P1 acid project

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MSIN-SSGB-CS-01: 00 1

6

Presentation

On

Six Sigma Project – Acid Case

By

ABC Ltd.

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ABC Limited

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ABC : A Unit of ABC Ltd.

PLANT INSTALLED : 1972

PRODUCT : Dissolving Pulp

CAPACITY : 70000 tpa PROCESS : Prehydrolysis Sulphate

RAW MATERIAL : Eucalyptus & Mix Hard Wood

UNIT PROFILE

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6 Forest To Fibre

Wood Chips Bleached Pulp

Fibre

Our RoleTo convert wood into pulp and supply to Fibre Plants to

produce Viscose Staple Fibre

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6

• M/s DEF Division, Delhi

• M/s XYZ Division, Chandigarh

Our Customers

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6 Capturing Customer Requirement

Direction of improvement

What Impo

rtanc

e

pH Visc

osity

, cP

Ash,

%

Acid

Inso

lubl

e, p

pm

R2O

3, p

pm

CaO

, ppm

Fe, p

pm

S 10

, %

S 18

, %

S 10

- 18

, %

S 7.

14, %

Pent

osan

s, %

Dry

Cont

ent,

%

Brig

htne

ss, %

ISO

Alph

a Ce

llulo

se, %

Hem

icel

lulo

se, %

Resi

n, %

Pack

ing

Mat

eria

l Qua

lity

Lower Dissolver Viscose KW 5

Lower Spinning Viscose KW 5

Min. Variation in Viscose BF, secs 5

Hihger Fibre Whiteness, Berger 5

Higher Fibre Tenacity, gm/denier 5

More Fault Free Fibre, % 4

Higher Yield, kgs 4

Lower Hemi Cellulose, gpl 4

Minimum Moisture Variation, % 3

Better Bale Condition 3

Absolute Importance 15 81 131 174 117 102 60 81 81 81 60 123 63 126 132 132 90 27

High Impact Characteristics

How

Relationships : 9 Strong

: 3 Medium : 1 Weak

Direction of Improvement : Higher the Better : Lower the Better : Nominal the Better

Final Pulp Acid Insoluble :

High Impact Characteristic

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Define

Effect of higher Acid Insoluble

To our Customer :• affects viscose filtration

• leads to spinnerets jet choking

To Us :• pulp loss in centricleaners

• centri cleaners cones jamming

Business Case

Loss of Rs 28,000 / day

Loss of Rs 45,000 / day

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DefineScope of The Project

Wood Chipping

Chips Cooking

Pulp Washing

UB Pulp Centricleaning

Unbleach Pulp Thickening

Pulp Bleaching

Pulp Drying Acid Insoluble Sampling Point - 2

Log Washing

Earliest Point of

Acid Insoluble

Measurement is at

Unbleach Pulp

Thickening stage

Acid Insoluble Sampling Point - 1

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DefineRelationship Between

Unbleached Pulp Acid Insoluble (UB AI) Vs Final Pulp Acid Insoluble Final AI)

Project focus : Reduction of Unbleached pulp Acid Insoluble

150160170180190200210220230

400 450 500 550 600 650 700Unbleached Pulp A.I.

Fina

l Pul

p A.

I.

Correlation Coefficient : 0.53

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DefineTeam Charter

Particulars ResponsibilityTeam Members

DM,KG, TMN, SND, MRN, AK, AM, HP.

To gather relevant data, to observe process performance, to implement changes

Team Leader S.CG

To plan the project, to assign responsibilities to team members & co-ordinate with team members for project implementation

Facilitator SPSTo ensure project runs on schedule, to provide resources, review the projects & motivate team members

Start Date 21.11.2006

Completion Date 31.05.2007

Milestone

Define phase : 30.11.2006Measure phase : 01.02.2007Analyse phase : 15.03.2007Improve phase : 31.05.2007

Control phase : C.E . from 01.06.2007

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S I P O C

Supplier Input Process Output Customer

WOOD

YARD

WOOD

LOGS

Log washing

Cooking

Washing

Centri cleaning

UNBLEACHED

PULP

Internal :BLEACHI N G

Define

External :

