Operations management siib

Production Viewed as a System

Su

pp

liers

of

Ma

teri

als

an

d

Eq

uip

men

t

Receipt and Test of Materials

Consumer FeedbackDesign and Re - design

Distribution

Production Assembly Inspection

Tests of Processes , Machines , Methods , Costs

“ I believe this Diagram made the difference in Japan….the greatest way I accomplished anything there was through this diagram ” W. Edwards Deming

Foundation of Modern Operations Management

Customers

Energy 30 crores per hourTelecommunication 20 crores per hourManufacturing 17.5 crores per hourFinancial 15 crores per hourInformation Technology 15 crores per hourInsurance 12.5 crores per hourRetail 10 crores per hourPharmaceutical 7.5 crores per hour

A META Group Study

Evolution of Operations Management

• Hunting• Planned approach towards slaying and hunting living

creatures in defence or for consumption• Agriculture

• Organising and coordinating groups of people to carry out tasks in the fields

• Military Operations• Regimented organisation of groups of people established to

protect a settlement from tyranny or conquer • Creation of Professions

• Essentially artisans who developed and passed on ‘trade secrets’ within their immediate families

• Handcrafting products or services for individual customers• Guilds

• Structured group of people involved with the same profession creating their own ‘set of rules’

Pre – Industrial Revolution Era


Harnessing of Steam Energy• James Watt

The First ‘Steam Engine’• George Stevenson

The First Steam Machine• Ginning Machines by Eli Whitney

Division of labour• Economist Adam Smith conceives Division of Labour

Interchangeable parts• Eli Whitney invents interchangeability of parts

Industrial Revolution


Principles of Scientific Management• Fredrick W. Taylor

Time and Motion Studies• Frank and Lillian Gilbreth

Activity Scheduling• Henry Gantt

The Moving Assembly Line• Henry Ford

Industrial Revolution


The Focus• Work Breakdown Structures• One best Way of carrying out Processes• Piece Rate System

• Elton Mayo• Abraham Maslow• Fredrick Herzberg• Douglas McGregor

The rise of Motivational Theorists

The Outcomes

• The Meteoric Rise of Financial Accounting• Extensive interest in Advertising and Branding


The Return of Operations

The Quality Revolution in Japan• W. Edwards Deming and Joseph M. Juran

The Development of the Toyota Production System• Eigi Toyoda , Taichi Ohno and Shiego Shengo

Modern Trends in Operations• Business Process Reengineering• Six Sigma

Operations in Today’s World

The Internet Revolution•E – Commerce •E – Businesses

B2BOEMs or ‘First Fit’ Businesses

B2CFranchises

C2BConsultation

C2CeBay,Portals,etc

Globalisation of tradeGlobalisation of Operations ( Development of the Virtual Organisation )

Definition of Operations Management

Production Management aims at achieving Production in the most efficient and effective manner .

Operations Management is the system of Selecting , Designing , Running and Improving all transformational processesTransformational processes include :

Governmental – Creating and Running Societal StructuresPhysical – ManufacturingExchange – Retail Operations , BanksLocational – Logistics and Transportation Physiological – Healthcare and HospitalityPsychological – EntertainmentInformational – Communication , InterpretationEducational – Structured Knowledge Transfer

Production is the outcome of the combination of different transformational processes ( operations ) aimed at meeting desired Customer needs .

Transformational Processes

Go

vern

men

tal

Ph

ysic

al

Exc

han

ge

Ph

ysio

log

ical

Psy

cho

log

ical

Lo

cati

on

al

Info

rmat

ion

al

Ed

uca

tio

nal

Org

anis

atio

ns

Operations

Pro

du

ctio

n

The Need for Operations Management in today’s World

In the ever changing Business Scenario in today’s fast developing world where we are witnessing

• Incessant Fragmentation of Markets• Highly Informed and Vocal Customers• Creation of Disruptive Technologies resulting in Specialised Knowledge

