Lean Six Sigma - Process Risk Analysis (FMEA)

1 December 17, 2019 – v 7.0
Process Risk Analysis (FMEA) & Mistake Proofing
by Operational Excellence Consulting LLC

3 December 17, 2019 – v 7.0
Process Risk Analysis & Mistake-Proofing - Overview
Our Process Risk Analysis & Mistake-Proofing Solution follows a proven 10 Step
Process, combining Process Failure Mode and Effects Analysis, Root Cause Analysis,
Poka-Yoke Principles and Process Control Plans with an effective team driven approach.
Perform Risk Analysis
Develop Mistake-Proofing Solutions
Implement Mistake-Proofing Solutions
Establish Process Control Plan
List Current Process ControlsDevelop a Process Variables Map
Develop a Cause & Effect Matrix
Determine Potential Root Causes
Determine Potential Failure Modes
Determine Potential Effects
This document is a partial preview. Full document download can be found on Flevy:
https://flevy.com/browse/document/lean-six-sigma--process-risk-analysis-fmea-600

5 December 17, 2019 – v 7.0
“Process Risk Analysis & Mistake Proofing” Agenda
1. Introduction to
Mistake-Proofing
(≈ 30 min)
2. Process Mapping &
Exercise (≈ 90 min)
3. Cause & Effect
Matrix & Exercise
(≈ 60 min)
4. Process FMEA &
Exercise
(≈ 60 min)
5. Risk Analysis &
6. Human Errors
and Poka-Yoke &
7. Process Control
Plan & Exercise
(≈ 60 min)

7 December 17, 2019 – v 7.0
 The responsibility for performing a Process Risk Analysis &
Mistake-Proofing of a process must be assigned to an individual.
 However, the responsible individual is expected to directly and
actively involve representatives from all affected areas.
 The team should reflect the needs and requirements that the
problem and culture of the organization requires.
 It normally consists of four to six individuals with multidiscipline and
multifunctional backgrounds. In addition, all members should have
ownership of the problem/process.
Process Risk Analysis & Mistake-Proofing - A Team Effort
 Mistake-Proofing should be a catalyst
to stimulate the interchange of ideas
between the functions effected and
thus promote a team approach.

9 December 17, 2019 – v 7.0
Process inputs can be categorized using the 6Ms
 Menpower
 Machines
 Materials
 Methods
 Measures
 Mother Nature
Process Inputs & The 6Ms

11 December 17, 2019 – v 7.0
The Human Being – Often the Biggest “Noise” Input …
The order really
has to go out
today !!!
Lost a lot of
money in Poker
last night.
Hopefully
Molly is doing
well in her test
today.
It is Friday !!!
Wonder what
I should wear
tonight.
… in your Process.

13 December 17, 2019 – v 7.0
Process Variables Mapping → Basics
• Process Variables Maps should include:
– All value-added and non-value-added process steps
– Major activities and/or tasks in each process step
– Process Inputs and Xs for each process step
– Process Outputs and Ys for each process step
– Data Collection Points if applicable
• The Process Variables Map documents the process as it is actually
performed, not necessarily as it is supposed to be performed
• Key deliverable from the Process Variables Map is a complete list of
all the Process Inputs and Xs within the project scope, from which
all future work will be performed

15 December 17, 2019 – v 7.0
Process Variables Mapping → Step-by-Step Approach
1. Identify the process or sub-process, with its external inputs and
customer outputs (High Level Process Map)
2. Identify all process steps in the process or sub-process graphically
3. List outputs and their Ys for each process step (before listing the
inputs)
4. List all inputs and their Xs for each process step and classify them
as controlled or uncontrolled
5. Optional: Add process specifications for the identified Xs and Ys

