Lost foam casting (LFC, also called as expandable pattern casting) is a type of evaporative-pattern casting process that is similar to investment casting except foam is used for the pattern instead of wax. The detailed process are : First, a pattern is made from polystyrene foam(EPS 、STMMA or EPMMA. Next, the foam cluster is coated with ceramic investment, also known as the refractory coating, via dipping, brushing, spraying or flow coating. This coating creates a barrier between the smooth foam surface and the coarse sand surface. After the coating dries, the cluster is placed into a flask and backed up with un-bonded sand. Once compacted, the mold is ready to be poured. Automatic pouring is commonly used in LFC, as the pouring process is significantly more critical than in conventional foundry practice.
Compared with traditional casting technology, LFC technology has incomparable advantages, and is called as “casting technology of the 21st century” and “green revolution of casting industry” in domestic and overseas casting circles.
The advantages of LFC are as following: 1) higher casting quality and lower cost; 2) no special requirements on material and size; 3) high precision,  maintains an excellent surface finish; 4) great reduction of internal defects; 5) being available for large-scale and mass production; 6) being applicable to the mass production and casting of the same castings; 7) being applicable to manual operation and automatic production line control; 8) the production state of production line meets the requirements of environmental protection; 9) being available to greatly improve the working environment and production conditions of casting line, to lower labor intensity and energy consumption.