1, reasonable wall thickness.Under the condition of promised to minimal casting wall thickness, may be a bit thin, as far as possible namely can guarantee molten metal has good mobility, can avoid to produce caused by excessive shrinkage of casting defects such as shrinkage cavity.2, uniform wall thickness.Refers to the various parts of the wall thickness uniform cooling rate.Thin wall partition, all round the walls should be thick.Objective: to reduce the stress, deformation and cracking;To prevent the hot section shrinkage cavity.3, transition connection.Structure of the rounded: avoid hot forming;To improve the stress distribution;Avoid the damage of sand mold and sand holes.Uniform transition: casting on wall or floor handover in different directions, should avoid to cause the metal gathered (hot), and produce shrinkage cavity.With rounded corners, cant, taper gradually transition purpose: to prevent stress concentration and cracking.4, the big plane tilt.Objective: to use padding and exhaust.5, reduce the deformation.(heat treatment) with symmetrical structure, adding stiffening ribs.6, free shrinkage.Objective: good decrease caused by shrinkage stress of stress cracking and deformation.