Injection Molding worked example
Shot Size with part weight plus runner weight per shot of 14 g: a worked example
This worked example runs the shot size numbers for a tougher week than the baseline: part weight plus runner weight per shot of 14 g instead of the typical 28 g. Calculate total shot size from part weight, runner weight, number of cavities, and an overfill safety factor.
The inputs for this scenario
- Part weight plus runner weight per shot: 14 g (the input this scenario stresses; the baseline uses 28)
- Number of cavities: 4 cavities (held at the documented default)
- Overfill/cushion factor: 1.08 x (held at the documented default)
Working through the calculation
- The calculation starts from the formula this tool documents: Total shot size = (Part + runner weight) x Cavities x Overfill factor.
- Result works out to 60.48 g at these inputs, and this is the headline figure for the scenario.
- Net shot weight (before overfill) works out to 60.48 value at these inputs.
- Multiplier works out to 1 x at these inputs.
- Factor A x B works out to 56 value at these inputs.
How this compares with the baseline
- Against the tool's baseline example, where part weight plus runner weight per shot sits at 28 g and the headline result is 121 g, this scenario comes in 50% below the baseline at 60.48 g.
- Use it during press selection and mold qualification to confirm the shot falls in the 20%-80% barrel-capacity window before the first trial. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.
Results at a glance
- Result: 60.48 g (headline result)
- Net shot weight (before overfill): 60.48 value
- Multiplier: 1 x
- Factor A x B: 56 value
Run it with your numbers
- To rerun this with your own numbers, open the live Shot Size calculator, set part weight plus runner weight per shot to your actual value, and adjust the remaining inputs to match your operation.
Last reviewed 2026-05-12.