Final Report Defense 021509

Design for Manufacturability and Assembly of the

endogo® Palmable Endoscopic Camera

Matthew R. Ostrander

February 17th, 2009

2

Overview

Background

Goal

Problem Definition

Approach

Results

Q&A

3

Background

Current archiving accomplished with large, expensive equipment

endogo® combines portability/simplicity with need for endoscopic imagery

Provides a platform that combines available imaging technology with the endoscope

Result: Compact, digital endoscopic imaging device, ergonomically designed to provide maximal comfort for short and prolonged use

4

Goal

Recommend design and assembly

process changes that will enable

production of the endogo® at reduced

cost, increased speed and higher quality

5

Problem Definition

Design effort focused on functionality –This project focuses on manufacturability

Metrics guide the project

Cycle Time

Metrics and Order-Winning Criteria (OWC) assist in identification of figures of merit

Weighting matrix resulted in metricsselected for this project

6

Approach

Model/Analyze Baseline Design

Extend® Model

Part-count reduction

DFA Index Estimation

Insertion Time Estimation

Acquisition Time Estimation

Defect Estimation and Defect Table

Cycle Time, Distance, Quality, Inventory

Estimation

7

Approach (continued)

Model/Analyze New Design

Extend® Model

Material Selection (Dimensionless Ranking)

DFA Index Estimation

Defect Estimation

Cycle Time, Distance, Quality, Inventory

Estimation

8

Approach

Flowchart

Tasks

Interdependent

- DFA Index

- Inventory Turns

- Quality

- Distance

- Cycle Time

Baseline Design

Extend

Model

Part-Count

Reduction

Assembly /

Acquisition

Time

Estimation

Probability

of Defect

Calculation

Metrics

“Filter”

Process

Redesgin

Material

Selection

(Dimensionless

Ranking)

New Process

(Assembly)

New Product

(Manufacture)

New Design

- DFA Index

- Inventory Turns

- Quality

- Distance

- Cycle Time

Compare

Baseline Extend

Model

10

Extend Model (1 of 2)

Benefits of Starting with the Model

Clear understanding of the process

Provides Inventory Turns estimate

Inventory Turns calculated for the baseline

and new designs

$,

$,

InventoryAverageDaily

AnnuallySoldGoodsofCostTurnsInventory

11

Extend Model (2 of 2)

Average daily inventory taken from the

model by determining stock and work in

process

Cost of goods sold in a year taken from

the total number of cameras produced in a

single model run (simulates one year)

12

Baseline Extend Model (1 of 5)

13


Order Size (Cameras per Order) is

calculated by dividing subassembly lead

time (Minutes per Order) by the endogo

lead time (Minutes per Camera)

TimeLeadendogo

TimeLeadySubassemblSizeOrder

14


15


16


Cycle Time variation due to production approach

10 built in rapid succession followed by long period

until next 10

With 1 piece flow, Cycle Time between 285 and 276

minutes at the 99% confidence level

Average Cycle Time representative of system’s true

capability because demand exceeds capacity

Inventory Turns calculated across 30 model runs

Metric Average Upper Bound (99% Confidence)

Lower Bound (99% Confidence)

Inventory Turns 10.9 11.0 10.8 Cycle Time, min 278 387 169

DFMA

Considerations

18

DFMA Considerations (1 of 12)

Part Count Reduction

During operation of the product, does the part move relative to all other parts already assembled?

Must the part be of a different material than or be isolated from all other parts already assembled?

Must the part be separate from all other parts already assembled because otherwise necessary assembly of other separate parts would be impossible?

19


Part count reduced from 92 to 42

Example: Display Mounting Ring and LCD Ring Neck

Injection Mold the neck and ring in once piece

The result, 42, is Nmin in the DFA Index (next)

20


DFA Index Calculation

assemblycompletetotimeestimatedt

partonefortimeassemblybasict

partsofnumberltheoreticalowestN

IndexDFAE

where

ttNE

ma

a

ma

maama

min

min

,

/

21


ta calculation

Boothroyd assumes 3 seconds

Assumes no knowledge of actual process

Attempt to find a basic assembly time tailored

to this particular design

22


ta calculation

First Attempt: DFA Index Greater than One

timecycletheofdevst

designbaselineinpartsofnumberactualN

cameraonebuildtorequiredtimeCT

where

N

CTt

CT

actual

actual

CTa

..

