Rare Earth Magnet & Motor Materials worked example

Rework Cost at 50% salvageable share: a worked example in rare earth magnet & motor materials

Suppose salvageable share falls to 50%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Estimate the cost of reworking sintered rare earth magnets through regrind, recoat and re-inspection before they re-enter the motor build.

The inputs for this scenario

  • Magnets reworked: 400 pieces (held at the documented default)
  • Rework labor and remachining rate: 6.5 $/piece (held at the documented default)
  • Salvageable share: 50 % (the input this scenario stresses; the baseline uses 70)
  • Recoat line setup charge: 850 $ (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Total rework = magnets reworked x remachining rate x salvageable share + recoat setup.
  • Total rework cost works out to 2,150 $ at these inputs, and this is the headline figure for the scenario.
  • Rework cost per unit works out to 5.38 $ / piece at these inputs.
  • Variable rework cost works out to 1,300 $ at these inputs.
  • Fixed rework cost adder works out to 850 $ at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where salvageable share sits at 70% and the headline result is 2,670 $, this scenario comes in 19.48% below the baseline at 2,150 $.
  • It computes total rework spend, per-magnet rework cost, and the split between variable remachining labor and the fixed recoat setup charge. 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

  • Total rework cost: 2,150 $ (headline result)
  • Rework cost per unit: 5.38 $ / piece
  • Variable rework cost: 1,300 $
  • Fixed rework cost adder: 850 $

Run it with your numbers

  • To rerun this with your own numbers, open the live Rework Cost calculator, set salvageable share to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.