Key takeaways
Short answer: Poka-yoke prevents the mistake — a fixture that only fits the right way, a sensor that blocks a missing step. Jidoka detects a defect or abnormality and stops the machine automatically so the problem is fixed before more bad parts are made. Poka-yoke stops the error; jidoka stops the line. Together they build quality at the source. See also oee for manufacturing.
Poka-yoke (mistake-proofing) makes the wrong action impossible or instantly obvious. A part that physically only seats one way, an interlock that will not let the cycle start with a tool missing, a light that flags a skipped step — all prevent the defect before it can be made.
Jidoka (autonomation) gives the machine the judgement to detect an abnormality and stop itself, signalling for help rather than producing scrap. It is the safety net for everything poka-yoke could not prevent — one bad part instead of a thousand.
An assembly station has a poka-yoke fixture so a bracket cannot be fitted backwards — that failure mode is now impossible. But a supplier sends a batch of brackets a millimetre out of tolerance, which the fixture cannot catch. Jidoka does: a downstream gauge detects the out-of-spec dimension on the first unit and halts the line, so one part is flagged instead of a full shift of bad assemblies shipping. Poka-yoke handled the foreseeable error; jidoka caught the one that slipped through.
Poka-yoke cannot anticipate every failure mode; jidoka backs it up by stopping the moment something unforeseen slips through. Prevention plus an automatic stop means one defect, not a batch — which is why mature lines invest in both rather than choosing.
Design poka-yoke at each workstation to make known errors impossible, and wire jidoka so the machine halts and calls for help on any out-of-spec signal. Both are quality-by-design, built into the process, not inspection bolted on after the fact.
1. Relying on inspection instead. Catching defects later is slower and more expensive than preventing or stopping them.
2. Poka-yoke only. No safety net for the failure modes you did not foresee.
3. Jidoka stops nobody answers. An automatic stop only helps if the response is fast.
4. Treating a small jidoka stop as bad for OEE. It trades a tiny Availability hit for a huge Quality gain.
Jidoka trades a small Availability stop for a large Quality gain — far cheaper than scrapping a batch — which is why OEE Quality on jidoka lines stays high. Poka-yoke keeps the defect from ever entering the Quality calculation.
Fabrico captures the stops and quality events these mechanisms generate, so you can see jidoka working and target where poka-yoke is still needed. Book a demo to see quality-at-source in your OEE.
No — poka-yoke prevents the error; jidoka detects a defect and stops the line.
It costs small Availability stops but saves large Quality losses — net positive.
Any mistake-proofing counts — fixtures, shapes, interlocks and checklists included.
Poka-yoke to prevent foreseeable errors; jidoka to catch whatever slips through.
End inspection is slower, more expensive, and lets defects accumulate before they are caught.
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