Method for microwave continuous vulcanization and seamless corner forming of automobile sealing strip

Abstract

This invention discloses a method for continuous microwave vulcanization and seamless corner molding of automotive sealing strips, relating to the field of automotive parts manufacturing technology. It involves mixing a surface-functionalized semiconductor quantum dot microwave sensitizer and a microencapsulated activator system with an EPDM rubber substrate to prepare a main intelligent composite material. A special digital material filament containing a depolymerizing agent and co-frequency heterogeneous quantum dots is prepared for the corners. After precision extrusion and shaping, the main intelligent composite material is fed into a dynamic microwave vulcanization chamber. Through quantum dot-catalyzed selective microwave vulcanization, continuous and uniform vulcanization of the sealing strip's main body is achieved. This invention achieves seamless molecular-level fusion between the corners and the main body, completely eliminating physical seams found in traditional processes, significantly improving the sealing performance and long-term durability of the sealing strip. The synergistic use of quantum dot-catalyzed selective microwave vulcanization and multi-energy field co-vulcanization ensures uniform vulcanization of the sealing strip's main body and corner areas, resulting in significantly improved performance consistency.

Description

Technical Field

[0001] This invention relates to the field of automotive parts manufacturing technology, and in particular to a method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips. Background Technology

[0002] Automotive sealing strips are key components that ensure vehicle sealing performance, sound insulation and noise reduction, waterproofing and dustproofing, and improve driving comfort. Their performance directly depends on molding precision, vulcanization uniformity, and the structural integrity of the joints.

[0003] The current production of automotive sealing strips generally adopts a sequential processing mode of "extrusion vulcanization first, then cutting corners". In this mode, the main body of the sealing strip is cured by steam vulcanization or whole-body microwave vulcanization after extrusion, and then the main body is cut into a preset length by mechanical cutting. Finally, the corners are formed by adhesive bonding, hot melt splicing and other methods.

[0004] However, traditional techniques have many inherent flaws: After the corner joints are cut and spliced, physical seams inevitably form, making this area a weak point in the seal. Long-term use can easily lead to cracking and detachment, seriously affecting sealing performance and service life. Traditional microwave vulcanization relies on sensitizers such as carbon black, which cannot achieve precise energy focusing. This results in uneven vulcanization in areas with varying thickness of the sealing strip, affecting the overall performance consistency. Corner forming relies on manual or mechanical positioning, resulting in low splicing accuracy. It is difficult to adapt to the forming requirements of sealing strips with complex cross-sections, and the serial process is inefficient, failing to meet the high-efficiency requirements of large-scale production. Existing improvement solutions are mostly limited to the optimization of a single process and do not build an integrated solution from the perspective of the synergy of materials, energy field, and digital control. Therefore, it is difficult to fundamentally solve core problems such as seams, uneven vulcanization, and insufficient accuracy.

[0005] Therefore, developing a method for forming automotive sealing strips that can achieve continuous vulcanization of the main body and seamless corner molding in parallel and in a coordinated manner, while also possessing high precision, high consistency, and high efficiency, has become a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0006] To solve the above-mentioned technical problems, this invention provides a method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips. The technical solution is as follows: A method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips includes the following steps: Step 1, preparation of intelligent composite material system: The surface-functionalized semiconductor quantum dot microwave sensitizer and microencapsulated activator system are mixed with EPDM rubber substrate to prepare the main intelligent composite material; Step 2: Prepare a special digital material wire for corners containing depolymerizing agents and quantum dots of the same frequency but different phases; Step 3: After the main intelligent composite material is precisely extruded and shaped, it is sent into the dynamic microwave vulcanization chamber. Through quantum dot catalyzed selective microwave vulcanization, the main body of the sealing strip is continuously and uniformly vulcanized. Step 4: Obtain geometric data of the sealing strip end through dual-view 3D laser scanning, generate a real-time printing path through AI modeling, and use ultrasonic field-induced material transport to accurately deposit digital material droplets onto the corner area; Step 5: Apply laser, microwave, and magnetic pulse multi-energy fields for co-sulfidation, followed by in-situ finishing and real-time quality control to form a joint that is seamlessly integrated with the main body; Step 6: The molded sealing strip is subjected to gradient cooling, and the finished automotive sealing strip is obtained by terahertz non-destructive testing.

[0007] Optionally, in step 1, the semiconductor quantum dots are lead sulfide or cadmium telluride with a particle size of 2nm-10nm, and are surface modified with a silane coupling agent, with an addition amount of 0.5%-1.5% of the mass of the EPDM rubber substrate.

[0008] Optionally, in step 1, the wall material of the microencapsulation activator system is polycaprolactone with a melting point of 120℃-140℃, the core material is a mixture of accelerator and activator in a mass ratio of 3:2, the microcapsule particle size is 50μm-200μm, and the addition amount is 3%-5% of the mass of the EPDM rubber substrate.

[0009] Optionally, in step 2, the diameter of the digital material filament is 1mm-3mm, the amount of depolymerizing agent added is 5%-8% of the mass of EPDM rubber, the amount of quantum dots added is 1.0%-2.0% of the mass of EPDM rubber, and the phase difference between the quantum dots and the quantum dots in the host material is 180°±30°.

[0010] Optionally, in step 3, the dynamic microwave vulcanizing cavity is equipped with 8-12 independently controllable microwave transmitters, with a single transmitter power of 0kW-10kW, a phase adjustment range of 0°-360°, a vulcanizing target temperature of 150℃-170℃, and a vulcanizing time of 5 seconds / meter-10 seconds / meter.

[0011] Optionally, in step 4, the dual-view 3D laser scanning uses two symmetrically arranged scanning heads, and the scanning speed is adaptively adjusted from 1000 points / second to 3000 points / second according to the cross-sectional complexity; the scanning is triggered by the photoelectric sensor at the microwave vulcanization cavity outlet, and data acquisition is started when the end of the sealing strip is 50mm away from the corner deposition station.

