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5-Why Training Agenda
Where does 5-Why Fit within the PRR process
Understanding of 5-Why
Quick 5-Why Exercise as a group
Critique Sheet
5- Why Examples
Wrap Up/Discussion
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5-WHY
After a supplier has submitted an initial response and
containment plan (Step # 2 in the PRR process), a detailed
investigation is necessary to determine what caused the
problem. Step # 4 (Supplier determines the root cause)
requires a 5-Why analysis to help in identifying the root cause
of the problem.
Going back to one of the elements within the Purpose of a
PRR “to facilitate problem resolution”, 5-Why is the prescribed
tool for determining the root cause of the problem to facilitate
problem resolution.
Where does it fit within the PRR process?
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Is the powerful question… own it!!
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Speed
Limit
Strictly
Enforced
No
Reaction
How
Fast
Are You
Going?
Cause
Reaction
(Look at speedometer)
How
Fast
Should
You Be
Going?
Cause
Reaction & Research
(Look at speedometer;
Search for speed limit sign)
Power of Asking Questions
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Who are the best at asking questions to
solve problems?
Power of Asking Questions
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When working with people to solve a problem,
it is not enough to tell them what the solution is. They
need to find out and understand the solution for
themselves. You help them do this by asking open-
ended , thought provoking questions.
Children!
Why?
…because they keep asking objective, open-ended questions
until the answer is simple and clear
Power of Asking Questions
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Close-Ended: Structures the response to be answered
by one word, often “yes” or “no”. Usually
gives a predetermined answer.
Example: “Did the lack of standardization cause the incorrect setup?”
Open-Ended: Leaves the form of the answer up to the
person answering which draws out more
thought or research.
Example: “How is setup controlled?”
Close-Ended vs. Open-Ended Questions
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Benefits of Open-Ended Questions
Requires thought
Promotes additional research
Enhances problem solving skills
Does not assume there is one right answer
Avoids predetermined answers
Stimulates discussion
Empowers the person answering
In many circumstances, it is not only the answer itself,
but the process by which the answer was determined
that is important when asking an Open-Ended question
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Example 1:
“What could have caused the tool to break?”
(Open-Ended, probing question forces the person to think about all
possibilities, not just PM)
Example 2: “Would improving material flow help reduce lead times?”
(Good question but it’s still Close-Ended, focuses the person on material
flow as a means to reduce lead time. Is this the best improvement?)
“Did the lack of a PM system cause this tool to break?”
(Close-Ended question, can be answered by a “yes” or “no”, gives the
person a predetermined answer that PM is to blame)
“What are some options on improving lead time?
(Open-Ended, triggering more thought and research on all variables
impacting lead time.)
Example 3: “Is equipment capability causing the variation in your process?
(Close-Ended, can be answered by a “yes” or “no”, focuses the person on
equipment being the source of variation)
“What could potentially cause variation in your process?
(Open-Ended, triggering more thought and research, opens up possibilities
of variation with man, material & method, not just machine)
More Examples
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5-Why Analysis Three Paths
5-Why:
Specific problem:
– Why did we have the problem?
Problem not detected:
– Why did the problem reach the Customer?
System failure:
– Why did our system allow it to occur?
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5-Why Analysis
Corrective Action
with Responsibility Date
Define Problem
Use this path for
the specific A
nonconformance
being investigated
Root Causes
WHY? Therefore
WHY? Therefore
Use this path to
investigate why the
problem was not
detected. WHY? Therefore B
WHY? Therefore WHY? Therefore
A
WHY? Therefore
Use this path to
investigate the
systemic root cause
(Quality System
Failures) WHY? Therefore
C
WHY? Therefore WHY? Therefore
B
Ref. No. (Spill, PR/R…) WHY? Therefore
Date of Spill WHY? Therefore
Product / Process Delphi Location Content Latest Rev Date WHY? Therefore
C
Problem Resolution Complete Communicate to Delphi Date: Process Change Break Point Date: Implement System Change Date:
Lessons Learned:
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Root Cause Analysis
Delco fuse box
Insert example
What tool do
We use for this?