17 December 17, 2019 – v 7.0
Process Variables Map → Step 2: Identify Process Steps
Identify Process Steps
 Include all value-added and non value-added process steps and
key activities or tasks. Keep it to 4 – 8 process steps, if possible.
 Hint: Process Step Names are verbs or gerunds
1. Preparing Coffee
Machine
(1. Checking for cleanliness
2. Checking that machine is
plugged into power outlet)
2. Adding Coffee into
Coffee Machine
(1. Getting coffee filter
2. Placing coffee filter into
coffee machine
3. Getting coffee powder
4. Adding coffee powder
into coffee filter)
3. Adding Water into
Coffee Machine
(1. Filling coffee pot with
water
2. Filling water into coffee
machine)
4. Turning on Coffee
Machine
(1. Checking coffee
machine
2. Turning on coffee
machine
3. Waiting for water to drip
into coffee pot)
5. Pouring Coffee into Cup
(1. Taking coffee pot out of
coffee machine
2. Pouring coffee into coffee
cup
3. Turning off coffee
machine)
6. Tasting Coffee
(1. Drinking coffee out of
coffee cup
2. Assessing coffee taste -
too weak, good, too strong)

19 December 17, 2019 – v 7.0
Process Variables Map → Step 4: List and Classify Xs
 List all Xs for each Inputs (usually specific attributes of the input
which could be a source of variation)
 Classify Xs
– Controlled (C): These are inputs that you adjust or control while
the process is running (Examples: Speed, feed rate, pressure,
temperature, experience level of worker, data system size)
– Uncontrolled (U): Noise variables. These are things you cannot,
or do not currently, control (Examples: Ambient temperature,
humidity, order quantity, training hours of worker)
• Could be due to the expense or difficulty controlling them
This step is where the team should spend most of its time

21 December 17, 2019 – v 7.0
Process Variables Map → Step 5: Add Specifications
 Document any known operating specification or requirements for
each X and Y if applicable

23 December 17, 2019 – v 7.0
1. Introduction to
Mistake-Proofing
(≈ 30 min)
3. Cause & Effect
Matrix & Exercise
(≈ 60 min)
4. Process FMEA &
Exercise
(≈ 60 min)
5. Risk Analysis &
6. Human Errors
and Poka-Yoke &
7. Process Control
Plan & Exercise
(≈ 60 min)

25 December 17, 2019 – v 7.0
Cause & Effect Matrix → Results
 Pareto of Process Xs to be evaluated further using the Process Failure
Mode and Effects Analysis (FMEA)
 Funnels the complete list of inputs and Xs generated in the Process
Variables Map
 Continues the review and assessment of the Process Control Plan

27 December 17, 2019 – v 7.0
Importance to Customer >>
(weighting value)
Process Step X
ProjectY1
ProjectY2
ProjectY3
ProjectY4
Total
1 Process Step 1 X 1 0
Cause & Effect Matrix → Step 1: List the Ys
1. List the
Process Ys
These Ys are
your high level
Ys from your
High Level
Process Map.
Most
processes will
have fewer
than 3 or 4.

29 December 17, 2019 – v 7.0
(weighting value)
Process Step X
ProjectY1
ProjectY2
ProjectY3
ProjectY4
Total
Cause & Effect Matrix → Step 3: List Steps and Xs
3. List
Process Xs by
Process Step
Be sure to include each
process step and all Xs
for each process step

31 December 17, 2019 – v 7.0
Relating Xs to Customer Requirements (Ys)
 The team is ready to relate the Ys to the Xs
 Correlational scores: No more than 4 levels
 0, 1, 3 and 9 are typical values
 Assignment of the scoring takes the most time
 Independent scoring can help speed up process by having each team
member first fill out the matrix silently
 The most common scoring values are:
0 = No relationship / impact
1 = The X only remotely affects the Y
3 = The X has a moderate effect on the Y
9 = The X has a direct and strong effect on the Y
 Some practitioners combine the 0 and 1 scores

33 December 17, 2019 – v 7.0
(weighting value)
Process Step X
ProjectY1
ProjectY2
ProjectY3
ProjectY4
Total
Cause & Effect Matrix → Step 5: Prioritize the Xs
Sum of Weighting values x Correlation scores across all Ys
5. Cross-
multiply, sort &
prioritize

35 December 17, 2019 – v 7.0
Cause & Effect Matrix → Example - Sorted
…

37 December 17, 2019 – v 7.0
Cause & Effect Matrix → Next Steps
 Process FMEA
• Transfer the highest ranked Xs to Process FMEA
• Consider what it means if many of your highly ranked Xs are classified
as Uncontrolled
 Process Control Plan Review
• Consider existing process controls for all highly ranked Xs and Ys from
the C&E Matrix
• Document short- and long-term Process Control Plan opportunities
• Identify and implement “Low hanging fruit” and “Quick wins”

