Dry goods sharing Coating common failure analysis and treatment

During the painting process, coating problems will inevitably occur, some defects occur during the curing and drying process of the coating, and some occur after it is put into use.
Poor construction coating procedures can create a variety of problems. If the construction equipment is not properly or usually not well maintained, or if the builder has poor skills, coating defects can easily occur. Experienced applicators can avoid some problems, but some are unavoidable. In addition to when weather conditions have a significant impact on the final result, we need to understand some other conditions that may produce coating defects so that problems can be effectively avoided.
Analysis and treatment of common coating faults
1. Oil removal is not clean
Water-based cleaning agent: (cause analysis)
1、Degreasing tank concentration is too low
2、Degreasing temperature is low and time is short
3、Slot liquid aging
Solution:
1、Add grease remover, adjust the concentration, test indicators
2、Raise degreasing tank temperature and extend dipping time
3、Replace the tank liquid
Organic solvent: (cause analysis)
1、The oil content in the solvent is too high
2、Degreasing time is too short
Solution:
1、Replace the solvent
2、Adjust the time

2. Poor shot blasting quality
Cause analysis:
1、Shot blasting oxidation skin is not clean
2、Steel shot with oil
3、Workpiece deformation and bruising
Solution:
1、Adjust shot blasting time and electric current
2、Replace the steel shot
3、Adjust the loading volume of shot blasting, electric current and blasting time (special workpiece can not be shot blasting)

3.Aging of the tank liquid
Cause analysis:
1、Sunlight shines on the tank liquid
2、The acid, alkali, phosphoric acid, hydrochloric acid or organic solvents are into the tank liquid
3、The steel shot and rust are into the tank liquid
4、The index of coating liquid is not normal
5、Tank liquid is not often updated
Solution:
1、Avoid sunlight exposure to the tank liquid
2、Tank liquid should be away from acid, alkali and organic matter, etc.
3、Regular cleaning of the tank, with 100 mesh filter, while putting a magnet in the tank liquid.
4、Inspect the tank liquid daily and adjust timely
5、Control the storage temperature of the tank liquid (10℃) strictly, and update it artificially when necessary.

4. Poor adhesion of workpiece
Cause analysis:
1、Inadequate oil removal
2、Ballast quality is not good
3、Slot liquid aging, unstable indicators and impurities in the slot liquid
4、Curing temperature and time are not enough
5、The coating layer is too thick
Solution:
1、Check the effect of oil removal
2、Check the quality of shot blasting
3、Detect and adjust tank liquid index timely
4、Check the curing temperature and time
5、Adjust the coating thickness to ensure the amount of coating and salt spray time

5. Workpiece with effusion
Cause analysis:
1、Viscosity is too high, the workpiece temperature is too high
2、Slow centrifugal speed, few times, short time
3、The workpiece has bubbles after dip coating
4、Special workpiece
Solution:
1、Lower the viscosity to the range, the workpiece should be  cooled to room temperature before coating
2、Adjust the centrifugal time, number of times and rotational speed
3、Blow the workpiece on the mesh belt after coating
4、Use brush as needed

6.Poor anti-corrosion performance of the workpiece
Cause analysis:
1、Inadequate oil removal
2、The quality of shot blasting is not good
3、Slot liquid aging, unstable indicators and impurities in the slot liquid
4、Curing temperature is too high or too low, not enough time
5、Coating amount is not enough
Solution:
1、Check the effect of oil removal
2、Check the effect of shot blasting
3、Inspect tank liquid indicators and adjust daily
4、Check the sintering temperature and adjust timely
5、Each coated with a good coating amount of experiments, in order to adjust the process

7. Dacromet coating is not successful
Cause analysis:
1、Workpiece oil removal is not clean
2、Workpiece has oxidized skin or rust
3、the viscosity and the specific gravity of the coating paint are too low
4、Over dumping dry
5、The temperature difference between the workpiece and the tank liquid is too large
Solution:
1、Re-oiling, water film method detection
2、Adjust the blasting time, until the blasting quality qualified
3、Adjust the coating paint index
4、Adjust the centrifugal speed, time and times
5、Ensure the coating amount and reduce the temperature difference