The first step in the water wax casting method is to use water-soluble wax to create an exact and detailed final product design. First, a comprehensive design and modelling phase is carried out, during which CAD (Computer-Aided Design) software generates a 3D model of the part. Here, accuracy is crucial since the model must include every final product feature, including intricate geometry and minute details.
A mould is constructed once the design is finished, usually out of aluminium or steel. The wax pattern will match precisely because the deterioration is a negative replica of the final result. After being heated to a liquid state, the water-soluble wax—well-known for having a strength-to-solubility balance—is extracted. This liquid wax is injected into the mould under pressure, filling the mould cavity.
When the wax cools and hardens inside the mould, the precise shape and features of the finished object are imprinted on it. The solid wax design is cautiously removed once the mould has been opened. Any design errors are corrected to ensure the final cast part is accurate.
Subsequently, the individual wax patterns are assembled onto a sprue to create a tree-like structure. Because it ensures that each component is correctly supported and influences the flow of molten metal throughout the casting process, this assembly step is crucial. The assembly also features gates and runners, which are channels that let air escape while guiding the molten metal to the proper locations.
It has to have a ceramic shell built around it after the wax assembly. This technique begins with mixing ceramic powder with a liquid binder to make a ceramic slurry. The content and consistency of this slurry determine the final shell’s strength and stability.
The wax assembly is then dipped into the slurry and thoroughly coated. While the slurry is still wet, a coarser ceramic particle known as stucco material is sprinkled over the body. The stucco material begins to construct the shell by adhering to the slurry. Repeating this process gives the construction more time to dry and firm between layers. The drying environment must be precisely controlled in terms of temperature and humidity to preserve the integrity of the shell.
Once it has set and firmed, the wax pattern inside the ceramic shell needs to be removed. The most common technique uses steam and pressure to melt wax in an autoclave. After that, the melted wax leaves the shell, leaving a hollow behind. Because the wax is soluble in water, it may be removed entirely, leaving a precise, clean mould in its place.
After being de-waxed, the ceramic shell is burned in a furnace at a high temperature. By doing this, any remaining wax residue is eliminated, and the ceramic substance is strengthened. Before the molten metal is cast, the shell is also heated to the proper temperature to prevent thermal shock and provide a high-quality cast.
When the shell is built, melted metal is carefully poured into the hollow made by the wax design. The type of metal utilised and the pouring process needs to be well controlled to ensure the quality of the final product and maintain the integrity of the shell. The metal inside the body is then given time to cool and solidify.
The ceramic shell is gently pulled off when the metal is fully formed to reveal the cast portion inside. The component is inspected for defects after removing any remaining ceramic material. The gates and runners that were utilised in the assembly process are also removed at this point.
Additional post-processing methods, such as machining or heat treatment, could be required to ensure that the final product meets specifications and has a satisfactory finish. To ensure that the part meets all applicable standards and requirements, quality assurance techniques are used throughout the process, in addition to strict inspection and testing procedures to identify any areas that need improvement.