carburetor main body machining

Lean Six Sigma Final Project Report-Out

Carburetor Main Body MachiningGreen Belt Project

Project Lead: Jonathan IddingsSponsor (Champion): Jon BigleyCompany/Department: CarburetionProject Timeframe: June-04 : April-05

Additional Team MembersProduct Engineer: Mike CalvinProduct Technician: Rex McCoyQuality Technician: Jayn AdkisonSetup Operator: Jasmin Kovacevic

Define … the process

1

Main Body Machining

Carburetor main body machining consists of a manual/Kingsbury line for two and four barrel (high volume), and an old CNC cell for spread bore and HP (low volume). Each part requires a minimum of nine machines on the manual line and 2 machines on the CNC line.

Equipment Flexibility

# of Operators RequiredLabor Cost

Setup TimeLine/Cell Scalability

Efficiency

CPK / Sigma Level

FPY

Tooling Robustness

Machine/Fixture Rigidity

# of Lines/Cells Required

IPO DIAGRAM

INPUTS PROCESS OUTPUTS

Define … the business case

2

• Problem Statement– Current process is labor intensive, dedicated to the current part

design, difficult to setup, dependent on 50 year old machinery, and incapable of high accuracy or repeatability. The importance of this project our business is very high. The current process is responsible for almost $400,000 per year in waste.

• Project Goals– Reduce labor requirements from 10 operators to 5.– Improve FPY from 96% to 99%– Improve “key characteristic” CPK from .2 to 1.5– Reduce changeover time from 90 minutes to 15 minutes

3

Define … the voice of the customer

WHAT CUSTOMER WANTS RankCleanliness (Internal/External) 5 1 9Dimensional Accuracy/Repeatability (Internal) 3 9 3 3On-time Delivery (External) 5 9Fast Time to Market (Internal/External) 1 3Pleasing Appearance (External) 4 3 1Reduced Warranty Returns (Internal/External) 3 3 9 1Low Cost (Internal) 2 9 1 1

119 76 14 2 9

Reb

uild

Exi

stin

g M

achi

nes

Re-

Layo

ut E

xist

ing

Line

New

Sho

p Fl

oor C

MM

Carburetor Main Body Machining QFD

HO

W T

O IM

PA

CT

New

CN

C M

achi

nes

New

Par

ts W

ashe

r

Direct & Strong = 9Direct = 3Indirect = 1

Importance: 5 = High, 1 = Low

Key Takeaways

Implementation of new CNC cell will impact accuracy, repeatability, fill rate, time to market, appearance, part cost, and warranty cost.

Measure … the current process performance

4

Baseline Data : Sigma Level / CPK

Cpk Analysis

2.23

112.

2316

2.23

222.

2327

2.23

322.

2337

2.23

422.

2348

2.23

53

2.23

582.

2363

2.23

682.

2374

2.23

79

2.23

842.

2389

2.23

942.

2400

2.24

052.

2410

2.24

15

2.24

202.

2426

2.24

312.

2436

2.24

412.

2446

2.24

51

2.24

572.

2462

2.24

672.

2472

2.24

772.

2483

2.24

88

2.24

93

In specOut spec leftOut spec rightLSLUSL

Mean = 2.2415StdDev = 0.0017569USL = 2.238LSL = 2.232Sigma Level = -2.0033Sigma Capability = -.5033Cpk = -.6678Cp = .5692DPM = 977,429N = 30

Pump Shooter Boss HeightOld Process

Cpk Analysis

0.31

050.

3110

0.31

150.

3120

0.31

250.

3130

0.31

350.

3140

0.31

45

0.31

500.

3155

0.31

600.

3165

0.31

70

0.31

750.

3180

0.31

850.

3190

0.31

950.

3200

0.32

05

0.32

100.

3215

0.32

200.

3225

0.32

300.

3235

0.32

40

0.32

450.

3250

0.32

550.

3260

0.32

650.

3270

0.32

75

0.32

80



Booster Hole SizeOld Process

Key Takeaways

• Boss height critical to performance, hole size critical to assembly.

• Baseline CPK was negative for both features.

• Our goal is to improve CPK to 1.5, which will yield Sigma Level of 4.5.


5

Baseline Data : First Pass YieldFPY OLD PROCESS

88%

90%

92%

94%

96%

98%

100%

Jun-04 Jul-04 Aug-04 Sep-04 Oct-04 Nov-04 Dec-04 Jan-05 Feb-05 Mar-05

MONTH

98%

Baseline Data : Labor

Key Takeaways•Scrap and rework data available at beginning of project was unreliable.

•FPY chart data reflects machining defects at flow, assembly, and machining.

