Lab Equipment & Scientific Instrument Manufacturing worked example

Clean Assembly Yield at 68% target first-pass yield: a worked example

This worked example runs the clean assembly yield numbers for a tougher week than the baseline: 68% target first-pass yield instead of the typical 95%. Calculate the first-pass yield for instruments assembled in a cleanroom or controlled environment. Measures the percentage of units that pass all quality checks (particle counts, contamination tests, functional verification) on the first attempt without rework. Helps quality managers track cleanroom assembly effectiveness and justify process improvements.

The inputs for this scenario

  • Units passed first time: 46 instruments (held at the documented default)
  • Total units assembled: 50 instruments (held at the documented default)
  • Target first-pass yield: 68 % (the input this scenario stresses; the baseline uses 95)

Working through the calculation

  • The calculation starts from the formula this tool documents: Clean assembly yield = units passed first time / total units assembled x 100.
  • Clean assembly yield works out to 92 % at these inputs, and this is the headline figure for the scenario.
  • Yield gap to target works out to -24 points at these inputs.
  • Units passed first time works out to 46 count at these inputs.
  • Total units assembled works out to 50 count at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where target first-pass yield sits at 95% and the headline result is 92 %, this scenario lands almost exactly on the baseline at 92 %.
  • Use it to monitor build quality on an instrument assembly line and to check whether a batch met its first-pass yield target. 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

  • Clean assembly yield: 92 % (headline result)
  • Yield gap to target: -24 points
  • Units passed first time: 46 count
  • Total units assembled: 50 count

Run it with your numbers

  • To rerun this with your own numbers, open the live Clean Assembly Yield calculator, set target first-pass yield to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.