• Volatile Inter – Organisational Relationships

Objectives of Operations Management

Strategy – Gaining a Competitive Edge

Processes and Systems – Alignment of Back-end activities

Quality – Scientific Methods to Create and Deliver Products / Services

Improvement – A Constant effort to challenge the Status Quo / Obvious

• Topic 1 – Introduction to Operations Management

• Topic 2 – Facility Location

• Topic 3 – Facility ( Plant ) Layout

• Topic 4 – Production Planning and Control

• Topic 5 – Materials Handling

• Topic 6 – Work Study

• Topic 7 – Systematic Maintenance

• Topic 8 – Quality Management

• Topic 9 – Modern Techniques in Operations Management

Regional Location Factors

• Business climate• Proximity to customers• Number of customers• Availability of sites• Land cost• Construction / leasing costs• Infrastructure (e.g., roads, water, sewers)• Financial services • Community incentives• Community services• Governmental Incentive• Government regulations• Environmental regulations

Regional Location Factors

• Labour (availability, education, cost, and unions)• Modes and Quality of transportation• Transportation costs• Local business regulations• Government services (e.g., Chamber of Commerce)• Raw material availability• Commercial travel• Climate • Quality of life• Taxes• Proximity of suppliers• Education system

Global Location Factors

• Government stability• Government regulations• Political and economic systems• Economic stability and growth• Exchange rates• Culture• Climate• Export import regulations• Duties and tariffs• Raw material availability • Number and proximity of suppliers

Global Location Factors

• Transportation and distribution system• Labour cost and education• Available technology• Commercial travel• Technical expertise• Cross-border trade regulations• Group trade agreements

Heavy-manufacturing facilities

Large, require a lot of space, and are expensive

Light-industry facilities

Smaller ( as compared to Large Industries ), cleaner plants and usually less costly

Retail and service facilities

Smallest and least costly

Types of Facilities

Multiattribute Preference Theory ( Location Rating Factor ) for Local Sites

•Is used when choices are available• Has no ‘scientific’ basis – just an ‘agreed upon’

weighted technique

Location Analysis Techniques

Attribute Weight

Labour Force 0.30

Proximity to Customers

0.20

Wage Rates 0.15

Proximity to Suppliers 0.15

Environment 0.10

Modes of Transport 0.05

Community Support 0.05


Guidelines for Scores : Labour Force

Highly Skilled75 –

100

Adequately Skilled 50 – 75

Semi Skilled 25 – 50

Unskilled 0 – 25


Guidelines for Scores : Proximity to Customers

Within 15 kilometres75 –

100

Between 15 to 30 kilometres 50 – 75


Above 50 kilometres 0 – 25


Guidelines for Scores : Wage Rates

Upto 10 % of total cost75 –

100

Between 10 – 15 % of total cost50 –

75

Between 15 – 20 % of total cost25 –

50

Above 20 % of total cost 0 – 25


Guidelines for Scores : Proximity to Suppliers

Within 15 kilometres75 –

100



Above 50 kilometres 0 – 25


Guidelines for Scores : Environment

Conducive to Ceaseless Productive Work75 –

100

Conducive to Productive Work over 25 % 50 – 75

Conducive to Productive Work for a day 25 – 50

Conducive to Productive Work for less than a day

0 – 25


Guidelines for Scores : Modes of Transport

Access to any two modes of transport at any given moment

75 – 100

Access to any one mode of transport at any given moment

50 – 75

Need to plan a day in advance for any mode of transport

25 – 50

Need to plan more than a day in advance for any mode of transport

0 – 25


Guidelines for Scores : Community Support

Extremely harmonious relationships with communities in close proximity

75 – 100

Have Legal relationships with communities in close proximity

50 – 75

Have dispassionate relationships with communities in close proximity

25 – 50

Have hostile relationships with communities in close proximity

0 – 25

Example

A company wanting to relocate its operations has assessed three sites and have tabulated the following results

Attribute Site 1 Site 2 Site 3

Labour Force 70 60 90


80 90 75

Wage Rates 60 95 70

Proximity to Suppliers 75 80 80

Environment 65 90 95

Modes of Transport 85 90 65

Community Support 80 65 90

Which Site qualifies based on the Multiattribute Preference Theory ?

