Plastic cover ultrasonic welding and top side gold stamping linkage processing technology

Abstract

The application discloses a plastic cover ultrasonic welding and top side gold stamping linkage processing technology, which takes the inner stopper / inner thread of a plastic cover as the only clamping reference, realizes one-time clamping full-process processing through multi-station continuous circulation, and comprises six processes of reference unified clamping, ultrasonic welding, welding stress online elimination, gold stamping base material preheating, top side integrated synchronous gold stamping, online visual quality detection and blanking sorting. The whole-process linkage closed loop is realized through central timing control, and the stress elimination and gold stamping preheating are cooperatively controlled by utilizing welding residual heat. The application completely solves the core pain points of traditional process dispersion, large positioning cumulative error caused by multiple clamping, low product qualification rate, low production efficiency and high energy consumption, realizes full-process linkage processing of plastic cover welding and gold stamping, and significantly improves production efficiency. The application can be widely applied to the automatic and standardized processing of various plastic bottle caps in the fields of food, medicine and daily chemical products.

Description

Technical Field

[0001] This invention belongs to the field of plastic packaging processing technology, specifically involving a process for ultrasonic welding of plastic caps and hot stamping on the top side. Background Technology

[0002] In the food, beverage, pharmaceutical, and daily chemical industries, plastic bottle caps (referred to as plastic caps) are core functional components of packaging containers. Their processing quality directly determines the sealing performance, safety, and appearance quality of the packaging. The conventional industrial processing flow for plastic caps is: injection molding → ultrasonic welding → transfer and handling → hot stamping of top pattern → transfer and handling → hot stamping of side circumferential pattern → manual full inspection → finished product warehousing. The entire process involves multiple completely independent and decentralized processes. In long-term industrial application, the existing processing technology has gradually exposed many unsolvable core defects and industry pain points: In the existing processing technology, ultrasonic welding and hot stamping are two completely independent processes. Furthermore, top and side hot stamping require separate processes. From injection molding to finished product, a single plastic cap needs to go through at least four independent processes and more than three transfers and clamping / positioning operations. The current multi-process technology can only achieve a single-shift capacity of 40,000-50,000 pieces, with a long production cycle. It requires at least 3-4 operators to oversee multiple processes, resulting in extremely high labor costs. Simultaneously, the dispersed processes lead to the need for a large number of turnover boxes for storing and transferring semi-finished products, resulting in high inventory levels, significant capital tied up, and multiple production lines required for multiple processes, leading to extremely low workshop space utilization. The overall production cost is more than twice that of continuous processing.

[0003] Plastic caps are thin-walled injection molded parts, with a typical wall thickness of only 0.8-1.5mm. Repeated clamping can easily cause deformation of the thin walls of the plastic caps. Furthermore, the positioning references for each process in the current process are completely inconsistent: the ultrasonic welding process uses the outer circle of the plastic cap as the positioning reference, the hot stamping on the top surface uses the edge of the top surface of the plastic cap as the positioning reference, and the hot stamping on the side uses the inner hole of the plastic cap as the positioning reference. The misalignment of the references leads to the continuous accumulation of positioning errors. Plastic caps produced by the current process generally have a coaxiality deviation of more than 0.1mm for welded parts and a registration deviation of more than 0.1mm for hot stamping patterns. This easily results in appearance defects such as pattern misalignment, broken gold, missing gold, and misaligned seams. The overall product pass rate is only 80%-85%, and a large number of defective products cause serious waste of raw materials. Especially for products with extremely high requirements for appearance precision, such as pharmaceutical oral liquid caps and high-end beverage anti-theft caps, the defect rate of the current process even exceeds 20%, which is completely unable to meet the quality requirements of the high-end market.

[0004] In existing processes, ultrasonic welding and hot stamping are completely separate. After prolonged handling, the internal stress generated during welding is completely released, making the caps highly susceptible to warping and flatness defects. This results in uneven substrate surfaces during subsequent hot stamping, leading to poor adhesion and easy peeling. Furthermore, the significant residual heat generated during welding is completely dissipated during handling, requiring the caps to be reheated for hot stamping. This not only wastes energy but also causes secondary deformation due to uneven reheating, further exacerbating product quality fluctuations. Caps produced using existing processes have a hot stamping layer that withstands less than 200 abrasion cycles and less than 30 rubs with 75% alcohol, failing to meet the high-performance requirements of food and pharmaceutical packaging for sterilization and transport abrasion resistance. This leads to hot stamping layer peeling during the product's shelf life, causing serious market complaints and brand damage.

