3, the weight tolerance test:Expressed in percentage of casting the nominal weight of the casting of the difference between the actual landed weight and the nominal weight maximum allowable values.With casting size tolerance corresponding divided into 16 levels, MT1 - MT16 said.4, partial weight: casting weight and the nominal weight is between deviation or negative deviation. 5, dimensional tolerance: casting parts size allowed limit deviation.6, size stability: casting during the process of use and storage performance of the same size remains the same.7, machining allowance:In order to ensure the casting dimensions and parts machining precision, advance more during the casting process design and cut off when machining metal layer thickness.8, hexing precision casting surface roughness: casting surface made up of tiny spacing and peak valley micro geometric features.