AttributeWei

ghtSit

e 1Site 2

Site 3

Labour Force 0.30 70 60 90


0.20 80 90 75

Wage Rates 0.15 60 95 70

Proximity to Suppliers

0.15 75 80 80

Environment 0.10 65 90 95

Modes of Transport 0.05 85 90 65

Community Support 0.05 80 65 90

Using Weights ascribed we get

Weighted Scores

Attribute Site 1 Site 2 Site 3

Labour Force 21.00 18.00 27.00


16.00 18.00 15.00

Wage Rates 9.00 14.25 10.50

Proximity to Suppliers

11.25 12.00 12.00

Environment 6.50 9.00 9.50

Modes of Transport 4.25 4.50 3.25

Community Support

4.00 3.25 4.50

Scores : Site 1 – 72.00 ; Site 2 – 79.00 ; Site 3 – 81.75

Site 3 – The preferred location

Typical Attributes that an MNC looks for in a Global Operations Site

Attribute Weight

Political Stability 0.25

Economic Growth 0.20

Port Facilities 0.13

Airline Support 0.10

Trade Regulations 0.08

Duties and Tariffs 0.08

Container Support 0.07

Transportation / Distribution

0.05

Area Roads 0.02

Land and Construction Cost

0.02

Centre of Gravity Technique

Normally used in computing location of sites for Warehouses / Distribution Centres

Current Location is set as ( 0 , 0 ) on a Cartesian Plane

Average Annual Despatch Loads to different sites are indicated in parenthesis

Distribution Site co-ordinates are computed accordingly

A Pictorial Representation in the form of a Graph is drawn

x1 x2 x3 x

y2

y

y1

y3

1 (x1, y1), W1

2 (x2, y2), W2

3 (x3, y3), W3

Current Site of Operations

Co-ordinates of New Location ( x , y ) are computed thus

x =(x1)(W1) + (x2)(W2) + (x3)(W3)

W1 + W2 + W3

y =(y1)(W1) + (y2)(W2) + (y3)(W3)

W1 + W2 + W3

A B C Dx 200 100 250 500y 200 500 600 300Wt 70 100 130 60

y

700

500

600

400

300

200

100

0 x700500 600400300200100

A

B

C

D

(130)

(100)

(70)

(60)

Kilometres

Kil

om

etre

sExample

Co-ordinates of New Location ( x , y ) are computed thus

x =(200)(70) + (100)(100) + (250)(130) + (500)(60)

70 + 100 + 130+ 60

= 240

y =(200)(70) + (500)(100) + (600)(130) + (300)(60)

70 + 100 + 130+ 60

= 444

y

700

500

600

400

300

200

100

0 x700500 600400300200100

A

B

C

D

(130)

(100)

(70)

(60)

Kilometres

Kilo

met

res

( 240 , 444 )

Location of the Warehouse

Load Distance Technique

Variation of the Centre of Gravity Technique

Used when Options available for Sites

Use of the Straight Line concept ( Based on Geometric Distance Formula )

∑ li di

i = 1

n

LD =

LD = load-distance value

li = load expressed as a weight being despatched

di = distance between proposed site and location i

di = (xi - x)2 + (yi - y)2 (x,y) = coordinates of proposed site

(xi , yi) = coordinates of existing facility

A B C Dx 200 100 250 500y 200 500 600 300Wt 70 100 130 60

Potential SitesSite X Y1 360 1802 420 4503 250 400

Suppliers


= (200-360)2 + (200-180)2

dA = (xA - x1)2 + (yA - y1)2

Computing distances for Site 1

= 161.2

= (100-360)2 + (500-180)2

dB = (xB - x1)2 + (yB - y1)2

= 412.3

= (250-360)2 + (600-180)2

dC = (xC - x1)2 + (yC - y1)2

= 434.16

= (500-360)2 + (300-180)2

dD = (xD - x1)2 + (yD - y1)2

= 184.31

Load Distance = (70)*(161.2)+(100)*(412.3)+(130)*(434.16)+(60)*(184.31)

= 120019.2

A B C Dx 200 100 250 500y 200 500 600 300Wt 70 100 130 60

= (200-420)2 + (200-450)2

dA = (xA – x2)2 + (yA – y2)2

Computing for Site 2

= 333.02

= (100-420)2 + (500-450)2

dB = (xB – x2)2 + (yB – y2)2

= 323.88

= (250-420)2 + (600-450)2

dC = (xC – x2)2 + (yC – y2)2

= 226.71

= (500-420)2 + (300-450)2

dD = (xD – x2)2 + (yD – y2)2

= 170

Load Distance = (70)*(333.02)+(100)*(323.88)+(130)*(226.71)+(60)*(170)