[0012] Optionally, in step 4, the AI ​​digital modeling includes noise filtering, rigid alignment, and elastic correction steps; the printing path adopts a layered deposition combined with contour filling mode; the ultrasonic field-induced material transport is atomized through the cavitation effect of a high-frequency ultrasonic transducer; the transducer is equipped with a water-cooling heat dissipation device; the focal point diameter of the focusing lens array is infinitely adjustable from 0.3mm to 0.5mm; and the material droplet particle size is 1μm-10μm. The ultrasonic field-induced material transport wire feeder has a built-in tension sensor and a feeding speed of 0.5m / min-2m / min. It transports materials through the coordinated use of a directional sound field and an electrostatic field. The sound intensity of the directional sound field is greater than or equal to 100W / m², and the direction adjustment range is ±15°. The electrostatic field uses a 5kV-10kV ring electrode for coordinated transport, with a transport distance of 20mm-30mm. The timing coordination of multi-energy field co-sulfidation is as follows: laser starts first for 0.1ms, microwave starts, and magnetic pulse starts synchronously with microwave; among them, CO2 laser power is 5W-10W and wavelength is 10.6μm, directional microwave power is 1kW-3kW, magnetic pulse intensity is 10T-20T and duration is 100ns-500ns.

[0013] Optionally, in step 5, multi-energy field co-sulfurization uses laser to melt droplets to form a molten blend layer, microwave-triggered synchronous sulfurization, and magnetic pulse to drive molecular penetration; microwaves and lasers are isolated by a metal shielding mesh, and the magnetic pulse device is equipped with an electromagnetic shielding cover; In-situ finishing and real-time quality control specifically involve: using a line-scanning confocal microscope to detect three-dimensional dimensions, an integrated roughness sensor to detect surface roughness, a miniature ultrasonic flaw detector to detect internal porosity, and a miniature tensile-shear sensor to detect interfacial bonding strength. The closed-loop correction strategy for real-time quality control is as follows: when the size is more than 0.1 mm larger than the set standard value, the feeding speed is reduced by 5%-10% and the cutting amount is increased by 5%-10%; when the size is more than 0.1 mm smaller than the set standard value, the feeding speed is increased by 5%-10% and the cutting amount is reduced by 5%-10%; when the surface scratch depth is greater than 0.02 mm, local re-deposition and secondary finishing are initiated; when internal defects are detected, an alarm is triggered and the energy field parameters are automatically adjusted.

[0014] Optionally, in step 6, the gradient cooling adopts a three-section tunnel with temperatures of 120℃-130℃, 80℃-100℃, and 40℃-60℃, respectively, with a cooling time of 2-3 seconds for each section and a temperature difference of less than or equal to 20℃ between the inside and outside of the sealing strip. The frequency of terahertz nondestructive testing is 0.1THz-1THz, and the scanning speed is 5m / min-10m / min.

[0015] Optionally, based on the data traceability unit, the entire production process data is associated with a unique ID to achieve quality traceability. The data traceability unit includes a laser marking module and an industrial database. The unique ID is a QR code or RFID chip. The stored data includes material formula, quantum dot parameters, microwave energy field data, corner printing path, and test results.

[0016] In summary, the present invention has at least one of the following beneficial technical effects: This invention provides a method for microwave continuous vulcanization and seamless corner molding of automotive sealing strips, achieving molecular-level seamless fusion between the corner and the main body, completely eliminating physical seams in traditional processes, and significantly improving the sealing performance and long-term durability of the sealing strip. By employing quantum dot-catalyzed selective microwave vulcanization and multi-energy field co-vulcanization in synergy, uniform vulcanization of the main body and corner areas of the sealing strip is ensured, resulting in a significant improvement in performance consistency. The main body vulcanization and corner molding are carried out in parallel. Combining digital modeling and field-induced transport technology, the molding efficiency and precision are greatly improved, which can meet the needs of large-scale production of complex cross-section sealing strips. The system integrates multi-dimensional real-time quality control and full-process data traceability, effectively reducing product defect rates and ensuring product quality stability. The integration of intelligent composite materials and advanced energy field control technology expands the design freedom of sealing strips, allowing them to adapt to the personalized structural needs of different vehicle models. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of the microwave continuous vulcanization and seamless corner forming method for automotive sealing strips of the present invention. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings.

[0019] This invention discloses a method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips.

[0020] Reference Figure 1 Example 1, a method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips, includes the following steps: Step 1, preparation of intelligent composite material system: The surface-functionalized semiconductor quantum dot microwave sensitizer and microencapsulated activator system are mixed with EPDM rubber substrate to prepare the main intelligent composite material; Step 2: Prepare a special digital material wire for corners containing depolymerizing agents and quantum dots of the same frequency but different phases; Step 3: After the main intelligent composite material is precisely extruded and shaped, it is sent into the dynamic microwave vulcanization chamber. Through quantum dot catalyzed selective microwave vulcanization, the main body of the sealing strip is continuously and uniformly vulcanized. Step 4: Obtain geometric data of the sealing strip end through dual-view 3D laser scanning, generate a real-time printing path through AI modeling, and use ultrasonic field-induced material transport to accurately deposit digital material droplets onto the corner area; Step 5: Apply laser, microwave, and magnetic pulse multi-energy fields for co-sulfidation, followed by in-situ finishing and real-time quality control to form a joint that is seamlessly integrated with the main body; Step 6: The molded sealing strip is subjected to gradient cooling, and the finished automotive sealing strip is obtained by terahertz non-destructive testing.

[0021] In Example 2, in step 1, the semiconductor quantum dots are lead sulfide or cadmium telluride with a particle size of 2nm-10nm. They are surface modified with silane coupling agent and the amount added is 0.5%-1.5% of the mass of the EPDM rubber substrate.

