1, metal materials 
Metal materials mainly comes from outsourcing materials precision casting enterprise.And outsourcing is often in bulk metal materials, very few have pressed into tubular, materials are easily confused with different material.Precision casting enterprise, therefore, as far as possible to the chemical composition of each batch purchasing materials with a spectrum analyzer for analysis. 
2, mold material
Performance indicators mainly include: the pattern material melting and solidification temperature interval, heat resistance, thermal expansion rate and shrinkage, strength, hardness, viscosity, liquidity, smearing and ash content, etc.As one of the most important performance indexes of pattern material, shrinkage rate, must be tested, shrinkage rate directly affects the dimension precision of casting and the quality of the shell. 3, silicon solSilica sol physico-chemical parameters mainly include: the content of SiO2, density, content of Na2O, PH, kinematic viscosity, colloid particle diameter, etc., the physical and chemical parameters of the main affects the stability of shell strength, coating and coating powder liquid ratio.