,

282.1

23


ta calculation

Second Attempt: Data not Normal

steppertimeassemblyestimatedtheofdevst

steppertimeassemblyestimatedaveraget

where

tt

estimated

averageestimated

estimatedaverageestimateda

..

,

282.1

,

,

24


ta calculation

Second Attempt: Data not Normal

Assembly Times, seconds

Pe

rce

nt

2520151050-5

99

95

90

80

70

60

50

40

30

20

10

5

1

Mean

<0.005

7.355

StDev 5.435

N 30

AD 1.967

P-Value

Normality Test of the Assembly Times

Normal

25


ta calculation

Third Attempt: Log-normal Successful

Log of Assembly Times

Pe

rce

nt

1.61.41.21.00.80.60.40.20.0

99

95

90

80

70

60

50

40

30

20

10

5

1 0.4

11

10

Mean

0.542

0.7733

StDev 0.2824

N 30

AD 0.307

P-Value

Normality Test of the Log of Assembly Times

Normal

26


ta calculation

Third Attempt: Log-normal Successful

Log of Assembly Times

Pe

rce

nt

1.61.41.21.00.80.60.40.20.0

99

95

90

80

70

60

50

40

30

20

10

5

1 0.4

11

10

Mean

0.542

0.7733

StDev 0.2824

N 30

AD 0.307

P-Value

Normality Test of the Log of Assembly Times

Normal

58.2411.0

411.0log

10

10

x

x

27


EASY TO

ALIGN

NOT EASY

TO ALIGN

EASY TO

ALIGN

NOT EASY

TO ALIGN

EASY TO

ALIGN

NOT EASY

TO ALIGN

0 1 2 3 4 5

NO ACCESS OR

VISION

DIFFICULTIES

0 1.5 3 2.6 5.2 1.8 3.3

OBSTRUCTED

ACCESS OR

RESTRICED VISION

1 3.7 5.2 4.8 7.4 4 5.5

OBSTRUCTED

ACCESS AND

RESTRICTED VISION

2 5.9 7.4 7 9.6 7.7 7.7

COPYRIGHT 1999 BOOTHROYD DEWHURST, INC.

SECURED BY SEPARATE OPERATION OR PART

NO HOLDING DOWN HOLDING DOWN

SECURED ON INSERTION

BY SNAP FIT

tma Calculation: Insertion Time Estimate

28


< 2mm < 2mm

SIZE > 15mm 6mm < SIZE < 15mm SIZE > 6mm SIZE > 15mm 6mm < SIZE < 15mm SIZE > 6mm

0 1 2 3 4 5

SYM < 360 0 1.13 1.43 1.69 1.84 2.17 2.45

360 ≤ SYM < 540 1 1.5 1.8 2.06 2.25 2.57 3

540 ≤ SYM < 720 2 1.8 2.1 2.36 2.57 2.9 3.18

SYM = 720 3 1.95 2.25 2.51 2.73 3.06 3.34

FOR PARTS THAT CAN BE GRASPED AND MANIPULATED WITH ONE HAND WITHOUT THE AID OF GRASPING TOOLS

COPYRIGHT 1999 BOOTHROYD DEWHURST, INC.

NO HANDLING DIFFICULTIES PART NESTS OR TANGLES

THICKNESS > 2mm THICKNESS > 2mm

tma Calculation: Acquisition Time Estimate

29


tma calculation: Sum all estimates

ta, s tma, s Nmin Ema Baseline Design 2.58 2273 33 0.04

Distance

Calculations

31

Clean Room

Flow Hoods

Ramp and Loading Dock

Warehouse

48' 8 x 45

Clean Room (Future)

General Manufacturing 70 X 50

20 X 18

Sink

40 x 45

ShopBiohazard LabHall

Lech

Scott Rosanna Mark

Endogo Work Station

Receiving

Receiving

Rack

Endogo Rack

Distance Calculations (1 of )

1 – Entry

2 – Receiving Rack

3 – Receiving


5 – Inspection


7 – Storage

8 – Machining

9 – Assembly

10 – Ship

25,500 feet

32

Clean Room

Flow Hoods

Ramp and Loading Dock

Warehouse

48' 8 x 45

Clean Room (Future)

General Manufacturing 70 X 50

20 X 18

Sink

40 x 45

ShopBiohazard LabHall

Lech

Scott Rosanna Mark

Endogo Work Station

Receiving

Receiving Rack

Endogo Rack

Distance Calculations (1 of )