[0022] In Example 3, in step 1, the wall material of the microencapsulation activator system is polycaprolactone with a melting point of 120℃-140℃, the core material is a mixture of accelerator and activator in a mass ratio of 3:2, the microcapsule particle size is 50μm-200μm, and the addition amount is 3%-5% of the mass of the EPDM rubber substrate.

[0023] By adopting the above technical solution, semiconductor quantum dots, after surface modification with a silane coupling agent, can be uniformly dispersed in an EPDM rubber substrate. Their specific particle size design allows them to precisely match industrial microwave frequencies, making them a highly efficient microwave energy absorption carrier. When microwaves are applied, the quantum dots rapidly absorb microwave energy and convert it into heat energy, achieving a precise increase in local temperature and providing a directional energy source for the vulcanization reaction.

[0024] The wall material melting point of the microencapsulated activator system is set higher than the EPDM processing temperature but lower than the vulcanization trigger temperature. During the material mixing, extrusion and other processing stages, the wall material remains intact, isolating the accelerator and activator and effectively avoiding pre-vulcanization. When the heat energy converted by quantum dots reaches the wall material melting point, the wall material melts and breaks down, and the released chemical substances can immediately trigger the vulcanization crosslinking reaction of EPDM rubber, achieving precise control of the vulcanization timing.

[0025] The addition of a depolymerizing agent lowers the melting temperature of EPDM rubber, making it easier for the filament to transform into micron-sized droplets during subsequent ultrasonic atomization, while ensuring the chemical compatibility of the material with the host substrate. The design of co-frequency heterogeneous quantum dots allows them to respond synergistically with the quantum dots in the host material at the same microwave frequency, absorbing energy synchronously during the co-vulcanization stage. This ensures that the vulcanization reaction rate at the junction region is consistent with that of the host, laying the foundation for interfacial fusion. The specific diameter design of the filament adapts to the feeding requirements of the ultrasonic transport system, ensuring the stability of material supply.

[0026] The dynamic microwave vulcanizing cavity contains multiple independently controllable microwave transmitters. By adjusting the power and phase of each transmitter according to the geometry of the sealing strip cross-section, a dynamic energy field precisely matching the contour of the sealing strip can be constructed. Under the action of microwave energy, quantum dots achieve selective heat absorption, focusing energy on the main body area of ​​the sealing strip, avoiding energy waste and local overheating, and achieving uniform heating from the inside out.

[0027] As the sealing strip is continuously pulled, the dynamic energy field moves synchronously, forming a "scanning" vulcanization mode, enabling the sealing strip to complete continuous vulcanization during transportation. This method overcomes the energy uniformity defects of traditional integral microwave vulcanization. Through the catalytic effect of quantum dots and the precise control of the dynamic energy field, it ensures consistent vulcanization degree in areas of different thicknesses and cross-sections, improving the performance stability of the main sealing strip.

[0028] Dual-view 3D laser scanning eliminates blind spots at the end of the sealing strip through symmetrically arranged scanning heads. Combined with trigger control by photoelectric sensors, data acquisition is precisely initiated when the end of the sealing strip reaches the preset position, ensuring the integrity and timeliness of geometric data. Noise filtering in the AI ​​modeling process eliminates invalid data, rigid alignment ensures that the scanned data is consistent with the benchmark of the ideal model, and elastic correction dynamically compensates for slight deformations after substrate extrusion, generating a printing path that perfectly matches the actual substrate, providing data support for accurate deposition.

[0029] The ultrasonic vibrations generated by the high-frequency ultrasonic transducer create a cavitation effect at the tip of the filament, causing the solid filament to instantly break into micron-sized droplets. A focusing lens array then converges these droplets into a directional material flow, increasing the droplet concentration. The directional sound field propels the droplets towards the junction region through gradient sound intensity, while the electrostatic field utilizes charge adsorption to further precisely control the droplet deposition position. The synergistic effect of these two technologies prevents droplet diffusion, ensuring deposition accuracy. Furthermore, the non-mechanically contactless transport method avoids damage to the incompletely vulcanized substrate.

[0030] Laser energy rapidly melts deposited droplets while softening the uncured layer on the substrate surface, forming a molten blend layer that promotes molecular contact between the corner material and the substrate. Microwave energy triggers quantum dot endothermy, raising the blend layer temperature to the curing threshold and initiating the curing crosslinking reaction. The instantaneous high pressure generated by the magnetic pulse compacts the molten blend layer, eliminating internal porosity and simultaneously promoting molecular chain interpenetration, achieving molecular-level fusion between the corner material and the substrate, and completely eliminating physical seams. The sequential synergistic design of the three energy fields avoids energy interference and ensures maximum effectiveness of each field.

[0031] In-situ finishing uses a high-precision five-axis finishing head to perform micro-cutting on the corner surface after multi-energy field action based on real-time detection data, correcting surface unevenness defects and ensuring that the corner surface finish is consistent with the main body. Multi-dimensional real-time quality control monitors dimensional accuracy, surface quality, internal structure, and interface strength through different detection devices, forming a closed-loop control; when defects are detected, processing deviations are corrected in real time by adjusting the feeding speed, cutting amount, and energy field parameters, ensuring the quality of corner forming.

[0032] The gradient cooling system employs a three-stage temperature gradient design to gradually reduce the temperature of the sealing strip, avoiding thermal stress caused by excessive internal and external temperature differences, preventing deformation or cracking of the sealing strip, and ensuring the dimensional stability of the product. Terahertz waves have the characteristic of penetrating rubber materials, enabling non-destructive testing of issues such as uneven vulcanization, interface defects, and bubbles inside the sealing strip. Its specific frequency and scanning speed design ensures testing accuracy while adapting to the efficiency requirements of large-scale production, achieving precise screening of defective products.