= 97036.8


A B C Dx 200 100 250 500y 200 500 600 300Wt 70 100 130 60

= (200-250)2 + (200-400)2

dA = (xA – x3)2 + (yA – y3)2

Computing for Site 3

= 206.19

= (100-250)2 + (500-400)2

dB = (xB – x3)2 + (yB – y3)2

= 180.27

= (250-250)2 + (600-400)2

dC = (xC – x3)2 + (yC – y3)2

= 200

= (500-250)2 + (300-400)2

dD = (xD – x3)2 + (yD – y3)2

= 269.25

Load Distance = (70)*(206.19)+(100)*(180.27)+(130)*(200)+(60)*(269.25)

= 74614.8


A B C Dx 200 100 250 500y 200 500 600 300Wt 70 100 130 60

Facility LayoutsDefinition of Facility Layout

Planned arrangement of areas within a facility commensurate with the product to be realised or service to be delivered

Objectives of Facility Layout

• Optimise material-handling ( transaction ) costs• Utilise space efficiently• Utilise manpower efficiently• Work around bottlenecks• Facilitate interaction• Reduce cycle time• Reduce customer turnaround time• Eliminate redundant movement• Increase capacity• Provide for entries, exits, placement of material ( in all stages

of realisation ), finished goods, and people

Facility Layouts

Objectives of Facility Layout ( continued )

• Incorporate safety and security measures• Promote product and service Quality• Facilitate proper maintenance activities• Provide for visual control• Provide for flexibility to adapt to changing conditions

Different Organisational Layout Representations

• Departmental Layout • Material Flow Layout• Equipment Layout• Transportation and Handling Layout• Utilities Layout• Communication Channel Layout

Basic Types of Layouts

Fixed-position layoutsare used where product cannot be moved

Used for Large Products and ProjectsUsually ‘one-of-a-kind’ products or projects

Process layoutsgroup similar activities together according to process or function they perform

Traditional Type of LayoutSuitable for Mass Production

Product layoutsarrange activities in line according to sequence of operations for a particular product or service

Modern Approach toward Creating LayoutsMore inclined towards Mass Customisation

Fixed-position layouts

Typically manufacture of Construction Projects , Rocket Launchers , Space Shuttles , Aircrafts , Ships , Surgeries , “Events”

Equipment, workers, materials, other resources brought to site

Highly skilled labour

Process Layout - Bookstore

Video CDs , DVDs

Cookbooks

Children’s Books

Cassettes

Billing and Information

Entry and display area

Audio CDs , DVDs

Technical and

Management Section

Coffee Shop

L

L

L

L

L

L

L

L

L

LM

M

M

M

D

D

D

D

D

D

D

D

G

G

G

G

G

G

A A AReceiving andShipping Assembly

Painting Department

Lathe Section Milling Section Drilling Section

Grinding and Finishing

P

P

Process Layout - Manufacture

Product A Product B

InIn OutOut

Product Layout - Manufacture

Product A

Product B

InIn OutOut

InIn OutOut

Product C

Comparisons between Product and Process Layouts

Product Layout Process Layout

• Sequential arrangement of Activities

• Intermittent work

• Adaptable Machinery

• Workers are extensively cross-trained

• Occupy smaller areas

• Highly flexible lines

• Lesser travel time

• Functional Grouping of Activities

• Continuous work

• General Purpose Machinery

• Workers are trained in a particular process

• Occupy larger areas

• Largely Rigid

• More travel time

Designing Layouts

Relationship Diagramming

• based on location preference between areas

• used when quantitative data is not available

• Schematic diagram that uses weighted lines to denote location preference

Use of a grid called “Muther’s grid”

Muther’s Grid

Different Sections / Areas in an organisation

Extent of their Interactions / Relationships

Production

Offices

Stockroom

Shipping and receiving

Locker room

Toolroom

A

A

O

U

O

O

U

A

U

O

E

U

I

X

O

A Absolutely necessaryE Especially importantI ImportantO OkayU UnimportantX Undesirable

Original layout

Offices

Stockroom

Locker room

Toolroom

Shipping and

receiving

Production

AEIOUX

Relationship diagram of original layout

Offices

Stockroom

Locker room

Toolroom


Production

AEIOUX

Production – 2 ‘Absolutely Necessary’ transactions ; 1 ‘Especially Important’ transaction ; 1 ‘Important’ transaction ; 1 ‘Okay’ transaction

Therefore Production needs to be centrally located with the other departments around it .