•Labor chart is derived from actual labor hours and actual overtime hours. Source: Intranet Efficiency Report

OLD PROCESS LABOR USAGE (CY 2004)

$36,792.02

$25,434.10

$35,182.96

$33,252.63

$26,787.38$25,957.16

$23,299.67$21,961.22

$14,362.04

$10,311.17$10,876.21

$28,899.89

$-

$5,000.00

$10,000.00

$15,000.00

$20,000.00

$25,000.00

$30,000.00

$35,000.00

$40,000.00

Janu

ary

Febru

ary

March

April

May

June July

Augus

tSep

tembe

r

Octobe

rNov

embe

rDec

embe

r

MONTH

MO

NTH

LY L

AB

OR

CO

ST

OLD PROCESS

TOTAL LABOR USAGE = $293,116


6

Baseline Data : Changeover Time

Key Takeaways•Average Changeover Time Within Family = 40 minutes

•Average Changeover Time Between Families = 90 minutes

•Changeover involves removing multiple tools from multiple machines and replacing with alternate tooling.

•Opportunity for operator error very high.

•Changeover process largely dependent on knowledge of ONE employee.


7

Baseline Data:Process Map

Key Takeaways• Red shapes represent 55 minutes of waiting time through the process, which results from the batch flow of the line.

• Green shapes show the quantity of machines required.

• Orange shapes represent movement of the parts from one stage to another.

Analyze … the root causes of poor performance

8

Sources of Waste and Variation

Measurement MethodMachine

Manpower Materials Environment

Output: Labor Cost

Blueprints not Correct

GAGES POORLY LABELED

Blueprints Confusing

Small Lot Sizes

MULTIPLE WORK CENTERS

MANUAL CLEANING PROCESS

EXCESSIVE PART HANDLING

FIXTURES WORN OUT

LACK OF SCALABILITY

LACK OF RIGIDITY

MANY MACHINES REQ'D

TIRED EQUIPMENT

Low Accountability

Desire for Overtime

Lack of Focus

Lack of Challenge

Inconsistent Cast Datums

POOR TOOL QUALITY

Damaged Castings

Fishbone Diagram

Key Takeaways•Primary sources of labor waste and process variation due to process design, age of equipment and tooling, and equipment type.

Improve … the process

9

• Alternate Solutions ConsideredDial Index/Transfer Machine Vertical Machining Centers- Complex - Cycle Times not Balanced- Costly - Tool capacity inadequate- Lacking Flexibility - Gravity works against us

• Actions– Decided on three Horizontal Machining Centers.– Determined Mori Seiki to be best overall choice.– Designed fixtures to allow completed part with every cycle.– Designed fixtures to allow rapid changeover from family to family.– Designed fixtures to require no changeover within family.– Specified/designed robust tooling solutions to yield long life, low cycle

times, and high part quality.– Wrote CNC programs utilizing advanced Macro B (Basic) to standardize

across part families, bullet-proof the changeover process, and allow streamlined response to part design changes.

Control … to hold the gains

10

QTY 3rd Shift QTY 1st Shift QTY 2nd Shift QTY Non-ConformingGood Parts Good Parts Good Parts Part MislocatedScrap Parts Scrap Parts Scrap Parts Broken DrillRework Parts Rework Parts Rework Parts Broken TapHours Worked Hours Worked Hours Worked 15 Degree Venturi Blend OversizeOrders Completed Orders Completed Orders Completed 15 Degree Venturi Blend UndersizeCompleted On Time Completed On Time Completed On Time Machined With Wrong Program

