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Split the Dictionary:
(Part) No Contrast
Parts were found out of specification randomly.
(Model) No Contrast
Out of specification parts were found on both gas and diesel models on both machines in
the same locations
(Machine) No contrast
Both Huffman #11 & #16 both had out of specification parts in the same locations with
roughly the same volume of scrap.
Location to Location
Same Part
Part to Part
Same Machine
Machine to Machine
Same Model
Same Time
Model to Model
 (Location) Strong Contrast
Out of specification locations were found concentrated to one location radially around
the Spoolshaft.
Clue Descriptions
Strategy Plan

Spool
Blanks
Spool Raw
Machining
Grind/
Stamp
Huffman Grind/
Wash
Grind Slots
and Flats
Feature
Machined
Valve
Assembly
Process Flow Diagram

Root Cause –
Flat Width Scrap
Δ PΔ M
Measurement Verification
• View Measurement System was found capable of
measuring flat width within 2%
Measurement
Position
Meas. 1 Meas. 2 Meas. 3 Meas. 4 Meas. 5 Meas. 6 Meas. 7 Meas. 8 Meas. 9 Meas. 10 Max Meas. Min Meas. Range Range x2 Capability
Tolerance 1 5.101 5.101 5.101 5.101 5.101 5.101 5.101 5.101 5.101 5.101 5.101 5.101 0.000 0.000 0%
5.135 2 5.082 5.081 5.082 5.082 5.082 5.081 5.081 5.081 5.082 5.082 5.082 5.081 0.001 0.002 2%
5.035 3 5.073 5.072 5.072 5.072 5.072 5.072 5.072 5.072 5.072 5.072 5.073 5.072 0.001 0.002 2%
.100mm 4 5.065 5.065 5.065 5.065 5.065 5.065 5.065 5.065 5.065 5.065 5.065 5.065 0.000 0.000 0%
5 5.06 5.06 5.06 5.06 5.06 5.06 5.06 5.06 5.06 5.06 5.06 5.06 0.000 0.000 0%
6 5.081 5.081 5.08 5.081 5.081 5.08 5.08 5.08 5.08 5.08 5.081 5.08 0.001 0.002 2%
7 5.123 5.123 5.123 5.123 5.123 5.123 5.123 5.123 5.123 5.123 5.123 5.123 0.000 0.000 0%
8 5.121 5.121 5.121 5.121 5.121 5.121 5.121 5.121 5.121 5.121 5.121 5.121 0.000 0.000 0%
Capability = [(Xmax – Xmin) x 2] / (Print Tolerance)
Root Cause Tree

Root Cause – Low Effort
Δ P (Defect)Δ M
Not Dimensional Dimensional
Dimensional Defect
• Parts are being scrapped as falling above or below
a specified tolerance range
Root Cause Tree

Δ P (Defect)Δ M
Too much Range piece to
piece
Process Mean not
Centered
Dimensional Defect
• Of data gathered, it was found that while the
mean of the process stays within the tolerance,
the range from piece to piece is too large to
constrain.
Too much Variation piece to
piece
Root Cause Tree

Δ P (Defect)Δ M
Too much Range piece to
piece
Process Mean not Centered
Too much Variation piece to
piece
Root Cause Tree

