Metals, Steel, Aluminum & Coil Processing worked example

Coil Defect Rate at 68% inspection coverage: a worked example

Suppose inspection coverage falls to 68%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Estimate the coil defect rate by dividing defects found by inspection hours and adjusting for inspection coverage to get defects per hour.

The inputs for this scenario

  • Defects found: 24 defects (held at the documented default)
  • Inspection hours: 8 hr (held at the documented default)
  • Inspection coverage: 68 % (the input this scenario stresses; the baseline uses 95)

Working through the calculation

  • The calculation starts from the formula this tool documents: Defect rate = defects found รท inspection hours.
  • Coverage-adjusted defect rate works out to 2.04 defects/hr at these inputs, and this is the headline figure for the scenario.
  • Raw throughput works out to 3 defects/hr at these inputs.
  • Inspection coverage works out to 68 % at these inputs.
  • Inspection hours works out to 8 hr at these inputs.

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 28.42% below the baseline at 2.04 defects/hr.
  • It computes raw defect rate as defects found divided by inspection hours, then multiplies by inspection coverage to give a coverage-adjusted defects-per-hour figure. When the numbers land here, the stressed input is the lever to work; the walkthrough above shows exactly how much each output recovers as it climbs back toward the baseline.

Results at a glance

  • Coverage-adjusted defect rate: 2.04 defects/hr (headline result)
  • Raw throughput: 3 defects/hr
  • Inspection coverage: 68 %
  • Inspection hours: 8 hr

Run it with your numbers

  • To rerun this with your own numbers, open the live Coil Defect Rate calculator, set inspection coverage to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.