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Simulation Canvas

Gating Flow Visualisation
Pouring BasinØ25mm180mmSprueRunnerGateCavityRiser

Learning Summary

Key Concepts

  • Bernoulli's principle and sprue velocity
  • Reynolds number and flow regime
  • Pressurised vs unpressurised gating ratios
  • Superheat and its effect on fluidity
  • Dross and slag control

Engineering Notes

A well-designed gating system delivers metal to the mold cavity at the lowest velocity consistent with complete filling, minimising turbulence (Re < 2000), temperature loss in the runner, and slag entrapment. Unpressurised systems (choked at the gate) are preferred for iron because the gate is the smallest cross-section, keeping the runner full and dross floating. Pressurised systems use higher velocities and suit non-ferrous alloys where rapid fill is critical.

Reflection

Why does increasing the sprue diameter beyond a certain point lower the quality score even though more metal enters faster? What does the Reynolds number tell us about the quality of the casting?

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