1 – Entry

2 – Receiving/Inspection


4 – endogo® Worksation

4,840 feet

Assembly

Modifications

34

Workstation Changes

Contain all parts on the workbench rather

than in the storage rack

Do not “kit” each camera in the same bin

Organize each part bin in order of

assembly

Mark bins with part number and picture bin

35

Pareto Chart

0

20

40

60

80

100

120

140

160

Process Steps

Acti

vit

y T

ime,

seco

nd

s

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Cu

mu

lati

ve %

Baseline New Design Average After Re-design

Cumulative %, New Design Cumulative %, Baseline

36

DFA Index Values ta, s tma, s Nmin Ema

Baseline Design 2.58 2273 33 0.04 New Design 2.58 221 33 0.4

tma estimated primarily by way of

Boothroyd techniques

10-fold decrease in tma led to 10-fold

increase in DFA Index

The ideal would take 85 seconds to

assemble

Quality Estimates

38

Quality Estimates

assemblyperoperationsofnumbern

soperationpertimeassemblyestimatedDFAaveraget

assemblyperdefectofyprobabilitD

where

tforD

tfortD

i

a

ia

i

n

ia

,

,

3,0

3,30001.011

n ti, seconds Da, ppm

Baseline Design 76 30 190,000 New Design 29 7.0 12,000

Material and

Process Selection

40

Material and Process Selection

Dimensionless Ranking

rd parametethe derived to form hat is useExponent tm

determined is being he N-valueor which tmaterial ftheofpropertynP

sg materialengineerinof common rangeaforparameterderivedLowestD

sg materialengineerinof common rangeaforparameterderivedHighestD

parameterDerivedD

PPPD

where

DDDDN

n

thn

m

n

mm n

min

max

21

minmax10min10

21

,

)/(log/)/(log100

Derived Parameter Description Exponents m1 m2 m3 m4 m5 Best YT at Minimized Weight and $ -1 1 0 0 -2 Best YC and Minimized Weight and $ -1 0 0 1 -2 Best Beam/Plate Strength at Minimized Weight and $ -1 1/2 0 0 -2 Best Stiffness at Minimized Weight and $ -1 0 1/3 0 -2

