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IENG 451. Jidoka. Jidoka. 3 Chinese characters meaning automation with human mind Improve process capability Contain defects Provide feedback so that countermeasures can be taken . Shigeo Shingo. 26 years to escape the spell of statistical methods (Deming)
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IENG 451 Jidoka
Jidoka • 3 Chinese characters meaning automation with human mind • Improve process capability • Contain defects • Provide feedback so that countermeasures can be taken
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
Poka Yoke • Error Proofing
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!
Everyday Poka Yoke Examples Pictures from mistakeproofing.com
Everyday Poka Yoke Examples Pictures from mistakeproofing.com
Everyday Poka Yoke Examples Pictures from mistakeproofing.com
Everyday Poka Yoke Examples Pictures from mistakeproofing.com
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.
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
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!
Fixed Stops Andon Jidoka Error Proofing Visual Controls Communications People Support
- 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!
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
Inspections • Judgment Inspections • Informative Inspections • Source Inspections • Vertical Source Inspections • Horizontal Source Inspections
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
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
Inspections • Judgment Inspections • Informative Inspections • Source Inspections • Discover errors that might lead to defects • Vertical Source Inspections • Horizontal Source Inspections
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
Inspections • Judgment Inspections • Informative Inspections • Source Inspections • Vertical Source Inspections • Horizontal Source Inspections • Seeks root cause within a department
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
Paths to Poka Yoke • Work piece deviations • Work method deviations • Deviations from fixed values
Paths to Poka Yoke • Work piece deviations • Weight, dimensions, shape, # parts (SCI, vision boards) • Work method deviations • Deviations from fixed values
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
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
Poka Yoke Detection • Contact sensors • Limit switch, • touch sensor • Weight check • Non-contact methods • Photo electric • Bar codes • Temperature • Pressure