This document discusses the Lean manufacturing concept of poka-yoke, or mistake-proofing. Poka-yoke aims to prevent errors by making it impossible for them to occur through simple mechanisms and tools. It defines poka-yoke and outlines its two statuses (fault will/has happened) and three functions (stop, check, alarm). Various types of poka-yoke for both providers/servers and customers are described. The principles of mistake-proofing and approaches - control vs warning systems - are also summarized.

1. LEAN MANUFACTURING
POKA-YOKE
• KARTHIK I-14BME068
• MANOBALAA R-14BME079
• MOHAMED DHALHA-14BME081
• PRAKASH-14BME103
• SAKTHIVEL-14BME119
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2. INTRODUCTION
 Shigeo shingo defined poka-yoke as POKA- ‘Inadvertent mistake
that anyone can make’ and YOKE- ‘To prevent or proof’
 Poka-yoke is a tool to have “zero defects” and even reduce or
eliminate quality control.
 Poka-yoke is a Japanese name for “fool-proofing”.
 Poka-yoke represents the intelligence of the operator by
excluding repetitive actions that require a thinking process.
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3. MISTAKE PROOFING
 Mistake-Proofing a product's design and its manufacturing
process is a key element of design for manufacturability /
assembly (DFM/A)
 Mistake proofing is also a key element of improving product
quality and reliability
FACTORS CONTRIBUTING TO MISTAKE PROOFING:
 Attention
 Perception
 Memory
 Logical reasoning
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4. PRINCIPLES OF MISTAKE-PROOFING
There are six mistake-proofing principles or methods.
 Elimination seeks to eliminate the possibility of error by
redesigning the product or process so that the task or part is no
longer necessary.
 Replacement substitutes a more reliable process to improve
consistency.
 Prevention engineers the product or process so that it is
impossible to make a mistake at all.
 Facilitation employs techniques and combining steps to make
work easier to perform.
 Detection involves identifying an error before further processing
occurs so that the user can quickly correct the problem.
 Mitigation seeks to minimize the effects of errors.
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5. 2-STATUS & 3-FUNCTIONS OF POKA-YOKE
POKA-YOKE HAS 2 STATUS AND 3 FUNCTIONS:
 Status:
1.The fault will happen or
2.The fault has happened
 Functions:
1.Stop
2.Check or
3.Alarm
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6. POKA-YOKE CLASSIFICATION
Poka-yoke is classified into the following types:
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Server Poka-Yokes
Task
Treatment Tangibles
Customer Poka-Yokes
Preparation
Encounter
Resolution

7. PROVIDER(SERVER) ERRORS
 Task Errors
• Doing the work incorrectly
• Doing work not requested
• Doing work in the wrong order
• Doing work too slowly
 Treatment Errors
• Not acknowledging the customer
• Not listening to the customer
• Not reacting appropriately to the customer
 Tangible Errors
• Failure to clean facilities
• Failure to control noise
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8. CUSTOMER ERRORS
Preparation Errors
• Failure to bring necessary materials to the encounter
• Failure to engage the correct service
Encounter Errors
• Failure to remember steps in the service process
• Failure to follow system flow
• Failure to follow instructions
Resolution Errors
• Failure to learn from experience
• Failure to adjust expectations appropriately
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9. SEVEN STEPS TO POKA-YOKE ATTAINMENT
 Quality Processes
 Utilize a team environment
 Elimination of Errors
 Eliminate the “Root Cause” of The Errors
 Do It Right The First Time
 Eliminate Non-Value Added Decisions
 Implement a Continual Improvement Approach
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10. POKA-YOKE APPROACH
Proactive Approach :
• A fully implemented ZERO DEFECT QUALITY system requires Poka-
Yoke usage at or before the inspection points during the process.
• Poka-yoke will catch the errors before a defective part is
manufactured 100% of the time.
Reactive Approach :
• Check occurs immediately after the process.
• Can be an operator check at the process or successive check at the
next process.
• Not 100% effective, will not eliminate all defects.
• Effective in preventing defects from being passed to next process.
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11. Two Poka-Yoke System approaches are utilized in manufacturing
which lead to successful ZERO DEFECT QUALITY:
1.Control Approach:
 Shuts down the process when an error occurs.
 Keeps the “suspect” part in place when an operation is
incomplete.
2.Warning Approach
 Signals the operator to stop the process and correct the
problem.
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12. CONTROL SYSTEM
 Takes human element out of the equation ; does not depend on
an operator or assembler.
 Has a high capability of achieving zero defects.
 Machine stops when an irregularity is detected.
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13. WARNING SYSTEMS
 Sometimes an automatic shut off system is not an option.
 A warning or alarm system can be used to get an operators
attention.
 Color coding is also an effective non-automatic option
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14. TEN TYPES OF HUMAN MISTAKES
 Forgetfulness
 Mis-understanding
 Wrong identification
 Lack of experience
 Willful (ignoring rules or procedure)
 Inadvertent or sloppiness
 Slowliness
 Lack of standardization
 Surprise (unexpected machine operation, etc.)
 Intentional (sabotage)
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15. POKA-YOKE DEVICES
 Poka yoke is implemented by using simple objects like fixtures,
jigs, warning devices and the like to prevent people from
committing mistakes, even if they try to!.
 The main feature of poka-yoke devices is their exceptional
suitability for reducing or eliminating defects through effective
feedback and instantaneous corrective action.
 These devices are capable of being used all the time by all
workers; simple and usually installed with low implementation
cost.
 Poka-yoke devices help eliminate errors and defects by giving
machines the “intelligence” to stop and signal when a error
occurs.
 Poka-yoke devices stop machines and alert workers when a
problem exists.March 11, 2017 15

16. THE THREE LEVELS OF POKA-YOKE:
There are three levels at which your company can effect poka-
yoke:
Eliminating errors defects and losses at the source or prevention
of a mistake from being committed..
Detection of a loss or mistakes it occurs,allowing correction before
it becomes a problem.
Detection of a loss or mistakes after it has occurred,just in time
before it blows up into a major issue(least effective).
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17. examples:
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18. ADVANTAGES
 They are simple and cheap.
 They are part of the process, implementing what Shingo calls
"100%" inspection.
 They are placed close to where the mistakes occur, providing
quick feedback to the workers so that the mistakes can be
corrected.
 Once put in place, they require minimal supervision.
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19. CONCLUSION
Poka-yokes deals with understanding
why people make errors and how to analyze the
process to know where errors are likely to occur
and what root causes contribute to them.
Since the poka-yoke devices detect errors at
their roots n prevent them from blowing up to
become bigger problems, there is consistency in
the quality of the products, saving the cost and
time spent in subsequent quality inspection
processes.
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20. THANK YOU
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