Lab Equipment & Scientific Instrument Manufacturing worked example

Clean Assembly Yield at 99% target first-pass yield: a worked example

What does the result look like when target first-pass yield reaches 99%? The full calculation is worked below with real intermediate numbers. Use after a cleanroom assembly batch to measure first-pass yield against your target. Low yield indicates contamination issues, gowning failures, or process deviations that need corrective action. Common for optical instruments, laser systems, semiconductor test equipment, and sterile lab devices.

The inputs for this scenario

  • Units passed first time: 46 instruments (unchanged)
  • Total units assembled: 50 instruments (unchanged)
  • Target first-pass yield: 99 % (raised for this scenario; the documented default is 95)

Working through the calculation

  • Applying the documented formula (Clean assembly yield = units passed first time / total units assembled x 100) to the inputs above produces each figure below.
  • At this operating point the engine returns 92 % for clean assembly yield, the number this scenario is built around.
  • At this operating point the engine returns 7 points for yield gap to target.
  • At this operating point the engine returns 46 count for units passed first time.
  • At this operating point the engine returns 50 count for total units assembled.

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 %.
  • A figure at this level is achievable when target first-pass yield is genuinely sustained, not just peaked for a shift. First-pass yield counts a pass or fail per unit but does not weight defect severity, so two batches with the same yield can carry very different rework burdens.

Results at a glance

  • Clean assembly yield: 92 % (headline result)
  • Yield gap to target: 7 points
  • Units passed first time: 46 count
  • Total units assembled: 50 count

Run it with your numbers

  • Every input above is editable in the live Clean Assembly Yield calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.