[name sponged] consulting project (2)
TRANSCRIPT
Spoolshaft Defect Correction
Split the Dictionary:
(Part) No ContrastParts were found out of specification randomly.
(Model) No ContrastOut of specification parts were found on both gas and diesel models on both machines in the same locations
(Machine) No contrastBoth 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%
.100 mm 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
Root Cause – Low Effort
Δ P (Defect)Δ M
Not Dimensional Dimensional
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
Root Cause – Low Effort
Δ P (Defect)Δ M
Not Dimensional Dimensional
Too much Range piece to piece Process Mean not CenteredToo much Variation piece to
piece
Root Cause Tree
Concentration Diagram
Min Specification 5.035 Measurement #1 5.144 Min Specification 5.035 Measurement #1 5.081Max Specification 5.135 Measurement #2 5.124 Max Specification 5.135 Measurement #2 5.064Spec. Range 0.100 Measurement #3 5.114 Spec. Range 0.100 Measurement #3 5.051Min Measurement 5.087 Measurement #4 5.087 Min Measurement 5.025 Measurement #4 5.025Max Measurement 5.144 Measurement #5 5.093 Max Measurement 5.084 Measurement #5 5.034Range 0.057 Measurement #6 5.112 Range 0.059 Measurement #6 5.064Average 5.119 Measurement #7 5.135 Average 5.060 Measurement #7 5.079
Measurement #8 5.142 Measurement #8 5.084Spec. Range on Effort 2.95-3.75 Spec. Range on Effort 2.95-3.75R.Effort 3.520 R.Effort 3.290L.Effort 3.430 L.Effort 3.270Differential 0.090 Differential 0.020
Min Specification 5.035 Measurement #1 5.140 Min Specification 5.035 Measurement #1 5.077Max Specification 5.135 Measurement #2 5.125 Max Specification 5.135 Measurement #2 5.060Spec. Range 0.100 Measurement #3 5.107 Spec. Range 0.100 Measurement #3 5.049Min Measurement 5.091 Measurement #4 5.091 Min Measurement 5.025 Measurement #4 5.025Max Measurement 5.140 Measurement #5 5.097 Max Measurement 5.077 Measurement #5 5.029Range 0.049 Measurement #6 5.097 Range 0.052 Measurement #6 5.044Average 5.115 Measurement #7 5.127 Average 5.053 Measurement #7 5.066
Measurement #8 5.137 Measurement #8 5.074Spec. Range on Effort 2.95-3.75 Spec. Range on Effort 2.95-3.75R.Effort 3.460 R.Effort 3.360L.Effort 3.520 L.Effort 3.470Differential -0.060 Differential -0.110
Min Specification 5.035 Measurement #1 5.144 Min Specification 5.035 Measurement #1 5.074Max Specification 5.135 Measurement #2 5.129 Max Specification 5.135 Measurement #2 5.058Spec. Range 0.100 Measurement #3 5.119 Spec. Range 0.100 Measurement #3 5.046Min Measurement 5.091 Measurement #4 5.091 Min Measurement 5.029 Measurement #4 5.029Max Measurement 5.144 Measurement #5 5.102 Max Measurement 5.074 Measurement #5 5.029Range 0.053 Measurement #6 5.115 Range 0.045 Measurement #6 5.044Average 5.122 Measurement #7 5.132 Average 5.052 Measurement #7 5.063
Measurement #8 5.141 Measurement #8 5.073Spec. Range on Effort 2.95-3.75 Spec. Range on Effort 2.95-3.75R.Effort 3.470 R.Effort 3.300L.Effort 3.590 L.Effort 3.240Differential -0.120 Differential 0.060
Huffman #11Huffman #11
Part #8Huffman #11
Part #9Huffman #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
Min Specification 5.035 Measurement #1 5.144 Min Specification 5.035 Measurement #1 5.081Max Specification 5.135 Measurement #2 5.124 Max Specification 5.135 Measurement #2 5.064Spec. Range 0.100 Measurement #3 5.114 Spec. Range 0.100 Measurement #3 5.051Min Measurement 5.087 Measurement #4 5.087 Min Measurement 5.025 Measurement #4 5.025Max Measurement 5.144 Measurement #5 5.093 Max Measurement 5.084 Measurement #5 5.034Range 0.057 Measurement #6 5.112 Range 0.059 Measurement #6 5.064Average 5.119 Measurement #7 5.135 Average 5.060 Measurement #7 5.079
