Example gallery · 28 examples · Quality management
A poka-yoke is anything that stops a mistake from turning into a defect: it either makes the mistake impossible or shows it the moment it happens. You already use dozens of them. A SIM card only fits one way, a microwave stops when the door opens, and a car won't leave Park until you press the brake. The examples below are sorted by the three methods (contact, fixed-value and motion-step) and marked as prevention or detection.
Want the long version? 10 Poka-Yoke Examples from Real Manufacturing Processes: Ten worked examples from automotive, electronics, medical, pharma and aerospace lines, each with the defect, the root cause and why that device was chosen.
Showing 28 of 28 examples
The part, plug or tool is checked by its shape, size, position or color. The wrong one won't fit, or it stands out straight away.
The connector shell is D-shaped or has an off-center tab, so it only lines up with its socket one way round.
One blade is wider than the other, so the plug only goes into the outlet one way and the neutral side stays neutral.
At many pumps the diesel nozzle is too wide to go into the filler neck of a petrol car.
Small medical gas cylinders have two holes in the valve, placed differently for each gas. The regulator's pins only fit the holes for its own gas.
One corner of the card is cut off and the tray has the same shape, so the card only sits flat the right way round.
Two locating pins of different sizes, or one set off the center line, match holes in the part, so it only drops onto the fixture the right way.
The designer adds a tab, a notch or an uneven hole pattern, so a part that looks symmetrical can only be fitted one way.
One end of the gauge has to fit (go) and the other must not (no-go). The answer is pass or fail, with no reading to get wrong.
A sensor in the fixture checks that the part is there and fully seated, and the machine won't start until it is.
Each line gets its own color on the hose, the fitting and the drawing, so a wrong match stands out. Color only warns, so pair it with a shape difference where a mix-up is costly.
A light curtain or a sensing edge across the doorway reopens the doors when something is in the way.
A set number of parts, doses or actions has to be done. A gap or a leftover shows that something was missed.
Each unit gets a tray with exactly one pocket for every part it needs. An empty tray at the end means every part went in; a full pocket shows what was missed.
One compartment per day or per dose. A full compartment shows a missed dose and an empty one shows it was taken.
The team counts instruments, swabs and needles before an operation and again before closing, and the two counts have to match.
Resin and hardener sit side by side in one cartridge, and the mixing nozzle dispenses both at the set ratio every time.
Each tool hangs on its own painted outline, so an empty outline shows at a glance which tool is missing.
A scale weighs each packed box against the weight of a full count and rejects any box that is light or heavy.
Some flat-pack kits pack the screws and fittings in one bag per step. A full bag or a spare screw at the end shows a step was missed.
A controller counts the screws driven to torque on each unit and won't release the unit until the count is right.
Steps have to happen in order. The next step waits until the last one is done, or a skipped step is flagged.
Switches in the door latch cut the power as soon as the door opens, so the oven only runs with the door shut.
A car with an automatic gearbox won't shift out of Park until the driver presses the brake pedal.
Many cash machines hand the card back before the cash, so you have to take the card to get what you came for.
The press only cycles while both buttons are held down together, which keeps both hands on the buttons and out of the tool area.
One person reads each item out and another confirms it before the next phase starts, as with a pre-flight checklist or the WHO surgical safety checklist.
When the car is moving and a front seat belt isn't buckled, a warning light and a chime keep going until it is.
The form checks the required fields and won't move to the next step until each one is filled in.
A light comes on at the bin for the next part, and a sensor at each bin flags a hand that reaches into the wrong one.
An interlock lets only one drawer open at a time, so the weight never all comes forward at once.
These are general, widely known examples, not case studies from a particular company. Details vary by country and model, so check the device in front of you before you copy one.
The cards are the short version. These guides explain the method and walk through examples in full.
All our articles on this subject are in the quality management topic.
Log quality issues from the floor, trace each one to its root cause and follow the corrective action through to closure.
See Quality ImprovementMoves non-conformance reports into an automated workflow and links each defect report to root-cause problem solving.
See Non-Conformance (NCR)FAQ
Or see all example galleries, the topics and the lean glossary.
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