Injection Molding worked example

Mold Trial Sample Size with number of cavities in mold of 20 cavities: a worked example

Push number of cavities in mold up to 20 cavities and the picture changes. This example computes every intermediate figure at that operating point. Use this when planning T1 or T2 mold trials, process capability studies (Cpk), or first article inspection sample requirements to ensure statistically valid results.

The inputs for this scenario

  • Number of cavities in mold: 20 cavities (raised for this scenario; the documented default is 8)
  • Minimum shots per cavity for confidence: 30 shots (unchanged)
  • Inspection multiplier (characteristics or repeats): 1 x (unchanged)

Working through the calculation

  • Applying the documented formula (Total sample size = Cavities x Shots per cavity x Inspection multiplier) to the inputs above produces each figure below.
  • At this operating point the engine returns 600 parts for result, the number this scenario is built around.
  • At this operating point the engine returns 600 value for cavities x shots per cavity.
  • At this operating point the engine returns 1 x for multiplier.
  • At this operating point the engine returns 600 value for factor a x b.

How this compares with the baseline

  • Against the tool's baseline example, where number of cavities in mold sits at 8 cavities and the headline result is 240 parts, this scenario comes in 150% above the baseline at 600 parts.
  • It multiplies the number of cavities by the minimum shots per cavity and an inspection multiplier to give the total trial part count. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Result: 600 parts (headline result)
  • Cavities x Shots per cavity: 600 value
  • Multiplier: 1 x
  • Factor A x B: 600 value

Run it with your numbers

  • Every input above is editable in the live Mold Trial Sample Size calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.