Solution 1

Offices

Stockroom

Locker room

Toolroom


Production

A EIOUX

Solution 2

Offices

Stockroom

Toolroom

Locker room


Production

AEI

OUX

Block Diagramming

Purpose is to minimise nonadjacent loadsUsed when quantitative data is available

Steps :

• Create load summary chart

• Calculate composite (two way) movements

• Develop trial layouts minimising number of nonadjacent loads

1 2 3 4 5

1 - 100 50 - -

2 - - 200 50 -

3 60 - - 40 50

4 - 100 - - 60

5 - 50 - - -

To

From

Load Summary Chart

Movement Total Load2 ↔ 3 200 2 ↔ 4 150 1 ↔ 3 110 1 ↔ 2 100 4 ↔ 5 60 3 ↔ 5 50 2 ↔ 5 50 3 ↔ 4 40 1 ↔ 4 0 1 ↔ 5 0

Composite Movements

1 2 3

4 5

Arranged in a 2x3 Grid

1 2 3

4 5

100 200

110

60

50150 50

40

1 2 4

53

100 150

200

50

60

40

110

Blocks Rearranged with Non-adjacent loads cancelled out

Cellular Layouts

Identify outputs with similar flow pathsGroup processes into cells based on outputArrange cells so transactions are minimisedLocate shared processes at point of use

Original Machine Layout

1 3

4

5

6 7

8

9

10

11

122

Original Process Layout

CA B Inputs

Outputs

1

2

3

4

5

6 7

8

9

10

11

12

Determine Flow Logic

A : 1 – 2 – 4 – 8 – 10B : 5 – 7 – 11 – 12 C : 3 – 6 – 9 D : 1 – 2 – 4 – 8 – 10E : 5 – 6 – 12 F : 1 – 4 – 8 G : 3 – 6 – 9 – 12 H : 7 – 11 – 12

Products

WorkstationsV

alue1 2 3 4 5 6 7 8 9

10

11

12

A X X X X X

B X X X X

C X X X

D X X X X X

E X X X

F X X X

G X X X X

H X X X

ValuValuee

Part Routing Matrix

Create Binary AlgorithmThe procedure works like this :

• Assign a value to each column ‘k’ , where the value is 2N-k N = total number of workstations ; k = chronological workstation number

• For each row obtain a sum by adding the 2N-k values• Rearrange the rows in the decreasing order of the

sums obtained• Assign a value to each row ‘k’ where the value is 2M-k

M = total number of products ; k = chronological ( rearranged ) sequence number of the product

• For each column obtain a sum by adding the values• Rearrange the columns in decreasing order of the

