Investment Casting Specialist
Investment casting, also known as lost-wax casting, is the cadillac of metal casting. The multi-step process produces cast metal parts with intricate shapes, smooth, non-porous surface finish, and very precise dimensional tolerances. The process Therma Fab uses involves creating a wax pattern or model of the desired part, coating it with a refractory material to form a mold, and then removing the wax to leave a cavity into which molten metal is poured.
Here's a step-by-step overview of the investment casting process Therma Fab can do for you:
Pattern Creation: A pattern or replica of the desired part is created using wax or another material that can be melted away. There is also a gate attachment to the part that is later removed (after its used to let metal flow into the mold).
Assembly: These wax patterns are attached to a central wax sprue to form a tree-like assembly, which will eventually allow the molten metal to flow through the entire mold.
De-waxing: Once the ceramic shell is sufficiently thick and dry, the entire assembly is heated in an autoclave or furnace to melt and remove the wax (hence the term "lost-wax casting"), leaving behind a cavity in the shape of the desired part.
Burnout: After the wax is removed, the ceramic shell mold is fired at a higher temperature to further strengthen it and remove any residual wax or moisture.
Casting: The ceramic mold is preheated, and molten metal is poured into the cavity created by the wax pattern. The metal fills the cavity and takes the shape of the original wax pattern.
Cooling and Solidification: After the molten metal is poured, it is allowed to cool and solidify within the ceramic mold.
Shell Removal and Finishing: Once the metal has solidified, the ceramic shell is broken away or removed using various methods, revealing the metal casting. The casting may undergo additional processes such as machining, polishing, or heat treatment to achieve the desired final shape, dimensions, and surface finish.
Investment casting is often chosen for parts that require complex geometries, high precision, intricate details, or a superior surface finish. Therma Fab can help you create your investment castings today!