39 December 17, 2019 – v 7.0
Workshop Exercise: Coffee Brewing Process
Instructions to Exercise 2:
Develop a Cause & Effect Matrix for the Coffee Making Process.
1. Rank order and assign priority factor to each Y
2. List all process steps and Xs from the Process Variables Map
3. Evaluate correlation of each X to each Y (Score: 0 – 1 – 3 – 9)
4. Cross multiply correlation values with priority factors for Ys and
sum for each X
5. Identify and review TOP 10 – 15 Xs and inputs
Resources for Exercise 2:
 Flip Charts
 Post-It Notes
 Markers
30 Minutes

41 December 17, 2019 – v 7.0
 First used in the 1960's in the Aerospace industry during
Apollo missions.
 In 1974 the Navy developed MIL-STD-1629 regarding
the use of FMEA.
 In the late 1970's, automotive applications driven by
liability costs, began to incorporate FMEA into the
management of their processes
 Now used across many industries as a method to
improve quality and reliability, and to manage risk.
Failure Mode and Effects Analysis → History

43 December 17, 2019 – v 7.0
The Different Types of FMEAs
 System FMEA is used to analyze systems and sub-systems in early
concept and design stage. A System FMEA focuses on potential
failure modes between the functions of the system caused by system
deficiencies. It includes the interactions between systems and
elements of the system.
 Design FMEA analyses products before they are released to
manufacturing. A Design FMEA focuses on failure modes caused by
design deficiencies.
 Process FMEA analyses manufacturing, service, and transactional
processes. A Process FMEA focuses on failure modes caused by
manufacturing, service, or transactional process deficiencies.
Failure Mode and Effects Analysis → The Different Types

45 December 17, 2019 – v 7.0
Outputs of a Process FMEA
A Process FMEA can be described as a systematic group of
activities intended to:
 recognize and evaluate the potential failure of a (new) process/
product and its effects,
 develop a ranked list of potential failure modes, thus establishing
a priority system for corrective action and improvement
consideration,
 identify actions which could eliminate or reduce the chance of the
potential failure occurring, and
 document the result of the process.
Process Failure Mode and Effects Analysis → Outputs

47 December 17, 2019 – v 7.0
Process FMEA → The Template

49 December 17, 2019 – v 7.0
Column: Potential Failure Mode
Potential Failure Mode is defined as the manner in which the specific
process input or X could potentially fail.
– How could this process input (X) fail for the process step to complete its
intended function?
Typical failure modes could be, but are not limited to:
– Too high, too low, inaccurate, incomplete, missing, mis-spelled, not
available, damaged, worn, broken, mis-aligned, …
In case of the Process Input (X) is “Operator (Experience)”, use the “16
Human Error Modes” (next slide) and be specific.

51 December 17, 2019 – v 7.0
Process FMEA → Potential Failure Modes
Process Step Description:
 “Inserting the Coffee Filter”
Process Step Success Criteria:
 Filter Present – Right Filter – Right Position – …
Potential Failure Modes:
 No Filter – Too many Filters
 Filter too small – Filter too large – Wrong Type
 Filter misaligned – Filter not opened

53 December 17, 2019 – v 7.0
Column: Potential Cause(s) of a Failure Mode
Potential Cause of Failure is defined as why the failure could occur, described in
terms of something that can be corrected or can be controlled.
Only specific errors or malfunctions should be listed; ambiguous phrases (e.g.
operator error, machine malfunction) should not be used. List, to the extent
possible, every conceivable failure cause assignable to each potential failure
mode.
– Why would this failure mode occur?
– What circumstances could cause the failure mode?
Typical potential causes could be, but are not limited to:
– improper heat treat (time, temperature), part missing or misaligned,
improper torque (under, over), inadequate control procedure, human error
like omission or incorrect selection, lack or improper operating instruction.

