Direct answer
MTBF indicates the average operating time between defined failures; MTTR indicates the average time needed to restore the asset after those failures. Used together, they show whether reliability work should focus on preventing repeat faults, diagnosing faster, improving access or ensuring parts and skills are available.
Practical objective: a consistent failure definition and a reliability plan that reduces both recurring faults and avoidable recovery delay.
Questions and phrases customers use
This guide also answers searches such as:
- MTBF MTTR packaging machine
- machine reliability metrics
- packaging line failure rate
- mean time to repair calculator
Information to collect first
Use one controlled set of figures and representative production conditions. Record the source and date of each assumption so quotations and improvement options can be compared on the same basis.
- Define what counts as a failure and when operating time starts and stops
- Record fault start, production stop, diagnosis, repair, test and release timestamps
- Classify the initiating failure rather than only the final alarm
- Separate planned maintenance and changeovers from unplanned failures
- Record parts, skills, access and waiting causes during repair
- Analyse by machine, subsystem, product and format
How to make the decision
Work from the required finished result back through the process. Keep compliance, product quality, sustained output and total ownership cost visible together.
- Use Pareto analysis to target the largest lost-time failure modes
- Improve MTBF through root-cause removal and preventive work
- Improve MTTR through diagnostics, access, spares, instructions and training
- Track repeat failures separately from one-off external events
- Verify improvement over enough operating time to avoid misleading short samples
Common mistakes to avoid
- Changing the definition of failure between shifts
- Using calendar time instead of actual operating time without stating it
- Treating every stop as a hardware failure
- Celebrating a high MTBF based on too little exposure time
Customer decision table
| Metric | Calculation and use |
|---|---|
| MTBF | Operating time divided by number of defined failures |
| MTTR | Total restoration time divided by number of repairs |
| Availability estimate | MTBF divided by MTBF plus MTTR |
| Repeat-fault rate | Failures recurring from the same unresolved cause |
Questions customers also ask
Is MTBF the expected life of a component?
Does low MTTR mean maintenance is good?
Should micro-stops be included?
How much data is needed?
Evidence to retain
Keep the controlled requirement, product and packaging samples, measurements, trial results, supplier scope and acceptance records used for the decision.
Download the planning template
Use the CSV worksheet to allocate evidence, owners, actions and dates before requesting quotations or approving a change.
Related guides and calculators
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Send the product, pack, current method, measured problem and required result. The more specific the evidence, the more useful the machinery review can be.