Identify the true sources of variation in your process. Used as the initial start to LEAN SIX SIGMA INITITIVE.

1. 10/30/2017 Six Sigma Black Belt
Larry Whitmarsh Ph.D.
Master Lean, Six Sigma, Statistical Engineering
Primary Consultant Statistical Engineering
1-248-880-1534
www.linkedin.com/in/dr-larry-whitmarsh-63076b10 whitmarsh.l@att.net

3. Lid guide
Y's =
Outputs/
Results Y1 Rec Plastic Y1
Convey to
Dryer Y1
Load Molding
Machine Y1 Molding machine Y1
In Process
Inspection Y1 Final Inspection
Critical
Operator
dominate Move Molding machine Process inspection Final Inspection
Process
Steps
Incoming
material
Drying time Move to machine Settings, warm-up
Bend test and size
every 100 parts
both cavities
Instructions
In any problem solving it is key to understand the entire process. I have found over the years
it is best done with Business Process Performance. First taught to me by PPG while problem solving
a major painting process located in Monterrey Mexico.
I have listed the Ys in this case as the steps in the process. I have always used the PFMEA to
gain the suppliers knowledge of their process. In most cases I find the PFMEA only reveals the
very basic steps. In one instance with a Die Caster the whole PFMEA relied on weekly CMM layouts
and no in-process inspection. When I asked the General Manager how this could happen he stated
“it comes from Japan like that”. Needless to say this changed very quickly.

4. Process
Steps
Incoming
material
Drying time Move to machine Settings, warm-up
Bend test and size
every 100 parts
both cavities
Instructions
X's =
Controls/
Inputs X1
Certification
review X1
Ensure
quality
inspected
material X1 Proper fill level, X1
Machine warn up
time X1 No brittleness X1 Special instructions
X2
Understand
limits X2
Pour into
dryer. X2 Correct color X2 Proper ID size
X3
Blind
sampling to
supplier X3
Establish
proper
settings and
time . X3 Purge barrel X3
Visual
characteristics
X3
Assure
virgin
Material X4
Run set up parts
until process is
capable. Hold and
release.
X4
Special reaction
instructions
X4
Identify
acceptable
or reject X5
First piece
inspection and
approval to run
The above was a plastic molding process. The part was failing in the field, at the time I got involved 4 users
had been struck in the head by the part failing. The real critical problem was; there were thousand’s more
in warehouses waiting to be shipped to the final customers.
The Xs are the FMEA instructions
DFMEA
PFMEA
Cause and Effect Dia.
Six Sigma

5. N's=
Noise/
Variatio
n N1
Supplier of
material N1 Dryers N1 Machine warm up N1 Run machine N1 Process Inspection N1 Final Insp
N2
Understand
process N2
Understand
settings, on
machine, hi
and lo limit
lights N2 Barrel purge N1
Inspect every 100
parts N2
Develop plan for
insp. At process N2
Develop random
sampling plan
N3
More
knowledge
of material N3
Can
material be
dried too
much N3 Machine settings N2
Operator reaction
plan N3
Manufacture
measure tool N3
assure no need to
look for short shot
due to warm up.
N4
Determine
critical info
from certs. N4
High and low limits
of material in
feeder N3
Mold angle too
sharp 90 degree
tool maker to
change to 45
degrees N4
Utilize test tool
N5
Gain
knowledge
from
supplier of
drying
concerns
and heat
setting. N5
Inspection approval
to run
N5
Training
N6
No regrind
and
material in
dryer is
destroyed
after run N6
Destroy set up
parts
The N's are the team brainstorming
opportunities. In this case you can
see 6 items in yellow directly
contributed to the failure. I have
Expanded this to use LEAN
calculations.

7. 7
4
First notified; June 29, 2010 contained to assembly plant
2nd incident; July 17th by distribution center internal
3rd Incident; July 19th by External distribution
4th Incident; July 20 Reports from customers
Clips found internally were shatter not just cracked.
Comments;
• Supplier had no knowledge why the part was failing. Material being used is the same
• 1500 pounds when this job 1st started up 07.2007. 1st clue
Next steps;
• Review supplier process for clues
• Visit polymer supplier for clues
• Determine proper material and handling
• Brainstorm all significant and important items in the process
• Control all items in process
• Perform 8 hour production run with improve product and track Win numbers
The team was starting
to worry that the age of
the plastic might cause
the material properties
to degrade

8. It is mandatory that you can measure what
you are working on. In this case we used a
die maker rule and tapped in into the sleeve
until the plastic broke. Not especially
repeatable nor especially accurate but for
our study was just what the doctor ordered.

11. 1.
2.
Number 1. the part from the mold before
any rework of the mold. Notice all the air
bubbles. Gating was at 90 degrees causing
turbulence during injection.
Number 2. Ground gate to 45 degrees which
eliminated the turbulence, no air bubble
present.

12. Old Process LS 10, US 12 New Process LS 13, US 15

13. 7 years later no
reported problems.
New clips sent to
warehouses and
replaced old clips.
No other failures
reported.

15. Larry Whitmarsh Ph.D.
Master Lean, Six Sigma, Statistical
Engineering
Statistical Engineering
1-248-880-1534
www.linkedin.com/in/dr-larry-whitmarsh-
63076b10 whitmarsh.l@att.net