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Grasp the Situation
Part I – Grasp the Situation
– Step 1: Identify the Problem
» In the first step of the process, you become aware of a problem that may be
large, vague, or complicated. You have some information, but do not have
detailed facts. Ask:
» What do I know?
– Step 2: Clarify the Problem
» The next step in the process is to clarify the problem. To gain a more clear
understanding, ask:
» What is actually happening?
» What should be happening?
– Step 3: Break Down the Problem
» At this point, break the problem down into smaller, individual elements, if
necessary.
» What else do I know about the problem?
» Are there other sub-problems?
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Grasp the Situation
– Step 4: Locate the Point of Cause (PoC)
» Now, the focus is on locating the actual point of cause of the problem. You
need to track back to see the point of cause first-hand. Ask:
» Where do I need to go?
» What do I need to see?
» Who might have information about the problem?
– Step 5: Grasp the Tendency of the Problem
» To grasp the tendency of the problem, ask:
» Who?
» Which?
» When?
» How often?
» How much?
» It is important to ask these questions before asking “Why?”
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5-Why Analysis
Step 1: Problem Statement
– Is the problem statement clear & accurate?
– Is the analysis on the problem as the customer sees it?
Step 2: Three Paths
– Are all three legs filled in?
– Are there any leaps in logic?
– Can you ask one, two, or three more Whys?
– Is there a cause-and-effect relationship in each path?
– Can the problem be turned “on” and “off”?
– Does the path make sense when read in reverse?
– Do the whys relate to the actual error?
– Does the non-conformance path tie to design, operations, dimensional issues,
etc.?
– Does the detection path tie to the customer, control plans, etc.?
– Does the systemic path tie to management issues or quality system failures?
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5-Why Analysis
Step 3: Corrective Actions
– Is there a separate action for each root cause?
– Is it possible to implement each corrective action?
– Do corrective actions require Customer approval? If so, how will they be
communicated to the Customer?
– Is there evidence to support verification of corrective actions?
– Are corrective actions irreversible?If not, do actions address ongoing
containment?
– Is there a plan to standardize lessons learned across products, departments,
etc?
Step 4: Lessons Learned
– How could the problem have been foreseen?
– How will information be implemented?
» On the line or in the plant?
» At the point of detection?
» Cross functionally at the Supplier?
» Other products/plants?
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5-Why Analysis
Step 5: Overall
– Are there gaps or “holes?”
» Are there things missed or not documented?
– Do corrective actions address actions the Supplier owns?
– How many iterations of 5 Why Analysis have there been?
– Who prepared the 5 Why Analysis?
» One person?
» Sales representative ?
» Clerk?
» The best answer is a cross functional team that understand the product and
process!
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5-Why Analysis
The problem is stated through
the eyes of the customer
Problem
The first why is the main cause
Etc.
You have root cause if you
can demonstrate:
• cause on, problem on
• cause off, problem off
Root Cause
The second why is what
causes the main cause
Etc.
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Cookies taste really bad
Problem
Used goose eggs rather than
chicken eggs
Recipe did not specify bird type
Root Cause
Ingredients are wrong
Cookies are undercooked
5-Why Example
(Non-conformance)
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PPAP submitted late
Problem
Test lead time not considered
No system to accurately assess
lead times of all PPAP elements
Root Cause
Validation testing not complete
PPAP package not complete
5-Why Example - PPAP Submittal
(Non-conformance)
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PPAP submitted late
Problem
No requirement to follow-up on
target submittal dates
No standard system to manage
PPAP submittal timeliness
Root Cause
Did not know the target
submittal date had passed
Did not react to the target
submittal date
5-Why Example - PPAP Submittal
(Detection)
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Did not meet the annual business
plan goal of a 10% increase in sales
Problem
Did not anticipate required
resources
Did not develop a plan as to
“how” the goal would be reached
Root Cause
Did not have adequate
resources
Did not thoroughly evaluate
market/competition
5-Why Example - Business Plan
(Non-conformance)
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5-Why Example - Business Plan
(Detection)
Did not meet the annual business
plan goal of a 10% increase in sales
Problem
Did not develop a plan to monitor
the status of reaching the goal
Root Cause
Did not know the goal was not
going to be met
Did not have alarms limits
identified at strategic intervals
(monthly, quarterly, etc.)
