2. GOALS of Gating System Fill the mold cavity completely before freezing Minimizing turbulence Removing inclusions Regulate flow of molten metal Avoiding erosion Trap contaminants Establish directional solidification

3. GATING SYSTEM continued… ELEMENTS OF GATING SYSTEM POURING BASIN – To prevent vortex formation – To hold the slag and dirt back SPRUE – Should be tapered – Eliminates the problem of air aspiration

7. DESIGN OF RUNNER AND INGATES

10. SPRUE BASE WELL – Reduce momentum – Reduce mould erosion – A general guide line RUNNER: – Located in parting plane – Connects sprue and in-gates – Extended further after it encounters the in-gate GATING SYSTEM continued…

11. IN-GATE: – Openings for metal to enter mould cavity – TOP GATE Metal falls from top Favourable temperature gradient But causes mould erosion – BOTTOM GATE Does not cause any erosion Very unfavourable temperature gradient – PARTING GATE Derives the best of the above Widely used GATING SYSTEM continued…

12. RISER: – A reservoir of molten metal – Supplies molten metal to avoid void formation – Should have sufficient volume to compensate shrinkage – Top Riser – Blind risers GATING SYSTEM continued…

16. SOLIDIFICATION OF METALS