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Poka-Yoke. TOTAL QUALITY MANAGEMENT. Poka-Yoke. This is known as ‘ MISTAKE-PROOFING ’ From Japanese: Yokeru (avoid) Poka (inadvertent errors). What is Poka-Yoke?. What Does Poka-Yoke Do?. Eliminates the cause of an error at the source; Detects an error as it is being made;
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Poka-Yoke TOTAL QUALITY MANAGEMENT Poka-Yoke
This is known as ‘MISTAKE-PROOFING’ From Japanese: Yokeru (avoid) Poka (inadvertent errors) What is Poka-Yoke?
What Does Poka-Yoke Do? • Eliminates the cause of an errorat the source; • Detects an error as it is being made; • Detects an error soon after it has been made but before it reaches the next operation.
Are Errors Unavoidable? • There are two approaches to dealing with errors: • 1. ERRORS ARE INEVITABLE! • 2. ERRORS CAN BE ELIMINATED!
1. Errors Are Inevitable • People always make mistakes. • While we accept the mistakes as natural, we blame the people who make them. • With this attitude, we are likely to overlook defects as they occur in production. • They may be detected at final inspection, or worse still, by the customer.
Any kind of mistake people make can be reduced or even eliminated. People make fewer mistakes if they are supported by proper training and by a production system based on the principle that errors can be avoided. 2. Errors Can Be Eliminated
One method of detecting errors is inspection. There are two major types of inspection. 1. SAMPLING INSPECTION. 2. 100% INSPECTION. Inspection
In some factories, the attitude is: “It may take all day to inspect all product”. “There may be a few defects, but sampling is the most practical way to check”. Sampling Inspection
Think about sampling. With sampling, there is a chance that an error may go undetected. Even if 1 part in 1000 is defective, the customer who buys that part has a 100% defective product! Sampling Inspection - Reflection
Sampling Inspection - Reflection SAMPLING INSPECTION MAKES SENSE ONLY FROM THE MANUFACTURER’S VIEW, NOT FROM THE CUSTOMER’S!
In the best factories, the attitude is: “We won’t tolerate a single defect!” “We will organize production so that 100% of the product can be easily inspected”. “That makes the most sense”. 2. 100% Inspection
Think about 100% inspection. Even one defective product is enough to destroy a customer’s confidence in a company. To stay competitive a company must supply good product in thousands. The best way to achieve this is to organize production to inspect 100% of the products. 100% Inspection - Reflection
The User Is The Best Inspector • No one intends to make mistakes. • While we are working, errors can show up without us noticing. • How can we catch these errors before they turn into defective products?
Finding Defects in the Subsequent Process • We don’t expect to find defects, but if a product we use doesn’t do what it is supposed to do, then we know it is defective. • Users are the best at discovering defects!
Finding Defects in the Subsequent Process • Since subsequent processes are also ‘users’ of the product being manufactured, they are also expert at finding defects. • If products are produced in a flow, each product is sent to the next process as soon as it is finished and defects are therefore found immediately.
Two Strategies for Zero Defects • 1. DON’T MAKE IT!
1. Don’t Make It! • Don’t make product you don’t need. • The more you make, the greater the opportunity for defects. • Follow ‘just-in-time’ principles by only making what is needed, when it is needed in the amount needed.
Two Strategies for Zero Defects • 2. Build Safeguards
2. Build Safeguards • The user is an expert in finding defects. • Therefore build safeguards into the production process. • Quality can be built into products by implementation of Poka-Yoke.
Poka-Yoke Devices • Human errors are usually inadvertent. • Poka-yoke devices help us avoid defects, even when inadvertent errors are made. • Poka-yoke helps build quality into processes.
Poka-Yoke Example • It is possible to mount the blank the wrong way onto the pierce tool. BLANK PIERCED BLANK INCORRECT • As the blank can fit the pierce tool in many ways, how can this be prevented?
Poka-Yoke Example • By fitting a block into the pierce tooling, the blank plate can only go on one way. BLOCK
Poka-Yoke POKA-YOKE MEANS ZERO DEFECTS