55 December 17, 2019 – v 7.0
How to apply the 5 Why’s
Description: The 5 Why’s Analysis helps to identify the root cause of a problem in a
graphical and systematic manner. It encourages the team to reach an answer that is
fundamental and actionable.
Procedure:
Step 1: Write the Failure Mode in the upper left corner of a flip chart or white board.
Step 2: Ask “Why?” this problem could occur. Write the potential cause underneath the
original Failure Mode.
Step 3: The potential cause identified in Step 2 now becomes a new Failure Mode. Repeat
Step 2 and ask “Why?”, e.g. “Why would this failure occur?", again.
Step 4: Continue Step 2 and Step 3 until you reach an answer that is fundamental and
actionable, e.g. standard operating procedure, work instruction, system issues, training
needs, … .

57 December 17, 2019 – v 7.0
Root Cause Analysis Tools → Why – Why Diagram
Description: The Why-Why Diagram helps to identify possible causes of
a problem or failure mode in a graphical and systematic manner. The
tools helps the team to recognize the broad network of possible causes
and the relationship among them.
Example:
Failure Mode:
Customer complaint
due to grinding marks
on the door frame
The door frame
had been
“over-ground”
Wrong Tool
was used
Operator was
untrained
Current
grinding
method is not
capable
Cosmetic
requirements
not understood
Current
grinding
method is too
complicated
No written
cosmetic
standard exists
No formal
training exists
Training
Process was
not applied
Tools are not
marked
…
…This document is a partial preview. Full document download can be found on Flevy:

59 December 17, 2019 – v 7.0
Root Cause Analysis Tools → Fishbone Diagram
The Fishbone Diagram (Cause-and-Effect or Ishikawa Diagram) is a
systematic way of looking at the causes of a problem and how they are
related using pre-defined categories, e.g. 4Ms & 1 E.
4M’s & 1E
= MEN
METHODS
MATERIALS
MACHINES
+ ENVIRONMENT
Effect or
Outcome
Machines
Materials Methods
Environment
Trunk
Primary Causal Factor
Main Branch
Minor Branch
Men
Potential
Failure Mode

61 December 17, 2019 – v 7.0
Column: Current Controls
Current Process Controls are descriptions of the controls that either
prevent to the extent possible the failure mode from occurring or detect
the failure mode should it occur.
The focus is on the effectiveness of the control method/technique to
catch the problem before it reaches the customer.
Typical process controls could be, but are not limited to:
– Standard Operating Procedures (“SOPs”) & Work Instructions
– Checklists
– Error-proofing systems and devices (e.g. Poka-Yoke)
– Color coding or tags
– Examining safety margins (e.g. Process Capability Studies)
– Statistical Process Control (SPC) or Pre-Control
– Post-process evaluation (sample based inspection AQL).

63 December 17, 2019 – v 7.0
Process FMEA → Example
Process Step
Key Process
Input
Potential Failure Mode Potential Failure Effects
S
E
V
Potential Causes
O
C
C
Current Controls
D
E
T
R
P
N
What is the
process step
What is the Key
Process Input?
In what ways does the
Key Input go wrong?
What is the impact on the Key
Output Variables (Customer
Requirements) or internal
requirements?
HowSevereistheeffect
tothecustomer?
What causes the Key
Input to go wrong?
Howoftendoescauseor
FMoccur?
What are the existing controls
and procedures (inspection and
test) that prevent either the
cause or the Failure Mode?
Should include an SOP
number.
Howwellcanyoudetect
causeorFM?
Adding Water
into Coffee
Machine
Coffee Maker or
Operator -
Experience
Adding too much water
(excessive repetition)
coffee too weak - too much
coffee - coffee overflow -
electrical shortage - operator gets
hurt - fire in the kitchen - …
no proper way to measure
correct amount of water
needed
none
0
no instruction available to
determine proper water
amount
none
0
Adding too little water
(insufficient repetition)
coffee too strong - not enough
coffee - dissatisfied spouse -
marriage crisis - ...
needed
none
0
amount
none
0
Forgetting to add water
(omission)
… … …
0

65 December 17, 2019 – v 7.0
1. Introduction to
Mistake-Proofing
(≈ 30 min)
3. Cause & Effect
Matrix & Exercise
(≈ 60 min)
4. Process FMEA &
Exercise
(≈ 60 min)
5. Risk Analysis &
6. Human Errors
and Poka-Yoke &
7. Process Control
Plan & Exercise
(≈ 60 min)