[0005] In the existing decentralized processes, the process parameters of each process are set independently without unified closed-loop control. Quality defects in the previous process cannot be fed back to the subsequent process in real time, and parameters cannot be adjusted in real time, resulting in the continuous generation of defective products. They can only be removed by manual full inspection in the final stage, which is not only costly in terms of labor but also poses a serious risk of missed inspections. At the same time, the production data of each process is statistically analyzed independently, making it impossible to achieve full-process quality traceability for a single product, which is completely unsuitable for the production management requirements of modern intelligent factories.

[0006] Therefore, the industry urgently needs a plastic cap processing technology that can achieve full-process linkage, unified benchmarks, and closed-loop control to fundamentally solve the aforementioned core pain points of existing processes. Summary of the Invention

[0007] To address the problems raised in the background technology, the purpose of this invention is to provide a process for ultrasonic welding and hot stamping of plastic caps, solving the problem of cumulative positioning errors caused by multiple clamping operations in existing processes; to solve the problems of dispersed processes, mismatched cycle times, and low production efficiency through synchronous linkage of the entire process sequence; to achieve integrated control of stress relief and hot stamping preheating through the synergistic utilization of welding residual heat, solving the problems of plastic cap deformation, poor hot stamping layer adhesion, and high energy consumption; and to achieve closed-loop quality control of the entire process through online visual inspection, ultimately realizing continuous, automated, and standardized production of plastic caps, significantly improving production efficiency and product quality, and reducing production costs and energy consumption.

[0008] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows: The ultrasonic welding and hot stamping process for the plastic cap includes the following integrated processing steps: S1 uses its inner stop or internal thread as the sole clamping reference to position and lock the plastic cap to be processed. After clamping, the plastic cap remains locked and this reference is used as the unified processing reference for all subsequent processes. S2 transfers the clamped plastic cap to the welding process. Based on the plastic cap material and welding structure, the welding process parameters are preset to complete the ultrasonic welding of the plastic cap and the part to be welded. After welding, pressure holding and cooling are performed simultaneously. The pressure holding time is perfectly matched with the single station turnover cycle. During the welding process, the plastic cap is kept in a locked state, and the welding processing reference is completely coincident with the clamping reference. S3 transfers the welded plastic cap to the temperature control process, using the residual heat generated by ultrasonic welding to perform temperature control treatment on the plastic cap using a stepped constant temperature control process. S4 transfers the temperature-controlled plastic cap to the hot stamping process, using the clamping reference as the hot stamping positioning reference, and simultaneously completes the hot stamping processing of the top surface pattern and the side circumference pattern of the plastic cap. The S5 transfers the hot-stamped plastic caps to the inspection process. It simultaneously acquires full-area images of the top and sides of the plastic caps through dual-view visual acquisition, and performs real-time analysis on welding quality, hot-stamping pattern integrity, overprinting accuracy, and adhesion pre-inspection indicators to accurately identify qualified and unqualified products. S6 transfers the inspected plastic caps to the unloading process. Based on the online visual inspection results, it automatically sorts qualified and unqualified products. Qualified products are transported to the finished product collection stage, while unqualified products are transported to the waste collection stage.

[0009] Further specifying that in S2, the ultrasonic welding process differentially adjusts the welding frequency, amplitude, welding pressure, welding time, and holding pressure time parameters according to the different materials of the plastic cap substrate; the holding pressure cooling stage adopts a gradient cooling process to cool the welding area of ​​the plastic cap, and the temperature of the welding area is collected in real time during the cooling process. When the temperature drops below the heat distortion temperature of the substrate, the holding pressure cooling ends; at the same time, through the dual-parameter closed-loop control of welding displacement and welding pressure, the system automatically switches to the holding pressure state when the welding displacement reaches a preset threshold.

[0010] Further specifying the requirements for PP plastic caps, the ultrasonic welding frequency should be controlled at 15-25kHz, amplitude at 15-45μm, welding pressure at 0.2-0.7MPa, welding time at 0.1-1.0s, and holding time at 0.2-1.2s. For PE plastic caps, control the ultrasonic welding frequency to 18-35kHz, amplitude to 10-35μm, welding pressure to 0.1-0.6MPa, welding time to 0.1-0.8s, and holding time to 0.1-1.0s. For PET plastic caps, control the ultrasonic welding frequency to 25-45kHz, amplitude to 5-30μm, welding pressure to 0.15-0.65MPa, welding time to 0.05-0.6s, and holding time to 0.15-1.0s.

