Spraying process
The surface of the structural parts of the shelf should adopt the powder electrostatic spraying process. When the structural parts of the shelf are coated by other coating processes, they should comply with the provisions of JB/T 5000.12.
Spray material
Thermosetting powder coatings should meet the requirements of HG/T 2006, in which hardness, adhesion, impact resistance, bending test, alkali resistance, acid resistance, etc. should be tested under the temperature conditions specified in GB/T 9278
Spraying environment requirements
The ambient temperature and relative humidity during coating should meet the requirements of the coating product specification; when the product specification does not require, the indoor temperature should be between 538 °C and the relative humidity should not exceed 85%. When there is condensation on the surface of the component, it should not be painted.
Pre-spraying treatment
- Before powder electrostatic spraying, impurities such as oil, rust and dust on the surface should be removed, and no pretreatment liquid (or cleaning liquid) or other impurities that affect the quality of the coating should be left.
- The quality inspection of the workpiece before and after phosphating shall be carried out in accordance with the provisions of GB/T 6807, including the inspection of the appearance of the phosphating film, the weight of the phosphating film, the corrosion resistance of the phosphating film and the corrosion resistance of the coating film.
- After the surface treatment, the powder spraying operation should be completed within 24 hours.
Spraying requirements
- The color of the coating should meet the color requirements of the sample or swatch confirmed by the customer or the requirements of the order. The coating color and the color of the color card should be visually compared at a distance of 0.5 m under natural light, and there should be no obvious color difference.
- The average thickness of the coating should not be less than 60μm, and the thinnest part should not be less than 40μm.
- The hardness of the coating should not be lower than the hardness of the pencil hardness H grade in GB/T 6739.
- The resistance of the coating to peel off from the substrate should reach the level 0 specified in the test result classification table of GB/T 9286-1998.
- The moisture and heat resistance of the coating should reach the level 1 specified in the GB/T 1740-2007 comprehensive damage rating table.
Quality determination of sprayed surface
If the coating of the storage racking for warehouse components has one of the following conditions, it is judged to be qualified:
- a) slight orange peel;
- b) Inconspicuous pinholes and shrinkage holes;
- c) Insignificant color difference.
If the coating of heavy duty industrial racking components has one of the following conditions, it will be judged as unqualified:
- a) severe orange peel;
- b) Obvious pinholes and shrinkage holes;
- c) serious chromatic aberration;
- d) Important surfaces are exposed or scratched;
- e) bubbling;
- f) Partial shedding.
