Production line stoppages: a practical root cause method
Capture the data
- Start time, duration, line and machine.
- A cause category chosen from a short, agreed list.
- A short note on what was seen and what was done.
- Include micro-stops, which are short but add up.
Classify stoppages
| Category | Examples |
|---|---|
| Mechanical | Jams, wear, breakage, lubrication |
| Electrical and controls | Sensors, drives, PLC faults, power |
| Material | Wrong, late or out-of-spec material |
| Quality | Rework, defects, stops to adjust |
| Changeover and set-up | Slow or inconsistent changeovers |
| Process and people | Method gaps, missing standards, training |
Focus on the biggest losses
Rank by total lost time, not by how often one person notices it. Start with the top three causes, because they usually account for most of the lost hours.
Analyse the cause
Use a fishbone to list possible causes across machine, method, material, people, measurement and environment, then 5 Whys to drill into the most likely branch.
| Step | Answer |
|---|---|
| Problem | A conveyor jams several times per shift. |
| Why 1 | Product arrives at the transfer point out of line. |
| Why 2 | The guide rail has shifted. |
| Why 3 | Its fixing loosens with vibration. |
| Why 4 | The fixing type is unsuitable and is not checked on the routine. |
| Root cause | The design and inspection routine did not allow for vibration. |
This example is illustrative.
Verify and sustain
- Compare availability or OEE before and after the change.
- Update the standard work or maintenance routine so that the fix stays.
- Track action completion and review the next loss on the list.
Frequently asked questions
What is the best way to find the cause of line stoppages?
Record stoppages consistently, rank them by lost time, and analyse the top causes with a fishbone and 5 Whys, then check the result in your availability or OEE figures.
Should I include micro-stops?
Yes. Short stops can add up to a large loss, so record them or sample them over a period.
Describe the failure or add a photo or file, and RapidRCA builds the 5 Whys, fishbone, actions and report, using the ROOTS method.
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Last updated 14 October 2026. These guides explain a method and give examples. Always follow your equipment manufacturer's manual, your site procedures and applicable regulations.