Dictionary · Manufacturing
Six Big Losses
The Six Big Losses are Nakajima's classification of equipment losses, mapped two per OEE component: breakdowns and setup/changeover (Availability); idling/minor stoppages and reduced speed (Performance); startup rejects and production rejects (Quality).
The taxonomy's value is that each loss pair has a different owner and a different first fix. “Our OEE is 63%” starts an argument; “changeovers cost us 41 minutes a shift” starts a project.
Sources: Nakajima (1988)
Reading it on the floor
The loss map
How LEANTA walks it on a first visit: Availability losses (breakdowns, changeovers) → first lever is scheduling and changeover discipline. Performance losses (micro-stops, slow cycles) → first lever is honest rated speeds and gap math. Quality losses (startup and production rejects) → first lever is upstream parameter control.
Where to start when output falls
Rank the six by minutes per week, measured, not remembered. Anecdote systematically over-weights the dramatic losses (breakdowns) and under-weights the chronic ones (changeovers, micro-stops) — and the chronic ones are usually bigger.
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LEANTA Dictionary
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