Did not evaluate the status of
the goal until December
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Flex Industries Case Study-
Background
Jake Ryan is the Quality Manager at Flex Industries. Flex is a component
supplier that manufactures metal stampings and light assembly products.
The company has a reputation for supplying high quality parts on a
consistent basis. Seldom has there been a customer complaint. Flex has
Quality representatives called Customer Support Engineers (CSE’s) at every
customer assembly plant. The CSE’s report any problems to Jake for
investigation and follow-up.
At 7:00 a.m. this morning, Jake received a call from Janet, CSE at the
Winding River Assembly Plant. Janet informed him that the customer had
found five defective stabilizing brackets on second shift last night. She
checked the remaining inventory and there were no defects in the remaining
326 pieces. The manufacturing sticker on the back of the brackets indicated
that they were made by the second shift operator. Normally, the stabilizing
bracket is fastened to the regulator motor with three rivets. The five defective
brackets had only two rivets in them. The lower set of rivets on all five
brackets was missing a rivet. This was the first time that the problem
occurred.
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Background
GOOD BAD
Jake set-up containment procedures at the plant warehouse to sort for discrepant materials. As
of this morning, two more defective brackets had been found in the remaining 2019 pieces of
inventory at Flex.
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Cause Investigation
Jake went out to the floor to talk with the team leader of the two rivet lines
(East and West) and the area quality assurance auditor. He informed Sam
(the team leader) of the quality problem and asked him to identify the line
which runs the stabilizing bracket assembly. Sam directed Jake to the East
line which runs Winding River assembly brackets only.
At the East Line, he spoke with Judy (the QA Auditor for the area) and asked
to see the quality log sheets. Jake and Judy reviewed the Nov. 11th log
sheet and could not find anything out of the ordinary. He asked her to set-up
in-house containment procedures to sort for any discrepant material in the
finished goods area.
Next, Jake tried to locate the second shift operator whose clock number was
on the defective parts. Since that operator was gone, Jake spoke with the
current machine operator (Ben). He asked Ben about any recent difficulties
with the rivet machine. Ben said that he hadn’t noticed anything out of the
ordinary. Ben also mentioned, however, that there had never been any
quality bulletins posted in the two years that this particular part has been
running.
Jake decided to stay in the area to watch the machine run for a while. After
about 15 minutes, he watched Ben dump rivets into the feeder bowl to
prepare for the next run.
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Cause Investigation
Shortly after restarting rivet operations, Ben walked over to another riveter
and came back with a steel rod. Ben poked around the rivet chute and then
continued working. Jake approached Ben and asked him about the steel
rod. Ben replied that from time to time the chute gets jammed and he has to
clear it out. This happens two or three times during a shift. He didn’t
mention this in his earlier conversation with Jake because the problem has
existed ever since he started working with this machine. The previous
operator showed him how to clear the chute. All the rivet machines are like
this.
Jake called the Machine Repair Department and asked that someone look at
the rivet track. A slight gap in the track was found and removed, and Ben
continued to work.
Two hours later, Jake got a call from Ben saying that the track was still
jamming. As far as Jake could see, only rivets were in the bowl. Next, Jake
looked into the rivet supplier containers. There was some foreign material in
the blue container, but none in the red container. The label on the blue
container showed that it was from Ajax Rivet, Inc., and the label on the red
container indicated that it was from Frank’s Fasteners. Obviously, the foreign
material was entering the rivet feeder bowl and jamming the track.
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Cause Investigation
Jake called Maintenance and requested that the bowl be cleaned. He also
added the cleaning operation to the preventive maintenance schedule on the
equipment. He then called both Ajax Rivet, Inc. and Frank’s Fasteners. He
asked about the cleaning procedures on the returnable containers. Frank’s
did a full container purge and clean. Ajax just re-introduced the containers
back into their system. When Jake asked why Ajax did not clean their
containers, he was told that Ajax was not aware that such a policy was
needed.
Upon further investigation, Jake learned that Frank’s Fasteners supplies
other major automotive companies. Since these companies require that all
returnable containers be cleaned, Frank’s instituted the purge as part of its
practice for all customers. Ajax Rivet, however, depends primarily on Flex as
its major customer. No such policy has ever been required of them.
