2 power one

Andrea Grilli
Quality Engineer
Sustain Engineer
Lean Six Sigma Green Belt
Master FESTO Academy 10°ed. 2012
Quality Department
Power-One Italy S.p.A.
2013 March 26th
(Minitab Convention reviewed. May 2013)
FTY improvement
(PVI-3KW area)

|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIAL
PVI-3KW family: PVI-3.0, PVI-3.6, PVI-4.2
The most common residential inverter is the ideal size for an average-sized
family home. This single-phase string inverter complements the typical number
of rooftop solar panels, allowing home-owners to get the most efficient energy
harvesting for the size of the property.
This rugged outdoor inverter has been designed as a completely sealed unit to
withstand the harshest environmental conditions. One of the key benefits of this
inverter is the dual input section to process two strings with independent MPPT
especially useful for rooftop installations with two different orientations (ie East
and West). The high speed MPPT offers real-time power tracking and improved
energy harvesting. The transformer-less operation gives the highest efficiency of
up to 96.8% (>95%; MEAN 96%). The wide input voltage range makes the
inverter suitable to low power installations with reduced string size.
Available in the following countries:
Australia – Belgium – China – Greece - Ireland
Israel – Portugal – Spain - Czech Republic
France – Germany – Hungary - Italy
Spain - United Kingdom - United States
Product Presentation
2 of 29

Business Case Team
In PVI-3KW [PVI-3.0KW, PVI-3.6KW, PVI-4.2KW] production area we have
a low rate of FTY%. This condition leads to negative economic results.
Leader: Andrea Grilli
Champion: Luciano Raviola
Problem Statement Coach: Giuseppe Mangano (BB)
The weekly rate of FTY% during year 2012 is low. In the last production
Month October 2012, FTY% was 88.8%.
Up to now we were focused on the fails gone through repair area with no
consideration of test Operator self-repair units; ATE inefficiencies; ATE
operator wrong operation; re-tested units.
Members: Paolo Donzellini (Testing)
Claudio Serboli (Mngr Mfg)
Letizia Badii (Ripair)
Luca Scala (IE)
Samanta Marzielli (QC)
Vincenzo Russino (R&D)
Project Scope (In-Out) Target
In scope
The Team will be focused on the October 2012 production data collection
as representative and significant sample of the entire year. All kind of
fails will be included in the analysis.
Out of scope
Fails for problems already under analysis at the beginning of this project.
Estimated Soft saving:
Employee at repair station will work part time to other jobs.
Estimated Hard Saving:
Increasing to 93% FTY rate will allow:
Remove two temporary employees at ATE.
Reduce cost for scrap components.
Reduce overtime work.
40.000€ per year starting from April 2013.
Milestones
D 29-11-2012 (Closed)
M 17-12-2012 (Closed)
A 18-01-2013 (Closed)
I 15-02-2013 (Closed)
C 20-03-2013 (Closed)
Project Charter
DEFINE MEASUREMEASURE ANALYZEANALYZE IMPROVEIMPROVE CONTROLCONTROL
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VOC: Increase FTY% in the «PVI-3KW» Department
%
#
#
100 %
#
#
100
Increase FTY Reduce total defects=
CTQ: FAIL %
VOC (Voice of the Customer) and CTQ (critical to quality)
DEFINE MEASUREMEASURE ANALYZEANALYZE IMPROVEIMPROVE CONTROLCONTROL
4 of 29

