Heat Exchanger, Coil & Radiator Manufacturing worked example

Header Drilling Rate at 68% target drilling rate: a worked example

This worked example runs the header drilling rate numbers for a tougher week than the baseline: 68% target drilling rate instead of the typical 95%. Calculate header drilling completion or defect rate from drilled holes, total required holes, and a target rate for heat exchanger headers and manifolds.

The inputs for this scenario

  • Drilled or accepted holes: 8 holes (held at the documented default)
  • Total header holes required: 250 holes (held at the documented default)
  • Target drilling rate: 68 % (the input this scenario stresses; the baseline uses 95)

Working through the calculation

  • The calculation starts from the formula this tool documents: Header drilling rate = drilled or accepted holes รท total header holes required.
  • Header drilling rate works out to 3.2 % at these inputs, and this is the headline figure for the scenario.
  • Gap to drilling target works out to 64.8 points at these inputs.
  • Drilled or accepted holes works out to 8 count at these inputs.
  • Total header holes works out to 250 count at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where target drilling rate sits at 95% and the headline result is 3.2 %, this scenario lands almost exactly on the baseline at 3.2 %.
  • Use it to track header drilling progress mid-run, gate a header to expansion, or spot a station falling behind its completion 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

  • Header drilling rate: 3.2 % (headline result)
  • Gap to drilling target: 64.8 points
  • Drilled or accepted holes: 8 count
  • Total header holes: 250 count

Run it with your numbers

  • To rerun this with your own numbers, open the live Header Drilling Rate calculator, set target drilling rate to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.