[0011] Furthermore, in S3, the stepped constant temperature control process uses a composite control method of hot air circulation and infrared heat compensation to adjust the temperature of the plastic cover. The heat preservation time of the stress relief stage is matched with the single-station turnover cycle. The preheating temperature of the hot stamping preheating stage is adjusted according to the material of the plastic cover substrate. The temperature difference between the top surface and the side hot stamping area of ​​the plastic cover is ≤5℃. The stepped constant temperature control process is divided into a first stage and a second stage. In the first stage, the temperature of the plastic cap is stabilized at 2-20℃ below the glass transition temperature (Tg) of the substrate, and the holding time is 0.5-2.5s. In the second stage, the preheating temperature is controlled at 50-80℃ for PP plastic caps, 40-70℃ for PE plastic caps, and 55-85℃ for PET plastic caps. During the composite control process, the hot air velocity is controlled at 1-6m / s, the hot air temperature is controlled at 35-85℃, and the temperature control accuracy of infrared heat compensation is ±2℃.

[0012] Further specified, in S4, during the hot stamping process, the rotation speed of the plastic cap around its own axis is controlled to be 3-20 r / min, and the hot stamping temperature, hot stamping pressure and holding time of the top surface and the side surface are independently controlled. During the side hot stamping process, the linear speed of the side hot stamping is controlled to be synchronized with the circumferential rotation linear speed of the plastic cap. The hot stamping temperature on the top surface is controlled at 85-135℃, the hot stamping pressure at 0.08-0.35MPa, and the hot stamping holding time at 0.2-1.2s; the hot stamping temperature on the sides is controlled at 80-130℃, and the hot stamping pressure at 0.1-0.4MPa.

[0013] Further specifying that in S5, an area array camera is used to acquire a full-area image of the top surface of the plastic cover, and a line array camera is used in conjunction with the uniform rotation of the plastic cover to acquire a 360° circumferential full-area image of the side surface of the plastic cover. Based on a deep learning algorithm, the acquired images are analyzed in real time, and the detection content includes defects such as poor welding, overflow, insufficient material, and weld penetration in the welding area, as well as defects such as misregistration of hot stamping patterns, broken gold, missing gold, scratches, color difference, and misalignment of seams.

[0014] Furthermore, between S4 and S5, a hot stamping post-processing step is provided, specifically: the hot-stamped plastic cap is first subjected to UV curing treatment, and after curing, ion wind is used to perform non-contact dust removal treatment on the surface of the plastic cap.

[0015] Further specified, the UV curing treatment controls the main wavelength to 360-410nm, the curing energy to 700-1600mJ / cm², and the curing time to 0.4-1.6s; the ion wind dust removal treatment controls the ion wind output pressure to 0.08-0.35MPa and the dust removal time to 0.2-1.0s.

[0016] Furthermore, before the integrated hot stamping process on the top side of S4, a hot stamping pre-positioning and alignment process is set up. Specifically, the position of the reference mark point on the surface of the plastic cover is collected by visual pre-positioning, and the rotation angle of the plastic cover and the starting position of the hot stamping process are adjusted according to the coordinates of the reference mark point to achieve pre-positioning and alignment of the hot stamping pattern. For the pattern seam of the side circumferential hot stamping, the accuracy of the pattern seam is ensured by the closed-loop control of the rotation angle of the plastic cover.

[0017] Further specified, the positioning accuracy of the hot stamping pre-alignment is ≤0.05mm, and the deviation of the pattern seam of the side circumferential hot stamping is ≤0.05mm.

[0018] The beneficial effects of this invention are: This invention, through a unified process design across the entire workflow, eliminates the cumulative positioning errors caused by multiple clamping operations and misaligned reference points in traditional processes. This significantly improves the coaxiality accuracy of plastic cap welding and the registration accuracy of hot stamping patterns, resulting in a qualitative improvement in overall product pass rate and quality stability. Simultaneously, through the synergistic control of welding stress relief and hot stamping preheating, it effectively avoids warping and deformation during plastic cap processing, greatly enhancing the adhesion, abrasion resistance, and media wiping resistance of the hot stamping layer. This ensures the final product meets the stringent quality requirements of high-end food and pharmaceutical packaging. Furthermore, by efficiently utilizing the residual heat from ultrasonic welding, this invention reduces the energy consumption of repeated heating in the hot stamping process. A single production line replaces multiple independent processing devices, eliminating standby energy consumption and significantly reducing overall production energy consumption. In addition, the centralized process design enables centralized collection and treatment of dust and waste foil during processing, significantly reducing dust concentration in the workshop and fully complying with the environmental protection requirements of green production.

