1. Beyond Shingo: Prompt, Do,
Check, Act (PDCA) & Universal
Mistake Prevention and Quality
Verification (UMPQV)
New tools for your "Lean" toolbox
Tom Wiesen
VP Engineering & Product Development - AVOW, LLC

2. Agenda
• Introduction to PDCA
• Poke-Yoke & UMPQV
• Relationship between PDCA & UMPQV
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3. What is PDCA?
• Prompt, Do, Check, Act
• Based on Shewhart Model (Plan, Do,
Study, Act) for continuous improvement
• Model for any manual process
Operation Post Operation
Prompt Do Check Act
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4. “Prompt” Explained
• What does a Prompt do?
– Initiate action
– Authorize
– Indicate
• What actions need to be performed
• How the action is to be performed
• Parameters of the action
• What constitutes completion of the action
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5. “Prompt” Explained
• A Prompt encourages humans to
perform the required process steps
correctly.
• PROACTIVE prompts are much more
effective than passive prompts
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6. “Prompt” Examples
Passive Proactive
• Paper Manuals • Buzzers
• Printed Instructions • Lights
• Files that musts be • Voice
opened manually • Electronic
• Training (Memory) displays
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7. “Do” Explained
• Perform (Control) the task
– Methods
• Automatic (PLC, PC, etc)
– Inputs: sensors, electronic data, software
– Outputs: actuators, data, alarms
• Manual (Human Brain)
– Inputs: touch, see, smell, hear, taste
– Outputs: muscles, speech
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8. “Do” Examples
• Picking parts from storage locations
• Placing parts in machines
• Assembling parts
• Operating hand tools (hammer, drill,
screwdriver, etc.)
• Mixing solutions
• Medical examinations/procedures
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9. “Check” Explained
• Verify that the “Do” was done right
– Operation completed
– Quality metrics
– Quantity
– Functionality
• Automatic checks are much more
effective than manual checks
• Check should be objective
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10. “Check” Explained
• Types of Checks
– Judgment
– Informative
• Source Inspection
• Self Check
• Successive Check
– “Inspection” is controversial (non-value
added)
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11. “Check” Explained
• Inspections should strive to be:
– Frequent (100%)
• Occurrences of mistakes in human controlled
processes are inherently unstable, making
sampling operations useless
– Inexpensive
– Simple
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12. “Check” Examples
• Visual inspection
• “Feel”
• Sound
• Measurement (distance, torque, etc.)
• Test equipment (pressure/leak test, etc)
• Functional test
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13. “Act” Explained
• Act - Negative Outcome
– Communicate outcome to:
• Operator
• Control system
• Quality/Production/Enterprise system
– Resolve negative outcome
• Fix/Re-work/Scrap part
• Find root cause
• Correct cause
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14. “Act” Explained
• Act - Positive Outcome
– Communicate outcome to:
• Operator
• Control system
• Quality/Production/Enterprise system
– Identify part
– Transfer part
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15. “Act” Examples
• Indicating light or display
• Transfer part to next station
• Engrave serial number
• Communicate results electronically
• Repair defect
• Remove part from line for disposition
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16. Part of a Lean Strategy
• What methods makes up Lean?
– 5S
– Kanban
– Kaizen
– Mistake Prevention (Poka-Yoke)
– Total Productive Maintenance
– Value Stream mapping
– Takt Time
– Cellular Manufacturing
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17. Part of a Lean Strategy
• How does PDCA fit into Lean?
– Prompting
• Reduces wasted production time through
increased productivity
• Reduces mistakes
– Check
• Reduces Re-work & Scrap
• Informative Inspection promotes Kaizen
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18. Part of a Lean Strategy
• How does PDCA fit into Lean?
