1.
Poka Yoke (ポカヨケ)
Target Process “Lock Out Tag Out” and preservation of Life
Created by Todd McCann
Contents:
> Shallow Instructions and foundations for use
A Quote from Taiichi Ohno
“ Where there is NO Standard
there can be NO KAIZEN”
We Serve the GEMBA
We Teach Leaders to “Learn to See” and “Serve the Gemba”
ERROR
DEFECT
ABNORMALITY
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Act
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Check
Standardize
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Check
Standardize
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Plan
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Do
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KAIZEN
ERROR
DEFECT
ABNORMALITY

2.
Technique: POKA YOKE
(Originally BAKA Yoke Idiot Proofing)
GOAL: Creates ideal state of 100% inspection.
ZERO based thinking > prevention of recurrence
Defined: The technique of installing
countermeasures and standards to create an
environment in work processes that focuses on
early detection and prevention of process
abnormalities errors and defects in process.
Target is ZERO. Focus and Aim is to eliminate all
known sources of process errors/defects.
Behaviors are changed in the worker. (Eliminating
Warusa Kagen > related to use of Poka Yoke)
2 Categories: Prevention and Detection
Detection Poka Yoke: are placed as close to
where errors occur, providing early /quick
feedback to the worker that an error/mistake is
about to occur, so the error/mistake can be
immediately corrected. (You can install andons,
visual and/or audible devices as well as check list
addressing steps that are error likely )
Prevention Poka Yoke: (JIDOKA) Engineered
into production devices to make it impossible to
perform an error. GO / NO GO devices
Selected Error Types:
-Processing error > Process operation missed or
not performed to a step in standard work.
-Setup error > Using the incorrect materials
tooling or setting machine adjustments incorrect
to specification.
-Missing part > Not all parts are available when
required to perform standard work.
-Improper part/item > Incorrect part is used in
the process.
-Operations error > Carrying out an operation
incorrectly; having the incorrect version of
documentation, specification, necessary
requirement to complete standard work
-Measurement error > Errors in machine
adjustment, human error in test measurement or
dimensions of a part, location, and installation.
How to Create Poka Yoke:
• Identify and expose area where error occurs
•Determine Root Cause of error: 5Whys/Ishikawa
/FMEA/Cause and Effect matrix, 5W+1H, etc
•Determine Poka Yoke type: ShutOut <> Control
type (preventing an error GO / NO GO /Attention
type (highlighting that an error has been made , is
occurring and requires attention for correction)
•Determine method type (human factoring):
Contact, Work Sequence, Constant #
•Change Standardized Work Ex: Check sheet
•Train to new condition
•Perform Equipment improvement (JIDOKA or
install audible and/or visual andon/controls)
(ポカヨケ) Poka Yoke> Evaluation, Creation and Installation Process TARGET: LOTO
Correction
required /error
has occurred
Analysis: Genchi
Genbutsu for Genjitsu
PDCA
Go to Gemba and Genchi
GO SEE what happened at the
Point of Origin
Seek out Point of Origin of Error
Use A3 to document condition
and environment > create “Hoken”
Have individuals involved with
error discovery present as well as
observers to re-create
error/abnormal conditions
Query individuals for their
knowledge of the error
Thoroughly understand current
condition at point of origin.
Differentiate Symptom from Cause
Move downstream, understand
and record effects of error
Move upstream and understand
conditions that may be
contributing causal factors to error
Potential Data to collect:
Facts and data at point of origin
regarding error causes
Occurrence, frequency & rate
of error over time intervals (when,
where and how often)
Upstream & downstream cause
and effects)
Skills required to perform task
Applied Measurement systems
Tolerances Form Fit Function
requirements
Standardized Work
Potential Outputs of Activities:
Comprehensive set of facts and
data regarding error 5W’s 1H
Ishikawa (4M or other as required)
Process Flow Diagram
Material & Information Flow
Diagram
Pareto Histogram 80/20
Run Chart / Control Chart
FMEA
Cause and Effect Matrix
Materials Required:
Blank A3 and pencil
Documentation, standard
work procedures, regulatory
requirements
Skills, Foundational
Knowledge and Mindsets
Required:
Tacit and Intrinsic knowledge
and demonstrated proficiency
of and Mastery of these skills:
POKA YOKE
Scientific Thinking
Method (STM) for solving
problems
Prevention of recurrence
mindset.