[0033] In Example 4, in step 2, the diameter of the digital material filament is 1mm-3mm, the amount of depolymerizing agent added is 5%-8% of the mass of EPDM rubber, the amount of quantum dots added is 1.0%-2.0% of the mass of EPDM rubber, and the phase difference between the quantum dots and the quantum dots in the host material is 180°±30°.

[0034] In Example 5, in step 3, the dynamic microwave vulcanizing cavity is equipped with 8-12 independently controllable microwave transmitters, with a single transmitter power of 0kW-10kW, a phase adjustment range of 0°-360°, a vulcanizing target temperature of 150℃-170℃, and a vulcanizing time of 5 seconds / meter-10 seconds / meter.

[0035] By adopting the above technical solution, the wire diameter is set at 1mm-3mm, which is the optimal range to balance ultrasonic atomization efficiency and feeding stability. A diameter that is too small (less than 1mm) will result in insufficient wire rigidity, making it prone to bending and breakage during feeding, and failing to guarantee continuous and stable feeding. A diameter that is too large (greater than 3mm) will increase the difficulty of ultrasonic atomization, requiring a significant increase in ultrasonic power to achieve micron-level droplet conversion. This not only increases energy consumption but may also lead to premature pre-vulcanization of the wire due to excessively high local energy, affecting the subsequent corner forming quality. This diameter range can be precisely matched with the feeding mechanism of the ultrasonic transport system, ensuring smooth wire feeding and providing a stable material basis for uniform droplet generation.

[0036] The amount of depolymerizing agent added should be controlled at 5%-8% of the EPDM rubber mass. The key is to balance the melting difficulty and mechanical properties of the material. If the addition amount is below 5%, the depolymerization effect is insufficient, the melting temperature of the EPDM rubber is too high, and it is difficult to quickly transform into uniform droplets during ultrasonic atomization. The droplet size is prone to being too large and unevenly distributed, affecting the deposition accuracy. If the addition amount is above 8%, although it can reduce the melting difficulty, it will excessively damage the molecular chain structure of the EPDM rubber, resulting in a significant decrease in the tensile strength, tear strength, and other mechanical properties of the joint area after vulcanization, failing to meet the requirements for sealing strips. An addition amount of 5%-8% can ensure easy atomization of the filament while preserving the mechanical properties of the main material, ensuring the consistency of performance between the joint and the main sealing strip.

[0037] The quantum dot addition amount is higher than that of the host material (0.5%-1.5%), set at 1.0%-2.0%, to enhance the microwave energy absorption efficiency of the corner region. The corner region is a localized deposition formation and needs to complete vulcanization synchronously with the host material within a short time. A higher quantum dot addition amount can improve the microwave absorption capacity of the corner material, ensuring that the vulcanization trigger temperature is reached quickly during the co-vulcanization stage, avoiding weak interfacial bonding due to the vulcanization rate of the corner region lagging behind the host. Simultaneously, this addition amount does not exceed the material compatibility threshold, preventing quantum dot agglomeration from affecting the uniformity of the corner material and ensuring stable performance of the corner region after vulcanization.

[0038] The phase difference between the quantum dots and the quantum dots in the host material is set at 180°±30°, the core of which is to achieve synergistic resonant absorption between the two in a microwave field. Quantum dots of the same frequency but different phases can produce complementary energy absorption effects under the same microwave frequency, ensuring that the vulcanization reaction rates of the host and junction materials are consistent. A phase difference deviating from this range (less than 150° or greater than 210°) will lead to asynchronous energy absorption, potentially resulting in excessively rapid vulcanization of the host material while the junction is not fully vulcanized, or excessively rapid vulcanization of the junction while the host interface is overly softened, both of which will affect the interfacial molecular fusion effect. A phase difference of 180°±30° ensures that the two materials absorb heat and vulcanize synchronously in the microwave field, providing synergistic energy support for seamless molecular-level fusion of the junction and the host.

[0039] Installing 8-12 independently controllable microwave transmitters is to achieve precise construction of a dynamic energy field. For sealing strips with complex cross-sectional shapes (such as multi-lip or irregular cavities), a single or small number of transmitters cannot cover the energy needs of different areas, easily leading to localized energy concentration or insufficient energy. 8-12 transmitters, arranged in an array, can comprehensively cover the width and thickness range of the sealing strip. Each transmitter corresponds to a specific area of ​​the sealing strip, and independent control enables zoned energy distribution, ensuring that all parts of the complex cross-section of the sealing strip receive uniform energy supply and avoiding differences in sulfidation caused by uneven energy distribution.

[0040] The power adjustment range of 0kW-10kW is key to adapting to the vulcanization requirements of sealing strips of different specifications. Sealing strips vary in thickness and cross-sectional area (e.g., door sealing strips are 2mm-10mm thick), requiring different amounts of microwave energy: thin or simple cross-section sealing strips require lower power (1kW-4kW) to reach the vulcanization temperature, avoiding excessive energy that could lead to material aging; thick or complex cross-section sealing strips require higher power (5kW-10kW) to ensure microwave energy penetrates into the material, achieving uniform vulcanization from the inside out.

[0041] The phase adjustment range, covering 0°-360°, is designed to focus and superimpose microwave energy. By adjusting the phase difference between different transmitters, microwaves can be superimposed on the target area of ​​the sealing strip, creating a "thermal focus" that matches the geometry of the sealing strip and increasing local energy density. Simultaneously, phase cancellation can weaken microwave energy in non-target areas, preventing energy waste. The 360° full-range adjustment can adapt to sealing strips of any cross-sectional shape, ensuring a precise fit between the energy field and the sealing strip contour, solving the problem of insufficient vulcanization in thick areas and excessive vulcanization in thin areas in traditional microwave vulcanization.