SSupplier
IInput
PProcess
OOutput
CCustomer
Internal External semi-finished
products Suppliers
Discrete component Supplier
Assembled PVI
VDR
Labels, Manuals
Mechanical parts
Packaging Company
Power-one
Compliant PVIs
Data Collection
Scrap
!Basic Process Flow diagram
SIPOC-process mapping (As Is)
DEFINE MEASUREMEASURE IMPROVEIMPROVE CONTROLCONTROL
5
ANALYZEANALYZE
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Test Line process mapping – ASME logic diagram (As Is)
DEFINE MEASUREMEASURE IMPROVEIMPROVE CONTROLCONTROL
BI
BURN-IN
RST
RESET TEST
OPOPOPOP
Burn-In
Deposit
OP
HP
SAFETY -TEST
OP
Take
label
Label Assembly
CAL
ATE 4 VDR Assembly
OP
Take
2 VDRs
INSP
AC Cable
connection
DC PAD
connection
RS485 cable
connection
Protection
install
AC Cable
screwing
AC Cable
connection
DC PAD
connection
AC Cable
screwing
OP
AC Cable
connection
DC PAD
connection
RS485 cable
connection
Protection
install
Bar-code
reading AC Cable
screwing
AUX BUS
Cable
connection
USB
Cable
Connection
FT
ATE
OPOP
OP
OP
ASSEMBLY LINE
FT OPERATOR
PHASES
CAL OPERATOR
PHASES
INSP
OP
AC Cable
connection
DC PAD
connection
AC Cable
screwing
OP
OP
OP
DC PAD
connection
Bar-code
reading
OP
Dc cable assembly
Take
2 VDRs
6
ANALYZEANALYZE
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!One Repair Station for 12
ATES and inspection phases
Repair process mapping – Flow diagram
MUDA
!One Quality Engineer
Station for 12
ATES and inspection phases
7
DEFINE MEASUREMEASURE IMPROVEIMPROVE CONTROLCONTROLANALYZEANALYZE
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W
eek
44
W
eek
42
W
eek
40
W
eek
38
W
eek
35
W
eek
32
W
eek
30
W
eek
28
W
eek
26
W
eek
24
W
eek
22
W
eek
20
W
eek
18
0,13
0,12
0,11
0,10
0,09
0,08
0,07
0,06
Production Week
Proportion
_
P=0,09225
UCL=0,12329
LCL=0,06120
P Chart of Failed
6 months Weekly FAIL proportion P-Chart (May - October 2012)
Project Ring
!Proportion of FAILS is stable.
8
CTQ FAIL%
# of Failed units through process
# of Outputs
100 11,26% (FTY%=88,74%)
We use all historical data recorded in October 2012 as year 2012 representative and significant sample. During October 2012 we have add new
manual data collection form in order to collect defects since now not analyzed (test Operator self-repair; ATE inefficiencies; ATE operator
inefficiencies and errors; units tested more than one time) because not automatically reported by Testing Software (Abort Test form).
Outputs test data and results are recorded automatically by «SigmaQuest-Camstar» System software.
ABORT TEST units are collected manually by Quality Control team in a dedicated excel form.
FAIL repaired units data collection are recorded by repair team in «Data Collection» System Software.
DEFINE MEASUREMEASURE IMPROVEIMPROVE CONTROLCONTROLANALYZEANALYZE
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Why use P-chart?
To see varible time trend when we have:
Discrete data by attributes (Proportion).
Varible subsroups.
To see dataprocess stability analysis

Data Collection reading (October-2012)
DEFINEDEFINE MEASURE IMPROVEIMPROVE CONTROLCONTROL
9
ANALYZEANALYZE
Project work will be developed for: «FAIL for manual
operation@ATE» and «FAIL for Low Efficiency on 3000W model»
«Defects already under analysis» will be not considered, their
analysis started before beginning of this project
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Why use Pareto Diagram?
To understand the factors (defects)
incidence on total effects (FAIL rate).
Defect Phase Work FAILs FAIL %
FAIL for manual operation @ ATE 5,57
Defects already under analysis 2,32
Low Efficiency on 3000W model 1,04
FAIL for Supplier process 0,31
TK58H005A Coil damaged 0,25
IGBT-damaged 0,22
Inverted Coil Cables at MB 0,18
50 Pole flat cable 0,16
Inverted Coil Cables at BB 0,16
Board 02 PTH Assembly 0,16
DSP-damaged 0,16
Mechanical assembly board 02 0,09
# of Outputs FAILs FAIL %
11,26
FAILs 8 8 8 8 32327 149 61 21 15 10 9 9
Percent 1 1 1 1 549 22 9 3 2 2 1 1
Cum % 92 93 94 95 10049 72 81 84 86 88 89 90
Other
M
echanical assem
bly
board
02
Inverted
Coil Cables
at BB
DSP-dam
aged
Board
02
PTH
Assem
bly
Inverted
Coil Cables
at M
B
50
Pole
flat cable
IGBT-dam
aged
TK58H005A
Coil dam
aged
FAIL
for
Supplier
process
Low
Efficiency
on
3000W
m
odel
Defects
already
under analysis
FAIL
for
m
anual operation
@
ATE
700
600
500
400
300
200
100
0
100
80
60
40
20
0
FAILs
Percent
Pareto Chart of Defect Phase Work
49
!
8 8 8 8 32327 149 61 21 15 10 9 9
M
8888323271496121151099
M

