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- MTTR stops the clock when the machine is repaired, not when it is recovered.<\/li>\n
- After a restart, reduced speed and first rejects keep costing parts.<\/li>\n
- That loss is split across availability, performance and quality.<\/li>\n
- Measure time to nominal rate and restart scrap for each machine.<\/li>\n<\/ul>\n<\/div>\n
Repaired is not recovered<\/h2>\n
Ray Harkins, who teaches through The Manufacturing Academy and is general manager of Lexington Technologies, develops this idea in Recovery Behavior: What Happens After the Stop Matters<\/a>, published on Accendo Reliability and adapted from chapter 11 of his book Measuring Manufacturing Effectiveness<\/a> (2026). Discussing the losses a restart creates, he writes: “Recovery behavior explains why improvements in MTTR alone may not produce proportional gains in output.”<\/p><\/blockquote>\n
His article draws a clear line between two things that plants often treat as one. MTTR measures the time needed to restore function. Recovery covers the whole span from abnormal operation back to stable, productive output: detecting the problem, reaching target speed again, reaching quality stability. Output can stay degraded well after the repair is closed. Harkins also notes that restart losses touch all three OEE components (availability, performance and quality), that they are split across categories and therefore underreported, and that recovery varies with operator experience, staffing, documentation and equipment design. He points out that recovery is rarely measured directly and is usually recognized through patterns: more scrap after downtime, performance that stays low after a restart, more operator intervention. This article takes the measurement side of that argument: how to turn those patterns into a number per machine.<\/p>\n
Why a lower MTTR does not always mean more parts<\/h2>\n
MTTR stops the clock when the machine is declared available again. The production loss does not stop there. After a jam, a tool change or a breakdown, many machines go through a stabilization phase: reduced speed while the operator watches the first cycles, temperature or tension that has not settled yet, first parts checked or rejected, a second adjustment. None of this belongs to MTTR, so a project that only targets repair time can improve the indicator while leaving the real loss almost unchanged, or even moving part of it into the minutes after the restart.<\/p>\n
Take, for example, a machine with a nominal rate of 10 parts per minute (the figures below are invented for illustration). A maintenance project brings the average repair time down from 12 to 8 minutes. To get there, restarts are made faster, with less time for setting checks, so the machine takes a little longer to settle and rejects a few more parts afterwards. In this example, the ramp-up is assumed to run at about half the nominal rate on average.<\/p>\n
![\"Four-step](\"https:\/\/teeptrak.com\/wp-content\/uploads\/2026\/11\/teeptrak-harkins2-en.png\")
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