sums obtained

Products

WorkstationsV

alue1 2 3 4 5 6 7 8 9

10

11

12

A 2048

1024

256

16

43

348

B 128

32

2 11

63

C 512

64

85

84

D 2048

1024

256

16

43

348

E 128

64

11

93

F 2048

256

16

2320

G 512

64

8 15

85

H 32

2 13

5ValuValuee

Part Routing Matrix

Products

WorkstationsV

alue1 2 3 4 5 6 7 8 9

10

11

12

A 2048

1024

256

16

43

348

D 2048

1024

256

16

43

348

F 2048

256

16

2320

G 512

64

8 15

85

C 512

64

85

84

E 128

64

11

93

B 128

32

2 11

63

H 32

2 13

5ValuValuee

Part Routing Matrix

Products

WorkstationsV

alue1 2 3 4 5 6 7 8 9

10

11

12

A X X X X X

D X X X X X

F X X X

G X X X X

C X X X

E X X X

B X X X X

H X X X

ValuValuee

Part Routing Matrix

Products

WorkstationsV

alue1 2 3 4 5 6 7 8 9

10

11

12

A1

281

281

281

281

28

D6

46

46

46

46

4

F3

23

23

2

G1

61

61

61

6

C 8 8 8

E 4 4 4

B 2 2 2 2

H 1 1 1

ValuValuee

222424

119292

2244

222424 66

2288

3322

242422

4411

9292 3322

33

Part Routing Matrix

Products

WorkstationsV

alue1 4 8 2

10

6 3 91

25 7

11

A1

281

281

281

281

28

D6

46

46

46

46

4

F3

23

23

2

G1

61

61

61

6

C 8 8 8

E 4 4 4

B 2 2 2 2

H 1 1 1

ValuValuee

222424

222424

222424

119292

119292

2288

2244

2244

2233

66 33 33

Part Routing Matrix

Products

Workstations

1 4 8 21

06 3 9

12

5 71

1

A X X X X X

D X X X X X

F X X X

G X X X X

C X X X

E X X X

B X X X X

H X X X

Part Routing Matrix

3

6

9

Outputs

12

4

8 10

5

7

11

12

A B C

Inputs

Cell 1 Cell 2 Cell 3

Revised Layout

Flow Logic

A : 5 – 6 – 8 B : 5 – 6 – 8 – 9 C : 2 – 4 – 5 – 7 D : 1 – 3 E : 5 – 6 F : 1 – 3 – 4 G : 4 – 5 – 6 – 8 - 9 H : 2 – 4 – 7

Products

WorkstationsV

alue1 2 3 4 5 6 7 8 9

A X X X

B X X X X

C X X X X

D X X

E X X

F X X X

G X X X X X

H X X X

ValueValue

Part Routing Matrix

Products

WorkstationsV

alue1 2 3 4 5 6 7 8 9

A1

68 2

26

B1

68 2 1

27

C1

283

21

64

180

D2

566

43

20

E1

68

24

F2

566

43

23

52

G3

21

68 2 1

59

H1

283

24

164

ValueValue

Part Routing Matrix

Products

WorkstationsV

alue1 2 3 4 5 6 7 8 9

F2

566

43

23

52

D2

566

43

20

C1

283

21

64

180

H1

283

24

164

G3

21

68 2 1

59

B1

68 2 1

27

A1

68 2

26

E1

68

24

ValueValue

Part Routing Matrix

Products

WorkstationsV

alue1 2 3 4 5 6 7 8 9

F X X X

D X X

C X X X X

H X X X

G X X X X X

B X X X X

A X X X

E X X

ValueValue

Part Routing Matrix

Products

WorkstationsV

alue1 2 3 4 5 6 7 8 9

F1

281

281

28

D6

46

4

C3

23

23

23

2

H1

61

61

6

G 8 8 8 8 8

B 4 4 4 4

A 2 2 2

E 1 1

ValueValue 119292

4488

119292

118484

4477

1155

4488

1144

1122

Part Routing Matrix

Products

WorkstationsV

alue1 3 4 2 7 5 6 8 9

F1

281

281

28

D6

46

4

C3

23

23

23

2

H1

61

61

6

G 8 8 8 8 8

B 4 4 4 4

A 2 2 2

E 1 1

ValueValue 119292

119292

118484

4488

4488

4477

1155

1144

1122

Part Routing Matrix

Products

Workstations

1 3 4 2 7 5 6 8 9

F X X X

D X X

C X X X X

H X X X

G X X X X X

B X X X X

A X X X

E X X

ValueValue

Part Routing Matrix

1 3

2 4 7

5 6 8 9

InInOutOut

Worker 1

Worker 2

Worker 3

Direction of part movement within cell

S

L

HM

VM

G

VM

L

Final inspection

Finished part

S = SawL = LatheHM = Horizontal milling machineVM = Vertical milling machineG = Grinder

Paths of three workers moving within cell

Material movement

Service Layouts

• Usually process layouts respond to customer needs

• Minimise flow of customers or transactions

• Retailing tries to maximise customer exposure to products

• Layouts must be aesthetically pleasing

Types of Layouts for Service Organisations

Freeflow Layout


Grid Layout


Spine Layout


Loopy Layout

Types of Production Processes

Criteria for Selection of Processes

Nature of the Inputs and Outputs Perishable and Non – Perishable

Quantum of Production One – of Few Numbers Mass

Nature of Operations Continuous Processes Intermittent Processes

Capacity of the PlantRestrictions in Space , Equipment , Labour , Technology


Types of Processes

Jobbing / Project Type MethodThis method is used where , although the Processes remain the same , the outputs are unique in nature .

Example : Construction Projects , Film Making , Job Shops

Features of this Approach• One – of or Very Small Quantity of Production• Highly Skilled Workforce• General Purpose Equipment• Unbalanced Processing• High Cost of Production


Types of Processes

Batch Type ApproachThis method is used where a limited amount of products ( batches ) are produced at a time either continuously or intermittently .