FAIL for Manual Operation @ ATE Analysis
DEFINEDEFINE MEASUREMEASURE ANALYZE IMPROVEIMPROVE CONTROLCONTROL
Quantitative Analysis
10
Qualitative Analysis
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Failed Q.ty 103 84 60 30 21 15 14
Percent 31,5 25,7 18,3 9,2 6,4 4,6 4,3
Cum % 31,5 57,2 75,5 84,7 91,1 95,7 100,0
A
BO
RT
Push
P
ro
tectio
n
m
ov ed
S
1
sw
itch
no
t m
oved
M
issin
g
reset
W
ron
g
VDR
assy
Serializzatio
n
Error
Interm
itten
t C
ablin
g
350
300
250
200
150
100
50
0
100
80
60
40
20
0
FailedQ.ty
Percent
Pareto Chart of Manual Operation @ ATE
8 8 8 8 32327 149 61 21 15 10 9 9
M

FAIL for Manual Operation @ ATE Root Causes 13
DEFINEDEFINE IMPROVEIMPROVE CONTROLCONTROL
1. Intermittent Cabling: The AC cable terminals could be deformed or damaged by use. If the operator doesn’t plug the cables correctly
or if he move the roll cable the connections could become intermittent. Also the narrow space makes it difficult to insert the cables.
2. VDR wrong assembly: This phase is performed at CAL test, in low light condition when the PVI is already assembled in Chassis. Also
VDR lead speacing doesn’t match with PCB Connector.
3. Serialization error: Because there are two PVIs in a trolley, the operator could wrongly read the Bar-code of the unit NOT under test.
4. S1 switch not moved: The S1 switching phases (3 times) are performed manually, in low light condition and by an inadequate tool.
Sometimes the operator switch partially the S1 causing a fail unit.
5. Protection moved: The Safety protection has two metal sensors that enable the beginning of the test when the sensors are in contact
with the metallic PVI chassis. Because of the protection is unstable, if the operator moves the protection the test will aborted.
6. Missing reset : The RESET TEST is a semi-manual test, the station is very close the ATE Final test. For this reason the operator can test
wrongly the PVI directly to FT instead of to RESET TEST.
7. ABORT button pushed: The safety «ABORT» push button is located in coincidence to trolley or PVI during the test. This could cause
the operator involuntary push of the button.
11
ANALYZEMEASUREMEASURE
ATE FT RESET
11 22 33 44
55 66 77
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C1
C2
C4
C5
C3
C7
C8
C9
C10
C12
C13
Low Illumination at ATE
RESET test station too close at ATE
C11Wrong VDR assembly phase (PVI in chassis)
To many manual phases at ATE
Two PVI in a trolley
RESET test is complicated Manual test
ATEs equipment safety protection poor design
ATEs equipment AC WIRINGS not sufficiently robust
ATEs equipment AC WIRINGS difficult insertion
C6Improper tool to switch S1
ATEs equipment ABORT button inadequate position
VDR-CONNECTOR pin step mismatch
VDR bad packaging cause terminals bent
Intermittent Cabling
Serialization Error
Wrong VDR assembly
Missing reset
S1 switch not moved
Protection moved
ABORT Push
Causes Effects
!A cause can produce more than one effect
12
DEFINEDEFINE IMPROVEIMPROVE CONTROLCONTROLANALYZEMEASUREMEASURE
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!An effect is produced by more than one cause

|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIAL13
C4
36%
C5
15%C8
11%
C9
11%
C1
5%
C3
4%
C2
4%
C13
3%
C11
3%
C12
3%
C10
2%
C6
2%
C7
1%
«Weight» of each cause on the CTQ (FAIL%).
Causes C4; C5; C8, C9 and C1 will be addressed as priority!
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96,396,095,795,495,194,8
Median
Mean
95,97595,97095,96595,96095,95595,950
1st Quartile 95,851
Median 95,957
3rd Q uartile 96,096
Maximum 96,479
95,954 95,972
95,948 95,969
0,225 0,238
A -Squared 28,69
P-V alue < 0,005
Mean 95,963
StDev 0,231
V ariance 0,053
Skewness -1,18216
Kurtosis 5,25829
N 2623
Minimum 94,620
A nderson-Darling Normality Test
95% C onfidence Interv al for Mean
95% C onfidence Interv al for Median
95% Confidence Interval for StDev
95% Confidence Intervals
Summary for EFFICIENCY
FAIL for Low Efficiency % Analysis 14
The minimum efficiency spec value for 3.0KW inverter is 95%. We have FAILs due to efficiency% lower than spec value. To repair these units,
we must replace output coils and scrap the removed ones.
Here we want to verify the data distribution.
!Data are not Normal; P-Value < 0,05.
!Box Plot shows there are lots of outliers.
!Some units are out of minimum spec (95%).
This condition requires further investigation.
14
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Why use Graphical Summary Tool?
Main Information:
Data (Efficiency%) distributionnormality
Position Indices
Dispersion Indices
Confidence Interval

