Coating on the vertical surface of the paint, during formation process of film process, wet film flow downwards by the influence of gravity, so that the paint film produces uneven streaks and flow marks phenomenon called flow hanging.
The cause of the flow hook
1, personnel factors:
(1) Spraying operation is improper, the gun moves too slowly, resulting in a spray overlap, paint film is too thick.
(2) Spray distance is less than the standard spray distance resulting in an increase in local spraying volume, paint film is too thick.
2, equipment factors:
(1) Improper use of the tool, spray gun nozzle diameter is too large, spray flow is large, resulting in flow hanging.
(2) Insufficient compressed air pressure, poor atomization of paint, uneven thickness of the paint film, resulting in flow hanging.
3, material factors:
(1) The paint used does not match.
(2) Solvent is too much, resulting in paint viscosity lower than the construction requirements, resulting in hanging.
(3) Heavy pigments or uneven grinding of pigment are used in the coating.
4, process factors:
(1) The robot spray distance setting is unreasonable, resulting in the local film thick too thick, resulting in flow hanging.
(2) The temperature and humidity setting range and construction requirements do not match.
(3) Spray parameters set unreasonable, resulting in local paint film too thick, resulting in flow hanging.
5, environmental factors:
(1) Spraying ambient humidity exceeds process requirements.
(2) The spray ambient temperature exceeds the process requirements.
(3) The spray ambient temperature is too low.
Common measures to solve the flow defect
1, improve the skill proficiency of paint personnel, control paint film spray uniform, not too thick spraying at a time (generally controlled at about 20 m).
2, strictly control the construction viscosity of paint.
3, choose the right spraying tools, before construction to check whether compressed air meets the process requirements.
4, strengthen the site temperature and humidity regulation, to ensure that the construction site temperature and humidity to maintain the process range.
5, adjust the coating formulation or add flow inhibitors.
6, reduce the spray flow, increase the spray distance.
7, in the old paint film before the new paint pre-polishing treatment.