Poka Yoke Types and its basic Function

Poka Yoke is a Japanese term that means “mistake-proofing” or “error prevention”. Poka-yoke was coined in Japan during the 1960s by Shigeo Shingo who was one of the industrial engineers at Toyota.

POKA YOKE-> MISTAKE PROOFING

• Poka meaning-> Inadvertent error
• Yoke meaning-> To avoid

The initial term was Baka-Yoke, which means ‘fool-proofing’. In 1963, actually worker at Arakawa Body Company refused to use Baka-Yoke mechanisms in her work area, because of the term’s dishonorable and offensive connotation. Hence, the term was changed to Poka-Yoke, which means ‘mistake-proofing’. Ideally. Poka-Yokes ensure that proper conditions exist before actually executing a process step. preventing defects from occurring in the first place. Where this is not possible, Poka-Yokes perform a detective function, eliminating defects in the process as early as possible.

POKA YOKE is part of Lean tools used in Lean Manufacturing.

To create value & wealth for a business organization, we need implement Lean manufacturing for which we need to improve quality, shorten delivery time, provide hassle free services and reduce cost.

Definition of Lean in Lean manufacturing

Deliver the most value to customer while consuming fewest resources. Less to More is Lean.

In lean manufacturing we need to reduce wastes within organization. Lean approach for waste management is Detect waste, eliminate waste & prevent waste.

Types of Lean Manufacturing tools: –

• One piece Flow
• Standard Work
• SMED (Single Minute Exchange of Die)
• Value stream mapping
• FMEA
• TPM (Total Productive Maintenance)
• Poka Yoke
• Level Mix Loading
• Kaizen & JIT
• 5S & Visual management
• Point of use storage
• Kanban

POKA YOKE prevent defects or mistakes to happen. Defects are one of waste from 8 types of waste. Defect is most common waste in any manufacturing industry.

Defect Vs Errors

Definition of defect- It is a product that deviates from specification or does not meet customer expectation. All defects are created by errors.

Defects are the result of errors, while errors are cause of defects. Poka Yoke is used to prevent these Errors /Mistakes to avoid defect generation & Outflow.

By implementing Poka Yoke in process, we not only eliminate defect also we reduce cost associate with defect. With this we achieve Zero Quality control.

Major causes of Defects

First 4 situations are predictable & solution can be implemented at the sources. But simple mistake – most frequent cause of defect occurs unpredictably.

How Poka Yoke works & prevent defect: – Poka Yoke basically do inspection along with process. They detect defect during inspection & stop defect to outflow.

Type of Inspection

There are 3 types of Inspection in Manufacturing

1. Judgment Inspection– Done after the process finished, conformity is done w.r.t standard.
2. Informative Inspection– Giving feedback to previous station if found any defect on check. It has 3 more subcategories

3. Source Inspection– It catches defect and give feedback about them before processing, so the error doesn’t turn into defects. Source inspection uses a Poka Yoke devices.

In any manufacturing industry, zero defect can be achieved by implementing 4 basic elements: – Source inspection, 100% inspection, Quick feedback, Poka Yoke. So, for zero defect we have to use Poka Yoke in source inspection & catch the errors before the production process creates a defective product.

Poka Yoke devices installed in the machine to do the source inspection and give feedback 100% of the time. Poka Yoke system use electronic sensors or passive devices to make sure inspection happens reliably. Most of the devices are inexpensive and can be built from simple parts.

Basic Function of Poka Yoke

A defect exists in one of two states:

Poka-yoke have three basic functions to use against defects – shutdown, control and warning.

The Poka Yoke Culture

Some Example of Poka Yoke

Hope you found this post informative & helpful. All suggestion & queries are welcome.