FIBRE

PL A NTSUn bleach

Thickening

Chipping

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Define

Voice of Customer

External Customer :• Less Filtration Difficulty• Less Spinneret jets choking incidents

Internal Customer :• Reduced loss of pulp in bleach centricleaners• Low frequency of Bleach Centricleaner cones jamming

CTQ Parameter

Acid Insoluble( Final Pulp )

Acid Insoluble( Unbleached

Pulp )

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Define

Project Title

To reduce Unbleached Pulp Acid Insoluble

GoalPresent Level : 577 ppmTarget : 527 ppm

(Reduction by 50 ppm)

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Measure

An inorganic impurity comprising Silica (SiO2), mud,

silt & sediments

Acid Insoluble

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Measure

Gage R & R

Parameter Unit Acid Insoluble

Repeatability % 2.64

Reproducibility % 8.67

Total R & R (Target : Max 20 %) % 11.31

Validation of Pulp Acid InsolubleMeasurement System

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Measure

Unbleached Pulp Acid Insoluble (Sept ‘01 to Jan ‘02)

200 400 600 800 1000 1200

USLUSL

Process Capability Analysis

USL

Target

LSL

Mean

Sample NStDev (Within)

StDev (Overall)

Cp

CPU

CPL

Cpk

Cpm

Pp

PPU

PPL

Ppk

PPM < LSL

PPM > USL

PPM Total

PPM < LSL

PPM > USL

PPM Total

PPM < LSL

PPM > USL

PPM Total

850.000

*

*

577.717

459 79.234

104.983

*

1.15

*

1.15

*

*

0.86

*

0.86

*

34858.39

34858.39

*

294.68

294.68

*

4748.92

4748.92

Process Data

Potential (Within) Capability

Overall Capability Observed Performance Exp. "Within" Performance Exp. "Overall" Performance

Within

OverallMean (ppm) 577 .7

s.d. 104.9

Ppk 0.86

Sigma Level 2.58

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Analyse

Chipping

Cooking

Washing

Centricleaning

Unbleach Thickening

Log Washing

Acid Insoluble Removal Processes

Potential “X”sStored wood : Fresh Wood, Wash Water Pressure, No. of nozzles, Wash Water Flow, Logs Feed Rate

Chips Wash Water Quantity, Wash Water Draining Rate, Chips Quantity

Pulp Consistency, Feed Rate,

Differential Pressure across cones,

Centricleaner Efficiency

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Analyse

Relationship Analysis :

Unbleached Pulp Acid Insoluble (Y) Vs

Critical “X”s

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Analyse

Regression Analysis : Stored Wood % < > Unbleached Pulp Acid Insoluble

Pearson correlation of Unbleached Pulp Acid Insoluble and % SW = 0.051(P-Value = 0.278)

No Significant Relationship

8070605040302010

1150

1050

950

850

750

650

550

450

350

% SW

UB A

IS = 105.028 R-Sq = 0.2 % R-Sq(adj) = 0.0 %

UB AI = 546.403 + 0.823978 % SW

Log washing

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Analyse FMEA : Log Washing

Porocess Potential Potential S Potential Causes/ O Current Process D R Recommended Actions Responsibility &Function / Failure Effects of e Mechanism of c Controls e P TargetRequirements Mode Failure v Failure c t N Completion

u e Dater c

tFunction :Washing of Higher Higher acid 7 Low water line 8 Visual checking 2 112 To increase water line Shift Engineerthe wood logs carry insoluble in pressure of water pressure pressure 25.03.02

over of unbleach ( once in a shift )mud & pulp

Requirement : sandSpray nozzles 6 Visual checking 2 84 To provide on-line strainer Shift Engineer

Log should choking of water jet nozzles & to water line 30.03.02be free from cleaning of nozzlesmud & sand as & when required

Inadequate 8 Water spraying with 5 280 1. To increase no. of Shift Engineerwashing 4 nos. of nozzles nozzles 25.03.02

2. To introduce water spray system throughout the the length of the conveyor3. To increase spray line dia

High mud 5 Informing the 5 175 ---- do --- Shift Engineercontent in logs Supplier 25.03.02

Mud pick up 2 Elevated platform 2 28 To continue with the -during storage for stacking present practice

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Analyse FMEA : Chips Washing