[0042] The target vulcanization temperature is set at 150℃-170℃, which is the optimal temperature range for the vulcanization reaction of EPDM rubber. The vulcanization reaction of EPDM rubber needs to be initiated at a specific temperature. Below 150℃, the microcapsule wall material cannot completely melt, resulting in insufficient release of accelerators and activators, incomplete vulcanization crosslinking, and the sealing strip's hardness, elasticity, and other properties failing to meet standards. Above 170℃, the vulcanization reaction rate is too fast, leading to uneven molecular chain crosslinking density, which can easily cause the material to become brittle and age. It may also trigger the volatilization of plasticizers, antioxidants, and other additives in the rubber, affecting the long-term durability of the sealing strip. The temperature range of 150℃-170℃ ensures a sufficient and gentle vulcanization reaction, achieving optimal sealing strip performance.

[0043] When the vulcanization time is less than 5 seconds / meter, the sealing strip does not remain in the microwave cavity long enough, the vulcanization cross-linking reaction is incomplete, the cross-linking density of the material is low, and it is prone to deformation and aging during use. When the vulcanization time is longer than 10 seconds / meter, although complete vulcanization can be guaranteed, it will lead to a significant decrease in production efficiency, which cannot meet the needs of large-scale production. At the same time, prolonged exposure to high temperatures may cause material performance degradation. This time range is precisely matched with the traction speed of the sealing strip (3m / min-5m / min), enabling efficient and continuous production while ensuring vulcanization quality.

[0044] In Example 6, in step 4, the dual-view 3D laser scanning uses two symmetrically arranged scanning heads, and the scanning speed is adaptively adjusted from 1000 points / second to 3000 points / second according to the cross-sectional complexity; the scanning is triggered by the photoelectric sensor at the microwave vulcanization cavity outlet, and data acquisition is started when the end of the sealing strip is 50mm away from the corner deposition station.

[0045] In Example 7, step 4, AI digital modeling includes noise filtering, rigid alignment, and elastic correction steps; the printing path adopts a layered deposition combined with contour filling mode; the ultrasonic field-induced material transport is atomized through the cavitation effect of a high-frequency ultrasonic transducer; the transducer is equipped with a water-cooling heat dissipation device; the focal point diameter of the focusing lens array is infinitely adjustable from 0.3mm to 0.5mm; and the material droplet particle size is 1μm to 10μm. The ultrasonic field-induced material transport wire feeder has a built-in tension sensor and a feeding speed of 0.5m / min-2m / min. It transports materials through the coordinated use of a directional sound field and an electrostatic field. The sound intensity of the directional sound field is greater than or equal to 100W / m², and the direction adjustment range is ±15°. The electrostatic field uses a 5kV-10kV ring electrode for coordinated transport, with a transport distance of 20mm-30mm. The timing coordination of multi-energy field co-sulfidation is as follows: laser starts first for 0.1ms, microwave starts, and magnetic pulse starts synchronously with microwave; among them, CO2 laser power is 5W-10W and wavelength is 10.6μm, directional microwave power is 1kW-3kW, magnetic pulse intensity is 10T-20T and duration is 100ns-500ns.

[0046] By adopting the above technical solution and the dual-view symmetrical scanning head design, the scanning blind zone at the end of the sealing strip can be eliminated, ensuring complete acquisition of complex cross-sectional geometric data.

[0047] The scanning speed is adaptively adjusted from 1000 points / second to 3000 points / second. The low speed is suitable for simple cross-sections to ensure efficiency, while the high speed is suitable for complex cross-sections to ensure accurate detailed data.

[0048] The photoelectric sensor triggers the scan, and combined with the 50mm acquisition start distance, it ensures that the data acquisition and corner deposition timing are connected, allowing sufficient processing time for real-time modeling.

[0049] Noise filtering removes invalid data, rigid alignment ensures consistent benchmarks, and elastic correction compensates for substrate deformation, ensuring that the modeling accuracy is adapted to actual processing.

[0050] Layered deposition combined with contour filling can precisely match the three-dimensional shape of the corner, avoiding material accumulation or gaps.

[0051] The high-frequency ultrasonic transducer achieves micron-level atomization of the filament through cavitation effect, and the water-cooling heat dissipation device ensures stable operation of the transducer and avoids excessive temperature affecting the atomization effect.

[0052] The focusing point diameter is infinitely adjustable from 0.3mm to 0.5mm to adapt to the deposition requirements of different sized contact angles, ensuring that the droplets converge and concentrate.

[0053] The wire feeder has a built-in tension sensor, which, combined with a feeding speed of 0.5m / min-2m / min, ensures stable wire feeding and avoids fluctuations in atomization.

[0054] The directional sound field and electrostatic field work together. The directional sound field drives the droplets to move, while the electrostatic field precisely adsorbs and positions them. The 20mm-30mm transport distance balances accuracy and efficiency, and the ±15° sound field direction adjustment adapts to different angles.

[0055] The timing-coordinated design avoids energy interference. The laser is activated first to melt the droplets and soften the substrate, while the microwave synchronously triggers the vulcanization and the magnetic pulse compaction eliminates porosity.

[0056] The CO2 laser power and wavelength are adapted to the droplet melting requirements, the directional microwave power is matched to the junction thickness, the magnetic pulse intensity and duration ensure molecular penetration and structural compactness, and the range of parameters ensures that the energy supply is precisely adapted to the sulfurization and fusion requirements.

[0057] In Example 8, in step 5, multi-energy field co-sulfurization uses laser to melt droplets to form a molten blend layer, microwave-triggered synchronous sulfurization, and magnetic pulse to drive molecular penetration; microwaves and lasers are isolated by a metal shielding mesh, and the magnetic pulse device is equipped with an electromagnetic shielding cover; In-situ finishing and real-time quality control specifically involve: using a line-scanning confocal microscope to detect three-dimensional dimensions, an integrated roughness sensor to detect surface roughness, a miniature ultrasonic flaw detector to detect internal porosity, and a miniature tensile-shear sensor to detect interfacial bonding strength. The closed-loop correction strategy for real-time quality control is as follows: when the size is more than 0.1 mm larger than the set standard value, the feeding speed is reduced by 5%-10% and the cutting amount is increased by 5%-10%; when the size is more than 0.1 mm smaller than the set standard value, the feeding speed is increased by 5%-10% and the cutting amount is reduced by 5%-10%; when the surface scratch depth is greater than 0.02 mm, local re-deposition and secondary finishing are initiated; when internal defects are detected, an alarm is triggered and the energy field parameters are automatically adjusted.

