Shell Making Process Of Investment Casting

1) Degreasing and degreasing of the module
When using wax-based molds to make investment molds, oil stains on the module surface need to be removed in order to improve the ability of the paint to wet the module surface.
2) Apply paint and sand on the module
Before coating the coating, the paint should be stirred evenly, as far as possible to reduce the precipitation of refractory materials in the paint barrel, adjust the viscosity or specific gravity of the coating, so that the paint can be well filled and wetted the investment mold, when hanging the coating, the module is soaked in the coating, left and right up and down, so that the paint can well wet the investment mold, evenly cover the surface of the module. Once the paint is applied, sanding is ready to begin.
3) The shell is dried and hardened
After each layer of shell is coated, it must be dried and hardened, so that the binder in the coating is transformed from sol to jelly and gel, and the refractory materials are connected together.
4) Melt the mold in the self-shaped shell
After the shell is fully hardened, the module needs to be melted from the shell, because the module is usually made of wax-based molding, so this process is also called dewaxing. According to the different heating methods, there are many, dewaxing methods, the more used is hot water method and the same pressure steam method.
5) Roasted shell
If molding (sand filling) is required, the sand grains in the demolded shell burial box are first baked in the oven before roasting. If the shell has high temperature strength and does not need to be poured, the demolded shell can be sent directly to the furnace for roasting. When roasting, gradually increase the furnace temperature, heat the shell to 800-1000 °C, keep warm for a period of time, and then pour.