Measurement #8 5.142 Measurement #8 5.084Spec. Range on Effort 2.95-3.75 Spec. Range on Effort 2.95-3.75R.Effort 3.520 R.Effort 3.290L.Effort 3.430 L.Effort 3.270Differential 0.090 Differential 0.020
Min Specification 5.035 Measurement #1 5.140 Min Specification 5.035 Measurement #1 5.077Max Specification 5.135 Measurement #2 5.125 Max Specification 5.135 Measurement #2 5.060Spec. Range 0.100 Measurement #3 5.107 Spec. Range 0.100 Measurement #3 5.049Min Measurement 5.091 Measurement #4 5.091 Min Measurement 5.025 Measurement #4 5.025Max Measurement 5.140 Measurement #5 5.097 Max Measurement 5.077 Measurement #5 5.029Range 0.049 Measurement #6 5.097 Range 0.052 Measurement #6 5.044Average 5.115 Measurement #7 5.127 Average 5.053 Measurement #7 5.066
Measurement #8 5.137 Measurement #8 5.074Spec. Range on Effort 2.95-3.75 Spec. Range on Effort 2.95-3.75R.Effort 3.460 R.Effort 3.360L.Effort 3.520 L.Effort 3.470Differential -0.060 Differential -0.110
Min Specification 5.035 Measurement #1 5.144 Min Specification 5.035 Measurement #1 5.074Max Specification 5.135 Measurement #2 5.129 Max Specification 5.135 Measurement #2 5.058Spec. Range 0.100 Measurement #3 5.119 Spec. Range 0.100 Measurement #3 5.046Min Measurement 5.091 Measurement #4 5.091 Min Measurement 5.029 Measurement #4 5.029Max Measurement 5.144 Measurement #5 5.102 Max Measurement 5.074 Measurement #5 5.029Range 0.053 Measurement #6 5.115 Range 0.045 Measurement #6 5.044Average 5.122 Measurement #7 5.132 Average 5.052 Measurement #7 5.063
Measurement #8 5.141 Measurement #8 5.073Spec. Range on Effort 2.95-3.75 Spec. Range on Effort 2.95-3.75R.Effort 3.470 R.Effort 3.300L.Effort 3.590 L.Effort 3.240Differential -0.120 Differential 0.060
Huffman #11Huffman #11
Part #8Huffman #11
Part #9Huffman #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
Valv
e Eff
ort
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.
Prop
osed
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 8.00Operational Activity (Hours) 7.20Cycle Time (Parts/Hour) x 45.00 Parts Made/Day (Gross) 324.00
Parts Made/Day (Gross) 324.00Scrap Rate x 6.0%Scrap Parts/Day 20.00Scrap Cost/Part x $7.48Scrap Cost/Day $149.60
Scrap Cost/Day $149.60Production Days x 240.00Scrap Cost/Year $35,904.00
Scrap Cost/Day $149.60Production Days x 240.00Scrap Cost/Year $35,904.00
• Productivity
• Daily Scrap Cost
• Annual Scrap Cost
• Comparison
Spoolshaft Scrap Improvement: Before
Track the Improvement & Control: After
Productivity 90.00%Shift Time (Hours) x 8.00Operational Activity (Hours) 7.20Cycle Time (Parts/Hour) x 45.00 Parts Made/Day (Gross) 324.00
Parts Made/Day (Gross) 324.00Scrap Rate x 6.0%Scrap Parts/Day 20.00Scrap Cost/Part x $7.48Scrap Cost/Day $149.60
Parts Made/Day (Gross) 324.00Scrap Rate x 1.2%Scrap Parts/Day 4.00Scrap Cost/Part x $7.48Scrap Cost/Day $29.92
Scrap Cost/Day $29.92Production Days x 240.00Scrap Cost/Year $7,180.80
Scrap Cost/Day $35,904.00Production Days $ 7,180.80Scrap Cost/Year $28,723.20
𝑂𝑙𝑑−𝑁𝑒𝑤𝑂𝑙𝑑 =𝑃𝑒𝑟𝑐𝑒𝑛𝑡 h𝐶 𝑎𝑛𝑔𝑒
Track the Improvement & Control: Before
𝑂𝑙𝑑−𝑁𝑒𝑤𝑂𝑙𝑑 =𝑃𝑒𝑟𝑐𝑒𝑛𝑡 h𝐶 𝑎𝑛𝑔𝑒
Scrap Cost/Day $149.60Production Days x 240.00Scrap Cost/Year $35,904.00
• Productivity
• Daily Scrap Cost
• Annual Scrap Cost
• Comparison
Spoolshaft Scrap Improvement: Before
Track the Improvement & Control: After
Productivity 90.00%Shift Time (Hours) x 8.00Operational Activity (Hours) 7.20Cycle Time (Parts/Hour) x 45.00 Parts Made/Day (Gross) 324.00
Parts Made/Day (Gross) 324.00Scrap Rate x 6.0%Scrap Parts/Day 20.00Scrap Cost/Part x $7.48Scrap Cost/Day $149.60
Parts Made/Day (Gross) 324.00Scrap Rate x 1.2%Scrap Parts/Day 4.00Scrap Cost/Part x $7.48Scrap Cost/Day $29.92
Scrap Cost/Day $29.92Production Days x 240.00Scrap Cost/Year $7,180.80
Scrap Cost/Day $35,904.00Production Days $ 7,180.80Scrap Cost/Year $28,723.20
$ 35,904.00−$7,180.80$35,904.00 =𝟖𝟎%
Questions?