Precautions of various Powder construction methods
Publish Time: 2018-10-15 Origin: Site
Precautions of various Powder construction methods
(1) Pretreatment of the surface of the substrate .This is the main step affecting the performance and quality of the Powder Coating film.Powder Coating of Industrial aluminum profiles generally include surface cleaning, degreasing, descaling and other pre-treatments; for coatings requiring high levels of phosphating. If the substrate is an aluminum and magnesium casting, a chromate treatment must be used. After treatment, the surface of the substrate reaches Sa2.5 level, the roughness is 20-50μm; when phosphating, it is heated 30~40°C to accelerate the phosphating rate. After phosphating, do not wash it, take natural drying or heat up 60~80°C. Dry, the surface of the ferrous ions and residual acid will continue to react to form a phosphate film.
(2) Covering For parts that do not need to be coated, it is necessary to apply a non-conductive silicone rubber solution or cover with a tape before the workpiece is preheated.
(3) Preheating of the workpiece. In order to obtain a Coating of the desired thickness for the workpiece, the workpiece can be heated to a certain temperature before Spraying. The preheating temperature of the workpiece should be slightly higher than the melting temperature of the Powder. The preheating time of the industrial aluminum profile depends on the size and thickness of the workpiece, and is generally limited to the heat balance between the workpiece and the oven temperature.
(4) When Powder Coating spray, the workpiece must be grounded and the Powder Coating gun head connected to a high voltage power supply. The choice of Powder Coating greatly affects the quality of the film. The coating efficiency of the Powder particles in a spherical shape is most desirable. A powder coating having a small particle size and a small density is less affected by gravity to obtain a higher Powder Coating efficiency.
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