Sand Casting Process Parameters

Machining Allowance: Refers to the predetermined metal layer thickness reserved on casting surfaces requiring machining. Its magnitude depends on the type of casting alloy, molding method, casting size, and the position of machined surfaces in the mold

Pattern Draft: An inclined angle added to vertical walls perpendicular to the parting plane to facilitate pattern removal from the mold

Casting Fillet: Rounded corners designed at wall junctions and corners to prevent stress concentration and cracks in castings, avoid mold corner damage, and reduce sand inclusion defects

Core Print: Projections on patterns and cores ensuring core positioning, fixation in the mold, and gas venting during pouring

Shrinkage Allowance: Additional dimensions added to patterns to compensate for solidification and cooling contraction of castings

Advantages:
Clay resources are abundant and low-cost. Recycled clay-bonded sand can be reused after treatment;
The mold manufacturing cycle is short with high efficiency;
Mixed sand maintains workability over prolonged periods;
Wide adaptability for small/large, simple/complex castings across batch sizes (single-piece to mass production)

Disadvantages and Limitations:
Low productivity: Each sand mold is destroyed after one-time pouring, requiring remolding;
Low dimensional accuracy: Poor mold rigidity leads to imprecise castings;
Defect susceptibility: Prone to sand erosion, sand inclusion, and gas porosity defects