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Cause Investigation
Jake called the Material Control Department and requested that
a container maintenance policy be drafted which would apply to
all their suppliers. He also asked that a machine modification
be developed to sense for the presence of rivets. Hopefully, this
would error-roof the process.
Key Players
– Jake Quality Manager
– Janet CSE, Winding River Plant
– Sam Team Leader, East Line
– Judy QA Auditor, East Line
– Ben Machine Operator
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The plant received a PR/R from a customer. (We use 5-Why
Analysis to answer every PR/R.)
The PR/R states that the customer received “Regular Cola in the
right container (same for both products) with the Diet Cola label”.
The order called for Regular Cola.
The plant has two identical lines that are capable of running either
of our two products. The lines are located immediately beside
each other. The only differences in the products are the syrup and
the labels.
The plant runs both lines 24 hours per day. There are three shifts
that run 7:00 a.m. to 3:00 p.m., 3:00 p.m. to 11:00 p.m., and 11:00
p.m. to 7:00 a.m.
The date code indicates that the defective product was
manufactured at 3:03 p.m.
Defective product has been contained and sorted.
Generic Information for 5-Why Example:
Regular Cola Soft Drink vs. Diet Cola
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Bottling Process Flow for 5-Why
INSPECT
LIDS
B
O
T
T
L
I
N
G
WATER
BOTTLES
SYRUP LABELS
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The plant received a PR/R from a customer. (We use 5-Why
Analysis to answer every PR/R.)
The PR/R states that the customer received “Mixed/Foreign
Material in Shipment”.
The supplied part is an “O” Ring seal for oil filter.
A cutting operation produces the part to specified size. As the raw
material (cylindrical component) goes through the cutting
operation, the irregular end-cuts are removed from the station.
Generic Information for 5-Why Real
Example: “O” Ring Seal
Cutting Station
Mat’l Flow
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Missing o-ring
on part number
K10001J
Parts missed the
o-ring installation
process
Parts had to be
reworked
Operator did not return
parts to the proper process
step after rework
No standard
rework procedures
exist
WHY?
WHY?
WHY?
WHY?
Why did they
have to rework?
This is still a systemic failure
& needs to be addressed,
but it’s not the root cause.
Is this a good or bad
“Non-Conformance” leg?
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Missing threads
on fastener part
number LB123
Did not detect
threads were
missing
Sensor to detect
thread presence
was not working
Sensor was
damaged
No system to
assure sensors are
working properly
WHY?
WHY?
WHY?
WHY?
What caused
the sensor to
get damaged?
This is still a systemic failure
& needs to be addressed,
but it’s not the root cause
of the lack of detection.
Is this a good or bad “Detection” leg?
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A good 5-Why will answer “Yes” to the five
PDCA questions:
PLAN
DO
CHECK
ACT
1. Is the problem statement
CLEAR and ACCURATE?
2. Has the SYSTEMIC
root cause(s) been
identified for all legs?
3. Has IRREVERSIBLE
CORRECTIVE ACTION(s)
been implemented for
ALL root causes?
4. Has a plan been identified
to verify the
EFFECTIVENESS
of all corrective
actions?
5. Has a plan been identified
to STANDARDIZE and take
all lessons learned across
products, processes,
plants, functional areas, etc.?
Understand the problem
Execute the Plan
Follow-up
Standardize
“A problem well defined
is a problem half solved”
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Is this a good Corrective Action plan?
A
Corrective Action
w/ Responsibility Date
Fastener P/N 10001
would not assemble
Burrs on the thread
Worn stamping
tool
Tool exceeded
recommended wear
life
PM interval not
adequate
PM failure; No system
to strategically set
PM intervals
WHY?
WHY?
WHY?
WHY?
WHY?