41

Initial broad group of

candidate materials

Cost Tensile Yield Strength Elastic

Modulus Compressive

Yield Strength Density

$/kg MN/m2 MN/m2 MN/m2 kg/m3

Gray Cast Iron 3.32E-01 2.93E+02 1.34E+05 2.93E+02 7.21E+03

Ductile Iron 4.08E-01 4.48E+02 1.65E+05 3.10E+02 7.13E+03

Malleable Iron 4.85E-01 3.45E+02 1.60E+05 3.45E+02 7.38E+03

Mild Steel 1.15E+00 2.62E+02 2.07E+05 2.62E+02 7.77E+03

Alloy Steel 7.14E+00 1.38E+03 2.07E+05 1.38E+03 7.85E+03

Stainless Steel 3.19E+00 2.48E+02 1.93E+05 2.48E+02 8.04E+03

Al (High Strength) 6.12E+00 1.93E+02 7.10E+04 1.93E+02 2.75E+03

Beryllium Copper 4.46E+01 1.10E+03 1.28E+05 1.10E+03 8.27E+03

Copper, Hard 3.32E+00 3.10E+02 1.17E+05 3.10E+02 8.96E+03

Magnesium 8.93E+00 2.34E+02 4.48E+04 2.34E+02 1.80E+03

Titanium 3.11E+01 9.45E+02 1.13E+05 9.45E+02 4.74E+03

Lead 3.32E+00 2.00E+01 1.52E+04 2.00E+01 1.14E+04

Epoxy 6.12E+00 6.55E+01 3.10E+03 2.48E+02 1.91E+03

HDPE 1.39E+00 2.48E+01 8.27E+02 2.48E+01 9.71E+02

Polycarbonate (Glass-

reinforced) 2.45E+00 1.59E+02 1.16E+04 1.45E+02 1.53E+03

Rubber 4.03E+00 2.76E+01 4.59E+00 2.76E+01 9.71E+02

Polyurethane Foam 2.04E+00 1.52E+01 1.08E+02 1.72E+01 4.99E+02

Particle Board 4.08E-01 1.55E+01 2.93E+03 1.45E+01 6.10E+02

Pine 2.38E+00 7.93E+01 8.27E+03 3.31E+01 3.61E+02

Diamond 8.42E+02 2.69E+02 1.03E+06 4.00E+03 3.52E+03

Silicon Carbide (Sintered) 7.65E+01 6.90E+01 3.31E+05 1.03E+03 2.97E+03

Tungsten Carbide 3.06E+02 8.96E+02 5.39E+05 4.95E+03 1.33E+04

Glass 3.83E-01 9.17E+01 7.31E+04 1.38E+03 2.47E+03

Pottery 7.65E-01 3.31E+01 7.03E+04 5.00E+02 2.22E+03

Concrete 1.53E-01 1.65E+00 3.00E+04 2.48E+01 2.50E+03

Cork 1.74E+00 1.00E+00 2.00E+01 1.00E+00 1.39E+02

Al-Li (2090) 1.66E+02 4.55E+02 6.90E+04 4.55E+02 2.55E+03

42

Stiffest at minimum

weight and cost

Strongest in Tension

at minimum weight

and cost

Stiffest Material at Minimum Weight and Cost

Strongest Tension Member at Minimum Weight and Cost

Particle Board 100 Pine 100

Cork 99 Particle Board 90

Pine 97 Glass 81

Concrete 90 Polyurethane Foam 78

Glass 85 Cork 78

Pottery 81 Polycarbonate (Glass-

reinforced) 77

Polyurethane Foam 79 Ductile Iron 74

Polyethylene (high-density) 77 Polyethylene (high-density) 73

Polycarbonate (Glass-reinforced) 71 Gray Cast Iron 72

Gray Cast Iron 69 Malleable Iron 69

Ductile Iron 68 Pottery 65

Malleable Iron 65 Magnesium 64

Magnesium 61 Rubber 63

Al (High Strength) 58 Al (High Strength) 57

Mild Steel 57 Mild Steel 56

Epoxy 55 Alloy Steel 54

Rubber 51 Epoxy 54

Stainless Steel 47 Concrete 48

Copper, Hard 44 Titanium 46

Alloy Steel 41 Stainless Steel 44

Silicon Carbide (Sintered) 38 Copper, Hard 44

Titanium 35 Aluminum-Lithium Alloys

(2090) 34

Lead 33 Beryllium Copper 32

Aluminum-Lithium Alloys (2090) 29 Silicon Carbide (Sintered) 19

Beryllium Copper 22 Lead 11

Diamond 17 Diamond 5

Tungsten Carbide 0 Tungsten Carbide 0

43

Strongest in

compression at

minimum weight and

cost

Strongest beam at

minimum weight and

cost

Strongest Compression Member at Minimum Weight and Cost

Strongest Beam or Plate at Minimum Cost and Weight

Glass 100 Cork 100

Pottery 84 Pine 100

Pine 82 Particle Board 99

Particle Board 81 Polyurethane Foam 88

Polyurethane Foam 70 Glass 82

Cork 68 Polyethylene (high-density) 81

Concrete 67 Polycarbonate (Glass-

reinforced) 76

Polycarbonate (Glass-reinforced) 67 Pottery 73

Polyethylene (high-density) 64 Rubber 72

Gray Cast Iron 62 Concrete 72

Ductile Iron 61 Ductile Iron 69

Malleable Iron 60 Gray Cast Iron 69

Epoxy 58 Malleable Iron 66

Magnesium 55 Magnesium 63

Rubber 53 Epoxy 60

Al (High Strength) 48 Al (High Strength) 58

Mild Steel 47 Mild Steel 56

Alloy Steel 45 Alloy Steel 46

Silicon Carbide (Sintered) 37 Stainless Steel 45

Titanium 36 Copper, Hard 44

Stainless Steel 34 Titanium 40

Copper, Hard 34 Aluminum-Lithium Alloys

(2090) 33

Aluminum-Lithium Alloys (2090) 23 Silicon Carbide (Sintered) 28

Diamond 22 Beryllium Copper 27

Beryllium Copper 22 Lead 27

Tungsten Carbide 7 Diamond 10

Lead 0 Tungsten Carbide 0

44

Full list of candidate

polymers Cost Tensile Yield

Strength Elastic

modulus Density Autoclave?