67 December 17, 2019 – v 7.0
Risk Priority Number (RPN):
For higher RPN’s the team must undertake efforts to reduce this
calculated risk through corrective action(s). In general practice,
regardless of the resultant RPN, special attention should be given
when severity is high.
0001)()()(  DetOccSevRPN
Process FMEA → Risk Priority Number - RPN

69 December 17, 2019 – v 7.0
Process FMEA → Example for Occurrence Ranking
Rank Probability of Failure Mode Occurrence
Possible Failure Rates
PPM*) Failure rate ppk
1 Remote: Failure is unlikely. No failures ever
associated with almost identical processes.
 1 1 out of
1 000 000
 1.67
2 Very Low: Only isolated failures associated
with almost identical processes.
 7 1 out of
150 000
 1.50
3 Low: Isolated failures associated with similar
processes.
 64 1 out of 15 000  1.33
4-6 Moderate: Generally associated with
processes similar to previous processes which
have experienced occasional failures, but not in
major proportions.
 500
 2700
 12 500
1 out of 2000
1 out of 400
1 out of 80
 1.17
 1.00
 0.83
7-8 High: Generally associated with processes
similar to previous processes that have often
failed.
 50 000
 125 000
1 out of 20
1 out of 8
 0.67
 0.51
9-10 Very high: Failure is almost inevitable.  333 000
 333 000
1 out of 3
 1 out of 2
 0.33
< 0.33
Please make sure that the Ranking Scheme reflects your organization’s needs. Otherwise, revise the
Ranking Scheme accordingly.

71 December 17, 2019 – v 7.0
Process FMEA → General Comments to Risk Analysis
Achieving agreement across the FMEA Team about the “correct” risk
ranking is not always easy or possible. Below some team decision rules
an organization may consider to not waste valuable time on non-value
add discussions.
 If the disagreement is an adjacent category, average out the
difference. For example, if one member says 4 and someone else
says 6, the ranking in this case should be 5.
 If the disagreement jumps one category, then consensus must be
reached. Even with one person holding out, total consensus must be
reached. No average, no majority. Everyone in that team must have
ownership of the ranking. They may not agree 100 %, but they need
to be able to “live with it”.This document is a partial preview. Full document download can be found on Flevy:

73 December 17, 2019 – v 7.0
Extreme cases where corrective & preventive actions must be
taken include the following process ratings.
Assessment Rating Causes of Failure Actions
OS D
11 1 Ideal situation (goal) No action (N/A)
11 10 Assured mastery N/A
110 1 Failure does not reach user N/A
110 10 Failure reaches user Yes
101 1 Frequent fails, detectable, costly Yes
101 10 Frequent fails, reach user Yes
1010 1 Frequent fails with major impact Yes
1010 10 Trouble ! Yes, Yes, Yes
Process FMEA → Risk Assessment

75 December 17, 2019 – v 7.0
Process FMEA → Example & RPN
Process Step
Key Process
Input
Potential Failure Mode Potential Failure Effects
S
E
V
Potential Causes
O
C
C
Current Controls
D
E
T
R
P
N
What is the
process step
What is the Key
Process Input?
In what ways does the
Key Input go wrong?
What is the impact on the Key
Output Variables (Customer
Requirements) or internal
requirements?
HowSevereistheeffect
tothecustomer?
What causes the Key
Input to go wrong?
Howoftendoescauseor
FMoccur?
What are the existing controls
and procedures (inspection and
test) that prevent either the
cause or the Failure Mode?
Should include an SOP
number.
Howwellcanyoudetect
causeorFM?
Adding Water
into Coffee
Machine
Coffee Maker or
Operator -
Experienced
Adding too much water
(excessive repetition)
coffee too weak - too much
coffee - coffee overflow -
electrical shortage - operator gets
hurt - fire in the kitchen
6
needed
8
none
10 480
6
amount
6
none
10 360
Adding too little water
(insufficient repetition)
coffee too strong - not enough
coffee - dissatisfied spouse -
marriage crisis - ... 8
needed 8
none
10 640
8
amount
6
none
10 480
Forgetting to add water
(omission)
… … …
0