1. Replace worn tool
(K. Jones)
2. Begin conducting PM on all
dies after every run, minimum
1 x / day, to collect history
(L. Burg)
A
6/1/03
6/1/03
3. Assess & adjust PM intervals
for all dies based on history
& mfg recommendations
(B. Clark)
7/31/03
Plan
Plan
Do
Do/Act
Do/Act
4. Track PM completion %
to assure 100% conformance
(C. Beckett)
6/1/03
6. Track FTQ at stamping to
monitor PM improvement
(S. Boland)
6/1/03
5. Check for burrs on threads
for 60 days to verify c/a
(M. Mendoeous)
6/1/03 -
7/31/03
Check
Check
Check
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5-Why Critique Sheet
General Guidelines: A.) Don’t jump to conclusions!; B.) Be absolutely objective. C.) Don’t assume the answer is
obvious. D.) If you are not thoroughly familiar with the process yourself, assemble a cross-functional team to
complete the analysis.
Step 1: Problem Statement
Is the analysis being reported on the problem as the Customer sees it?
Step 2: Three Paths (Dimensional, Detection, Systemic)
-Are there any leaps in logic?
-Is this as far as the Whys lead? Can you still ask one, two, three more why’s)?
-Is there a true cause-and-effect path from beginning to end of each path? Is there statistical data/evidence to prove
it? ---Can the problem be turned off and on?
-Does the path make sense when read in reverse from cause to cause? (e.g.—We did this, so this happened, so
this happened, and so on, which resulted in the original problem.)
-Do the why’s go back to the actual error?
-Does the systemic path tie back to management systems/issues?
-Does the nonconformance path ties back to issues such as design, operational, tiered supplier management,
etc…?
-Does the detection path ties back to issues such as protect the customer, control plans, etc…?
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5-Why Critique Sheet (cont)
Step 3: Corrective Actions
-Does each corrective action address the root cause from a path?
-Is there a separate corrective action for each root cause? If not, does it make sense that the corrective action
applies to more than one root cause?
-Is each corrective action possible to implement?
-Are there corrective actions that affect the Customer or require customer approval? How will they be
communicated to the Customer?
-Is there evidence and documentation to support the validity of the corrective actions?
-Are the corrective actions irreversible? If not, are there corrective actions in place that address containment?
Step 4: Lessons Learned
-How could this problem have been foreseen?
-How will this information be implemented:
a.) on the line or in the plant?
b.) at the point of detection?
c.) cross-functionally at the Supplier?
d.) other product/plants?
-Are there lessons learned for the Customer?
Step 5: Overall
-Do there seem to be big holes where ideas, causes,
corrective actions, or lessons learned are being avoided?
-Where things are missed or not documented?
-Do the corrective actions address the actions the supplier owns?
-How many iterations has the supplier gone through so far in preparing
this 5-why (It doesn’t happen on the first try!)
-Who prepared the 5-why?
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5-Why Analysis: Cola Example –
Path A
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5-Why Analysis: Cola Example –
Path B
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5-Why Analysis: Cola Example –
Path C
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5-Why Analysis: “O”Ring
Example – Path A
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5-Why Analysis: “O”Ring
Example – Path B
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5-Why Analysis: “O”Ring
Example – Path C
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5-Why Analysis: Green, Yellow, Red
– G: Can follow logic and flow of all 3 legs of 5 why's. The legs all
differentiate "What is the problem, why wasn't it detected, and what
happened systemically."
– Y: All 3 legs filled out, some leaps of logic, needs minor corrections to
improve.
– R: 1 or 2 legs missing, Leg 1 repeated as leg 2 or 3, not understanding
what the different legs mean--typically missing what the systemic leg is.
Poor answers on 2 or more legs.
Problem Case Audit Standards
Editor's Notes
1
1
Once the problem has been defined (as the customer sees it) a cause/effect relationship investigation for each path will help in determining the root cause.
Objective: To use the 5-Why Problem-Solving Process in conjunction with brainstorming to investigate, solve, and report corrective actions in a problem-solving activity.
- Use only the information provided. The purpose of this activity is to use the 5-Why analysis chart to build a chain of cause/effect relationships that lead to the root cause, corrective actions and lessons learned.
- After the first attempt in using the 5-Why tool, reference the 5-Why Critique Sheet that follows to help you evaluate your work.
Graphical representation of the 5-Why sample exercise as a group.
Second example describing, in general terms, an actual quality situation at one of Delphi’s divisions.
For reviewing suppliers’ 5-Why as part of the PRR root cause analysis.