Poka Yoke Definition

• Techniques that help operators avoid mistakes in their work caused by choosing the wrong part, leaving out a part, installing a part backwards, etc.
• It involves the implementation of fail-safe ways methods that detect or prevent human and machine error at or near the source
• It provides instant feedback and prevention of quality problems

Definition of a Defect

• The result of any deviations from product specifications that lead to customer dissatisfaction

Definition of an Error

• Any deviation from a specified manufacturing process
• The result of an error is shown in a defect.

Prevention Device

• Is a device or process that prevents errors from occurring or prevents these errors from creating defects
• Examples: part locators, part present sensors

Detection Device

• Is a device that will detect a defect or concern and initiate a corrective action
• Examples: vision system, limit sensors

Causes of Errors

• Processing omissions
• Processing errors
• Error in setting up the work piece
• Missing parts
• Improper item
• Processing wrong work piece
• Operations errors
• Adjustment, measurement, dimension errors
• Errors in equipment maintenance/repair
• Errors in preparation of tools/jigs
• Areas with high error potential Adjustments
• Areas with high error potential Tooling and tooling changes
• Areas with high error potential Dimensions/specifications
• Areas with high error potential Many mixed parts
• Areas with high error potential Multiple steps
• Areas with high error potential Infrequent production
• Areas with high error potential Lack of an effective standard
• Areas with high error potential Symmetry
• Areas with high error potential Asymmetry
• Areas with high error potential Rapid repetition
• Areas with high error potential High volume
• Areas with high error potential Environmental conditions

Implementation

• Develop team
• Create Error Proofing Implementation Sheet
• Identify and describe defect
• Determine location the defect was found & made
• Identify root cause
• Current process and deviations from standards
• Propose and implement improved process
• Measure
• Standardize

Guidelines for error proof devices

• Low cost, easy to implement
• Prevent the ability to make a defect / prevent the defect from being passed on
• Provide immediate feedback

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