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Shot Weight

Estimate the material needed for one injection shot from part weight, cavity count, and discharged runner weight.

Example starting values are prefilled to demonstrate the calculation. Replace them with your measured, quoted, or job-specific inputs before relying on a result.

Inputs

Molded shot inputs

Range: at least 0.0

Measured finished-part mass for one cavity. Enter in the selected unit; positive mass required.

Defaults to lb for US shop use. Conversion factors: 16 oz/lb and 453.59237 g/lb.

Range: at least 1

Count only cavities producing parts in this cycle. Enter a whole number; fractional counts are rejected.

Range: at least 0

Measured or supplier-provided mass discharged with one shot. Enter 0 for hot-runner systems without discharged runner/sprue material.

Defaults to lb; it may differ from the part-weight unit. Values are converted to lb for the mass balance.

Result

Total molded-part mass (lb)
2.0000
Runner/sprue share of shot mass
0.00
Cold runner/sprue mass (lb)
0.0000
Estimated molded shot mass (lb)
2.0000
Estimated molded shot mass (oz)
32.00
Result interpretation and limitation
Estimated shot mass is the active-cavity part mass plus measured discharged cold runner/sprue mass. For hot-runner molds, enter zero if no runner material is discharged. Compare this estimate with the press maker's resin-specific shot-capacity rating; this calculator does not approve press capacity, barrel utilization, cushion, or process settings.

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