In the surface spraying process of bear ornaments, orange peel texture is a key issue affecting the appearance quality of the ornaments. Its occurrence is closely related to multiple factors, including paint characteristics, spraying parameters, environmental conditions, and substrate treatment. To avoid this defect, systematic control is needed from dimensions such as paint mixing, spraying process optimization, environmental control, and equipment maintenance.
Paint mixing is fundamental to preventing orange peel texture. The viscosity of vinyl paint directly affects leveling properties. If the viscosity is too high, the paint will not flow sufficiently after spraying to form a smooth surface, easily leading to orange peel texture. Therefore, the paint viscosity should be adjusted according to the ambient temperature, following the principle of "slightly higher viscosity at low temperatures and slightly lower viscosity at high temperatures." Simultaneously, the choice of solvent is crucial. Low-boiling-point thinners tend to evaporate before the paint mist reaches the surface of the coated object,
leading to reduced paint flowability. High-boiling-point organic solvents should be used or leveling agents should be added to extend the leveling time and reduce the risk of orange peel texture. Furthermore, the paint should be used promptly after mixing to avoid performance changes due to hardener reactions.
Optimizing spraying process parameters is key to preventing orange peel texture. The spray gun pressure, nozzle diameter, and spraying distance must be precisely matched. Insufficient pressure or an excessively large nozzle diameter will result in poor paint atomization, failing to evenly cover the bear-shaped decorative item. If the spraying distance is too close, paint will accumulate in certain areas; if the distance is too far, excessive solvent evaporation will occur, both leading to orange peel texture. It is recommended to use a layered spraying process, following the principle of "thin coats, multiple passes," allowing sufficient flash-dry time after each coat to avoid excessively thick coats that cause rapid solvent evaporation on the surface and residue on the underlying layers. Simultaneously, the spray gun speed must be uniform to avoid uneven film thickness, affecting leveling.
Environmental conditions significantly affect spraying quality. Excessively high temperatures accelerate solvent evaporation, shortening the paint leveling time and causing premature film setting. Excessive humidity may interfere with normal coating leveling; generally, relative humidity should be controlled within 60%-70%. Excessive wind speed in the spray booth will also accelerate solvent evaporation and disrupt the film leveling process. Therefore, the spray booth temperature should be maintained at around 20℃, the airflow adjusted to the specified range, and construction should be avoided during high-temperature periods. For bear-shaped ornaments, if the substrate temperature is too high, it must be cooled to below 50℃ before spraying to reduce the risk of orange peel texture caused by temperature differences.
Substrate preparation is a crucial step in preventing orange peel texture. Oil, dust, or uneven roughness on the surface of vinyl ornaments will affect paint adhesion and leveling. Before spraying, the substrate surface must be thoroughly cleaned, and surface roughness should be increased through sanding or sandblasting to ensure sufficient paint penetration and mechanical anchoring. For complex bear-shaped ornaments, special attention should be paid to cleaning and treating details to avoid orange peel texture caused by paint buildup or incomplete coverage.
Equipment maintenance and process monitoring are necessary measures to ensure spraying quality. Poor atomization of the spray gun, nozzle wear, or clogged air caps will lead to uneven paint atomization. Nozzles and air caps must be cleaned regularly, and worn parts replaced. Meanwhile, coating equipment must be kept clean to prevent oil, water, and other foreign matter from contaminating the paint and affecting leveling. At the coating inspection station, visual inspection or an orange peel analyzer can be used to check the paint film surface, promptly identifying and addressing orange peel issues, providing quantitative data for quality control.
Optimizing the drying process is equally important for reducing orange peel. Water-based topcoats should be heated slowly during drying to avoid premature drying of the paint film surface without complete evaporation of the internal solvent, which can cause orange peel. It is recommended to control the heating time within a reasonable range to ensure uniform drying and improve leveling.
Preventing orange peel defects in the surface spraying process of bear ornaments requires comprehensive measures across multiple aspects, including paint mixing, spraying parameters, environmental control, substrate treatment, equipment maintenance, and drying processes. Through systematic control, spraying quality can be significantly improved, ensuring a smooth and even surface for the ornaments, meeting both aesthetic and functional requirements.
