On the phenomenon of flow hanging in painting
First, the definition of sagging
When the coating is applied to the vertical surface, the wet film is flowed downward due to poor resistance to sagging or poor spraying, excessive spraying of paint, etc., resulting in a variety of uneven edges of the lower edge.
Second, the type of sag:
1, sagging. Sink is the phenomenon that the coating is cured and attached to the surface of the board after the vertical and peripheral edges of the processing plate are accumulated.
2, sink. Sinking is the completion of the coating to dry during the coating of local vertical flow, resulting in uneven film thickness of the semicircular, ice-like, wavy and so on the status quo.
3, flowing. Flow is the processing of vertical surface coating a large area of sagging phenomenon.
Third, the impact of sagging:
Serious sagging defects will directly pull down the pass rate of paint, repair will also cause secondary defects, such as: polished after the end, leaving marks, etc., and repair will cause this area coating performance degradation.
Fourth, the cause:
1, improper construction, spray gun and processing board surface too close.
2, the gun speed is too slow, a spray too thick.
3, the spray paint viscosity is not enough, can not be well attached to the board.
4, the construction environment temperature is low, paint drying time is slow.
5, spraying pressure is too low, and the gun diameter is too large.
6, the surface of the processing board unclean, oil, water and other dirt, spray paint can not be well attached to the board.
Fifth, preventive measures:
1. Use the correct spraying method, timely adjust the distance between the gun and the processing plate, using a number of thin coating, appropriate to reduce the size of paint spray fog and other methods to control.
2. Dilute the paint as far as possible in accordance with the provisions of the proportion of the construction viscosity in the process range; the correct choice of solvent, pay attention to the solvent dissolution and evaporation rate.
3. When the temperature is low, please ensure that the temperature is above 10 ℃ to room temperature; strengthen the ventilation, strictly control the spray ambient temperature.
4. Between the two processes to ensure adequate spacing and drying time.
5. Clean up the surface of the debris quickly.