Precautions for Powder-Coated Aluminum Profiles
1. Substrate pretreatment
Surface cleanliness: Before spraying, the oil, oxide layer and impurities on the surface of the aluminum profile must be thoroughly removed to avoid insufficient coating adhesion or bubbles. Chemical treatment process: It is recommended to perform chromization or phosphating treatment to enhance the bonding between the coating and the substrate and improve corrosion resistance. Alloy type adaptation: 6063 aluminum alloy is easier to achieve uniform coating due to its good ductility and high surface flatness; 6061 aluminum alloy should pay attention to its high copper content, which may affect the color consistency of the coating and require optimization of pretreatment parameters.
2. Powder spraying process control
Spraying temperature: The curing temperature must be strictly controlled at 180-200℃. Too low temperature will result in insufficient coating hardness, and too high temperature may cause deformation of the substrate or embrittlement of the coating. Powder uniformity: The spray gun distance and air pressure should be adjusted during electrostatic spraying to avoid uneven coating thickness or missed spraying (recommended thickness 60-80μm).
Environmental conditions: The spraying workshop needs to be kept dry and dust-free. When the humidity is higher than 70%, it is easy to cause granularity or orange peel phenomenon on the coating surface.
3. Finished product quality control Adhesion test: Verify the coating bonding strength through the cross-cut method or impact test to avoid peeling during transportation or installation.
Weather resistance verification: For outdoor use scenarios (such as building doors and windows), ultraviolet aging tests are required to ensure that the coating's anti-fading ability meets the standard.
Color difference and appearance inspection: Color cards need to be compared between batches to prevent color differences due to differences in powder batches or fluctuations in curing parameters.
4. Installation and maintenance Cutting protection: When cutting profiles on site, the incision needs to be protected to avoid local corrosion caused by metal exposure. It is recommended to apply special protective paint.
Cleaning method: Use neutral detergent for daily maintenance, and prohibit strong acid/alkali solvents to prevent chemical damage to the coating.
Adaptability to extreme environments:
In coastal areas with high salt fog, 6063 aluminum alloy + thick coating solution is preferred;
In industrial pollution areas, the coating density needs to be increased or chemically resistant powder types need to be selected.
5. Selection and design recommendations
Structural matching: Complex cross-section profiles (such as broken bridge aluminum with insulation strips) need to ensure that powder spraying covers all grooves to avoid weak coating areas.
Economic balance: Standard powder process can be used for ordinary building scenes; fluorocarbon powder is recommended to improve durability for high-demand scenes (such as airports and hospitals).
