Poka Yoke - Six Sigma

What is Poka Yoke?

•  PokaYoke can be translated as “Mistake Proofing”.
• Eliminate error before occur rather than finding and fixing them

The ideal Poka Yoke are:

1. Inexpensive
2. Simple and easy to implement
3. Deployed to every employee

The 2 types of Poka Yoke are:

The two main types of Poka Yoke (mistake-proofing) are generally categorized by their function in relation to the error:

1. Prevention Poka Yoke (Control Method): These techniques are designed to make it physically or logically impossible for an error to occur in the first place, or they automatically stop the process immediately when an error is detected, forcing corrective action. This is the most effective type.

   • Example: A microwave oven that will not turn on if the door is open.

2. Detection Poka Yoke (Warning Method): These techniques are designed to detect an error as soon as it happens and alert the operator, so they can take corrective action before the mistake becomes a defect that moves further down the process or reaches the customer.

   • Example: A buzzer that sounds if a car is turned off but the headlights are still on.

The three primary methods used for implementing either the Prevention or Detection types are:

• Contact Method: Uses physical attributes (shape, size, color, etc.) to detect errors (e.g., a uniquely shaped connector that only fits one way).

• Fixed-Value Method/ Constant Number Type: Ensures a set number of actions or components are used (e.g., a container with the exact number of parts needed for an assembly step).

• Motion-Step Method (or Performance Sequence Method): Ensures a correct sequence of operations is followed (e.g., a system that won't allow the next step to start until the previous one is confirmed).

Poka Yoke 3 Golden Rules:

1. Don't accept defects from your suppliers
2. Don't make your defect yourself
3. Don't pass on a defect to your customer