Example : Chemicals , Pharmaceuticals , Paints , Foods and some types of metal items

Features of this Approach• Fixed Quantities Produced• Semi – Skilled Workforce• General Purpose Equipment• Balanced Processing• Low Cost of Production


Types of Processes

Mass ProductionThis method is used where a very large amount of products ( batches ) are produced at a time either continuously .

Example : Engineered Products , Fertilisers

Features of this Approach• Very Large Quantities Produced• Semi – Skilled Workforce• General Purpose Equipment• Very High Flows• Low Cost of Production


Types of Processes

Process Based ProductionThis method is used where Bulk items are producedExample : Sugar , Aluminium , Zinc , Iron and Steel

Features of this Approach• Bulk Items Produced• Semi – Skilled Workforce• General Purpose Equipment• Very High Flows• Low Cost of Production

K

PRODUCT MIX

Jumbled

PR

OC

ES

S P

AT

TE

RN

Jumbled But Dominant

Line Flow

Continuous Flow

One of Low Volume High Volume Mass

Project Job Shop

Batch

Line

Continuous

Ways of Doing Work

Production Planning and ControlIntroduction

• Coordination of materials function with suppliers

• Efficient utilisation of people and machines

• Efficient flow of materials within the organisation

The “Seepok” Model

Inputs

Production

Outputs

Suppliers Customers

S I P O C

Decision Support

• PPC system does not make decisions but provides support for decision making

• Managers make decisions

Software for Decision Support• Software not only to support decision

makers but also make some of the decisions• Expert Systems • Neural Networks • Algorithms • Evolutionary Programming • Genetic Programming • Tabu Search• Simulated Annealing

Activities

• Materials Planning• Purchasing• Raw Material Inventory Control• Capacity Planning• Scheduling Machine and People• Work-in-Process (WIP) Inventory Control• Coordinate Customer Orders• Finished Goods Inventory Control

Ill-effects of a lack of PPC

• poor customer service• excessive inventories• low equipment and people utilisation• high rate of part obsolescence• large number of expediters

Work Study

Specifications

Inventory Management

Production Planning and Control

Routing LoadingSchedulin

gDespatching

Expediting

Production Plan

Routing

• Determine the Processes to be followed• Determine the Sequence of the Processes• Determine the Flow of Materials / Activities

Loading

• Determine the Number of Workstations• Determine their operational characteristics ( speeds ,

capabilities )• Selection of Workstations• Creating a Contingency Plan

Scheduling

• Determining the exact time at which the Operations will materialise

• Timing the arrival of material ( finished / semi-finished part at different workstations )

• Usually done on a ‘Gantt Chart’

Despatching

• Creating Work Orders• Creating Shop Travellers• Issuing Authorisations

Expediting

• Creating Routine Reports• Creating Check Points• Follow up

Master Production Scheduling

Detailed Material Planning

Material and Capacity Plans

Purchase Order

Demand Management

Resources Planning

Rough-Cut Capacity Planning

Detailed Capacity Planning

Work Order

Production Planning and ControlGeneral Framework

• Forecasting• Order Processing• Order Acceptance• Order Confirmation

Demand Management

• Long-Range Capacity Requirements• Number of Plants• Number of Workstations• Number of Employees• Shifts• Overtime

Resource Planning

Production Planning

Plans for Product FamiliesMaster Planning Schedule ( MPS )

Anatomy of a Plan

Annual Plan

Quarterly PlanMonthly Plan

Fortnightly Plan

Fixed Could be subject to minor changes

Capacity Requirement Planning for Master Production Scheduling• Open Orders• Planned Orders• Resource Profiles

Rough-Cut Capacity Planning

Inputs :• Master Production Schedule (MPS) • Bill of Materials (BOM)• Inventory Status• Leadtime (LT)

Detailed Materials PlanningMaterials Requirements Planning

Shows the constituent components and how many of those are required to build the composite part

Bill of Material (BOM)

Product Structures and Parts

C

A B

X X Y

Finished Product

Manufactured Part

Sub Assembly

Purchased Parts

Single Level Bill of Material

Level 0 Parent A

Level 1 Component X X 2

2 units of component X are used to make 1 unit of item A

Indented Bill of Material ( BOM ) for A is

Level

Part ( nos )

