Investment casting is a sophisticated metal forming process that generally involves using a wax pattern surrounded by a ceramic shell to form a mold. Once the shell is dry, the wax is melted out, and a ceramic mold is formed. Molten metal is poured into this mold to form a casting component, which may require additional machining after cooling to achieve the desired end results. Intricate shapes can be produced while maintaining extremely high degrees of dimensional accuracy and surface quality.
During the design process, investment casting can also be a useful option for prototyping purposes. Rapid prototyping, in particular, can help designers and engineers quickly gather feedback on the viability of a potential component, by creating a physical representation based on the initial drawings and designs. Corrections and revisions can then be made before the final production process begins. This article looks at the rapid prototype for investment castings.
Making prototypes is one of the building blocks of proving a design concept before going into full production. It helps to spotlight any potential problems and allows process engineers to make necessary adjustments. Rapid prototyping is a fast design process that involves creating an idea, quickly generating a prototype, and testing that physical part or model.
A hard-tooled wax pattern can be used for prototyping, but most modern foundries use as a cost-effective and efficient solution for rapid prototyping, as well as small production runs. 3D printing can be used to develop complex investment castings which require design alterations, or are under a tight deadline. 3D printing eliminates the need for pattern tooling production; speeds up the casting process, design, and validation; and reduces overall development time when a hard tool is desired for scalable mass production.
The amount of precision in the prototype is based on the stage of development. A low-fidelity prototype might be created initially to study perceived advantages and potential problem areas, whereas a high-fidelity prototype is created as the design moves closer to that of finished investment casting.
In general, the steps in the rapid prototype for investment casting process are:
3D printing is considered to be a layered additive form of rapid prototyping (RP). Other processes which may be used to create prototypes include subtractive, where material is removed through CNC processes.