Investment casting large castings can be considered in moderately batch application self-hardening resin sand molding and core making.investment casting of heavy castings for sheet small batch production, manual modeling is still important, the method of manual can meet the requirements of various complex is more flexible, does not require a lot of process equipment.Can be used sodium silicate sand, sodium silicate sand mold VRH law, organic ester sodium silicate self-hardening sand, clay self-hardening sand mould and dry type, resin cement sand mold, etc.;For a single production of heavy castings, pit modelling method of low cost, fast production.Batch production or long-term production of finalize the design product box, split box shape modelling method is appropriate, although high mould and sand box to start investing, but from compensated save modelling cycle time, improve the quality of its products.Low pressure casting, die casting, centrifugal casting and other casting method, for equipment and mold is expensive, so only suitable for mass production.