[0019] The process parameters of this invention can be flexibly adjusted according to different substrates and plastic caps of different specifications, making it easy to change models and adaptable to the processing needs of plastic caps in various food, pharmaceutical, and daily chemical fields, with extremely strong process adaptability. At the same time, this process can be directly connected to the production cycle of plastic cap injection molding, realizing unmanned continuous production of the entire process of injection molding, welding, hot stamping, and testing. Process data can achieve full-process traceability of single products, and can be seamlessly integrated into the production system of intelligent factories, possessing extremely high industrial application value. Attached Figure Description

[0020] The present invention can be further illustrated by the non-limiting embodiments given in the accompanying drawings; Figure 1 This is a flowchart illustrating the steps of an embodiment of the ultrasonic welding and hot stamping process for the plastic cap of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments. 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0022] like Figure 1 As shown, the ultrasonic welding and hot stamping process for the plastic cap of the present invention includes the following fully integrated processing steps: S1 uses its inner stop or internal thread as the sole clamping reference to position and lock the plastic cap to be processed. After clamping, the plastic cap remains locked and this reference is used as the unified processing reference for all subsequent processes. S2 transfers the clamped plastic cap to the welding process. Based on the plastic cap material and welding structure, the welding process parameters are preset to complete the ultrasonic welding of the plastic cap and the part to be welded. After welding, pressure holding and cooling are performed simultaneously. The pressure holding time is perfectly matched with the single station turnover cycle. During the welding process, the plastic cap is kept in a locked state, and the welding processing reference is completely coincident with the clamping reference. S3 transfers the welded plastic cap to the temperature control process, using the residual heat generated by ultrasonic welding to perform temperature control treatment on the plastic cap using a stepped constant temperature control process. S4 transfers the temperature-controlled plastic cap to the hot stamping process, using the clamping reference as the hot stamping positioning reference, and simultaneously completes the hot stamping processing of the top surface pattern and the side circumference pattern of the plastic cap. The S5 transfers the hot-stamped plastic caps to the inspection process. It simultaneously acquires full-area images of the top and sides of the plastic caps through dual-view visual acquisition, and performs real-time analysis on welding quality, hot-stamping pattern integrity, overprinting accuracy, and adhesion pre-inspection indicators to accurately identify qualified and unqualified products. S6 transfers the inspected plastic caps to the unloading process. Based on the online visual inspection results, it automatically sorts qualified and unqualified products. Qualified products are transported to the finished product collection stage, while unqualified products are transported to the waste collection stage.

[0023] In the practical application of this embodiment, in step S2, the ultrasonic welding process differentially adjusts the welding frequency, amplitude, welding pressure, welding time, and holding pressure time parameters according to the different materials of the plastic cap substrate; the holding pressure cooling stage adopts a gradient cooling process to cool the welding area of ​​the plastic cap, and the temperature of the welding area is collected in real time during the cooling process. When the temperature drops below the heat distortion temperature of the substrate, the holding pressure cooling ends; at the same time, through the dual-parameter closed-loop control of welding displacement and welding pressure, the system automatically switches to the holding pressure state when the welding displacement reaches a preset threshold.

[0024] In the practical application of this embodiment, for PP plastic caps, the ultrasonic welding frequency is controlled at 15-25kHz, the amplitude at 15-45μm, the welding pressure at 0.2-0.7MPa, the welding time at 0.1-1.0s, and the holding time at 0.2-1.2s. For PE plastic caps, control the ultrasonic welding frequency to 18-35kHz, amplitude to 10-35μm, welding pressure to 0.1-0.6MPa, welding time to 0.1-0.8s, and holding time to 0.1-1.0s. For PET plastic caps, control the ultrasonic welding frequency to 25-45kHz, amplitude to 5-30μm, welding pressure to 0.15-0.65MPa, welding time to 0.05-0.6s, and holding time to 0.15-1.0s.

[0025] Furthermore, in S3, the stepped constant temperature control process uses a composite control method of hot air circulation and infrared heat compensation to adjust the temperature of the plastic cover. The heat preservation time of the stress relief stage is matched with the single-station turnover cycle. The preheating temperature of the hot stamping preheating stage is adjusted according to the material of the plastic cover substrate. The temperature difference between the top surface and the side hot stamping area of ​​the plastic cover is ≤5℃. The stepped constant temperature control process is divided into a first stage and a second stage. In the first stage, the temperature of the plastic cap is stabilized at 2-20℃ below the glass transition temperature (Tg) of the substrate, and the holding time is 0.5-2.5s. In the second stage, the preheating temperature is controlled at 50-80℃ for PP plastic caps, 40-70℃ for PE plastic caps, and 55-85℃ for PET plastic caps. During the composite control process, the hot air velocity is controlled at 1-6m / s, the hot air temperature is controlled at 35-85℃, and the temperature control accuracy of infrared heat compensation is ±2℃.

