Poka-Yoke: Meaning, Types & Examples
Definition
Poka-yoke is a Japanese term meaning 'mistake-proofing' — designing a process or fixture so an error cannot happen, or is detected immediately.
| Term | Poka-yoke |
|---|---|
| In Hindi | पोका-योके (गलती-रोधी उपाय) |
| Area | Production & quality |
| Search phrase | poka yoke |
| Try it | CAPA |
पोका-योके (गलती-रोधी उपाय) — हिंदी में अर्थ
पोका-योके जापानी शब्द है जिसका अर्थ है 'गलती से बचाव' — प्रक्रिया या फिक्स्चर ऐसे बनाना कि गलती हो ही न सके या तुरंत पकड़ी जाए।
Types of poka-yoke
Contact method — the part's shape or a sensor detects whether it is correct (a fixture a wrong part will not fit into). Fixed-value method — a set number of actions must happen (a tray with exactly 8 bolts). Motion-step method — steps must happen in order (a machine that will not start until the guard is closed).
Prevention vs detection
The best poka-yoke prevents the error; the next best detects it immediately and stops the process. Inspection at the end of the line is not poka-yoke — by then the defect has already been made.
Example
An asymmetric locating pin means a bracket can only be loaded into the welding jig the right way round.
Related tools and guides
Frequently asked questions
What does poka-yoke mean?
Mistake-proofing — preventing errors by design.
Who developed poka-yoke?
Shigeo Shingo, as part of the Toyota Production System.
What is an everyday example of poka-yoke?
A car that will not shift out of park unless the brake is pressed, or a microwave that will not run with the door open.
How does poka-yoke relate to CAPA?
Poka-yoke is often the most effective corrective action — it removes the possibility of the error.
Related terms
- 5 Whys (root cause analysis)The 5 Whys is a root cause analysis technique in which a team asks 'why?' repeatedly — typically about five times — starting from a problem, until it reaches a cause that, if fixed, stops the problem coming back.
- 5S5S is a workplace organisation method with five steps: Sort (Seiri), Set in order (Seiton), Shine (Seiso), Standardise (Seiketsu) and Sustain (Shitsuke).
- CAPA (Corrective and Preventive Action)CAPA stands for Corrective and Preventive Action — a structured process to find the root cause of a quality problem, fix it so it does not recur (corrective), and stop similar problems before they occur (preventive).
- DMAIC (Six Sigma)DMAIC — Define, Measure, Analyse, Improve, Control — is the five-step, data-driven problem-solving method used in Six Sigma to improve an existing process by finding and removing the root causes of defects and variation.
- First pass yield (FPY)First pass yield (FPY) is the percentage of units that pass a process step correctly the first time, without rework, repair or scrap. FPY = units passed first time ÷ units entering the step × 100.
- Fishbone diagram (Ishikawa)A fishbone diagram, also called an Ishikawa or cause-and-effect diagram, lays out all the possible causes of a problem in categories along the 'bones' of a fish whose head is the problem, so that a team can brainstorm and then test the likely ones.