MANUFACTURING – CATING & FOUNDRY CALCULATOR
Riser Volume
A precise tool.
What is the Riser Volume & How does it work?
Risers act as molten‑metal reservoirs that feed a casting during solidification, compensating for the volumetric shrinkage that occurs as the metal changes phase.
The amount of metal a riser must supply is directly related to the casting’s shrinkage allowance. By assuming a uniform shrinkage percentage (S), the required riser volume can be estimated with a simple proportional relationship.
V_{riser}=\frac{V_{casting}\,S}{100 – S}
V_{riser} = required riser volume (cm³)
V_{casting} = net casting volume (cm³)
S = shrinkage allowance (%)
V_{casting} = net casting volume (cm³)
S = shrinkage allowance (%)
Designers often adjust the riser shape or add a safety factor to ensure the calculated volume is sufficient under real‑world cooling conditions, but the formula above provides a solid baseline for quick engineering estimates.
Parameters
Result
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Frequently Asked Questions
What is a riser in casting?
A riser is a molten-metal reservoir that feeds a casting during solidification, compensating for metal shrinkage.
How do I calculate the required riser volume?
Use the formula V_riser = (V_casting * S) / (100 – S), where V_riser is the required riser volume, V_casting is the net casting volume, and S is the shrinkage percentage.
What factors affect the riser volume?
The riser volume is affected by the casting’s volume and its shrinkage allowance. A higher shrinkage percentage requires a larger riser.
Why is a riser necessary in casting?
A riser ensures that the casting receives enough molten metal during solidification, compensating for the metal’s volumetric shrinkage as it cools and changes phase.
Can I use this formula for any type of metal?
This formula assumes a uniform shrinkage percentage, which may vary by metal. It is most accurate for metals with consistent shrinkage characteristics.
Results are for informational purposes only and do not constitute professional advice.