Investment casting and lost foam casting differ significantly in terms of process flow, material utilization, cost structure and application scope.
Investment Casting, also known as lost-wax casting, is an ancient foundry technique. Its process workflow includes wax injection, pattern finishing, cluster assembly, ceramic shell coating, dewaxing, molten metal pouring and post-processing.
Lost Foam Casting, by contrast, follows this process sequence: foam pre-expansion, foam pattern molding, drying, cluster assembly, refractory coating application, sand molding and final pouring.
Regarding material usage: Investment casting utilizes wax to create patterns, which are then coated with refractory materials; the wax is subsequently melted out to create a hollow cavity. Lost foam casting employs expanded polystyrene (EPS) or foam plastic patterns that are embedded directly in sand; the pattern vaporizes and decomposes upon contact with molten metal.
In terms of cost: Lost foam casting involves relatively high initial tooling costs, but offers savings by reducing or eliminating secondary machining operations. Investment casting also incurs significant tooling expenses due to the multi-step wax pattern handling and ceramic shell preparation requirements.
Application Scope:
Lost Foam Casting accommodates a wide range of metal materials, including aluminum alloys, titanium alloys, nickel-based superalloys, and various steels.
Investment Casting is suitable for virtually all types of alloys and excels particularly in producing components with complex geometries, tight dimensional tolerances and excellent surface finishes.