In the production of interior aluminum-plastic panels, the composite quality of the aluminum sheet and plastic is a core factor determining product performance. Its control requires a comprehensive approach encompassing multiple dimensions, including raw material selection, pretreatment processes, composite parameter adjustment, equipment precision maintenance, environmental control, process monitoring, and process optimization.
The quality of raw materials is fundamental to composite quality. The aluminum sheet must be a high-quality substrate with a smooth surface, free of scratches, oil stains, and oxide layers. Its alloy composition must meet design requirements to ensure strong adhesion to the plastic. The plastic core material must be polyethylene (PE) or other suitable materials with a stable melt flow index and low impurity content to avoid uneven composite formation due to differences in melt flowability. Simultaneously, the activity of the adhesive (such as polymer films or modified resins) must match the chemical properties of the aluminum sheet and plastic core material to ensure stable chemical bonding during hot pressing.
The pretreatment process of the interior aluminum-plastic panel directly affects the bonding strength of the composite interface. Pretreatment typically includes three steps: degreasing, neutralization, and oxide film formation. Degreasing thoroughly removes rolling lubricant, anti-oxidation grease, and other contaminants from the aluminum plate surface to prevent residues from hindering adhesive penetration. Neutralization removes impurities such as silicon and magnesium from the aluminum material, preventing them from affecting the uniformity of the oxide film. Oxide film formation involves chromate treatment to generate a fine and stable oxide film on the aluminum layer surface, enhancing the coating's adsorption capacity and providing favorable interface conditions for subsequent lamination. Precise control of lamination parameters is crucial for controlling lamination quality. During hot-pressing, temperature, pressure, and time must be controlled in tandem: excessively high temperatures may cause plastic decomposition or aluminum oxidation, while excessively low temperatures will fail to activate the adhesive. Pressure must be evenly distributed to avoid localized stress concentration that could lead to delamination at the lamination interface. Time must be set appropriately based on material thickness and thermal conductivity to ensure complete adhesive curing. Furthermore, the combined use of short-wave heating and medium-to-long-wave heating can improve heating efficiency and reduce the risk of thermal deformation. Equipment precision and maintenance have a decisive impact on composite quality. The length-to-diameter ratio of the extruder screw must be ≥32 to ensure uniform plasticization of the plastic core material and avoid surface roughness caused by pressure fluctuations; the surface flatness of the hot press rollers must be strictly controlled to prevent indentations or wavy edges on the composite board due to roller surface defects; the automatic edge-aligning conveyor must adjust the offset of the PE core material in real time to ensure precise alignment with the aluminum coil; the electrostatic dust removal device must efficiently remove dust from the core material surface to prevent impurities from being trapped in the composite layer.
Production environment control is a hidden factor in ensuring composite quality. The workshop must maintain constant temperature and humidity to avoid excessive humidity leading to aluminum plate oxidation or adhesive moisture absorption failure; cleanliness must meet cleanroom standards to prevent dust, oil, and other contaminants from adhering to the material surface; lighting must be uniform and free of direct sunlight to avoid material deformation due to localized overheating. In addition, operators must wear anti-static clothing to reduce the impact of static electricity from the human body on the composite process.
Process monitoring and real-time feedback are important means of controlling composite quality. Online inspection equipment, such as laser thickness gauges, infrared thermometers, and vision inspection systems, should be installed at key nodes of the composite production line to monitor the thickness, temperature, and surface defects of the composite panels in real time. Peel strength tests, temperature difference resistance tests, and heat distortion temperature tests should be conducted on sampled products to verify the bonding strength and stability of the composite interface. A quality traceability system should be established to record the raw materials, process parameters, and test data for each batch of products, facilitating problem tracing and process improvement. Process optimization and continuous improvement are long-term strategies for improving composite quality. Production data should be analyzed regularly to identify key factors affecting composite quality, such as adhesive formulation, heating method, and cooling rate, and process parameters should be optimized through Design of Experiments (DOE). New materials and technologies, such as co-extruded adhesive resins and nano-modified plastic core materials, should be introduced to improve the chemical bonding strength of the composite interface. Strengthened technical cooperation with suppliers is essential to ensure the stability and consistency of raw material performance, controlling composite quality fluctuations from the source.
