CNC Machining worked example

Lights-Out Machining Capacity at 94% unattended uptime expectation: a worked example

This scenario runs the lights-out machining capacity calculation on the strong side: 94% unattended uptime expectation, with every other input held at its documented default. estimating lights-out machining capacity for production planning, quoting, staffing, or automation review

The inputs for this scenario

  • Unattended parts produced per cycle: 6 parts / cycle (unchanged)
  • Lights-out cycles available overnight: 72 cycles (unchanged)
  • Unattended uptime expectation: 94 % (raised for this scenario; the documented default is 82)
  • Lights-out first-pass yield: 96 % (unchanged)

Working through the calculation

  • Applying the documented formula (Gross lights-out machining capacity = unattended parts per cycle × lights-out cycles available) to the inputs above produces each figure below.
  • At this operating point the engine returns 390 parts for good lights-out machining capacity, the number this scenario is built around.
  • At this operating point the engine returns 432 parts for gross lights-out machining capacity.
  • At this operating point the engine returns 25.92 parts for lights-out machining capacity loss from downtime.
  • At this operating point the engine returns 16.24 parts for lights-out machining capacity loss from scrap or rework.

How this compares with the baseline

  • Against the tool's baseline example, where unattended uptime expectation sits at 82% and the headline result is 340 parts, this scenario comes in 14.63% above the baseline at 390 parts.
  • Use it when planning overnight or weekend unattended runs and committing how many good parts will be waiting at the start of the next shift. Treat this as a target state: the delta against the baseline quantifies what the improvement is worth before you commit to chasing it.

Results at a glance

  • good lights-out machining capacity: 390 parts (headline result)
  • gross lights-out machining capacity: 432 parts
  • Lights-Out Machining Capacity loss from downtime: 25.92 parts
  • Lights-Out Machining Capacity loss from scrap or rework: 16.24 parts

Run it with your numbers

  • Every input above is editable in the live Lights-Out Machining Capacity calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.