The gap between investment enterprises at home and abroad was described

and improving quality of investment castings by strengthening process control was reviewed.Trial-production and process control before production-volume should be strengthened to improve the geometric accuracy

including improving design of product

strictly measuring the sizes of mould

wax pattern and castings

and strictly controlling the quality of wax

temperature of injection

temperature and humidity of wax pattern chamber.Besides controlling the viscosity of coating

SiO2 content and pH values

the humidity and uniform temperature of surface layer of mold shell should be considered in eliminating surface defects in the castings.