Machine Performance
Doubling MTBF is a capital project. Halving MTTR is often a shelf of spares — and moves availability about as far.
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Operating hours per failure
This is inherent availability, which counts repair time only. Operational availability additionally counts waiting for a technician, waiting for a part and waiting for a production window to release the machine, and in most textile plants that waiting exceeds the wrench time by a wide margin — so the figure here is the optimistic bound. A constant failure rate is also assumed, which suits the flat middle of an asset's life and misrepresents both early-life defects and end-of-life wear-out, exactly the two regimes where maintenance decisions are hardest. Averaging across dissimilar assets destroys the signal; compute it per asset.
MTBF, MTTR & Availability Calculator for Plant Assets — free, with the formula and a worked example, at Textile School.