MIN Downtime MIN Downtime MIN Downtime Misc. Machining ScrapChangeover Fixture/Tooling/Progam Changeover Fixture/Tooling/Progam Changeover Fixture/Tooling/Progam Missing OperationChangeover Tooling/Program/Stamp Changeover Tooling/Program/Stamp Changeover Tooling/Program/Stamp Ran Multiple TimeEngineering - Program Error Engineering - Program Error Engineering - Program Error Setup ScrapEngineering - Running Samples Engineering - Running Samples Engineering - Running Samples Choke Shaft Hole OversizeMachine Down - Hydraulic System Alarm Machine Down - Hydraulic System Alarm Machine Down - Hydraulic System Alarm Shaft Hole Out of LocationMachine Down - Hydraulic Leak Machine Down - Hydraulic Leak Machine Down - Hydraulic Leak Choke Shaft Hole UndersizeMachine Down - Operator Error Machine Down - Operator Error Machine Down - Operator Error Booster Hole Out of LocationMachine Down - Pallet Changer Machine Down - Pallet Changer Machine Down - Pallet Changer Booster Hole OversizeMachine Down - Servo Alarm Machine Down - Servo Alarm Machine Down - Servo Alarm Booster Hole UndersizeMachine Down - Tool Magazine Machine Down - Tool Magazine Machine Down - Tool Magazine Air Bleed Hole Undersize**Machine Down - Misc. **Machine Down - Misc. **Machine Down - Misc. Air Bleed Hole Oversize**Operator - Cleaning up **Operator - Cleaning up **Operator - Cleaning up Pump Shooter Boss Too HighOperator - Getting Castings Operator - Getting Castings Operator - Getting Castings Pump Shooter Boss Too LowOperator - Running OP30 / Spec. Line Operator - Running OP30 / Spec. Line Operator - Running OP30 / Spec. Line Vendor - Dimensional Operator - Waiting On Castings Operator - Waiting On Castings Operator - Waiting On Castings Vendor - Bent CastingOperator - Filling out paperwork Operator - Filling out paperwork Operator - Filling out paperwork Vendor - Misc. **Operator - Preventative Maintenance **Operator - Preventative Maintenance **Operator - Preventative Maintenance Vendor - PorosityOperator - Loaned Out Operator - Loaned Out Operator - Loaned Out Vendor - Warped Cracked CastingsPlant - No Air Plant - No Air Plant - No Air Wrong Indentification StampPlant - Power Outage Plant - Power Outage Plant - Power Outage COMMENTS**Plant - Misc. **Plant - Misc. **Plant - Misc.Quality - Process Out of Spec. Quality - Process Out of Spec. Quality - Process Out of Spec.Service - Outside Service S/N 16 Service - Outside Service S/N 16 Service - Outside Service S/N 16Service - Outside Service S/N 26 Service - Outside Service S/N 26 Service - Outside Service S/N 26Service - Outside Service S/N 33 Service - Outside Service S/N 33 Service - Outside Service S/N 33Service - Adding Coolant Service - Adding Coolant Service - Adding CoolantService - Adding Hydraulic Oil Service - Adding Hydraulic Oil Service - Adding Hydraulic OilService - Out of Hydraulic Oil Service - Out of Hydraulic Oil Service - Out of Hydraulic Oil**Service - Preventative Maintenance **Service - Preventative Maintenance **Service - Preventative Maintenance**Service - Misc. **Service - Misc. **Service - Misc.Tooling - Replace Dull/Broken Tool Tooling - Replace Dull/Broken Tool Tooling - Replace Dull/Broken ToolTooling - Change Inserts Tooling - Change Inserts Tooling - Change Inserts**Tooling - Misc. **Tooling - Misc. **Tooling - Misc.Checking Parts Checking Parts Checking Parts

Department 1151 March Production Output

700 Units/day Goal

0

100

200

300

400

500

600

700

800

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Date

Part

s P

rodu

ced

Good Parts Linear (Production Rolling Avg.) Linear (Production Goal)

Key Takeaways• Tracking: FPY, Efficiency, Downtime, Conformance to Schedule, Scrap, Production, MRO Spending

• Use these tracking tools to ensure we are maintaining or continually improving all aspects of the process.

Project Results … Verification of Improvement

11

BEFOREPROCESS MAPS

Key Takeaways• Total distance traveled reduced from 87 feet to 16 feet.

• Total waiting time reduced from 55 minutes to 3.2 minutes

• Each part now complete after one machine, compared to 8-15 machines previously.

• Cleared 600 sq. ft. of floor space. AFTER


12

Cpk Analysis

0.31

050.

3110

0.31

150.

3120

0.31

25

0.31

300.

3135

0.31

400.

3145

0.31

500.

3155

0.31

60

0.31

650.

3170

0.31

75

0.31

800.

3185

0.31

90

0.31

950.

3200

0.32

050.

3210

0.32

150.

3220

0.32

25

0.32

300.

3235

0.32

40

0.32

450.

3250

0.32

55

0.32

600.

3265

0.32

70

0.32

750.

3280



Booster Hole SizeOld Process

Cpk Analysis

2.23

112.

2316

2.23

222.

2327

2.23

32

2.23

372.

2342

2.23

482.

2353

2.23

582.

2363

2.23

68

2.23

742.

2379

2.23

84

2.23

892.

2394

2.24

00

2.24

052.

2410

2.24

152.

2420

2.24

262.

2431

2.24

36

2.24

412.

2446

2.24

51

2.24

572.

2462

2.24

67

2.24

722.

2477

2.24

83

2.24

882.

2493



Pump Shooter Boss HeightOld Process

Cpk Analysis

0.31

390.

3140

0.31

410.

3141

0.31

420.

3142

0.31

430.

3144

0.31

440.

3145

0.31

450.

3146

0.31

470.

3147

0.31

480.

3148

0.31

490.

3150

0.31

500.

3151

0.31

510.

3152

0.31

530.

3153

0.31

540.

