Lost foam casting technology, also known as full mold casting, is a casting method in which the foam pattern with the same shape and size as the casting is coated with water-based refractory, dried and put into the sand box, and then added with dry loose sand particles for direct compaction molding. During pouring, the foam pattern is not taken out, and the liquid metal is directly poured onto the pattern. The pattern is gasified under the action of the liquid metal, and the casting is obtained after the liquid metal solidifies. This technology is a kind of non bonding mold (core) casting technology developed on the basis of the patent of “cavity free casting method” invented by the Americans (1958). The main advantages of lost foam casting include:
- The structural design of the casting is flexible, no core and parting surface are required in the casting process, which simplifies the casting process and can produce castings with complex structure;
- Lost foam casting technology improves the precision of castings and the utilization rate of metal materials, and significantly reduces the scrap rate of castings;
- Lost foam casting technology reduces the machining allowance and subsequent processing cost of castings and saves materials;
- Lost foam casting adopts dry (loose) sand compaction molding, which does not need binder, reduces environmental pollution, and is easy to achieve cleaner production.
Therefore, lost foam casting is a near net shape technology, known as “new casting technology in the 21st century” and “green engineering in casting”.