[0026] In the practical application of this embodiment, in S4, the rotation speed of the plastic cap around its own axis is controlled to be 3-20 r / min during the hot stamping process. The hot stamping temperature, hot stamping pressure and holding time of the top surface and the side surface are independently controlled. During the side hot stamping process, the linear speed of the side hot stamping is controlled to be synchronized with the circumferential rotation linear speed of the plastic cap. The hot stamping temperature on the top surface is controlled at 85-135℃, the hot stamping pressure at 0.08-0.35MPa, and the hot stamping holding time at 0.2-1.2s; the hot stamping temperature on the sides is controlled at 80-130℃, and the hot stamping pressure at 0.1-0.4MPa.

[0027] In the practical application of this embodiment, in step S5, an area array camera is used to acquire a full-area image of the top surface of the plastic cover, and a line array camera is used in conjunction with the uniform rotation of the plastic cover to acquire a 360° circumferential full-area image of the side surface of the plastic cover. The acquired images are analyzed in real time based on a deep learning algorithm. The detection content includes defects such as poor welding, overflow, insufficient material, and burn-through in the welding area, as well as defects such as misregistration of hot stamping patterns, broken gold, missing gold, scratches, color difference, and misalignment of seams.

[0028] In the practical application of this embodiment, a hot stamping post-processing step is also provided between S4 and S5. Specifically, the hot stamped plastic cap is first subjected to UV curing treatment, and after curing, the surface of the plastic cap is subjected to non-contact dust removal treatment by ion wind.

[0029] In the practical application of this embodiment, the UV curing treatment controls the main wavelength to 360-410nm, the curing energy to 700-1600mJ / cm², and the curing time to 0.4-1.6s; the ion wind dust removal treatment controls the ion wind output pressure to 0.08-0.35MPa and the dust removal time to 0.2-1.0s.

[0030] In the practical application of this embodiment, before the top and side integrated hot stamping process of S4, a hot stamping pre-positioning and registration process is also set up. Specifically, the position of the reference mark point on the surface of the plastic cover is collected by visual pre-positioning, and the rotation angle of the plastic cover and the starting position of the hot stamping process are adjusted according to the coordinates of the reference mark point to realize the pre-positioning and registration of the hot stamping pattern; for the pattern seam of the side circumferential hot stamping, the pattern seam accuracy is ensured by the closed-loop control of the rotation angle of the plastic cover.

[0031] In the practical application of this embodiment, the positioning accuracy of the hot stamping pre-positioning and registration is ≤0.05mm, and the deviation of the pattern seam of the side circumferential hot stamping is ≤0.05mm.

[0032] The present invention will be further described in detail below with reference to specific embodiments and comparative examples. The processing objects of all embodiments and comparative examples of the present invention are 38mm diameter PP material food and beverage anti-theft caps, and the accessories to be welded are PE sealing gaskets. The processing requirements are: the gaskets are welded with no leakage, the brand logo on the top surface is hot stamped with gold, the anti-counterfeiting pattern on the side is hot stamped with gold, and the hot stamping overprint accuracy is ≤0.05mm. Example

[0033] This embodiment employs the linkage processing technology of the present invention, and the specific process steps and parameters are as follows: S1 datum unified clamping: adopts 12-station intermittent indexing flow, single station cycle time 2.0s, indexing positioning accuracy ±3 arcseconds; uses the inner stop of the plastic cap as the only clamping datum, internal support locking, clamping force 0.35MPa, after clamping, the radial runout of the plastic cap ≤0.015mm, the axial positioning error ≤0.01mm, and maintains a locked state throughout the clamping process; S2 ultrasonic welding: welding frequency 20kHz, amplitude 30μm, welding pressure 0.45MPa, welding time 0.5s, holding time 0.6s, gradient cooling is used during the holding process, cooling rate 8℃ / s, and the holding state is automatically switched when the welding displacement reaches the preset threshold. S3 Stress Relief and Synergistic Preheating: Stepped constant temperature control, first stage stress relief, temperature 60℃, holding time 1.2s; second stage hot stamping preheating, temperature 65℃, control the temperature difference between the top and side surfaces ≤1℃; S4 Top and Side Integrated Synchronous Hot Stamping: Control the plastic cap rotation speed at 10 r / min, the top hot stamping temperature at 110℃, the hot stamping pressure at 0.2 MPa, and the holding time at 0.6 s; the side hot stamping temperature at 105℃, the hot stamping pressure at 0.25 MPa, and the synchronization error between the hot stamping line speed and the plastic cap circumferential line speed ≤ 0.3%; the unwinding tension of the hot stamping foil is 5 N, and the rewinding tension is 6 N. S5 hot stamping post-treatment: UV curing energy 1200mJ / cm², curing time 1.0s; ion wind pressure 0.2MPa, dust removal time 0.5s; S6 Online Visual Inspection: Uses a 20-megapixel area scan camera to capture top images and a 4096-dpi line scan camera to capture side images. The inspection time for a single plastic cap is 0.6 seconds, enabling real-time identification of defective products. S7 material unloading and sorting: Automatically sorts qualified and unqualified products based on the test results; The entire process is controlled in a time-series linkage manner through a central control system, with the indexing encoder signal as the synchronization reference.