3154

0.31

550.

3156

0.31

560.

3157

0.31

570.

3158

0.31

590.

3159

0.31

600.

3160


Mean = 0.31541StdDev = 0.00010196USL = 0.316LSL = 0.314Sigma Level = 5.8015Sigma Capability = 7.3015Cpk = 1.9338Cp = 3.2693DPM = .00328685N = 30

Booster Hole SizeNew Process

BEFORE AFTERCpk Analysis

2.23

072.

2310

2.23

122.

2315

2.23

18

2.23

202.

2323

2.23

26

2.23

282.

2331

2.23

34

2.23

362.

2339

2.23

42

2.23

442.

2347

2.23

50

2.23

522.

2355

2.23

57

2.23

602.

2363

2.23

65

2.23

682.

2371

2.23

73

2.23

762.

2379

2.23

81

2.23

842.

2387

2.23

89

2.23

922.

2395

2.23

97

2.24

00


Mean = 2.2354StdDev = 0.0010372USL = 2.238LSL = 2.232Sigma Level = 2.5263Sigma Capability = 3.9935Cpk = .8421Cp = .9642DPM = 6,324N = 30

Pump Shooter Boss HeightNew Process

CPK / SIGMA LEVEL

Key Takeaways• Pump shooter boss height CPK increased from -.67 to .84.

• Pump shooter boss height Sigma Level increased from -2.0 to 2.5.

• Booster hole size CPK increased from -.56 to 1.93.

• Booster hole size Sigma Level increased from -1.69 to 5.8.

13


MONTHLY LABOR COST

Key Takeaways• Blue line represents actual 2004 labor cost from intranet efficiency report.

• Red line represents estimated 2005 labor cost based on measured throughput of new cell and equal sales to 2004.

• 2004 Labor Cost: $293,116

• 2006 Labor Cost: $128,300

• Savings: $164,816$-

$5,000.00

$10,000.00

$15,000.00

$20,000.00

$25,000.00

$30,000.00

$35,000.00

$40,000.00

Janu

ary

Februa

ry

March

April

May

June July

Augus

tSep

tembe

r

Octobe

rNove

mber

Decembe

r

OLD PROCESSNEW PROCESS


14

First Pass Yield

80%

82%

84%

86%

88%

90%

92%

94%

96%

98%

100%

Jun-04 Jul-04 Aug-04 Sep-04 Oct-04 Nov-04 Dec-04 Jan-05 Feb-05 Mar-05

OLD PROCESSNEW PROCESSTARGET

Key Takeaways• Blue line represents FPY of old line.

• Red line represents FPY of new cell.

• We are exceeding our goal of 98% FPY.


15

Key Takeaways• Changeover time within family reduced from 40 minutes to 5 minutes.

• Changeover time between families reduced from 90 minutes to 15 minutes.

CHANGEOVER TIME

Within Family

Within Family

Between Families

Between Families

0

10

20

30

40

50

60

70

80

90

100

Before After

MIN

UTE

S

Project Summary

16

• Problem– Carburetor main body machining consisted of antiquated manual/Kingsbury line for

two and four barrel (high volume), and an old CNC cell for spread bore and HP (low volume). Each part requires a minimum of nine machines on the manual line and 3 machines on the CNC line.

• Baseline and Target Performance– Reduce labor cost from $412k to $128k– Reduce warranty cost by $100,000– Improve “key characteristic” CPK from .6 to 1.33– Improve FPY from 87% to 98%– Reduce setup time from 90 minutes to 15 minutes

• Analysis and Solution– Analysis revealed that process design, type of equipment, age of equipment, and

age of tooling were primary contributors to labor waste and process variation.– Our new CNC machining cell consists of three computerized horizontal machining

centers with automatic work piece changers, state-of-the-art tooling, and quick change fixtures.

Project Summary Scorecard … before and after

17

metric before after improvementLabor $293,116 annually $128,304 annually $164,816

CPK / Sigma Level -0.6 CPK-0.75 Sigma Level

1.5 CPK3.5 Sigma Level

Delta= 2 CPKDelta= 4.25 Sigma Level

Setup Time 90 minutes 15 minutes 84% Reduction

Tooling Cost $57,600 $14,400 $43,200

Repair Parts Cost $57,000 annually for Carb BU 10% Reduction $5,700

Floor Space 1800 Sq. Feet 1200 Sq. Feet 600 Sq. Feet

Line Shutdown Risk Series production yields 100% down if 1 machine down

Parallel production yields 33% down if 1 machine down

66% Reduction

FPY(Scrap/Rework Cost)

96%(7000 scrap/rework units per year)

99.5%(875 scrap/rework units per year)

$52,924

Total: $267,000

carburetor main body machining

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