In the aluminum-glass lamination process, bubble formation is a core issue affecting product quality, stemming from multiple factors including raw materials, equipment condition, process parameters, and operational procedures. Optimizing the lamination process requires systematic improvements in three aspects: source control, process monitoring, and end-stage adjustments, to reduce the negative impact of bubbles on the performance and appearance of the laminated components.
Raw material quality control is the primary step in reducing bubbles. EVA film, a key lamination material, directly influences bubble formation due to its hygroscopicity and molecular structure stability. If the film is exposed to high humidity after cutting, it will absorb moisture from the air, which vaporizes during lamination heating, forming bubbles. Therefore, it is crucial to strictly control the humidity of the film's storage environment, ensure its airtight packaging, and use it promptly after cutting to avoid prolonged exposure. Simultaneously, it is essential to select a reliable film supplier to avoid decomposition and gas generation during lamination due to unreasonable formulations or excessive impurities. Furthermore, the flatness and cleanliness of the glass surface are equally critical. If the glass has tiny pits or dust deposits, air can easily be trapped in the gaps during lamination, forming bubbles. Therefore, thorough cleaning and visual inspection of the glass are necessary before lamination.
The equipment status and parameter settings of the aluminum plate glass laminating machine are crucial for bubble control. Insufficient vacuum capacity is a common cause of bubble formation. If the vacuuming time is too short or the vacuum pump performance deteriorates, gas inside the module cannot be fully expelled, and during pressurization, the gas is compressed between layers, forming bubbles. Therefore, it is necessary to regularly check the performance of the vacuum pump and the sealing of the vacuum pipeline to ensure vacuuming efficiency. The uniformity of the heating plate temperature is equally critical. If the local temperature is too high, the EVA will solidify prematurely, causing gas to be trapped in uncrosslinked areas. This can be addressed by laying a high-temperature cloth on the heating plate or adjusting the heating power distribution to control the temperature difference within a reasonable range. Furthermore, the lamination pressure needs to be dynamically adjusted according to the material characteristics and module thickness. Too low a pressure will result in poor adhesion between EVA and glass, leaving gas residue; too high a pressure may cause material deformation or equipment overload. The optimal pressure range needs to be determined through testing.
Precise matching of process parameters is a key technology for reducing bubbles. Lamination time and temperature need to be controlled in tandem. If the lamination time is too long or the temperature is too high, the organic peroxides in EVA will decompose excessively, producing oxygen and forming bubbles. If the time is too short or the temperature is too low, the EVA will not be able to fully melt and cross-link, resulting in insufficient interlayer bonding. A layering temperature rise profile needs to be developed based on the film type and glass thickness. For example, low-temperature pre-pressing can initially expel gas, followed by high-temperature curing to ensure complete cross-linking. Furthermore, the timing of vacuuming and pressurization needs optimization. During the vacuuming stage, segmented evacuation can be used, first rapidly reducing the pressure to a certain value, then slowly evacuating to the ultimate vacuum to reduce gas backflow. During the pressurization stage, the pressure should be gradually increased after the EVA is completely melted to avoid gas being compressed between layers.
Standardized execution of operating procedures is the final guarantee for bubble control. Operators must strictly adhere to the material loading time limits to avoid premature melting of EVA due to material delays, which would affect the vacuuming effect. Simultaneously, the laying method of EVA film and glass must be standardized to ensure the film is flat and wrinkle-free, and the glass is accurately positioned without deviation, avoiding residual gas in the interlayer gaps due to uneven layout. Furthermore, residual EVA and impurities inside the aluminum plate glass laminating machine must be cleaned regularly to prevent contamination of new components or blockage of vacuum lines, thus affecting vacuuming efficiency.
Environmental control and process monitoring are auxiliary means of bubble prevention. Excessive humidity in the workshop will cause raw materials to absorb moisture; humidity must be controlled within a reasonable range using dehumidification equipment. Excessive dust in the workshop will contaminate material surfaces; air purification systems must be used to reduce suspended particles. At the same time, a process monitoring system must be established to monitor parameters such as vacuuming pressure, heating plate temperature, and lamination time in real time using online detection equipment. If abnormalities are detected, adjustments should be made promptly to avoid batch bubble defects.
