor detects the actual physical pressure applied by the pad printing cylinder to the pad printing head in real time, and feeds back the collected analog pressure signal to the central control unit. The central control unit calculates the theoretical target driving force based on the set target contact pressure and the instantaneous contact area, and outputs an analog control signal to the electro-proportional valve. The electro-proportional valve adjusts the compressed air pressure entering the pad printing cylinder according to the received analog control signal, so that the actual contact pressure of the pad printing head on the contact plane is dynamically maintained within the set tolerance range of the target contact pressure value.

7. The system for analyzing and repairing erroneous text on the surface of a finished packaging box according to claim 1, characterized in that, The UV curing module includes a local UV light source, a light source focusing component, and a light source power controller; The central control unit reads the average irradiation intensity set by the local UV light source and calculates the target irradiation time by combining it with the preset radiation energy threshold. When the packaging box with special ink transferred on its surface reaches the working area of ​​the UV curing module, the central control unit sends a start electrical signal to the light source power controller, and the light source power controller drives the local UV light source to output ultraviolet radiation. After the total irradiation time of the local UV light source reaches the target irradiation time, the central control unit sends a power-off signal to stop the radiation operation.

8. The system for analyzing and repairing erroneous text on the surface of a finished packaging box according to claim 1, characterized in that, The customized hot stamping repair module includes a temperature-controlled pressing component and a multi-layer customized silicone mold; The multi-layered customized silicone mold is composed of an aluminum substrate layer, a base adhesive layer, a sloping connecting end, and a silicone hot stamping end, stacked from top to bottom. The temperature-controlled pressing assembly is equipped with an electric heating element and a temperature sensor. The central control unit calculates the set compensation temperature of the heating plate based on the steady-state heat conduction model, combined with the target working temperature required by the bottom surface of the silicone hot stamping end, the downward output heat flow of the heating plate, and the comprehensive thermal resistance of the multi-layer customized silicone mold in the vertical direction. The central control unit compares the actual physical temperature read by the temperature sensor with the set compensation temperature, calculates the temperature deviation value at the current moment, adjusts the duty cycle of the pulse width modulation signal output to the external power execution element, and dynamically adjusts the heating power.

9. The system for analyzing and repairing erroneous text on the surface of a finished packaging box according to claim 1, characterized in that, The analysis and repair system also includes a finished product inspection module, which is located in the downstream section of the customized hot stamping repair module; The finished product inspection module includes a back-end industrial camera, a high-brightness coaxial light source, and a mistake-proof sorting mechanism. The high-brightness coaxial light source irradiates a uniform parallel beam onto the repaired area of ​​the cured packaging box, and the rear-end industrial camera captures the detection image of the packaging box surface and transmits the detection image data to the central control unit. The central control unit extracts the contour features and area parameters of the actual hot stamping pattern, and calculates the hot stamping area deviation rate and the center position offset of the actual hot stamping pattern between the actual hot stamping pattern and the standard reference image. When the hot stamping area deviation rate or the center position offset exceeds the set maximum allowable threshold or maximum allowable tolerance, the central control unit sends an exclusive command to the error prevention sorting mechanism, and the pneumatic rejection pusher moves to push the unqualified packaging box out of the normal transmission route.

10. A method for analyzing and repairing erroneous text on the surface of a finished packaging box, characterized in that, An analysis and repair system for erroneous text on the surface of a finished packaging box, as described in any one of claims 1-9, comprises the following steps: The packaging box to be repaired is fixed to the cleaning and error removal module, the erroneous hot stamping graphics on the surface of the packaging box are removed, the base surface of the area to be repaired of the packaging box is cleaned, and a cleaned packaging box is generated. The cleaned packaging box is transferred to the special material pad printing module. The visual positioning and correction module acquires the reference feature image of the surface of the cleaned packaging box. The central control unit calculates the coordinate deviation and drives the special material pad printing module to adjust the spatial position. The position is checked simultaneously to generate a packaging box with the spatial position locked. The central control unit triggers the mechanical action of the special material pad printing module to transfer the special ink to the repair area on the surface of the packaging box after the spatial position is locked, thereby generating a packaging box with the special ink transferred to its surface. The packaging box with special ink transferred to its surface is transferred to the working area of ​​the UV curing module. The central control unit turns on the UV light source to perform photocuring treatment on the transferred special ink, generating a cured packaging box. The cured packaging box enters the customized hot stamping repair module. The visual positioning and correction module performs secondary positioning and correction verification. The customized hot stamping repair module performs hot stamping on the surface of the cured packaging box repair area according to the set pressure and temperature parameters to generate a packaging box with completed hot stamping. The packaging box after the hot stamping operation is completed is output to the finished product inspection station. The inspection equipment verifies the graphic position tolerance and surface adhesion status of the repair area of ​​the packaging box after the hot stamping operation. The repair system analyzes and records the inspection data and performs the release of qualified products or the interception of unqualified products.

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