Mistake Proofing (Poka-yoke)-How it save upto one million dollar in industry

Good Morning Friends,

Today's our topic is Mistake proofing/Poka-Yoke.

Generally the most effective way to achieve quality is to avoid having defects in the first place. It is much less costly to prevent a problem from ever happening than it is to find and correct the problem after it has occurred. In this article we can learn What is Poka Yoke, How it helps save the million of money, When to use it, how to use it, benefits of Poka yoke etc.

What is Mistake proofing/Poka yoke?

Poka-Yoke is a Japanese term that means “mistake-proofing”. It is the use of any automatic device or method that either makes it impossible for an error to occur or makes the error immediately obvious once it has occurred.  In other words, the goal is to make an object that prevents the user from messing up. Small design features and visual clues can influence the safety and efficiency of everyday objects.

The main aim of mistake proofing is:

Prevent a defect from occurring and when this is not possible, Detect the defect every time  occurs.

When to use mistake proofing?

Poka-yoke can be used wherever something can go wrong or an error can be made. It is a technique, a tool that can be applied to any type of process be it in manufacturing or the service industry. Errors are many types -

Processing error: Process operation missed or not performed per the standard operating procedure. 

Setup error: Using the wrong tooling or setting machine adjustments incorrectly.                     Missing part: Not all parts included in the assembly, welding, or other processes.
Improper part/item: Wrong part used in the process.  

Operations error: Carrying out an operation incorrectly; having the incorrect version of the specification.

Measurement error: Errors in machine adjustment, test measurement or dimensions of a part coming in from a supplier.

How to use mistake proofing?

Step by step process in applying Poka-yoke:

1. Obtain or create a process flow chart also Pareto chart of the error. Review each step, thinking about where and when human errors are likely to occur.
2. For each potential error, work back through the process to find its source.
3. For each error, think of potential ways to make it impossible for the error to occur. Consider:  Elimination—eliminating the step that causes the error,Replacement—replacing the step with an error-proof one,Facilitation—making the correct action far easier than the error.
4. If you cannot make it impossible for the error to occur, think of ways to detect the error and minimize its effects. Consider Inspection method , setting function and regulatory function.
5. Choose the best mistake-proofing method or device for each error. Test it, then implement it. Three kinds of inspection methods provide rapid feedback:

• Self-inspection means workers check their own work immediately after doing it.
• Successive inspection is done at the next step of the process by the next worker.
• Source inspection checks, before the process step takes place, that conditions are correct. Often it’s automatic and keeps the process from proceeding until conditions are right.

Practical Example of Poka yoke:

1. Sensors

Proximity sensors emit a high-frequency magnetic field and detect an upset in the field when an object enters it. They can be used to detect the presence or absence of an object.

Applications

• Sensing of tank or bin level
• Confirmation of part or object passes by
• Detection presence or absence of object
• Positioning of work piece

2. Error Detection & Alarms

In general, an error detection device can provide a visual alarm such as a flashing light or an audible alarm such as a horn or siren.These devices signal that a problem is either about to occur or has just happened. With a warning effect, the response is not automatic; someone has to take action.

Applications

• The signal must be triggered by something in the process, usually a sensor.

3 Some bad and good Poka Yoke

Here we can consider example of credit card

bad Poka yoke- credit card slot requires card to be slid in only one (of four possible) directions
better Poka yoke -credit card slot accepts card either direction, but only on correct side
even better Poka yoke - credit card slot accepts card slid no matter how you do it
poke-yoke = chip in credit card, just get it anywhere near card reader


Ideally, poka-yoke ensures that proper conditions exist before actually executing a process step, preventing defects from occurring in the first place. Where this is not possible, poka-yoke performs a detective function, eliminating defects in the process as early as possible. Don't allow defects to occur in your processes by neglecting to prevent mistakes in your work. Use poka-yoke to make the work easier and mistake proof your process


Thanks friend for reading, I welcome for any comments or feedback about post.
also please reply for any details information.
Thank You.