Zero Based Thinking
Open mindedness not
looking for Right and
Wrong only looking for
condition of Good<>No
Good to Target Condition
Socratic Method
Fault/Decision Tree Analysis
5 Why’s/ 5Why’s and 1 How
A3 and Hoken Development
Direct observation 3GEN
Event recreation
3M Muda Mura Muri
5S
KAIZEN Spirit
Challenge Spirit
Jidoka
7 Tools of Quality
1. Ishikawa diagram
2. Check sheet
3. Control chart
4. Pareto chart
5. Histogram
6. Scatter diagram
7. Stratification flow chart
or run chart)
Failure Modes & Effects
Analysis (FMEA)
Factors /tolerances
related to Critical to
Form Fit and Function
Factors /tolerances
related to Critical to
Quality (CTQ)
Use of Standard Worksheets
Nemawashi
Yokoten
Warusa Kagen
Generic Error Modeling
System (GEMS > James
Reasons)
Behavior Shaping Constraint
identification
Created by: Todd McCann
Date: 1-1-1999
Subject: (ポカヨケ) Poka Yoke Thinking
Analysis: Create Hypothesis >
Determine Root Cause of Error
PDCA
Determine , Create and Plan
appropriate Countermeasure
Select Type of POKA YOKE to
install, WHY and HOW
PDCA Perform Test and Trial of Poka
Yoke at origin of error
PDCA
Permanently
Install Poka Yoke
PDCA
Use Facts and Data >
Determine what SHOULD be
happening versus what IS
happening in current condition
Use A3 to document condition
and environment > continue to
create “Hoken”
Share work outputs & conditions
discovered with those involved
with error so Learning takes
place
Thoroughly understand current
condition & causal/contributing
factors
Create Hypothesis’ (Null and
Alternative)
Potential Data to collect:
Collect additional , at point of
origin of error, data and facts
regarding error during hypothesis
creation as required
Potential Outputs of Activities:
Null and Alternate hypothesis
Comprehensive set of facts and
data regarding error at point of
origin
Clear and concise understanding
of what SHOULD be happening in
current condition not What is
Happening!
Install Poka Yoke
Install Poka Yoke(s)
Install Measurement System
Remember to Measure Process
Performance > NOT PEOPLE
performance
Document process and approve
new ways of working
Instruct LOTO workers in use of
Poka Yoke System
Instruct LOTO workers of Target
Condition of Poka Yoke System
and Target Condition of LOTO
Poka Yoke(s)
Measure to new standard
 Record learning and improve
again
Use Facts and Data > Create 3
countermeasures for Trial
application and measurement
at Origin of error.
Create 3 A3’s to document
hypothesis and 3 trials for
application of Poka Yoke(s)
continue to record your thinking
and create “Hoken”
Share 3 alternatives with those
involved with error so Learning
takes place (Nemawashi &
Yokoten)
Decide on type of Poke Yoke
Shut Out <>Attention
!Decide on Method!:
CONTACT - use of shape, size or
other physical attributes for early
detection of Non-Standard
Installation of LOTO
SEQUENCE > MOTION STEP - use
of a checklist to ensure
completion of all installation
process step are completed to
standard
Potential Data to collect:
Collect additional data and facts
regarding error during hypothesis
creation as required
Potential Outputs of Activities:
3 Countermeasure Alternatives
3 A3’s documenting Alternatives
Determine duration of Trial
Measurement system for
implementation of 3 Trials
Select 1 of 3 trials
Perform Trial 1 at Origin of
error.
Use A3 to document results of
Poka Yoke Test and Trial
Continue to record your thinking
and create “Hoken”
Share results of Trail 1 with
those involved with error so
Learning takes place and sharing
of new learning must occur
(Yokoten)
Potential Data to collect:
Collect additional data and facts
regarding effectiveness of new
condition(s) created and cause
and effect during trial at point
of origin
Potential Outputs of Activities:
Results of Test and Trial to
Eliminate known source (s) of
error
Definable, Predictable and
Repeatable process to Prevent
recurrence of errors
Development of measurement
system to check effectiveness of
Poka Yoke at point of origin and
for measuring effectiveness of
overall Poka Yoke system
Development of Training
activities for use of Poka Yoke
and new ways of working with
Poka Yoke in Target Condition
S
D
Do
A
Act
C
Check
Standardize
S
D
Do
A
Act
C
Check
Standardize
ERROR
DEFECT
ABNORMALITY
S
D
Do
A
Act
C
Check
Standardize
S
D
Do
A
Act
C
Check
Standardize
P
Plan
D
Do
A
Act
C
Check
P
Plan
D
Do
A
Act
C
Check
KAIZEN
ERROR
DEFECT
ABNORMALITY
P
Plan
D
Do
A
Act
C
Check
P
Plan
D
Do
A
Act
C
Check
P
Plan
D
Do
A
Act
C
Check
P
Plan
D
Do
A
Act
C
Check
P
Plan
D
Do
A
Act
C
Check
P
Plan
D
Do
A
Act
C
Check
P
Plan
D
Do
A
Act
C
Check
P
Plan
D
Do
A
Act
C
Check
P
Plan
D
Do
A
Act
C
Check
P
Plan
D
Do
A
Act
C
Check