Investment castings are known as the oldest way to create precision parts with metal. To create a desired shape of metal, create the desired pattern out of wax that replicates the shape. The hardened wax design is then dipped in a ceramic material and then removed; later to be melted away or "lost" as heat melts away the wax. After the ceramic material is hardened, molten steel is poured into the opening. The ceramic mold is then removed or broken away from the solid steel which is then ready to use.
History of investment casting dates back to thousands of years ago. Initially bees wax was used to form the desired pattern and then covered in clay. Coal firs were used to melt the metal which was mostly used to form shapes such as idols, jewelry, and art. As technology advanced the precision of metals and its processes yielded extremely predictable results. Dentists were actually some of the first users of investment casting on a more industrial level, using it to create fillings and false teeth.
Advancements in the pattern making, wax, refractories, and melting equipment have resulted in processes that can hold extremely tight dimensional properties. Modern investment castings generally hold dimensions that are measured by a few thousandths of an inch per inch. This allows components to be made that often can be used directly from the manufacturer without subsequent machining. Worst cases allow the parts to be near net shape, which minimizes the amount of handling and processing to be completed on the casting. Users of these casting processes can also deploy the process to create parts that can be poured in thousands of different materials including steel, non-ferrous materials, duplex alloys, aluminum, iron, and more.
Investment casting applications have grown tremendously during modern times. The process is used today to create material handling, pumps and valves, transportation, components in aerospace, food processing and more. Sculptures and original art also use investment casting to create a metal version of the artistic creation. Investment casting may also be used to create medical implements and components used inside the human body.
As history continues to be made, investment castings will continually be redefined through the advancements of materials employed in the process. Improvements in process and cost both show that with each passing year, raw materials combined in such a way can be very beneficial. Investment cast wax, ceramic, and alloys combined with improved equipment to produce castings on a high or low volume basis ensure that the process will be deployed well into the future.