[0058] By adopting the above technical solutions, laser melting of droplets forms a molten blend layer, while softening the surface of the main substrate, creating conditions for interface fusion; microwave-triggered quantum dot endothermy enables the blend layer to simultaneously initiate a sulfurization reaction; magnetic pulse generates instantaneous high pressure, driving molecular chain penetration and achieving molecular-level fusion between the interface and the main substrate.

[0059] Metal shielding mesh isolates microwaves and lasers, preventing microwaves from interfering with laser focusing accuracy; the magnetic pulse device is equipped with an electromagnetic shield to prevent the pulse magnetic field from interfering with other fields, ensuring that each energy field operates independently and efficiently.

[0060] Line scanning confocal microscopes accurately detect the three-dimensional dimensions of the joint, integrated roughness sensors monitor surface finish, miniature ultrasonic flaw detectors investigate internal pore defects, and miniature tensile-shear sensors assess interface bonding strength. Through multi-dimensional detection, key indicators of joint quality are comprehensively covered.

[0061] Processing parameters are dynamically adjusted for different defect types: dimensional deviations are corrected by increasing or decreasing the feeding speed and cutting amount; surface scratches are repaired by local deposition and secondary finishing; internal defects trigger alarms and adjust energy field parameters, forming a real-time quality control closed loop of detection, feedback and correction to ensure stable corner forming quality.

[0062] In Example 9, in step 6, gradient cooling adopts a three-section tunnel with temperatures of 120℃-130℃, 80℃-100℃, and 40℃-60℃, respectively. The cooling time for each section is 2-3 seconds, and the temperature difference between the inside and outside of the sealing strip is less than or equal to 20℃. The frequency of terahertz nondestructive testing is 0.1THz-1THz, and the scanning speed is 5m / min-10m / min.

[0063] Example 10: Based on the data traceability unit, the entire production process data is associated with a unique ID to achieve quality traceability. The data traceability unit includes a laser marking module and an industrial database. The unique ID is a QR code or RFID chip. The stored data includes material formula, quantum dot parameters, microwave energy field data, corner printing path and test results.

[0064] By adopting the above technical solution, the first stage, 120℃-130℃, is close to the final vulcanization temperature. This stage is mainly for balancing the beginning and end of the vulcanization reaction. It ensures that the cross-linking reaction is fully completed and avoids internal stress caused by the molecular chains not having enough time to adjust due to a sudden drop in temperature. The second stage, 80℃-100℃, is a transitional cooling stage. Through a moderate temperature gradient (temperature difference of about 40℃ per stage), the heat inside the material is slowly released, reducing the temperature difference between the surface layer and the core layer of the sealing strip. The third stage, 40℃-60℃, is close to room temperature, achieving the final shaping of the material and avoiding structural embrittlement caused by low-temperature impact.

[0065] The 2-3 second cooling time for each segment is precisely matched with the traction speed of the sealing strip (3m / min-5m / min) to ensure that the sealing strip has sufficient time to complete heat transfer in each cooling area. The internal and external temperature difference is strictly controlled to be less than or equal to 20℃ because EPDM rubber has a large coefficient of thermal expansion. Excessive temperature difference will cause the surface shrinkage rate to be much faster than the core layer, which will generate tensile stress or cracks, affecting the sealing performance and service life of the sealing strip.

[0066] Terahertz nondestructive testing, based on the unique physical properties of terahertz waves, enables precise and efficient screening of the internal quality of sealing strips, balancing testing depth and production efficiency.

[0067] The penetrating power of terahertz waves is negatively correlated with frequency. At frequencies too low (<0.1THz), the wavelength is too long, resulting in insufficient resolution for minute defects (such as bubbles with a diameter <0.2mm). At frequencies too high (>1THz), the wavelength is short, but the penetration depth decreases, making it impossible to detect uneven vulcanization or interface defects in the core layer of the sealing strip. The 0.1THz-1THz frequency band balances penetration depth and resolution, enabling penetration of sealing strips 2mm-10mm thick while clearly identifying internal pores, unvulcanized areas, interface delamination, and other defects. Contrast imaging is generated through amplitude attenuation and phase changes at the defect locations.

[0068] The scanning speed is designed to be adaptable from 5m / min to 10m / min: This scanning speed matches the continuous production rhythm of the main sealing strip (extrusion and vulcanization speed 3m / min-5m / min), ensuring that the inspection process does not become a bottleneck in production; at the same time, the frame rate and scanning speed of the terahertz imaging system are optimized in synergy; at a speed of 5m / min-10m / min, the system can acquire ≥10 pixels per millimeter of sealing strip length, ensuring the coverage and accuracy of defect detection, and avoiding missed detections or misjudgments due to excessively fast scanning.

[0069] The following specific embodiments illustrate the implementation principle of the present invention: For a certain car door sealing strip (cross-section size: 15mm × 8mm, corner type: 90° right angle), the above technical solution is used for production, and the specific steps are as follows: Step 1: Preparation of intelligent composite material system; The semiconductor quantum dots are made of lead sulfide (PbS) with a particle size of 5 nm, and are surface-modified with γ-aminopropyltriethoxysilane. The amount added is 1.0% of the mass of the EPDM rubber substrate. The wall material of the microencapsulation activator system is polycaprolactone (melting point 130℃), and the core material is a mixture of N-cyclohexyl-2-benzothiazole sulfenamide (accelerator) and zinc oxide + stearic acid (activator) in a mass ratio of 3:2. The microcapsule particle size is 100μm, and the addition amount is 4% of the mass of the EPDM rubber substrate. EPDM rubber (ML1+4100℃=60), carbon black N550 (50 parts), paraffin oil (20 parts), and antioxidant (2 parts) were put into a mixer and mixed at 85℃ and 70r / min for 6 minutes. Then, quantum dot dispersion and microencapsulation activator were added and mixed at 95℃ and 55r / min for 9 minutes. The mixture was then sheeted and cooled to 25℃ to obtain the main intelligent composite material.