$/kg MN/m2 MN/m2 kg/m3

Polyethylene (high-density) 1.39 24.8 1080 971 No

Polycarbonate (30% Glass-reinforced) 2.45 118 11600 1433 Yes

Elastomer - Nitrile

Elastomer - SBR

Elastomer - Thermoplastic

For design simplification, elastomers will not be used. Buttons will be of the same material as the case.

Epoxy Epoxy was lower rated than HDPE in initial screening. Typically used in

composites. This is also a thermoset.

Nylon 6,6 1.79 69 2515 1140 No

Phenolic Brittle thermoset

Polycarbonate (PC) 2.45 63.8 7580 1200 Yes

Polyester (thermoset) Thermoset

PEEK Not injection moldable and is very expensive

LDPE 1.79 11.75 225 924.5 No

UHMWPE 2.49 24.5 690 940 ?

PET 2.82 59.3 3450 1345 ?

PMMA Transparent

Polypropylene(PP) 1.81 32.6 1345 931 Yes

PS Relatively brittle and transparent

PTFE Poor cold flow properties

PVC 1.98 42.75 3250 1440 No

Silicone, flexible cast Not injection moldable

Heat Resistant ABS 2.19 43.5 2200 990 Yes

Acrylic Transparent

Acetal 3.09 66 3800 1465 No

45

Final list of candidate

polymers

Compared relative to one

another

Some compared but not

listed:

High Density Polyethylene

Nylon 6,6

Low Density Polyethylene

Polyvinyl Chloride

Acetal

Tension

Beam or Plate

Strength Stiffest Beam Average

Polycarbonate (30% Glass-reinforced)

73 29 65 56

Polycarbonate (PC)

64 39 76 60

Ultra-high Molecular Weight

Polyethylene (UHMWPE)

62 69 81 71

Polyethylene Terephthalate

(PET) 65 43 70 59

Polypropylene (PP)

100 100 100 100

Heat Resistant Acrylonitrile

butadiene styrene (ABS)

98 89 95 94

New Design Extend

Model

47

New Design Extend Model

Fundamental structure remains the same

Reduction of the number of steps due to

part count reduction

Elimination of “pre-work”

Reduction of re-work

48

Baseline Extend Model Results

0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 55000 60000

0

3.05

6.1

9.15

12.2

15.25

18.3

21.35

24.4

27.45

30.5

33.55

36.6

39.65

42.7

45.75

48.8

51.85

54.9

57.95

61

TIME, MINUTES

CAMERASModel Output, Baseline

TOTAL STOCK WIP True INVENTORY

49

New Extend Model Results

0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 55000 60000

0

0.95

1.9

2.85

3.8

4.75

5.7

6.65

7.6

8.55

9.5

10.45

11.4

12.35

13.3

14.25

15.2

16.15

17.1

18.05

19

TIME, MINUTES

NUMBER OF CAMERASModel Output, New Design

TOTAL STOCK TOTAL WIP INSTANTANEOUS I… INVENTORY AVERA…

50

Results Summary Metric Average

Inventory Turns 16.4 Baseline Design

Cycle Time, min 267

Inventory Turns 107 New Design

Cycle Time, min 111

Inventory Turns 30 Target

Cycle Time, min ≤ 120

n ti, seconds Da, ppm

Baseline Design 76 30 190,000

New Design 30 7.0 12,000

Target - - ≤ 44,000

Distance, feet

Baseline Design 25,500

New Design 4,840

Target ≤ 5,000

53

Deliverables

Product design changes

Process design changes

Material selection changes

Inventory Turns estimation for baseline and new design

Quality estimation for baseline and new design

Distance estimation for baseline and new design

Cycle Time estimation for baseline and new design

Extend® - based model of manufacturing processes for baseline and new design

Final report

Final defense briefing

54

Weighting Matrix

Metrics

OWC Set-Up Time Quality

Space Ratio Inventory Flexibility Distance Uptime Weight

Price 1

Quality 10

Lead Time 1

Delivery Reliability 2

Flexibility 0

Innovation 0

Size 0

Design Leadership 0

BACK

55

OWC

BACK

Order-Winning Criterion Definition

Price The cost to the consumer of the product under consideration.

Quality The perceived quality by the consumer of the product under consideration.

Lead Time The duration of time from the moment the consumer orders the product under consideration to the moment of consumer receipt.

Delivery Reliability The repeatability of lead time.

Flexibility The number of parts that can be produced on the same machine.

Innovation Ability An organization’s capacity for producing new marketable products.

Size The volume of the product under consideration.

