Black Belt project for manufacturing defect reduction

1. T4 Head Scrap/Rework Reduction
Mike Hutchings/Matt Heath
1MBB Peer Review | 21 Jan 2015
Target date
 Problem Definition Tree
 Measurement System Validation
 Baseline Process Capability
 Solution Tree
 Post Improvement Process Capability 12/4
 Benefits / Business Impact 12/11
 Control Plan 12/18
√
√
√
√
√
√
√

2. Commitments from last meeting
Action Date Owner Status
Plan to accomplish before next meeting
Action Date Owner Status
Determine Post Improvement Process Capability 12/16 Hutchings
Complete 12/2
Est. Control Plan & finalize benefits/business impact 12/17 Hutchings/Heath
Complete 12/17
Current Phase: DMAICT4 Head Scrap/Rework Reduction

3. CTQ: Exhaust Face Profile must measure
between -.250 and .250 millimeters.
Defect: Any resulting measurement higher
than .250, or less than -.250 MM.
Metrics:
Baseline: 112,330 DPMO
Goal: 11,233 DPMO
Stretch Goal: 1,123 DPMO
Green Belts : Mike Hutchings
Mentor: Dennis Magerle
Project Approach: DMAIC
Team Members:
Matt Heath- PME
Alex Prizzi- QTA
Champion/Sponsor(s): Jeff Reynolds
Benefits: 24,000 cost reduction &
increased output by turning a rework only
machine into solely production for
Strongbacks /Heads.
Schedule:
Problem Statement
Since FW 37, 58 Heads in GRV have been scrapped resulting in a
loss of $40,136. 130 T4 Heads have been reworked during this
time. This prohibits machining & adversely impacts throughput on 1
additional machine for Strongbacks & Heads, since it must solely
be used for rework. Additionally, one operator works 2-3 full
days/week on rework for T4 heads.
Define problem, prob. Def. tree. ID CTQ’s NLT COB
10/07
Measurement system analysis. NLT COB 10/09
Create Problem Solution Tree, execute Process
Capability & conduct Multi-Vari. 10/13-10/16
Screen potential causes & ID relationships, est.
operating tolerances 10/23
Validate measurement system for Xs 11/02
Determine process capability & implement process
control 12/16
GRV T4 Heads Scrap/Rework Reduction Current Phase: DMAIC

4. T4 Cylinder Head Yield
Big Y
GRV Scrap/Rework Rate from FW 37-40 is 2.67 DPU.
188 Scrap/Rework out of 501 Heads.
Quality
Since FW 37, 58 Heads have been scrapped resulting in a
loss of $40,136. 130 T4 Heads have been reworked during
this time. This prohibits machining on1 additional machine
for Strongbacks & Heads, since it must solely be used for
rework. Additionally, one operator works 2-3 full days/week
on rework for T4 heads.
T4 Strongback Yield is being worked in another project.
Problem Definition Tree
GRV DMR’s
T4 Strongback Yield
Exhaust Face Profile All other dimensions
Process capability conducted on all 92 areas of
measurement on T4 Head dimensions for 463
Scrap/Rework heads resulted with the Exhaust Face
Profile as having the highest PPM. RTV is being worked
by Michaele Carney & her team.

5. Product
Variation
Measurement
Variation
Gage R&R (ANOVA)
%Study Var= 7.9%
Exhaust Face Profile
Required
Existing
.250
USL
-.250
LSL
Millimeters

6. Operator to
Operator
Supplier to
Supplier
Machine to
Machine
Part to
Part
Product
Variation
Measurement
Variation
Gage R&R (ANOVA)
%Study Var= 7.9%
(Multi Vari)
Exhaust Face Profile
Required
Existing
.250
USL
-.250
LSL
Millimeters
Time to
Time

7. +.250 MM Rework
0.00 Nominal

8. Operator to
Operator
Supplier to
Supplier
Machine to
Machine
Part to
Part
Product
Variation
Measurement
Variation
Gage R&R (ANOVA)
%Study Var= 7.9%
(Multi Vari)
Exhaust Face Profile
Required
Existing
.250
USL
-.250
LSL
Millimeters
OP-OP was eliminated due to limited interaction with the operator & process. Once
the head is placed in the fixture, the machine takes over and controls the necessary
modifications to the exhaust face plane.
Time to
Time

9. USL: .250 MM
LSL: -.250 MM

10. Pre-Improvement Multi-vari
Rework
Scrap

11. Operator to
Operator
Supplier to
Supplier
Machine to
Machine
Part to
Part
Product
Variation
Measurement
Variation
Gage R&R (ANOVA)
%Study Var= 7.9%
(Multi Vari)
Exhaust Face Profile
Required
Existing
.250
USL
-.250
LSL
Millimeters
OP-OP was eliminated due to limited interaction with the operator & process. Once
the head is placed in the fixture, the machine takes over and controls the necessary
modifications to the exhaust face plane.
Time to
Time

12. *Adjusted the g55 z
workoffset in program
2100 from -731.498 to -
731.648
*Work offset adjustment *Change G54 X
work offset by .100
From -1394.982 to -
1394.882
USL: .250 MM
LSL: -.250 MM

13. Rework
Scrap
Before After
Pre & Post Improvement Multi-vari
After adjustments to the machine based off of the Z &
Y dimensions from Long Reports

14. Stabilized process
Defect Reduction: 112,330->5199

15. T4 Head Post Benefits
Current scrap rate cost of a T4 Head: $682.78
YTD T4 Heads machined: 7,767
Fully Burdened Labor Rate: $175.66 (overhead & salary)
Pre Improvement:
2.9% scrap LSL process capability: .029 x7,767 Heads: 225 Heads scrapped YTD
Post Improvement:
0% current scrap LSL process capability
$153,791.42 cost reduction in scrap
Pre Improvement:
8.2% scrap LSL process capability: 636 Heads Reworked YTD
3 Heads reworked per hour
.33x $175.66x 225 Reworked Heads= $36,867.52
Post Improvement:
.5% current scrap LSL process capability: 38 Heads (P) rework
.33x $175.66x 38 (P) Heads rework= $2,251.17
Total: (Improvement Pre-Post) $34,616.35
Scrap Reduction: $153,791.42 +
Rework Reduction: $34,616.35
Total cost reduction= $188,407.77
Additionally, a machine that was solely used for Head rework has been opened up to machine T4 Strongbacks
starting January 2016, which will significantly increase Time on Product.
PRE POST

16. Control Plan
Given that the post-improvement DPMO results in around 1 defect per week
and the process already contains 100% Inspection, the following Control
Measures will be implemented:
• Any Head that results in a “Red” Category (greater than +- .250
MM) will result with the next series of Heads from that exact
machine being immediately sent to the CMM run to run a Long
Report on the Heads (skipping any other Heads that are
awaiting CMM). The feedback from the Long Report will tell the
Operators if the machine needs to be adjusted based off of the
Z & Y dimensions.
• Contact has been initiated with PrimeTech (programmer for the
CMM reports) to see if they can alter the program to include the
Z & Y dimensions on the Short Report.