Here we want to establish a FULL DOE (Design Of Experiment) to understand the more impacting factors on efficiency %, in order to get more
stable and within spec this value.
1. Statement of the Problem:
Basing on the results of the meetings and brainstorming performed in December 2012:
the most probable cause of Efficiency % variation is the saturation Inductance value of the Output Coils.
Since now we never studied the effects of the difference Inductance between the two inverter coils on the Efficiency. We want also
understand if a longer warm up time of the Inverter (rise of the internal inverter temperature) could change the efficiency.
2. Response Variable :
Efficiency %.
3. Factors and Levels:
FactorA: L1 Inductance – Level+: 540uH (SAT inductance@20A); Level-: 470uH (SAT inductance@20A).
FactorB: L2 Inductance – Level+: 540uH (SAT inductance@20A); Level-: 470uH (SAT inductance@20A).
Factor C: Inverter Warm-up Time – Level+: 10min; Level-: 1min
4. Choice of Design:
Full Factorial Design – 3 repetitions.
!3 Factors; 2 levels = 23 Tests x 3 repetition = 24 Tests
15
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5. Perform Experiment
The more impacting factor on the Efficiency % is the
interaction of A+B (Inductance L1 + inductance L2) .
6. Data Analysis part 1
16
B
A
BC
AC
ABC
C
AB
140120100806040200
Term
Standardized Effect
2,1
A L1(SA T)
B L2(SA T)
C Warm-Up Time
Factor Name
Pareto Chart of the Standardized Effects
(response is Efficiency, Alpha = 0,05)
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Why use DOE Tool?
To understand the more impacting
factors (L1SAT,L2SAT, Warm-ip Time), on
Response Variable (Efficiency%)

540470
95,8
95,6
95,4
95,2
95,0
94,8
94,6
L2(SAT)
Mean
470
540
L1(SAT)
Interaction Plot for Efficiency
Data Means
FAIL for Low Efficiency % Root Causes 44
7. Data Analysis part 2
If L1 and L2 inductances have different value we obtain a low Efficiency%. We have higher Efficiency% when L1 and L2 have the same value.
17
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0,040,030,020,010,00-0,01-0,02-0,03-0,04
99
95
90
80
70
60
50
40
30
20
10
5
1
Residual
Percent
Mean 2,960595E-15
StDev 0,01445
N 24
RJ 0,997
P-Value >0,100
Probability Plot of Residual
Normal
Why use Residual Normality Tool?
To understand if other unknown factors
occurred and influenced measurements,
then if the results are reliable. Residual is
the difference between 3repMean and
the relative measure.

FAIL for Manual Operation @ ATE Solutions 14
DEFINEDEFINE ANALYZEANALYZE IMPROVE CONTROLCONTROL
Add a portable Led light for each
operator at ATE
Modified transport: One PVI for Trolley
Installed VDR pins preforming machine
and packaging
New ATE interface PAD and SWS5
S1
S4
S8
Protected ABORT button
(keeping safety standards)S6
RESET automated in new ATE HWSWS2
C1
C2
C4
C5
C3
C7
C8
C9
C10
C12
C13
Low Illumination at ATE
RESET test station too close at ATE
C11Wrong VDR assembly phase (PVI in chassis)
Operator Oversight. To many manual phases at ATE
Two PVI in a trolley
RESET test is complicated Manual test
ATEs equipment safety protection poor design
ATEs equipment AC WIRINGS not sufficiently robust
ATEs equipment AC WIRINGS difficult insertion
C6Improper tool to switch S1
ATEs equipment ABORT button inadequate position
VDR-CONNECTOR pin step mismatch
VDR bad packaging cause terminals bent
Modified Work-phases flow layoutS3
MOVED VDR1 and VDR3 at ICTS7
18
MEASUREMEASURE
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FAIL for Manual Operation @ ATE Solutions 2/4
DEFINEDEFINE IMPROVE CONTROLCONTROL
BI
BURN-IN
OPOPOP
Burn-In
Deposit
OP
OP
Take
label
LABEL
Label Assembly
CAL
PRE-TEST
ONE OPERATOR
DRIVE TWO ATE
Take
2 VDRs
2 VDR Assembly
VDR
OP
INSP
AC Cable
connection
DC PAD
connectionAC Cable
screwing
OP
FT
RST
FINAL TEST
OPOP
ASSEMBLY LINE
CAL OPERATOR
PHASE
INSP
OP
DC PAD
connection
AC PAD
screwing
OP
Protection
install
Protection
install
OP
DC PAD
connection
AC PAD
screwingFT OPERATOR
PHASE
S3 Test Line process mapping – ASME logic diagram (After)Modified Work-phases flow layout
19
ANALYZEMEASUREMEASURE ANALYZEANALYZE
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SAFETY -TESTSAFETY -TEST
RESET-TESTRESET-TEST

