First steps
- Log every failure with component and cause.
- Pareto by downtime.
- Fix the top failure for good, then the next.
How to measure success
MTBF, MTTR and unplanned downtime. Record the value before you start, so the effect of every action can be shown.
When these methods are the wrong choice
- TPM: One-off breakdowns with a known cause.
- Pareto chart: A single defect type with one known cause.
- 5 Why: Problems with many interacting causes; use data and DOE there.
- Weibull analysis: Defects found at the end of line.
- OEE analysis: Manual processes without a machine cycle.
- PFMEA / DFMEA: Fixing a problem that has already happened; update it after the 8D instead.
The methods in one line
| Method | What it is |
|---|---|
| TPM | Total productive maintenance: operator care, planned maintenance and loss elimination. |
| Pareto chart | Ranks defect types or causes so the team works on the vital few first. |
| 5 Why | Ask “why” until you reach a cause you can act on, with one chain for occurrence and one for escape. |
| Weibull analysis | Models failures over time or mileage: early failures, random failures or wear-out. |
| OEE analysis | Splits equipment losses into availability, performance and quality to show where time is lost. |
| PFMEA / DFMEA | Analyses how a process or design can fail, rates the risk (AP) and defines prevention and detection. |