77 December 17, 2019 – v 7.0
1. Introduction to
Mistake-Proofing
(≈ 30 min)
3. Cause & Effects
Matrix & Exercise
(≈ 60 min)
4. Process FMEA &
Exercise
(≈ 60 min)
5. Risk Analysis &
6. Human Errors
and Poka-Yoke &
Exercise (≈ 60
min)
7. Process Control
Plan & Exercise
(≈ 60 min)

79 December 17, 2019 – v 7.0
 Human Errors are inevitable !!!
Errors can´t be avoided. People will always make mistakes.
Human Errors → Dealing with Human Errors
 Human Errors can be eliminated !!!
Any kind of mistake people make can be reduced or even eliminated.
People make fewer mistakes if they are supported by a production
system based on the principle that human errors can be prevented.
 An organizations must establish a mistake-proofing
mindset that promotes the belief that it is
unacceptable to allow for even a small number of
product or service defects caused by human
errors.

81 December 17, 2019 – v 7.0
Please write down 3 Human Errors that have happened in your
organization over the last couple of weeks.
Quick Exercise
Identify 3 Human Errors

83 December 17, 2019 – v 7.0
1. Omission
2. Excessive / insufficient repetition
3. Wrong order
4. Early / late execution
5. Execution of restricted work
6. Incorrect selection
7. Incorrect counting
8. Misrecognition
9. Failing to sense danger
10. Incorrect holding
11. Incorrect positioning
12. Incorrect orientation
13. Incorrect motion
14. Improper holding
15. Inaccurate motion
16. Insufficient avoidance
Human Errors → The 16 Human Error Modes

85 December 17, 2019 – v 7.0
1. Failures in “Understanding the Work Progress”
1. Omission
→ What part of the process is prone to be omitted?
2. Excessive / Insufficient Repetition
→ What part of the process is prone to be excessively repeated?
3. Wrong Order or Sequence
→ In what wrong sequence can the process be executed?
4. Early / Late Execution
→ What execution can be early or late?
5. Execution of Restricted Work
→ What tasks could be executed by unauthorized personnel?
The Human Work Model & The 16 Human Error Modes

87 December 17, 2019 – v 7.0
3. Failures in “Recognizing the State of the Work Object”
8. Misrecognition (or Misunderstanding or Misreading)
→ What misunderstanding or misreading is prone to occur?
→ What information, risk or failure/error is prone to be overlooked?
→ What miscommunication is prone to occur?
→ What incorrect decision is prone to occur?

89 December 17, 2019 – v 7.0
5. Failure in “Recognizing the Danger in the Motion”
9. Failure to Sense Danger
→ What information, risk or failure/error is prone to be overlooked?

91 December 17, 2019 – v 7.0
1. Work Progress
Understanding
Error Modes (1) - (5)
Start
End
2. Work Object
Selection
3. Recognition of
Work Object’s State
Error Modes (8)
4. Recognition of the
Motion to be done
on the Work Object
6. Motion Execution
5. Recognition of the
Danger in the Motion
Error Modes (9)
The Human Work Model & Error Modes

93 December 17, 2019 – v 7.0
A worker reads a work-order sheet, selects an appropriate part, and assembles it
onto a corresponding sub-assembly product.
Decomposition in Work Segments:
i. reading the work-order sheet
ii. getting a part to be assembled from parts boxes
iii. assembling the part onto the sub-assembly product
Human Error Modes:
i. Reading the work-order sheet
1. Forgetting to read the sheet (mode 1: omission)
2. Reading the wrong sheet (mode 6: incorrect selection)
3. Misreading the sheet (mode 8: misrecognition)
Human Work Model & Error Modes → Example
ii. Getting a part to be assembled from parts boxes
1. Forgetting to get the part (mode 1: omission)
2. Selecting the wrong part (mode 6: incorrect selection)
3. Dropping the part (mode 14: improper holding)

95 December 17, 2019 – v 7.0
Human Errors → Six Mistake Proofing Principles
1. Elimination seeks to eliminate an error-prone process step by
redesigning the product or process so that the task or part is no longer
necessary.
Example: An example of elimination is the use of ambient-
light sensors to turn outside lighting on and off.
2. Prevention modifies the product or process so that it is impossible to
make a mistake or that a mistake becomes a defect.
Example: An example would be the change from a rectangular to a
round manhole.This document is a partial preview. Full document download can be found on Flevy:

