Gate design is a major decision in mold construction. Gate location, size, and type will influence ease of molding, part dimensional stability, toughness, appearance, need for trimming, and electrical properties. Problems relating to venting, core deflection and weld or knit lines can be prevented or solved using the proper gate and location. Stat-Rite compounds can be molded with a variety of different gate designs, but very high shear pin gating that produces substantial additional heat or melt fracture should be avoided when ever possible.
Because the gate area is often highly stressed, it should be located so that the product''s properties and appearance are not adversely affected.
GATE LOCATIONS SHOULD:
1. Ensure a balanced flow (rapid and uniform filling) in the cavity so that certain areas of the part are not over packed;
2. Ensure mold fills under realistic temperatures and pressures;
3. Minimize weldlines as much as possible, or position them in non critical areas;
4. Prevent "jetting" by positioning the gate so that the material flow is smooth and uniform;
5. Avoid air entrapment;
6. Gate into the thickest section and direct material flow from thick to thin sections.