[0070] Step 2: Preparation of digital material wires for corner joints; Select EPDM rubber compatible with the main body, add 7% (EPDM mass) of polyethylene glycol diglycidyl ether (depolymerizing agent) and 1.5% (EPDM mass) of co-frequency heterogeneous lead sulfide quantum dots (180° phase difference with the main quantum dots). Feed the material into a twin-screw extruder and extrude it at 105℃ and 90r / min. The filament is formed through a circular die (2mm in diameter), cooled to room temperature by air, and then wound for later use.

[0071] Step 3: Microwave continuous vulcanization of the main sealing strip; The main intelligent composite material is extruded through a single screw extruder (barrel temperature: 85℃ in the feeding section, 95℃ in the compression section, and 105℃ in the homogenization section), with a die exit temperature of 105℃ and an extrusion speed of 4m / min; After extrusion, the material is shaped by water cooling and air cooling at 60℃ and then enters a dynamic microwave vulcanization chamber (2.5m long, with 10 independent microwave transmitters). The transmitter power is set to 5kW, the phase is adjusted to match the cross-section of the sealing strip, the vulcanization temperature is controlled by infrared thermal imaging closed loop at 160℃, the traction speed is 4m / min, and the vulcanization time is 7.5 seconds / meter, so as to achieve continuous vulcanization of the main body.

[0072] Step 4: Preparatory work for seamless corner molding; A dual-view 3D laser scanning head (120° angle) is installed at the end of the microwave cavity. The photoelectric sensor triggers the scanning. Data acquisition starts when the end of the sealing strip is 50mm away from the corner deposition station. The scanning speed is 2000 points / second. After AI modeling is denoised by Gaussian filtering and median filtering, rigid alignment (reference deviation ≤ 0.01mm) and elastic correction are performed to generate a printing path with a layer thickness of 0.08mm and an outline fill density of 90%. Ultrasonic field-induced transport system startup: The ultrasonic transducer (30kHz, 800W) is equipped with a water-cooling device (40℃), the focusing lens has a focal point diameter of 0.4mm, the wire feeding speed is 1.2m / min (tension 0.3N), and the directional sound field (sound intensity 120W / m², direction 0°) and the 8kV ring electrostatic field work together for transport, with a transport distance of 25mm.

[0073] Step 5: Multi-energy field co-sulfurization and quality control; Multi-energy field timing: CO2 laser (8W, 10.6μm) starts 0.1ms first, directional microwave (2kW) starts 0.1ms later, and magnetic pulse (15T, 300ns) starts synchronously with microwave; Laser melting droplets form a 0.15mm molten blend layer, microwave-triggered synchronous vulcanization, and magnetic pulse compaction (pressure 550MPa). The miniature five-axis finishing head (diamond ball end mill, 15000r / min) finishes the surface according to real-time detection data, the line scanning confocal microscope detects the dimensions, the integrated roughness sensor monitors the surface, and the ultrasonic flaw detector detects the internal structure, forming a closed-loop correction.

[0074] Step 6: Post-processing and inspection; The molded sealing strip enters a three-stage gradient cooling tunnel: the first stage is 125°C, the second stage is 90°C, and the third stage is 50°C. Each stage has a cooling time of 2.5 seconds, and the temperature difference between the inside and outside is 15°C. Terahertz non-destructive testing (frequency 0.5THz, scanning speed 8m / min) is performed. Qualified products are then marked with a QR code by a laser marking machine (linking the entire process data to the industrial database) to obtain the finished sealing strip.

[0075] The performance test results of the finished sealing strip are shown in Table 1: Table 1

[0076] The performance comparison results of the finished sealing strip and traditional products are shown in Table 2: Table 2

[0077] As can be seen, this technical solution completely eliminates the physical seams of traditional processes, significantly reduces internal porosity, and increases interfacial bonding strength by over 75%, fundamentally solving the industry pain point of easy cracking and detachment at the joints.

[0078] The molding accuracy and surface quality are significantly optimized: the cross-sectional size deviation is reduced by more than 70%, the surface roughness is reduced by 60%, which can accurately adapt to complex assembly requirements and improve the sealing fit of the whole vehicle.

[0079] The mechanical and sealing performance has been comprehensively upgraded: the tensile strength and tear strength at the joints have been increased by 36% and 54.5% respectively, the leakage rate has been reduced by 87%, the thermal aging stability has been significantly improved, and the service life of the sealing strip has been extended.

[0080] Significantly improved production efficiency: The continuous parallel processing mode increases production efficiency by 60%, balancing the needs of high-quality and large-scale production, and reducing the unit product manufacturing cost.

[0081] Outstanding comprehensive performance advantages: This technology surpasses traditional processes in three core dimensions: structural integrity, performance consistency, and production efficiency, providing a higher quality solution for automotive sealing strips.

[0082] The preferred embodiments of the invention are not intended to limit the scope of protection of the invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the invention should be covered within the scope of protection of the invention.

