Time to Resolution (TTR) measures the time span from the occurrence of a problem to its complete resolution. In manufacturing this applies to machine failures, quality issues or process deviations. The clock starts when a disruption is detected – and stops only when the equipment is running stably and within specification again.
TTR therefore covers not just the first response but the entire path: detection, diagnosis, repair, testing, approval and stable resumption of production.
TTR is frequently equated with MTTR (Mean Time to Repair) – which is imprecise. MTTR typically measures only the actual repair time. TTR covers the complete resolution process including response time, diagnosis, repair, functional test and sign-off. A short MTTR combined with a long TTR reveals that repair is fast but diagnosis or approval is the bottleneck – information that pure MTTR measurement conceals.
Every unplanned disruption blocks capacity. A long TTR means high downtime, declining OEE, missed delivery dates and rising maintenance costs. Systematic TTR measurement reveals where time is lost in the resolution process – enabling targeted intervention.
Long TTRs often point to missing spare parts, incomplete failure documentation, unclear responsibilities or missing escalation paths. These are organizational problems that need to be made visible with technical means.
An MES that records failure start, first alert, intervention time and restart with timestamps provides the data foundation for reliable TTR analysis – per machine, failure type, shift or responsibility area. This makes systematic weaknesses visible that disappear in aggregated OEE figures.
How is TTR calculated? TTR = time of complete problem resolution minus time of failure detection. The definition of "completely resolved" is critical – in practice the recommended endpoint is production sign-off after stable resumption, not the moment repair work is finished.
What is a good TTR in manufacturing? This depends heavily on equipment type, industry and failure class. More relevant than an absolute target value is the trend: if TTR for recurring failure types decreases over time, measures are working. If it increases, there are systemic problems in maintenance or documentation.
How can TTR be reduced effectively? The most effective levers are structured failure documentation with root cause classification, defined escalation paths with clear response time targets, spare parts availability for frequent failure causes and digital work instructions for standard repairs. Systematic TTR analysis enables prioritized action rather than gut-feel decisions.