Process Potential Potential S Potential Causes/ O Current D R Recommended Actions RespnsibilityFunction Failure Effects of e Mechanism of c Process Controls e P & TargetRequirements Mode Failure v Failure c t N Completion

u e Dater c

tFunction : Higher carry Higher 8 Less chips wash 7 Monitorng in DCS 1 56 To increase chips wash Shift Washing of over of AI/SiO2 water charge water volume Inchargechips in sand & silica in pulp 01.04.02digester

Improper 4 Monitoring LC 1 32 To continue with the -circulation of pump load (amps) present practicewater throughchips

Requirement :Removal Higher 3 Double chips 5 120 To increase chips wash Shift of sand & silica contamination washing water volume Inchargefrom chips in incoming C.E. from

chips 01.04.02

Less chips 7 Monitoring in DCS 1 56 To increase chips wash Shiftwash draining water drain line dia Engineertime 01.04.02

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Analyse Unbleach Centricleaner System

Regression Analysis : UB Centricleaning Efficiency < > Unbleached Pulp Acid Insoluble

Pearson correlation of UB CC Efficiency and UB A.I.

= -0.920(P-Value = 0.000)

20 30 40 50

400

500

600

UBCC Efficy

UB A

. I.UB A. I. = 788.030 - 8.04498 UBCC Efficy

S = 26.2218 R-Sq = 84.6 % R-Sq(adj) = 83.7 %

Significant relationship exists. Higher the Unbleched Centricleaner efficiency, lower the Unbleached Pulp Acid Insoluble level

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Analyse

Critical “X”sStage Critical “X”s

Log Washing 1. Number of Nozzles2. Wash Water Line Diameter /

Quantity3. Wash Water Pressure

Chips Washing 1. Chip Wash Water Volume2. Wash Water Line Diameter

CentriCleaning 1. Pump Throughput2. Delivery Line Jamming &

Equipment Availability3. Backwater Pump Efficiency

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Improve

Modification in Log Washing SystemHigh RPN

CausesFactors Affected Modification

Inadequate log washing

No. of Nozzles No. of nozzles increased from 4 to 60

Wash water quantity

Water spray system introduced throughout the length of the conveyor including hopper lengthHigher mud

content in logs Spray line

diameterSpray water line dia increased from 4” to 6”

Less log wash water pressure

Water pressure Water line pressure increased from 1.5 kg/cm2 to 4 kg/cm2

Choking of spray nozzles

Water discharge

On-line water strainer provided to avoid choking of nozzles

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Improve

Modification in Log Washing System

Water spray system introduced throughout the length of the conveyor including hopper length

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On-line water strainer provided to avoid choking of nozzles

Improve

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MSIN-SSGB-CS-01: 00 27Water line pressure increased from 1.5 to 4 kg/cm2


Improve

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Spray water line diameter increased from 4” to 6”

Improve

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Improve

FMEA : Log WashingPorocess Potential Potential S Potential Causes/ O Current Process D R Recommended Actions Responsibility & Action Taken S O D RFunction / Failure Effects of e Mechanism of c Controls e P Target e c e PRequirements Mode Failure v Failure c t N Completion v c t N

u e Date u er c r c

t tFunction :Washing of High carry Higher acid 7 Less water line 8 Periodical checking 2 112 To increase water line Shift Engineer Water line Pr. 7 2 1 14the wood logs over of insoluble in pressure of water pressure pressure 25.03.02 increased from

mud & unbleach ( once in a shift ) 1.5 kg/cm2 tosand pulp 5 kg/cm2

Requirement :Spray nozzles 6 Periodical checking 2 84 To provide on-line strainer Shift Engineer On-line strainer 2 1 14

Log should choking of water jet nozzles & to water line 30.03.02 providedbe free from cleaning of nozzlesmud & sand as & when required

Inadequate 8 Water spraying with 5 280 1. To increase no. of Shift Engineer 1. No. of nozzles 3 2 42washing 4 nos. of nozzles nozzles 25.03.02 increased

2. To introduce water spray from 4 to 40 system throughout the 2. Water spray the length of the introduced conveyor throughout 3. To increase spray line the length of dia the conveyor