[0034] This embodiment operates continuously for 8 hours, with a single-shift output of 144,000 pieces, a comprehensive product qualification rate of 99.62%, an average deviation of 0.022mm in hot stamping, a hot stamping layer adhesion grade of 0, a friction resistance of 580 times, and a resistance to 120 wipings with 75% alcohol without peeling off. The overall energy consumption is reduced by 48% compared to the traditional process. Example

[0035] This embodiment employs the linkage processing technology of the present invention. The object being processed is a 28mm diameter PE material oral liquid cap, and the component to be welded is a butyl rubber sealing inner plug. The specific process parameters are as follows: S1 standard unified clamping: adopts 8-station indexing flow, single station cycle time 1.5s, clamping force 0.25MPa, radial runout ≤0.01mm after clamping; S2 ultrasonic welding: welding frequency 25kHz, amplitude 20μm, welding pressure 0.3MPa, welding time 0.3s, holding time 0.4s, gradient cooling rate 6℃ / s; S3 Stress Relief and Synergistic Preheating: Stress release temperature 50℃, holding time 0.9s, hot stamping preheating temperature 55℃; S4 Top and Side Integrated Synchronous Hot Stamping: Plastic cap rotation speed 8r / min, top surface hot stamping temperature 100℃, pressure 0.15MPa, holding time 0.4s; side surface hot stamping temperature 95℃, pressure 0.2MPa; The remaining steps are the same as in Example 1, with full-process time-series linkage control.

[0036] This embodiment operates continuously for 8 hours, with a single-shift output of 192,000 pieces, a comprehensive product qualification rate of 99.71%, an average deviation of 0.018mm in hot stamping, a hot stamping layer adhesion grade of 0, and resistance to 150 wipings with 75% alcohol without peeling off, fully meeting the sterility and high stability requirements of pharmaceutical packaging. Example

[0037] This embodiment employs the linkage processing technology of the present invention. The processing object is a 50mm diameter PET daily chemical care cap, and the component to be welded is a PP guide nozzle. The specific process parameters are as follows: S1 standard unified clamping: adopts 16-station indexing flow, single-station cycle time 2.5s, clamping force 0.45MPa, radial runout ≤0.02mm after clamping; S2 ultrasonic welding: welding frequency 35kHz, amplitude 20μm, welding pressure 0.5MPa, welding time 0.4s, holding time 0.7s, gradient cooling rate 10℃ / s; S3 Stress Relief and Synergistic Preheating: Stress release temperature 70℃, holding time 1.5s, hot stamping preheating temperature 75℃; S4 Top and Side Integrated Synchronous Hot Stamping: Plastic cap rotation speed 12r / min, top surface hot stamping temperature 125℃, pressure 0.25MPa, holding time 0.8s; side surface hot stamping temperature 120℃, pressure 0.3MPa; The remaining steps are the same as in Example 1, with full-process time-series linkage control.

[0038] This embodiment operates continuously for 8 hours, with a single-shift output of 115,200 pieces, a comprehensive product qualification rate of 99.55%, an average deviation of 0.025mm for hot stamping, a hot stamping layer adhesion grade of 0, and a friction resistance of 620 cycles, fully meeting the high-end appearance requirements of daily chemical products.

[0039] Comparative Example 1 This comparative example adopts the existing traditional multi-process processing technology. The specific process is as follows: injection molding → ultrasonic welding machine welding gaskets → turnover and transfer → top surface hot stamping machine hot stamping → turnover and transfer → side hot stamping machine hot stamping → manual full inspection. The core process parameters of each process are consistent with those of Example 1, and the cycle time of a single process is consistent with that of a single station in Example 1.