Concentration Diagram
Min Specification 5.035 Measurement #1 5.144 Min Specification 5.035 Measurement #1 5.081
Max Specification 5.135 Measurement #2 5.124 Max Specification 5.135 Measurement #2 5.064
Spec. Range 0.100 Measurement #3 5.114 Spec. Range 0.100 Measurement #3 5.051
Min Measurement 5.087 Measurement #4 5.087 Min Measurement 5.025 Measurement #4 5.025
Max Measurement 5.144 Measurement #5 5.093 Max Measurement 5.084 Measurement #5 5.034
Range 0.057 Measurement #6 5.112 Range 0.059 Measurement #6 5.064
Average 5.119 Measurement #7 5.135 Average 5.060 Measurement #7 5.079
Measurement #8 5.142 Measurement #8 5.084
Spec. Range on Effort 2.95-3.75 Spec. Range on Effort 2.95-3.75
R.Effort 3.520 R.Effort 3.290
L.Effort 3.430 L.Effort 3.270
Differential 0.090 Differential 0.020
Differential -0.060 Differential -0.110
Differential -0.120 Differential 0.060
Huffman #11Huffman #11
Part #8
Huffman #11
Part #9
Huffman #11
Part #10
Part #1
Part #2
Part #3
Huffman #11
Huffman #11
Sample DataANALYSIS
A-Start
8
7
6
5 4
3
2
1
• There Are Eight Slots With Flat Widths Ground Around the Spoolshaft.
• Starting With A-start, and Measuring Clockwise, the View Measurement
System Supplied the Data Where it was Found That All Measurements Near
the Top (or A-start) Were High in the Range and All Measurements on the
Bottom Were at the Minimum of the Range

Concentration Diagram
Differential 0.090 Differential 0.020
Differential -0.060 Differential -0.110
Differential -0.120 Differential 0.060
Huffman #11Huffman #11
Part #8
Huffman #11
Part #9
Huffman #11
Part #10
Part #1
Part #2
Part #3
Huffman #11
Huffman #11
Sample Data
A-Start
8
7
6
5 4
3
2
1
This data was supplied to the appropriate Manufacturing
Engineer who listed many things that could be done to the two
Huffmans to improve the range and variability. All of these
options were not financially viable to fix this issue when
weighted against cost to implement and scrap savings.
MID-PROJECT CONCLUSION

Correlation – Built Into Valves
BOBs
WOWs
ValveEffort
High Effort Spec
Low Effort Spec
Old Low Flat
Width Spec
Current Low Flat
Width Spec
High Flat
Width Spec
Flat Width
ANALYSIS
• The Specification of flat widths
is to prevent High & Low Effort
Valve Assemblies
• Recently the grind sheets were
updated:
• Previous 4.985 - 5.135
• Status Quo 5.035 - 5.135
• We collected BOBs/WOWs that
were above and below the
current specification limit to
correlate flat width to effort. Proposed

CORRECTIVE ACTION
Corrective Action
Proposal would be to adjust the Low Flat Width Spec Limit
lower by 20μm. This would allow the Huffman to adjust the
mean and produce less scrap at the current machine capability.

• Productivity
• Daily Scrap Cost
• Annual Scrap Cost
Spoolshaft Scrap Improvement: Before
Track the Improvement & Control: Before
Productivity 90.00%
Shift Time (Hours) x 8.00
Operational Activity (Hours) 7.20
Cycle Time (Parts/Hour) x 45.00
Parts Made/Day (Gross) 324.00
Scrap Rate x 6.0%
Scrap Parts/Day 20.00
Scrap Cost/Part x $7.48
Scrap Cost/Day $149.60
Production Days x 240.00
Scrap Cost/Year $35,904.00

• Productivity
• Comparison
Track the Improvement & Control: After
Productivity 90.00%
Scrap Rate x 6.0%
Scrap Rate x 1.2%
Scrap Cost/Day $35,904.00
Production Days $ 7,180.80
𝑂𝑙𝑑 − 𝑁𝑒𝑤
𝑂𝑙𝑑
= 𝑃𝑒𝑟𝑐𝑒𝑛𝑡 𝐶ℎ𝑎𝑛𝑔𝑒
Track the Improvement & Control: Before

𝑂𝑙𝑑 − 𝑁𝑒𝑤
𝑂𝑙𝑑
= 𝑃𝑒𝑟𝑐𝑒𝑛𝑡 𝐶ℎ𝑎𝑛𝑔𝑒
• Productivity
• Comparison
Track the Improvement & Control: After
Productivity 90.00%
Scrap Rate x 6.0%
Scrap Rate x 1.2%
Scrap Cost/Day $35,904.00
Production Days $ 7,180.80
$35,904.00 − $7,180.80
$35,904.00
= 𝟖𝟎%

[Name Sponged] Consulting Project (2)

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