Metals, Steel, Aluminum & Coil Processing worked example
Coil Defect Rate at 99% inspection coverage: a worked example
What does the result look like when inspection coverage reaches 99%? The full calculation is worked below with real intermediate numbers. Use it when a quality manager tracks how many surface or edge defects are caught per inspection hour across coils.
The inputs for this scenario
- Defects found: 24 defects (unchanged)
- Inspection hours: 8 hr (unchanged)
- Inspection coverage: 99 % (raised for this scenario; the documented default is 95)
Working through the calculation
- Applying the documented formula (Defect rate = defects found รท inspection hours) to the inputs above produces each figure below.
- At this operating point the engine returns 2.97 defects/hr for coverage-adjusted defect rate, the number this scenario is built around.
- At this operating point the engine returns 3 defects/hr for raw throughput.
- At this operating point the engine returns 99 % for inspection coverage.
- At this operating point the engine returns 8 hr for inspection hours.
How this compares with the baseline
- Against the tool's baseline example, where inspection coverage sits at 95% and the headline result is 2.85 defects/hr, this scenario comes in 4.21% above the baseline at 2.97 defects/hr.
- A figure at this level is achievable when inspection coverage is genuinely sustained, not just peaked for a shift. Multiplying by coverage scales the visible rate to what you sampled; it does not statistically project defects in the uninspected fraction.
Results at a glance
- Coverage-adjusted defect rate: 2.97 defects/hr (headline result)
- Raw throughput: 3 defects/hr
- Inspection coverage: 99 %
- Inspection hours: 8 hr
Run it with your numbers
- Every input above is editable in the live Coil Defect Rate calculator, which recalculates instantly and can be shared with the inputs intact.
Last reviewed 2026-05-12.