[0040] This comparative example requires 4 operators to operate continuously for 8 hours, with a single-shift output of 48,000 pieces, an overall product qualification rate of 83.2%, an average deviation of 0.087mm in hot stamping, a hot stamping layer adhesion grade of 1, a friction resistance of 220 times, and a resistance to alcohol wiping for 28 times before peeling off. The overall energy consumption is 1.92 times that of Example 1.

[0041] Comparative Example 2 This comparative example uses an existing simple series process, which only realizes the series connection of ultrasonic welding and top hot stamping. There is no stress relief and coordinated preheating process. The side hot stamping still requires secondary clamping processing. The other core process parameters are the same as those in Example 1.

[0042] This comparative example requires 2 operators to operate continuously for 8 hours, with a single-shift output of 72,000 pieces, a comprehensive product qualification rate of 90.5%, an average deviation of 0.062mm in hot stamping overprinting, a deviation of 0.09mm in the side hot stamping seam, a hot stamping layer adhesion grade of 1, a friction resistance of 280 cycles, and a comprehensive energy consumption that is 1.46 times that of Example 1.

[0043] A comparison of the above embodiments and comparative examples shows that: Compared with the traditional multi-process process, the linkage processing technology of this invention improves production efficiency by more than 140%, increases product qualification rate by more than 16 percentage points, and reduces overall energy consumption by more than 45%, fully achieving the expected technical effects. The stress relief and synergistic preheating process is the core process step to ensure product qualification rate and hot stamping performance. After eliminating this step, the product qualification rate drops by more than 7 percentage points, the performance of the hot stamping layer decreases significantly, and energy consumption increases significantly. Furthermore, the unified benchmark and time-series linkage control throughout the entire process are the core to ensure processing accuracy and production efficiency. The traditional process of multiple clamping not only significantly reduces production efficiency, but also fails to meet the processing accuracy requirements of high-end products. The process of this invention can be directly connected to the injection molding machine to achieve unmanned production throughout the entire process, further reducing production costs, adapting to the production requirements of intelligent factories, and has extremely strong industrial application value.

[0044] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0045] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A process for simultaneous ultrasonic welding and hot stamping of the plastic cap, characterized by: This includes the following fully integrated processing steps: S1 uses its inner stop or internal thread as the sole clamping reference to position and lock the plastic cap to be processed. After clamping, the plastic cap remains locked and this reference is used as the unified processing reference for all subsequent processes. S2 transfers the clamped plastic cap to the welding process. Based on the plastic cap material and welding structure, the welding process parameters are preset to complete the ultrasonic welding of the plastic cap and the part to be welded. After welding, pressure holding and cooling are performed simultaneously. The pressure holding time is perfectly matched with the single station turnover cycle. During the welding process, the plastic cap is kept in a locked state, and the welding processing reference is completely coincident with the clamping reference. S3 transfers the welded plastic cap to the temperature control process, using the residual heat generated by ultrasonic welding to perform temperature control treatment on the plastic cap using a stepped constant temperature control process. S4 transfers the temperature-controlled plastic cap to the hot stamping process, using the clamping reference as the hot stamping positioning reference, and simultaneously completes the hot stamping processing of the top surface pattern and the side circumference pattern of the plastic cap. The S5 transfers the hot-stamped plastic caps to the inspection process. It simultaneously acquires full-area images of the top and sides of the plastic caps through dual-view visual acquisition, and performs real-time analysis on welding quality, hot-stamping pattern integrity, overprinting accuracy, and adhesion pre-inspection indicators to accurately identify qualified and unqualified products. S6 transfers the inspected plastic caps to the unloading process. Based on the online visual inspection results, it automatically sorts qualified and unqualified products. Qualified products are transported to the finished product collection stage, while unqualified products are transported to the waste collection stage.

2. The ultrasonic welding and hot stamping process for the plastic cap as described in claim 1, characterized in that: In step S2, the ultrasonic welding process differentially adjusts the welding frequency, amplitude, welding pressure, welding time, and holding pressure time parameters according to the different materials of the plastic cap substrate. The holding pressure and cooling step uses a gradient cooling process to cool the welding area of ​​the plastic cap. During the cooling process, the temperature of the welding area is collected in real time. When the temperature drops below the heat distortion temperature of the substrate, the holding pressure and cooling ends. At the same time, through the dual-parameter closed-loop control of welding displacement and welding pressure, the system automatically switches to the holding pressure state when the welding displacement reaches a preset threshold.