97 December 17, 2019 – v 7.0
Human Errors → Six Mistake Proofing Principles
5. Detection involves identifying a mistake before further processing
occurs so that the operator can quickly correct the defect.
Example: Examples would include a weld counter to ensure the correct
number of welds or a software modification that will not allow incorrect
entries.
6. Mitigation seeks to minimize the effects of the mistake. This includes
mechanisms that reduce the impact of a error and defect; products
designed with low-cost, simple rework procedures when an error is
discovered; extra design margin or redundancy in products to
compensate for the effects of errors.
Example: An example would be a smoke or heat detector
detecting a hazardous situation.

99 December 17, 2019 – v 7.0
Poka (= inadvertent error) - Yoke (= avoid)
devices help us avoid defects, even when inadvertent errors are
made.
Poka - Yoke helps build Quality
into Processes and Products
Human Errors → Poka-Yoke Mistake Proofing
Poka-yoke (poh-kah yoh-keh) was coined in Japan during
the 1960s by Shigeo Shingo who was one of the
industrial engineers at Toyota.

101 December 17, 2019 – v 7.0
Good Poka-Yoke devices, regardless of their implementation, share
many common characteristics:
 they are simple and cheap. If they are too complicated or
expensive, their use will not be cost-effective.
 they are part of the process, implementing what Shingo calls
"100%" inspection.
 they are placed close to where the mistakes occur, providing quick
feedback to the workers so that the mistakes can be corrected.
Characteristics of a Good Poka-Yoke Device

103 December 17, 2019 – v 7.0
1. Guide Pins
Guide pins of different sizes and/or shapes and placed in the proper locations ensure
that parts are being assembled correctly by providing the operator feedback when a
mistake has been made. Guide pins can also be used in jigs to ensure proper
positioning of the part.
Applications
• Proper alignment of a work piece
• Proper orientation of a work piece
Features
• Easy to develop & implement
• May be the result of DFA and DFM activities
(Product Quality Planning)
Human Error Prevention
• wrong order, incorrect selection, incorrect positioning, incorrect orientation, …
Seven Best Poka-Yoke Devices → Guide Pins

105 December 17, 2019 – v 7.0
Problem Statement: How to ensure that everything makes it in the box?
Solution: Use of a scale connected with a visual & audio alarms when the
weight of a package falls outside pre-defined specification limits.
Seven Best Poka-Yoke Devices → Error Detection/Alarms
Cons: Variation in material may result in false fails and pass packages.

107 December 17, 2019 – v 7.0
4.1 Proximity Sensors
Proximity sensors emit a high-frequency magnetic field and detect an upset in the field
when an object enters it. They can be used to detect the presence or absence of an
object.
Applications
• Sensing of tank or bin level
• Confirmation of part or object passes by
• Detection presence or absence of object
• Positioning of work piece
Features
• Non-contact - Work in harsh environments - Small sensors are available for
installation in tight areas - Fast response speed
• Omission, excessive/insufficient repetition, incorrect selection, incorrect counting,
incorrect positioning, incorrect orientation, …
Seven Best Poka-Yoke Devices → Sensors

109 December 17, 2019 – v 7.0
5. Vision Systems
Vision systems use cameras to look at a surface and then compare the surface viewed to a
“standard” or reference surface stored in the computer. They can be used to detect the
presence or absence of an object, the presence of defects, or to make distance
measurements.
Applications
• Missing or incorrect parts in an automated assembly line
• Poor quality surfaces or components
• Correct orientation of parts or labels
• Ensure correct relative position
• Color detection
Features
• Non-contact - Need to have sufficient light - Flexible (can be reprogrammed for a variety
of applications) - Compact systems are now available.
• Omission, incorrect selection, incorrect positioning, incorrect orientation, misrecognition,
…
Seven Best Poka-Yoke Devices → Vision Systems
Checking for Label Presence, Color,
Orientation, & Alignment.

