Coating is the key process in the entire color coated aluminium production line. The quality of the coated products directly affects the decorative effect of the product. Therefore, it is necessary to first understand common causes of defects during the painting process. Although there are many causes, the following types are common: paints, aluminum coil roll (the most important factors), color differences between the batches of the coating, insufficient fineness of the aluminum coating, short coating rate, not matched coating and solvent, layering, uneven aluminum coil substrate, uneven film thickness, poor edge deflection etc.

Therefore, raw materials of colour coated aluminium sheet rolls should be selected strictly. The painting equipment must be in good condition and runs stably. No horizontal shaking or vertical shaking should be spotted on the surface. All the rollers of the coating machine will jump laterally and must be controlled within the allowable range, otherwise the surface quality of the coating will be seriously affected. The coating process is closely related to the quality of the coating, and it is necessary to control the relative line speed ratio of the coating roller, the paint roller, the metering roller and the substrate within a certain range. According to the different system and the film thickness of the coated aluminium products, a certain viscosity range is set for the coating to ensure smooth coating and promote the improvement of product quality.

In the curing process of the coating, oven control must be controlled according to requirements, otherwise it will seriously affect the color difference and performance of the pe and pvdf coated aluminum coil. It is required to clean the interior of the painting room to prevent dust, insects and certain ventilation, and to ensure that the surface quality of the coating is not polluted. At the same time, human factors, operator responsibility, technical proficiency and operational normativeness are the key to achieving high quality coating results. Therefore, it is necessary to strengthen the training of operators and let the operators grasp the principles and points of painting technology, strengthen the responsibility, and strictly operate according to the operating procedures to ensure high-quality coated products.