3. Spray line dia increased from 2" to 6"

High mud 5 To inform wood yard 5 175 ---- do --- Shift Engineer ---- do --- 3 2 42content in logs 25.03.02

Mud pick up 2 Elevated platform 2 28 To continue with the - - - - - -during storage for stacking present practice

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Improve

Modification in Chips Washing System

High RPN Causes

Factors Affected Modification

Less Chips wash watercharge

Chips wash water volume

Chips wash water volume increased from 35 m3/dig to 39 m3/digHigher

contamination of chips

Slow wash water draining rate

Wash water line diameter

Chips wash water drain line diameter increased from 4” to 6”

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Improve FMEA : Chips Washing

Process Potential Potential S Potential Causes/ O Current D R Recommended Respnsibility Action Taken S O D RFunction Failure Effects of e Mechanism of c Process Controls e P Actions &Target e c e PRequirements Mode Failure v Failure c t N Completion v c t N

u e Date u er c r c

t tFunction : Higher carry Higher 8 Less chips wash 7 Monotoring 1 56 To increase chips wash Shift Chips wash 8 2 1 16Washing of over of AI/SiO2 water charge in DCS water volume Incharge water volumechips in sand & silica in pulp 01.04.02 increased by

4 m3/digesterdigester

Improper 4 Monitoring 1 32 To continue with the - - - - - -circulation of LC pump load present practicewater through (amps)chips

Requirement :Removal Contamination in 3 Double chips 5 120 To increase chips wash Shift Chips wash 8 2 1 16of sand & silica incoming chips washing water volume Incharge water volumefrom chips is high C.E. from increased by

01.04.02 4 m3/digester

Chips wash 7 Monitoring 1 56 To increase chips wash Shift Chips wash 8 3 1 24draining time is in DCS water drain line dia Engineer water line dialess 01.04.02 increased

from 4" to 6"

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Improve

Modification in Unbleached Stage Centricleaning System

Factors affecting efficiency Actions initiated

Pump Throughput

Impeller diameter of back water pumps increased from 255 mm to 260 mm to increase pump throughput

Delivery line jamming & equipment availability

Secondary stage pump delivery valve relocated to avoid jamming

Backwater Pump Efficiency

Backwater pump delivery lines were rerouted to improve pump efficiency

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Secondary stage pump delivery valve relocated to avoid jamming


Improve

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Backwater pump delivery lines were rerouted to improve pump efficiency


Improve

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Improve

Improvement in Unbleached Stage Centricleaning Efficiency

Particulars Efficiency

Before Modification 31 %

After Modification 42 %

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Improve

Piloting

Parameter Observed : Unbleached Pulp Acid Insoluble

Period : Apr ’07 to May ’07

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Improve

Unbleached Pulp Acid Insoluble ( Apr ‘07 to May ‘07)

350 450 550 650 750 850

USLUSL


USL

Target

LSLMean

Sample N

StDev (Within)

StDev (Overall)

Cp

CPU

CPL

Cpk

Cpm

Pp

PPU

PPLPpk

PPM < LSL

PPM > USL

PPM Total

PPM < LSL

PPM > USL

PPM Total

PPM < LSL

PPM > USL

PPM Total

850.000

*

*518.441

179

56.2744

58.8720

*

1.96

*

1.96

*

*

1.88

*1.88

*

0.00

0.00

*

0.00

0.00

*

0.01

0.01

Process Data



Within

Overall

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Improve

12001000800600400200

USLUSL

350 450 550 650 750 850

USLUSL

Before

After

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Parameter Before After

Mean (ppm) 577.7 518.4

s.d. 104.9 58.8

Ppk 0.86 1.88

Sigma Level 2.58 5.64

Improve

Reduction in Unbleached Pulp Acid Insoluble

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Improve

Final Pulp Acid Insoluble ( Sep ’06 to Jan ‘07)

100 150 200 250 300

USLUSL

Process Capability Analysis for Final AI (Se

USL

Target

LSLMean

Sample N

StDev (Within)

StDev (Overall)