DEFINEDEFINE IMPROVE CONTROLCONTROL
Work phases BeforeAfter Comparison
Takt time = Daily available time = 14h = 50400sec = 102.8“
Customer Demand 490 490
Cycle Time(Before) = 1110sec
N° operators(Before) = Cycle Time(Before) = 1110sec = 10,8
Takt time 102,8sec
Symbol Meaning Work Process before Corrective action Work process after corrective action "Saving"
Transformation Operation 3 2 1
InspectionTest 7 5 2
TransportMovement 34 24 10
Waiting 8 5 3
DepositStorage 1 1 0
Transformation Operation Support 24 11 13
N° operators(After) = Cycle Time(After) = 810sec = 7,8
Takt time 102,8sec
Cycle Time(After) = 810sec
S3
20
ANALYZEANALYZEMEASUREMEASURE
SortingSorting SettingSetting ShineShine StandardizingStandardizing SustainSustain
Eliminated
useless tools and
documents.
Made process
more ergonomic
(toolsdocument)
Add procedure to
keep place clean
and well organized
Standardized
Tools and
Work-stations
Keep control
maintaining and
reviewing standards
Three temporary operators less
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Here we want to evaluate the possible risk we could have using the new ATE Interface PAD, understanding witch kind of failure it could
cause and provide a preventive corrective action. So we use a FMEA (Failure Mode Effect Analysis).
Occurrence
Detection
Severity
RPM
Occurrence
Detection
Severity
RPM
Breaking of the
connector
FAIL RESET test
Interface bumps with connectors if not
centered during his installation
7 2 8 112
Add plastic guide to keep Interface in
the right position during his
installation
3 2 8 48
Plastic Slip off
Radio Board cannot be
installed
PCB connector not perfectly straight 6 4 8 192
Modified Soldering tray to keep
straight connector.
2 4 8 64
Termination
Switch
Break of the cursor
(not identifiable)
Missing termination
line on the field
AB interface bumps with TS if not well
lifted up
5 7 6 210
Modified AB interface lift system
adding a magnet to keep it lifted.
2 6 7 84
INDPAR Switch Break of the cursor Fail Cal or Ft test
AB interface bumps with IP swotch if not
well lifted up
3 2 8 48
Automatic bar code reader out of
position for wrong pressure calibration
2 2 8 32
Wrong barcode label Position 3 2 8 48
AUX BUS
connector
Serialization
FMEA parameter Final Parameter
Component Fail Mode Effect Cause Modification
Wrong seril number
recorded in memory
Test FAIL
FAIL for Low Efficiency % Solutions
As per result of DOE the root cause is the
unbalancing SAT Inductances (20A)
between the two Inverter coils.
In order to improve and keep stable > 95%
the Efficiency we will use coils paired with
balanced Inductance Value (6 pairings).
S9C14
21
DEFINEDEFINE IMPROVE CONTROLCONTROLANALYZEANALYZEMEASUREMEASURE
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S1 S3
S2
Solutions Implementation Stages
Solution Implementation Stage1
Start date 07-Jan-2013 Solution Implementation Stage2
Start date 11-Feb-2013
S9S9
S7S7S8S8
Solution # Stage2 Solutions short description
S07 MOVED VDR1 and VDR3 at ICT
S08 Installed VDR pins preforming machine and packaging
S09 Coils paired with balanced Inductance Value (6 pairing).
Solution
#
Stage1 Solutions short description
S01 Add a portable Led light for each operator at ATE
S02 RESET automated in new ATE HWSW
S03 Modified Work-phases flow layout
S04 Modified transport: One PVI for Trolley
S05 New ATE interface PAD and SW
S06 Protected ABORT button
22
S4 S5
S6
DEFINEDEFINE IMPROVE CONTROLCONTROLANALYZEANALYZEMEASUREMEASURE
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Control Systems
DEFINEDEFINE IMPROVEIMPROVE CONTROL
Visual alarms at ATE
New Work-phases flow layout
New Specification
And Procedure
ANALYZEANALYZEMEASUREMEASURE ANALYZEANALYZE
New ATE fixture
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Project Work control
DEFINEDEFINE IMPROVE CONTROLANALYZEMEASUREMEASURE ANALYZEANALYZE IMPROVEIMPROVE
BEFORE – (4 Weeks October 2012) AFTER – (4 Weeks FebMar 2013)
#$%&% '() *+,-+. /01)+23(,@$56 7, 78%
#$%&% '() &(9 6'' :;;;< *(=1. >, ;?%
#$%&% '() *+,-+. /01)+23(,@$56 >, @A%
#$%&% '() &(9 6'' :;;;< *(=1. ;%
-77,4%
Cleared
FTY=88,74% FTY=94,47%
24
ResultsResults
of 29
Defects already
under analysis
5(2+. #$%&% >>, @A% #$%&% 7, 7:%-51%
B=-4,31%B=-4,31%
B=-1,04%B=-1,04%
Week 15Week 10Week 05Week 50Week 45Week 40Week 34Week 28Week 23Week 18
0,150
0,125
0,100
0,075
0,050
Production Week
Proportion
_
P=0,0555
UCL=0,0778
LCL=0,0332
Before Project Work Start Stage 1 Start Stage 2
1
1
1
1
1
1
P Chart of Failed by Time

