First, powder coating powder construction requirements
Electrostatic spraying (refer to the coating process of powder coating powder for details)
Coated surface treatment → electrostatic powder coating → melting leveling or crosslinking curing → cooling → product
1. In order to give full play to the characteristics of powder coating powder and extend the service life of the coating film, the surface of the coated material should be strictly pre-treated first.
2. When spraying, the coating must be completely grounded to increase the spraying efficiency of powder coating.
3. The coating with large surface defects should be coated with conductive putty to ensure the level and smoothness of the coating film.
4. After spraying, the objects shall be heated and cured. The curing conditions shall be subject to the technical indicators of the powder products, but the curing temperature and time must be fully ensured to avoid the insufficient curing caused by quality accidents.
5. Check immediately after powder spraying.
6, recycled powder must be screened to remove sundries, according to a certain proportion and new powder mixed.
7, powder supply bucket, powder spraying room and recycling system should avoid the pollution of other different colors of powder, so every time the color must be cleaned.
Matters needing attention
1. Keep away from fire and avoid direct sunlight. It should be placed in a well-ventilated place with a temperature below 35℃.
2. Avoid storing in places easily contaminated by water, organic solvents, oil and other materials.
3. The equipment used in painting operation should be well grounded to eliminate static electricity.
4, avoid the coating machine gratuitous discharge phenomenon.
Two, powder coating powder coating inspection standard
1, appearance inspection: under natural light, different angles of the workpiece detection.
1. Surface smoothness: the paint film on the whole workpiece must be flat, without obvious particles, stains, blisters and pits.
2. Scratches: If the film is not removed, very shallow scratches can be accepted.
3. Insufficient powder (exposed bottom): The lack of spray on the surface seen by the customer is not acceptable.
4. Spot welding marks: If the spot welding marks have been marked on the drawing, the spot welding marks are acceptable.
5. Powder stacking: customers can see that there is no powder stacking on the surface.
6 film color: according to the standard card, check for discoloration. Any color change is not acceptable.
7. Orange stripes: No obvious orange stripes.
2, film thickness: using magnetic thickness meter, accuracy 2um, measurement of no less than three positions, thickness 80-120um.
3, hardness: the use of hardness tester, with 1H pencil line, check whether there is a depression, no is qualified.
4, adhesion: standard reference GB - T9286-1998:0-1 grade for qualified use of a hundred grid knife to draw a series of 1-2mm standard grid line, stick transparent tape (18 to 24mm wide and 50mm long, adhesion greater than 2.94N/10mm). After 1--2min, hold one end of the tape, perpendicular to the coating, and quickly pull apart the coating to see whether it meets the qualification standard of 0-1 level. (Level 0: cutting edge completely smooth, no grid off; grade 1: a little coating is shed at the cut intersection, but the cross cut area is not significantly affected by more than 5%)
5, impact resistance: standard reference GB - T1732-93 using impact meter for 3 times of impact test, check whether cracking, such as no is qualified (50cm. Kg, punch ball diameter 20mm).
6, gloss: 60 degrees mirror reflectivity greater than 75% is qualified.
7, aging resistance: standard reference GB - T1766-2008:0-1 for qualified artificial accelerated aging test 500h, test method refers to GB - T1865-2009 method one. Comprehensive evaluation of grade 0-1 is qualified.