How to configure the coating of precision casting
It is really interesting to have some curious customers. Recently, everyone is interested in the preparation method of precision casting coatings, so our company will explain to you:
The physical and chemical parameters of silica sol mainly include SIO2 content, density, Na2O content, PH value, kinematic viscosity, colloidal particle diameter, etc. These physical and chemical parameters mainly affect the strength of the precision casting shell, the stability of the coating and the powder-to-liquid ratio of the coating.
Because it is very difficult for precision casting companies to test these physical and chemical parameters, on the one hand, it is necessary to strengthen the selection, evaluation and confirmation of suppliers. S-830 silica sol, S-1430 silica sol for the back layer. The preparation method of coatings will directly affect the quality of castings in precision casting.
In the preparation of coatings, silica sol is usually added first, then wetting agent is added to mix evenly, refractory powder is added during stirring, and defoamer is added. In order to ensure the quality of the coating, when the surface coating is all new, the stirring time should be more than 24 hours before use. If some of the coating is new, the stirring time can be shortened to 12 hours. The mixing time for the transition layer and the back coating can be less. For the surface coating, when all the new coatings are used, the stirring time is more than ten hours, and when some are new, the mixing time can be shortened by half. If the prepared paint is not used, it should be covered and sealed to prevent water evaporation.