FAIL for Manual Operation @ ATE control
25
Missing RESET
S1 Switch not moved
Protection Moved
ABORT Push
Cleared
Intermittent Cabling 80,6% reduced
Wrong VDR Assembly 72,5% reduced
RS485 not inserted
AUX-BUS not inserted
USB not inserted
New Issues
05/03/201327/02/201321/02/201316/02/201312/02/201429/10/201223/10/201217/10/201211/10/201205/10/201201/10/2012
0,10
0,08
0,06
0,04
0,02
0,00
MFG Data
Proportion
_
P=0,0126
UCL=0,0280
LCL=0
Before After
P Chart of FAIL for Manual operations@ATE by Time
ResultsResults
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Failed Q.ty 103 84 60 30 21 15 14
Percent 31,5 25,7 18,3 9,2 6,4 4,6 4,3
Cum % 31,5 57,2 75,5 84,7 91,1 95,7 100,0
ABORT
Push
Protection
m
oved
S1
sw
itch
not m
oved
M
issing
reset
W
rong
VDR
assy
Serializzation
Error
Interm
ittent Cabling
350
300
250
200
150
100
50
0
100
80
60
40
20
0
FailedQ.ty
Percent
Pareto Chart of FAIL for Manual Operation @ ATE Oct-12
Failed Q.ty 33 27 26 19 16
Percent 27,3 22,3 21,5 15,7 13,2
Cum % 27,3 49,6 71,1 86,8 100,0
USB
Cable
not inserted
AUX-BUS
connector not inserted
RS485
Connector
NO
T
Inserted
W
rong
VDR
Assem
bly
Interm
ittent Cabling
120
100
80
60
40
20
0
100
80
60
40
20
0
FailedQ.ty
Percent
Pareto Chart of Manual Operation @ ATE - AFTER
8 8 8 8 32327 149 61 21 15 10 9 9
M
8 8 8 8 32327 149 61 21 15 10 9 9
M
8888323271496121151099
M
8888323271496121151099
M

