Quality
What is Poka yoke?
Poka yoke means mistake proofing: designing a process so errors are prevented or caught at once. Types, examples and how digital poka yoke works with MES.
Quick answer
Poka yoke is Japanese for mistake proofing. It means designing a product, fixture or process so a mistake cannot be made, or is detected immediately before it becomes a defect. Examples are fixtures that accept a part only one way, sensors that check every hole is drilled, and scanners that block the wrong component.
Updated 30 October 2026. Written by the Ajinkya Technologies engineering team, reviewed by Amey Kadle.
Poka yoke explained
The concept was developed by Shigeo Shingo as part of the Toyota Production System. It accepts that people make mistakes and moves the burden from attention to design: instead of asking operators to be careful, the process makes the wrong action impossible or obvious.
Poka yoke devices are usually described by how they detect an error. Contact methods check a physical attribute such as shape or position, for example a locating pin. Fixed value methods check that a set number of actions happened, for example a counter that confirms all bolts were torqued. Motion step methods check that steps happen in the right order. Devices either prevent the error (control) or alert the operator immediately (warning).
Digital poka yoke uses scanners, vision cameras and software interlocks. A barcode or RFID scan confirms the right component or material lot before assembly; the MES refuses to start an order if the setup or tool is wrong; a camera confirms every feature is present. Because each check is recorded, it also produces traceability: proof of what was checked on every unit.
Key concepts
- Prevention beats inspection
- Contact, fixed value and motion step methods
- Control devices stop the process; warning devices alert
- Digital poka yoke uses scans, vision and interlocks
- Every check becomes a traceability record
Questions
What is an example of poka yoke?
A fixture that only accepts a part in the correct orientation, a sensor that stops the press if a part is missing, or a scan that blocks assembly when the wrong component is picked.
What is the difference between poka yoke and inspection?
Inspection finds defects after they are made. Poka yoke prevents the mistake or catches it at the moment it happens, before it becomes a defect.
Can software be a poka yoke?
Yes. MES interlocks, barcode and RFID verification and vision checks are digital poka yoke, and they also record each check for traceability.
References
How we help with poka yoke
We build digital poka yoke into MES and traceability systems: scan to verify materials and tools, interlocks that stop the wrong order, and vision checks, all recorded per unit.
Set the reject threshold yourself and watch escapes trade against false rejects (simulated data).
Related terms
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