I. Defect classification and causes

1. Defects classification

1) Geometric defects: die casting shape, size and technical requirements have deviation, size over the difference, deflection, deformation, and so on.

2) Surface defects: die casting appearance is bad, there are patterns, flow marks, cold segregation, spots, lack of meat, burrs, and flying edges.

3) internal defects: porosity, shrinkage, shrinkage, cracks, inclusions, etc., internal organization, and mechanical properties do not meet the requirements.

2. Causes and factors affecting

(1) die-casting machine cause

Die casting machine performance. The energy provided can meet the required injection conditions: injection force, and injection speed. Clamping force is sufficient. Die casting process parameters selection and regulation is appropriate, including pressure, speed, time, and punch stroke.

(2) die-casting mold cause

Mold design: mold structure, gate size, and location, overflow system size and location, top rod and layout, cooling system mold processing: mold surface roughness, processing accuracy, hardness

Mold use: temperature control, surface cleaning, maintenance

(3) die casting design cause

Die casting wall thickness, corner position, pulling mold slope, hot section position, deep concave position, etc.

(4) Die casting operation caused by

Alloy pouring temperature, melting temperature, coating and spraying amount, production cycle

(5) alloy material caused by

Raw materials and furnace composition, cleanliness, ratio; melting process. Any of the above factors are incorrect, and may lead to defects in the production of