First steps
- Go to the station and watch the job.
- Ask why the error is possible.
- Prefer error-proofing over retraining.
How to measure success
Errors per million operations and repeat rate. Record the value before you start, so the effect of every action can be shown.
When these methods are the wrong choice
- Poka-yoke: Causes in the material or the supplier’s process.
- Standard work / work instruction: Processes that are still changing every week.
- 5 Why: Problems with many interacting causes; use data and DOE there.
- PFMEA / DFMEA: Fixing a problem that has already happened; update it after the 8D instead.
- Skill matrix and training: Problems that occur with qualified, experienced people.
- Layered process audit (LPA): Finding root causes.
The methods in one line
| Method | What it is |
|---|---|
| Poka-yoke | Makes the error impossible or detects it immediately, so it does not depend on attention. |
| Standard work / work instruction | The current best way to do a job, with key points and reasons, used for training and audits. |
| 5 Why | Ask “why” until you reach a cause you can act on, with one chain for occurrence and one for escape. |
| PFMEA / DFMEA | Analyses how a process or design can fail, rates the risk (AP) and defines prevention and detection. |
| Skill matrix and training | Shows who is qualified for which job and plans training before people are needed. |
| Layered process audit (LPA) | Short daily checks of key process controls by several management layers. |