Claims

1. A method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips, characterized in that, Includes the following steps: Step 1: Mix the surface-functionalized semiconductor quantum dot microwave sensitizer and microencapsulation activator system with EPDM rubber substrate to prepare the main intelligent composite material; Step 2: Prepare a special digital material wire for corners containing depolymerizing agents and quantum dots of the same frequency but different phases; Step 3: After the main intelligent composite material is precisely extruded and shaped, it is sent into the dynamic microwave vulcanization chamber. Through quantum dot catalyzed selective microwave vulcanization, the main body of the sealing strip is continuously and uniformly vulcanized. Step 4: Obtain geometric data of the sealing strip end through dual-view 3D laser scanning, generate a real-time printing path through AI modeling, and use ultrasonic field-induced material transport to accurately deposit digital material droplets onto the corner area; Step 5: Apply laser, microwave, and magnetic pulse multi-energy fields for co-sulfidation, followed by in-situ finishing and real-time quality control to form a joint that is seamlessly integrated with the main body; Step 6: The molded sealing strip is subjected to gradient cooling, and the finished automotive sealing strip is obtained by terahertz non-destructive testing; In step 2, the diameter of the digital material filament is 1mm-3mm, the amount of depolymerizing agent added is 5%-8% of the mass of EPDM rubber, the amount of quantum dots added is 1.0%-2.0% of the mass of EPDM rubber, and the phase difference between the quantum dots and the quantum dots in the host material is 180°±30°.

2. The method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips according to claim 1, characterized in that, In step 1, the semiconductor quantum dots are lead sulfide or cadmium telluride with a particle size of 2nm-10nm. They are surface modified with silane coupling agent and the amount added is 0.5%-1.5% of the mass of the EPDM rubber substrate.

3. The method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips according to claim 2, characterized in that, In step 1, the wall material of the microencapsulation activator system is polycaprolactone with a melting point of 120℃-140℃, the core material is a mixture of accelerator and activator in a mass ratio of 3:2, the microcapsule particle size is 50μm-200μm, and the addition amount is 3%-5% of the mass of the EPDM rubber substrate.

4. The method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips according to claim 3, characterized in that, In step 3, the dynamic microwave vulcanizing cavity is equipped with 8-12 independently controllable microwave transmitters, with a power of 0kW-10kW for each transmitter, a phase adjustment range of 0°-360°, a vulcanizing target temperature of 150℃-170℃, and a vulcanizing time of 5 seconds / meter-10 seconds / meter.

5. The method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips according to claim 4, characterized in that, In step 4, the dual-view 3D laser scanning uses two symmetrically arranged scanning heads, and the scanning speed is adaptively adjusted from 1000 points / second to 3000 points / second according to the cross-sectional complexity. The scanning is triggered by the photoelectric sensor at the microwave vulcanization cavity outlet, and data acquisition starts when the end of the sealing strip is 50mm away from the corner deposition station.

6. The method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips according to claim 5, characterized in that, In step 4, AI digital modeling includes noise filtering, rigid alignment, and elastic correction steps; the printing path adopts a layered deposition combined with contour filling mode; the ultrasonic field-induced material transport is atomized through the cavitation effect of a high-frequency ultrasonic transducer; the transducer is equipped with a water-cooling heat dissipation device; the focal point diameter of the focusing lens array is infinitely adjustable from 0.3mm to 0.5mm; and the material droplet particle size is 1μm-10μm. The ultrasonic field-induced material transport wire feeder has a built-in tension sensor and a feeding speed of 0.5m / min-2m / min. It transports materials through the coordinated use of a directional sound field and an electrostatic field. The sound intensity of the directional sound field is greater than or equal to 100W / m², and the direction adjustment range is ±15°. The electrostatic field uses a 5kV-10kV ring electrode for coordinated transport, with a transport distance of 20mm-30mm. The timing coordination of multi-energy field co-sulfidation is as follows: laser starts first for 0.1ms, microwave starts, and magnetic pulse starts synchronously with microwave; among them, CO2 laser power is 5W-10W and wavelength is 10.6μm, directional microwave power is 1kW-3kW, magnetic pulse intensity is 10T-20T and duration is 100ns-500ns.

7. The method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips according to claim 6, characterized in that, In step 5, multi-energy field co-sulfurization uses laser to melt droplets to form a molten blend layer, microwave-triggered synchronous sulfurization, and magnetic pulse to drive molecular penetration; microwaves and lasers are isolated by a metal shielding mesh, and the magnetic pulse device is equipped with an electromagnetic shielding cover; In-situ finishing and real-time quality control specifically involve: using a line-scanning confocal microscope to detect three-dimensional dimensions, an integrated roughness sensor to detect surface roughness, a miniature ultrasonic flaw detector to detect internal porosity, and a miniature tensile-shear sensor to detect interfacial bonding strength. The closed-loop correction strategy for real-time quality control is as follows: when the size is more than 0.1 mm larger than the set standard value, the feeding speed is reduced by 5%-10% and the cutting amount is increased by 5%-10%; when the size is more than 0.1 mm smaller than the set standard value, the feeding speed is increased by 5%-10% and the cutting amount is reduced by 5%-10%; when the surface scratch depth is greater than 0.02 mm, local re-deposition and secondary finishing are initiated; when internal defects are detected, an alarm is triggered and the energy field parameters are automatically adjusted.

8. The method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips according to claim 7, characterized in that, In step 6, gradient cooling adopts a three-section tunnel with temperatures of 120℃-130℃, 80℃-100℃, and 40℃-60℃, respectively. The cooling time for each section is 2-3 seconds, and the temperature difference between the inside and outside of the sealing strip is less than or equal to 20℃. The frequency of terahertz nondestructive testing is 0.1THz-1THz, and the scanning speed is 5m / min-10m / min.

9. The method for microwave continuous vulcanization and seamless corner forming of automotive sealing strips according to claim 8, characterized in that, The data traceability unit links all production data throughout the process to a unique ID, enabling quality traceability. The data traceability unit includes a laser marking module and an industrial database. The unique ID is a QR code or RFID chip, and the stored data includes material formulas, quantum dot parameters, microwave energy field data, corner printing paths, and test results.

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