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IENG 451

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IENG 451

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  1. IENG 451 Jidoka

  2. Jidoka • 3 Chinese characters meaning automation with human mind • Improve process capability • Contain defects • Provide feedback so that countermeasures can be taken

  3. Shigeo Shingo • 26 years to escape the spell of statistical methods (Deming) • Statistics is based on the expectation of defects • Goal was to reduce (eliminate) defects Stop Production so that production never stops

  4. Poka Yoke • Error Proofing

  5. Poka Yoke • “Mistake proofing” • Uses prediction and detection to prevent an error from occurring • Devices should be: • Simple • Focused • Inexpensive • Applied at the Source • User-Friendly Fix the SYSTEM!

  6. Everyday Poka Yoke Examples Pictures from mistakeproofing.com

  7. Everyday Poka Yoke Examples Pictures from mistakeproofing.com

  8. Everyday Poka Yoke Examples Pictures from mistakeproofing.com

  9. Everyday Poka Yoke Examples Pictures from mistakeproofing.com

  10. Jidoka Definition: The ability of production processes to stop in the event of abnormalities. Purpose: To assure that quality is controlled within the process itself.

  11. Making Jidoka Work • Response System • Small Teams • Containment • Root Cause Analysis What needs to be present on the shop floor? • Status At A Glance • Visual & Audio Signals • Andon • Error Proofing • Operator Responsibility • Next process is the customer • Never pass a defect Continuous Improvement • Stability & Consistency • Standardized Work • Quality Standards

  12. Jidoka = Mindset (Paradigm) Shift Tolerance for Defects Only Perfect Quality Leaves Workstation • Process can be improved. • I can make a difference. • Fix it now. • Fix it here. • I will do it. • Defects are unavoidable. • I have no control. • Fix it later. • Fix it somewhere else. • Someone else will fix it. People want to do this, but must have a system that enables them to do it. Or else they will do this!

  13. Fixed Stops Andon Jidoka Error Proofing Visual Controls Communications People Support

  14. - Philosophy Andon doesn’t mean STOP the process! ¶ Andon means Help! ¶ With Andon, if a problem is not fixed be fore the unit reaches the fixed position stop, the line will stop ¶ 1 2 3 4 5 Help!

  15. Quality Andon Cords & Lights

  16. Chassis 1 Quality Andon Board 3-015 03/13/2002 LGR Pictures.ppt J. Blaska 4 03/13/2002 LGR Pictures.ppt J. Blaska 4

  17. Inspections • Judgment Inspections • Informative Inspections • Source Inspections • Vertical Source Inspections • Horizontal Source Inspections

  18. Inspections • Judgment Inspections • Inspection department to keep bad junk from being shipped, entails little root cause analysis • Informative Inspections • Source Inspections • Vertical Source Inspections • Horizontal Source Inspections

  19. Inspections • Judgment Inspections • Informative Inspections • Discover defects and give feedback to source which then takes corrective action, uses SPC, self-checking, successive checking • Source Inspections • Vertical Source Inspections • Horizontal Source Inspections

  20. Inspections • Judgment Inspections • Informative Inspections • Source Inspections • Discover errors that might lead to defects • Vertical Source Inspections • Horizontal Source Inspections

  21. Inspections • Judgment Inspections • Informative Inspections • Source Inspections • Vertical Source Inspections • Requires an upstream search for the root cause; e.g., burrs on metal pieces in assembly came from welding • Horizontal Source Inspections

  22. Inspections • Judgment Inspections • Informative Inspections • Source Inspections • Vertical Source Inspections • Horizontal Source Inspections • Seeks root cause within a department

  23. Actions in Poka Yoke • Shutdown • Light sensor fails to detect required number of holes and stops machine • Machine stops if piece is positioned incorrectly • Warning • Warning light or sound warns of possible defect, part moves to next station before line is stopped, this allows prompt correction but still allows one additional cycle

  24. Paths to Poka Yoke • Work piece deviations • Work method deviations • Deviations from fixed values

  25. Paths to Poka Yoke • Work piece deviations • Weight, dimensions, shape, # parts (SCI, vision boards) • Work method deviations • Deviations from fixed values

  26. Paths to Poka Yoke • Work piece deviations • Work method deviations • Photo sensor counts # drills – piece not released until correct number of drills • Deviations from fixed values

  27. Paths to Poka Yoke • Work piece deviations • Work method deviations • Deviations from fixed values • Weld tips changed after yyy welds • Kitting, no parts left over • Torque wrenches • Pressure gauges

  28. Poka Yoke Detection • Contact sensors • Limit switch, • touch sensor • Weight check • Non-contact methods • Photo electric • Bar codes • Temperature • Pressure