111 December 17, 2019 – v 7.0
7. Checklists
A checklist is a type of informational job aid used to reduce failure by compensating for
potential limits of human memory and attention. It helps to ensure consistency and
completeness in carrying out a task.
Applications
• Shift Start-up
• Product Changeover
• Equipment Set-up
Features
• Easy to develop - Easy to use - Easy for people to understand
• omission, early/late execution, wrong order, misrecognition, …
Seven Best Poka-Yoke Devices → Checklists

113 December 17, 2019 – v 7.0
Human Errors → Mistake-Proofing Examples
Never forget your cell phone again.
«Pick to Light»: on an assembly line, if the above light
is green means that you must take the piece. If the
light above the rack is red means that you must not
take that piece.This document is a partial preview. Full document download can be found on Flevy:

115 December 17, 2019 – v 7.0
It only fits one way by using guide pins and
asymmetric product design. Good Product
Quality Planning. → Guide “Pin”
Human Error prevention through a visual
workplace.

117 December 17, 2019 – v 7.0
Human Error detection through automated defect
detection devices such as sensors, limit switches,
scales, … .
Getting the torque on bolts right is very tricky
business for many companies. Huck fasteners
mistake-proof this problem using a hybrid: half
“pop-rivet”, half bolt.
The tension on the bolt is created in a linear
fashion and the “nut” is clamped in place and the
excess bolt length is cut off.

119 December 17, 2019 – v 7.0
Consumer friendly Mistake-Proofing product
design improves usability and Customer
Satisfaction.
… and many more.
Preventing missing weld nuts, with a
sensor linked to a visual & audio alarm.
Process will stop automatically and a
corrective action is required.

121 December 17, 2019 – v 7.0
1. Introduction to
Mistake-Proofing
(≈ 30 min)
3. Cause & Effect
Matrix & Exercise
(≈ 60 min)
4. Process FMEA &
Exercise
(≈ 60 min)
5. Risk Analysis &
6. Human Errors
and Poka-Yoke &
7. Process
Control Plan &
Exercise (≈ 60
min)

123 December 17, 2019 – v 7.0
Process Control Plan → Template
Supplier: Product:
Key Contact: Process:
E-Mail / Phone:
Product
Characteristic
Process
Characteristic
Characteristic
Process Step
Specification
(LSL, USL &Target)
Date (Orig):
Date (Rev):
Control Method Reaction Plan
Control Limits
(LCL & UCL)
Measurement
System
Sample Size Sample Frequency
Operational Excellence
Process Control Plan

125 December 17, 2019 – v 7.0
 Sample Size: Sample size specifies how many parts are evaluated at any
given time. The sample size will be “100 %” and the frequency
“continuous” in case of 100% inspection.
 Sample Frequency: Sample frequency specifies the how often a sample
will be taken, e.g. once per shift or every hour.
 Control Method: Brief description of how the information/data will be
collected, analysed/controlled and reported. More detailed information
may be included in a named work instruction.
 Reaction Plan: Necessary corrective actions to avoid producing non-
conforming products or operating out-of-control. Corrective actions should
normally be in the responsibility of the person closest to the process, e.g.
the machine operator. This is to secure, that immediate corrective actions
will take place and the risk of non-conforming products will be minimized.
More detailed information may be included in a named work instruction.
Process Control Plan → Template

127 December 17, 2019 – v 7.0
 The OCAP is a systematic and ideal problem-solving tool for
process problems because it reacts to out-of-control situations in
real time.
 OCAPs standardize the best problem-solving approaches from the
most skilled and successful problem solvers (experts/operators).
 The OCAP also allows (and requires) off-line analysis of the
terminators to continually improve OCAP efficiency.
Some Benefits of Out-of-Control-Action-Plans

129 December 17, 2019 – v 7.0
Workshop Exercise: Coffee Brewing Process
Instructions to Exercise 6:
Develop a Process Control Plan for the Coffee Making
Process.
 Create a Process Control Plan Template on a Flip
Chart
 Develop a Process Control Plan for all 3 process
steps analyzed in the Process FMEA
Resources for Exercise 6:
 Flip Charts
 Post-It Notes
 Markers
45 Minutes

131 December 17, 2019 – v 7.0
The End …
“Perfection is not attainable, but if we chase perfection we can catch
excellence.” - Vince Lombardi

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