3. The ultrasonic welding and hot stamping process for the plastic cap as described in claim 2, characterized in that: For PP plastic caps, control the ultrasonic welding frequency to 15-25kHz, amplitude to 15-45μm, welding pressure to 0.2-0.7MPa, welding time to 0.1-1.0s, and holding time to 0.2-1.2s. For PE plastic caps, control the ultrasonic welding frequency to 18-35kHz, amplitude to 10-35μm, welding pressure to 0.1-0.6MPa, welding time to 0.1-0.8s, and holding time to 0.1-1.0s. For PET plastic caps, control the ultrasonic welding frequency to 25-45kHz, amplitude to 5-30μm, welding pressure to 0.15-0.65MPa, welding time to 0.05-0.6s, and holding time to 0.15-1.0s.

4. The ultrasonic welding and hot stamping process for the plastic cap as described in claim 1, characterized in that: In S3, the stepped constant temperature control process uses a combination of hot air circulation and infrared heat compensation to adjust the temperature of the plastic cover. The heat preservation time of the stress relief stage is matched with the single-station turnover cycle. The preheating temperature of the hot stamping stage is adjusted according to the material of the plastic cover substrate. The temperature difference between the top surface and the side hot stamping area of ​​the plastic cover is ≤5℃. The stepped constant temperature control process is divided into a first stage and a second stage. In the first stage, the temperature of the plastic cap is stabilized at 2-20℃ below the glass transition temperature (Tg) of the substrate, and the holding time is 0.5-2.5s. In the second stage, the preheating temperature is controlled at 50-80℃ for PP plastic caps, 40-70℃ for PE plastic caps, and 55-85℃ for PET plastic caps. During the composite control process, the hot air velocity is controlled at 1-6m / s, the hot air temperature is controlled at 35-85℃, and the temperature control accuracy of infrared heat compensation is ±2℃.

5. The ultrasonic welding and hot stamping process for the plastic cap as described in claim 1, characterized in that: In S4, during the hot stamping process, the rotation speed of the plastic cap around its own axis is controlled to be 3-20 r / min. The hot stamping temperature, hot stamping pressure and holding time of the top surface and the side surface are independently controlled. During the side hot stamping process, the linear speed of the side hot stamping is controlled to be synchronized with the circumferential rotation linear speed of the plastic cap. The hot stamping temperature on the top surface is controlled at 85-135℃, the hot stamping pressure at 0.08-0.35MPa, and the hot stamping holding time at 0.2-1.2s; the hot stamping temperature on the sides is controlled at 80-130℃, and the hot stamping pressure at 0.1-0.4MPa.

6. The ultrasonic welding and hot stamping process for the plastic cap as described in claim 1, characterized in that: In step S5, an area array camera is used to acquire images of the entire top surface of the plastic cover, and a line array camera is used in conjunction with the uniform rotation of the plastic cover to acquire images of the entire 360° circumference of the side surface of the plastic cover. Based on a deep learning algorithm, the acquired images are analyzed in real time. The detection content includes defects such as poor welding, overflow, insufficient material, and burn-through in the welding area, as well as defects such as misregistration of hot stamping patterns, broken gold, missing gold, scratches, color difference, and misalignment of seams.

7. The ultrasonic welding and hot stamping process for the plastic cap as described in claim 1, characterized in that, Between S4 and S5, a hot stamping post-processing step is also provided, which is: the hot stamped plastic cap is first subjected to UV curing treatment, and after curing, the surface of the plastic cap is subjected to non-contact dust removal treatment by ion wind.

8. The ultrasonic welding and hot stamping process for the plastic cap as described in claim 7, characterized in that: The UV curing treatment controls the main wavelength to 360-410nm, the curing energy to 700-1600mJ / cm², and the curing time to 0.4-1.6s; the ion wind dust removal treatment controls the ion wind output pressure to 0.08-0.35MPa and the dust removal time to 0.2-1.0s.

9. The ultrasonic welding and hot stamping process for the plastic cap as described in claim 1, characterized in that, Before the top and side integrated hot stamping process of S4, a hot stamping pre-positioning and alignment process is also set up. Specifically, the position of the reference mark point on the surface of the plastic cover is collected by visual pre-positioning, and the rotation angle of the plastic cover and the starting position of the hot stamping process are adjusted according to the coordinates of the reference mark point to realize the pre-positioning and alignment of the hot stamping pattern; for the pattern seam of the side circumferential hot stamping, the pattern seam accuracy is ensured by the closed-loop control of the rotation angle of the plastic cover.

10. The ultrasonic welding and hot stamping process for the plastic cap as described in claim 9, characterized in that: The positioning accuracy of the hot stamping pre-alignment is ≤0.05mm, and the deviation of the pattern seam of the side circumferential hot stamping is ≤0.05mm.

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