S=0,1 (StD estimated)
d=0,018 (accuracy established)
C
2
D
2
= 123 units
FAIL for Low Efficiency % control 1/2
26
Sample size (min) calculation to estimate the Efficiency% MEAN
96,5
96,0
95,5
Mean
51464136312621161161
1,0
0,5
0,0
Range
51464136312621161161
Xbar-R Charts
Confirm that the Before and After process conditions are stable.
Normality Plots
The points should be close to the line.
Normality Test
(Anderson-Darling)
Results Fail Pass
P-value < 0,005 0,080
Before After
Before/After Capability Comparison for Efficiency A vs Efficency Af
Diagnostic Report
Before After
Before After
100%
> 0,50,10,050
NoYes
P = 0,029
> 0,50,10,050
NoYes
P = 0,189
Before
LSL USL
After
Actual (overall) capability is what the customer experiences.
-- The process mean did not change significantly (p > 0.05).
-- The process standard deviation was reduced significantly (p < 0.05).
Conclusions
Before: Efficiency A After: Efficency Af
95 * 97
Lower Spec Target Upper Spec
Customer Requirements
Mean 95,951 95,985 0,033926
Standard deviation 0,26381 0,19539 -0,068420
Capability
Pp 1,26 1,71 0,44
Ppk 1,20 1,68 0,48
Z.Bench 3,55 4,97 1,42
% Out of spec 0,02 0,00 -0,02
PPM (DPMO) 191 0 -191
Statistics Before After Change
Reduction in % Out of Spec
to 0,00%.
% Out of spec was reduced by 100% from 0,02%
Before/After Capability Comparison for Efficiency A vs Efficency Af
Summary Report
Was the process standard deviation reduced?
Did the process mean change?
Actual (overall) Capability
Are the data inside the limits?
Comments
of 29
Why use Xbar-R Chart?
To see varible time trend when we have:
Continuos data.
Sample subgroups size<10 and>1.
To see dataprocess stability.
Why use BeforeAfter tool?
To compare data before - after improve:
Normality, StDV, Mean, Capability,
DPPM, final response of improvement
= 112 units112 units112 units112 unitsCK =
C
1 L
C
Efficiency% manual measurements using LAB instruments during
production. Because the large production per day , it is not possible
measure 100% of the produced units. Basing on production
timequantity, we can perform a systematic subgroups sampling: 3
untis each 30 produced (38 sampling) repeated for units «before» and
units «after» Solution.

FAIL for Low Efficiency % control 2/2
Specification for Efficiency% MEAN is 96%. Here we want to understand if, after improvement, Efficiency% MEAN of population (EFF%PMEAN)
will be statistically equal to Spec value 96% (EFF%SMEAN). We use the 1-Sample-t test (Hypothesis Testing).
96,3096,1596,0095,8595,70
20
15
10
5
0
X
_
Ho
Efficency After
Frequency
Histogram of Efficency After
(with Ho and 95% t-confidence interval for the mean)
Hypotesis:
H0: EFF%PMEAN = EFF%SMEAN
HA: EFF%PMEAN ≠ EFF%SMEAN
Results:
P-Value >0,05 (HA refusal).
Population MEAN is statistically not different from Spec Value
(with 95% of confidence)
The Confidence Interval of the sample MEAN contains H0 that
means the Population MEAN is not different than MEAN Spec
Value (with 95% of confidence)
27
of 29
Why use Hypotesis Test 1 sample T-test?
To compare MEAN of the statistic sample
with Reference MEAN; see if there are
statistically equal or not (with 95% of
confidence).

Scrap coils: 9.000€
3 temporary employees operators at ATE: 120.000€
Savings of the Project Work
DEFINE MEASURE IMPROVE CONTROL
Considering a 2013 stable production rate we can
estimate the following SAVINGS:
Charges for ATEs new release: 51.000€
+
+
-
=Total Saving: 86.000€ (first year)
Overtime work: 8.000€
Removed one ATE and used in another AREA.
+
Lesson learned
Six Sigma and Lean tools
DMAIC approach as problem solving
Team Work
Sampling efficacy
HARD SAVINGS
ANALYZEMEASURE ANALYZE IMPROVE
Next Steps
Improvement of VDR assembly
Know How exporting in other areas
New Project work development
Improvement of Intermittent cabling
Start new Lean &Sigma Projects
The reduction by half of the FAIL% allowing saving:
SOFT SAVINGS Operator at repair station can be dedicated also to other jobs.
Sustaining Engineer can be dedicated to other Project Work.
of 29

End of Project Work
DEFINE CONTROLMEASURE ANALYZE IMPROVE
End
of
project
work
End
of
project
work
DD
MM
AAI
C
Quality Department
Power-One Italy S.p.A.
Andrea Grilli
of 29

2 power one

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