Design Leadership An organization’s capacity for transforming concepts into finished products.

56

Metrics Identified for Project

BACK

Metric Weighted Score

Redesign Target

Inventory 14 30 turns

Quality 11

Captured and

Warranty: ≤ 44000 ppm

Distance 11 ≤ 5000 feet

Cycle Time – ≤ 120

minutes

57

Metrics

BACK

58

Metric Units Definition

Inventory Inventory Turns

Inventory Turns for a product is equal to the cost of goods sold divided by the average inventory value

Flexibility number of parts

The number different parts that can be produced on the same machine.

Distance feet The measure of the total linear feet of a part’s travel through the plant from raw material in receiving to finished products in shipping. This includes the sum of the individual routes of each subassembly. For example, if a plant manufactures a paper cup, the side of the cup travels 10 feet to get to the location where it is mated to the bottom. The bottom at that point has also traveled 10 feet. After the two are mated, it travels another 10 feet to be given a finish and then to shipping. The total Distance is then 30 feet.

Uptime percent The percentage of time a machine is producing to specifications compared to the total time that production can be scheduled.

Metrics (continued)

BACK

59

Inventory Turns

$,

$,

InventoryAverageDaily

AnnuallySoldGoodsofCostTurnsInventory

BACK

60

Dimensionless Ranking

rd parametethe derived to form hat is useExponent tm

valuethe lowestat it has except thSame as PP

ialsring materon engineege of comm for a ranhest valueas the higial that hof a mater property nP

determined is being he N-valueor which tmaterial ftheofpropertynP

propertiesvaluedlowesttheofallofncombinatiothewithparameterDerivedD

propertiesvaluedhighesttheofallofncombinatiothewithparameterDerivedD

parameterDerivedD

PPPD

PPPD

PPPD

where

DDDDN

n

n,n

thn

thn

m

n

mm

m

n

mm

m

n

mm

n

n

n

maxmin,

max,

min

max

min,min,2min,1min

max,max,2max,1max

21

minmax10min10

21

21

21

,

)/(log/)/(log100

BACK

61

Dimensionless Ranking Example

Five parameters form derived

parameters

1. Cost, $/kg

2. Tensile Yield Strength, MN/m2

3. Elastic Modulus, MN/m2

4. Compressive Yield Strength, MN/m2

5. Density, kg/m3

BACK

62

Most likely derived parameter will be “best

tensile yield strength at minimized cost”

Using previous numbering convention and

dimensionless parameter equation: m2 = 1,

m1 = m5 = -1, and m3 = m4 = 0

This produces the derived parameter:

Yt /r Cm


BACK

63


BACK

m1 m2 m3 m4 m5

-1 1 0 0 -1

Cost

Tensile

yield str.

Elastic

modulus

Compressive

yield str. Density

Derived

parameter N

$/kg MN/m2

MN/m2

MN/m2

kg/m3

Pmax 7.26E+02 1.38E+03 1.03E+06 4.95E+03 1.33E+04 1.43E-04 100

Pmin 1.32E-01 1.00E+00 4.95E+00 1.00E+00 1.39E+02 5.45E-02 0

Polyethylene

(high-density) 7.48E-01 2.48E+01 8.27E+02 2.48E+01 9.71E+02 3.41E-02 8

Titanium 2.68E+01 9.45E+02 1.13E+05 9.45E+02 4.74E+03 7.44E-03 34

64

Part-count Reduction

During operation of the product, does the part move relative to all other parts already assembled?

Must the part be of a different material than or be isolated from all other parts already assembled?

Must the part be separate from all other parts already assembled because otherwise necessary assembly of other separate parts would be impossible?

BACK

65

DFA Index

assemblycompletetotimeestimatedt

partonefortimeassemblybasict

partsofnumberltheoreticalowestN

IndexDFAE

where

ttNE

ma

a

ma

maama

min

min

,

/

BACK

66

Basic Assembly Time

timecycletheofdevst

designbaselineinpartsofnumberactualN

camerapertimecycleCT

where

N

CTt

CT

actual

actual

CTa

..

,

282.1

BACK

67

Probability of Defect (Entire

Assembly)

assemblyperoperationsofnumbern

soperationpertimeassemblyestimatedDFAaveraget

assemblyperdefectofyprobabilitD

where

tforD

tfortD

i

a

ia

i

n

ia

,

,

3,0

3,30001.011

BACK

Final Report Defense 021509

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