Cp

CPU

CPL

Cpk

Cpm

Pp

PPU

PPLPpk

PPM < LSL

PPM > USL

PPM Total

PPM < LSL

PPM > USL

PPM Total

PPM < LSL

PPM > USL

PPM Total

250.000

*

*195.1

533

11.9064

23.0429

*

1.66

*

1.66

*

*

0.86

*0.86

*

11257.04

11257.04

*

0.32

0.32

*

5054.35

5054.35

Process Data



Within

Overall


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Improve

Final Pulp Acid Insoluble (Apr ‘07 to May ‘07)

120 140 160 180 200 220 240 260

USLUSL

Process Capability Analysis for Final AI (Ap

USL

Target

LSLMean

Sample N

StDev (Within)

StDev (Overall)

Cp

CPU

CPL

Cpk

Cpm

Pp

PPU

PPLPpk

PPM < LSL

PPM > USL

PPM Total

PPM < LSL

PPM > USL

PPM Total

PPM < LSL

PPM > USL

PPM Total

250.000

*

*169.3

183

10.3606

15.2469

*

2.43

*

2.43

*

*

1.65

*1.65

*

0.00

0.00

*

0.00

0.00

*

0.37

0.37

Process Data



Within

Overall


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Improve

300250200150100

USLUSLBefore

260240220200180160140120

USLUSLAfter

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Parameter Before Present

Mean, ppm 195.1 169.3

s.d. 23.04 15.24

Ppk 0.86 1.65

Sigma Level 2.58 4.95

Improve

Reduction in Final Pulp Acid Insoluble

• Viscose KW stabilized• Spinnerets choking incidents reduced • Reduction in loss at Fibre plant : Rs 9,500 / day• Reduction in loss at Pulp plant : Rs 13,000 / day

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Control Plan

Process Name

Characteristics Unit Specificat

ionFrequency

Inspection Method

Reaction Plan

Responsibility

Wood Logs washing

Water pressure

kg/cm2

4 - 5Once in 2 hrs

Visual Inspection

To increase / Decrease water pressure

Shift Officer

Chips washing in Digester

Wash water volume

m3/day

39 Continuous DCS DCS Shift

Sr.Officer

Wash water draining time

mts

1st drain : 5 mts2nd drain:10 mts

Each Digester DCS DCS

Shift Sr.Officer

Control

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Control PlanProcess Name

Characteristics Unit Specificat

ionFrequency

Inspection Method

Reaction Plan

Responsibility

UB CC

Pulp Rate m3/hr 300-330 CE DCS DCS Shift

Sr.Off.

Feed Pulp consistency % 1.0 – 1.4 CE

Visual inspection at UB thickener inlet

To adjust UB Back water addition

Shift Sr.Off.

Differential pressure across CC cones

kg/cm2

Min 0.5 CE Pr. gauge

To adjust accept pulp flow rate through v/v

Shift Sr.Off.

CC cones jamming nos No cone

jamming

Once in 2 hrs

Visual inspection of rejects flow

Cones cleaning during stoppage

Shift Sr.Off.

Control

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Control Chart For Unbleached Pulp Acid Insoluble

Control

DateDept

USL 850 Mean Pp -LSL SD Ppk 1.47

UCL 654.9 CL 553.5 LCL 452.0

Remarks

UCLR 124.60 CL 38.15

Remarks

494.125079.4789

CONTROL CHART10.08.02

Chipper HouseCharacteristicOperator

UB A.I.

Moving Range Chart

0.00

100.00

200.00

300.00

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Individual Chart

400

500

600

700

800

Back Print

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Key Learning

6

• Improvement in sigma level need not be a cost intensive programme all the time

• “No correlation situation” is also a good source of information

• Daily interaction with the customer – a good practice to understand customer’s problems & requirements

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Thank You

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MSIN-SSGB-CS-01: 00

Quiick wins

• Easy• Not costly• Within team’s power• Reversible• Fast to do

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MSIN-SSGB-CS-01: 00

Tools

• Histogram• Normal curve (Frequency Distribution curves)• Scatter• Correlation • Regression• Control chart• QFD

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MSIN-SSGB-CS-01: 00

• Sample size• Process capability• Pareto (stratification)• Fish bone diagram (Brain storming)• Process mapping (SIPOC & Flow chart)• MSA (R & R study)

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MSIN-SSGB-CS-01: 00

TEAMS

• Quick wins for productivity improvement• Ideas for line balancing• Ideas for redesign

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