Quality control of prepainted steel coils

The control of coating quality of color coated board is usually divided into three stages.

That is, pre-coating control, coating construction process and after coating according to the degree of failure control coating.
The control before coating and in the coating construction process is very important, can be said to play a decisive role, and the quality control after coating is actually the feedback of the first two stages, is a quality defect causes of the search means.
Therefore, operators in the whole process of coating construction, to strictly follow the process and operation procedures.

The pre-coating control mainly includes the following inspection steps:

(1) check whether the steel strip has been tested and analyzed for surface defects and shape before surface treatment.

(2) check the degreasing cleaning effect of the steel strip surface.

(3) check whether the thickness of chemical liquid film on the surface of steel belt is in accordance with national or industrial standards.

(4) check whether the surface of the steel strip meets the requirements of surface temperature and humidity of the coated substrate.

(5) models and specifications of coatings and diluents, and viscosity before use.

(6) ambient temperature of coating chamber.

The control of coating construction process mainly includes the following inspection links:

(1) wet film thickness of base and finish coatings.

(2) whether the wet film is missing or discontinuous.

(3) whether the speed ratio of each roller on the coating head to the production line meets the technical requirements.

(4) drying temperature of each section of the curing furnace.

The control after coating mainly includes the following inspection steps:

(1) check the state of the coating surface, including whether there are surface defects, gloss and color.

(2) check whether the total dry film thickness meets the design requirements according to national or industry standards.

(3) check the adhesion of the coating to the substrate and the adhesion between the coatings.

(4) check other properties of the coating according to the quality standard of the coating.