– Act
• Reduces time, money, and effort through
communication with other systems
– Supply chain
– Production systems
– Quality systems
• Visibility of the entire enterprise allows what
was previously seen as waste to be seen as
added value
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19. Applying PDCA
• Use as design criteria for design of new
manual processes
• Incorporate into Process FMEA
– Instead of just looking at ways the process
can fail, look for absence of PDCA steps
that ensure that process is correct
• Use to evaluate/improve current manual
processes
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20. Overview of Poke-Yoke
• Japanese for “Mistake proof”
• Developed by Shigeo Shingo
• Primarily focused on preventing
mistakes before they become defects
• Poke Yoke devices help prevent errors
and defects
• Product Focused devices
• Based on 100% inspection (Informative)
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21. Overview of Poke-Yoke
• Generally applied to discrete systems or
processes
• Best applied to high volume, low variety
production
• Generally not well applied to high
variety production or complex
operations
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22. UMPQV vs. Poka-Yoke
Universal Mistake Prevention and Quality
Verification
• Includes all the elements of Poke-Yoke
• Universal
– Process Oriented, not product oriented
– Inexpensive, Redeployable, COTS
• “Mistake-Proof” split into Mistake
Prevention and Quality Verification
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23. UMPQV - Universal
• Process oriented, not product oriented
– Configurable to multiple product
applications
• Easy to Integrate
– Standard physical and electronic interfaces
– Programmable (Configurable)
• Expandable & Easy to change
• Communication
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24. UMPQV - Mistake Prevention
• Essence of Poke-Yoke
– Prevent mistakes before they happen
• Source Inspection
• Self Check
• Subsequent Check
– Based on 100% informative inspection
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25. UMPQV - Quality Verification
• Verify that the outcome is “Good” not
just “Not Bad”
• Mistake Prevention is a precursor
• “Mistake-Proof” does not imply that
quality is verified
• Informative - If quality is not verified,
find out why and correct
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26. UMPQV - Examples
• DC Torque Tools
– Socket Tray Indicates socket and proper torque
program (Prompt, Mistake Prevention)
– Operator presses trigger, Controller Controls (Do)
– Transducer/Current sensor verifies torque (Check,
Quality Verification)
– Controller displays & communicates result (Act)
– Tool is process oriented (torquing), product
independent, and provides communication
(Universal)
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27. UMPQV - Examples
• Sensor-based Pick-to-light
– Prompt light indicates bin (Prompt, Mistake
prevention)
– Worker picks parts (Do)
– Sensor detects proper pick (Check, Quality
Verification)
– Controller communicates result (Act)
– Tool is process oriented (part picking), product
independent, and provides communication
(Universal)
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28. UMPQV – Poke-Yoke Conversion
• UMPQV devices do not have to be COTS
– Go/No-Go gage used to verify/modify several
critical dimensions
– Started with a few product variations
– New Poke-Yoke devices (Custom designed
reference fixtures) were created for each product
variation
– Over time, more than 30 custom devices created
at significant expense and are complicated to use
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29. UMPQV – Poke-Yoke Conversion
• Poka-Yoke Issues
– No method to ensure correct gage is used
– No method to ensure any gage is used
– Operator dependent results (subjective)
– No communication or requirement for correction of
negative results
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30. UMPQV – New UMPQV Solution
• Electronic Measuring Device
– Custom tool developed to measure critical
dimensions
– Device has highly repeatable results
– Communicates results to operator and
electronically to other systems
– Setup/measurement requirements selected by
product model (Barcode or RFID)
– Applicable to all product variations
– Can require defect resolution (tagging, electronic
acknowledge, etc.)
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31. Example Comparison
Poke-Yoke UMPQV
– Array of Physical gages – One electronic measuring device
– No method for selecting – Barcode/RFID selects proper
proper gage program (Prompt, Mistake
– No method to ensure that prevention)
any gage was used – High repeatability and objectivity
– High level of variation in in results (Check, Quality
results Verification)
– No communication – Communication to Operator and
– No requirement for defect electronically (Act, Universal)
resolution – Lower life cycle cost of device
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32. Poke-Yoke vs. UMPQV
Poke-Yoke Device UMPQV Device
– 100% inspection – 100% inspection
– Poke-Yoke principles – Poke-Yoke principles+
– Simple, Fast, Cheap – Simple, but more complex
and higher initial cost
– Product specific – Process specific
– Low level communication – High level communication
– Best applied to high – Best applied to high variety,
volume, low variety complex production
production
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33. Mistake Prevention Strategy
• Design mistakes out of product/process
• Analyze process using PDCA Manual Process Model
• Where mistakes can occur, use Source Inspection to
prevent occurrence of mistakes that lead to defects
• Use Self and Subsequent inspections to detect
defects (100%)
• Use Control methods over warning methods when
feasible
• Use UMPQV solutions where there are common
processes and/or high variety
• Use end-of-line testing as a last resort
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34. Questions?
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35. Pick-to-Light examples
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36. Torque Tool Examples
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37. SPC Example
Inspected Samples
SPC Error Catching
Actual Defects
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Samples
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