0 A ( 1 )

1 X ( 2 )


Level 0 Parent B

Level 1 Component X X 2

2 units of component X and 1 component of Y are used to make 1 unit of item B

Indented Bill of Material ( BOM ) for B is

Level

Part ( nos )

0 B ( 1 )

1 X ( 2 )

1 Y ( 1 )

Level 1 Component Y X 1


Level 0 Parent C

Level 1 Component A X 2

2 units of component A and 3 components of B are used to make 1 unit of item C

Indented Bill of Material ( BOM ) for C is

Level

Part ( nos )

0 C ( 1 )

1 A ( 2 )

1 B ( 3 )

Level 1 Component B X 3

Multi Level Bill of Material

Level 0 Parent C

Level 1 2 x A

Level 2

3 x B

2 x X 2 x X 1 x Y

Summary Bill of Material

Level PartCumulati

ve

0 C 1

1 A 2

2 X 4

1 B 3

2 X 6

2 Y 3

Summary BOM for C

X 10

Y 3

Create a BOM for a Two layered McDonald’s Maharaja Mac

Bottom Bun Patty Sauce Lettuce

Bottom Bun Sub Assembly

Cheese Patty Onions

Middle Bun Sub Assembly

Sesame Seed Top bun

Middle Bun

Inventory Status

On Hand (OH) QuantityWhat is physically available in the warehouse

On Order or Scheduled Receipt (SR)What has been ordered but not received ( transitory )

Allocated Inventory (AI)What is in the warehouse but reserved for existing orders (i.e., not available to be used for incoming orders)

Time between placing an order and receiving the partsParts could be •Purchased – Dependant on Vendor•Manufactured or assembled in house – Dependant on Process / Manufacturing Personnel

Leadtime

Leadtime Offsetting

1.Front Schedule ApproachSchedule as early as possibleAdvantage: Minimise risk of shortageDisadvantage: Higher Inventory Levels

2.Back Schedule ApproachSchedule as late as possibleAdvantage: Minimise InventoryDisadvantage: Higher Risk of Shortage

Gross Requirements – Derived from the MPS of the Parent Part

Scheduled Receipts – On Order or Scheduled to be received

On Hand – Physical Available Inventory

Allocated Inventory – Inventory scheduled to be used

Nett Requirements – Actual Quantities Required

Planned Order Receipts – Offset time when Materials are needed

Planned Order Releases – Offset Time when materials need to be ordered ( function of lead time )

Important Terms / Conventions used in MRP

HeadingWeek Number

1 2 3 4 5

Gross Requirements 85 95

120

100

100

Scheduled Receipts

175

On Hand 45

Allocated Inventory 20

Nett Requirements

Planned Order Receipts

Planned Order Releases

MRP Matrix

HeadingWeek Number

1 2 3 4 5


120

100

100

Scheduled Receipts

175

On Hand 4511

5


Nett Requirements 0



MRP Matrix

MRP Matrix

HeadingWeek Number

1 2 3 4 5


120

100

100

Scheduled Receipts

175

On Hand 4511

520


Nett Requirements 0 0



MRP Matrix

HeadingWeek Number

1 2 3 4 5

Gross Requirements

85

95

120

100

100

Scheduled Receipts

175

On Hand4

51

152

0

Allocated Inventory

20


100


100


100

MRP Matrix

HeadingWeek Number

1 2 3 4 5

Gross Requirements

85

95

120

100

100

Scheduled Receipts

175

On Hand4

51

152

0

Allocated Inventory

20


100

100


100

100


100

100

MRP Matrix

HeadingWeek Number

1 2 3 4 5

Gross Requirements

85

95

120

100

100

Scheduled Receipts

175

On Hand4

51

152

0

Allocated Inventory

20


100

100

100


100

100

100


100

100

100

Detailed Capacity PlanningCapacity Requirements Planning

Creates a load profileIdentifies under-loads and over-loadsInputs

Planned order releasesRouting fileOpen orders file

Routing File

Inputs• Flow Time• Cycle Time• Number of Workstations• Capabilities of Work Stations

Scheduling

Last stage of planning before production occursSpecifies when labour, equipment, facilities are needed to produce a product or provide a service

Objectives in Scheduling

Meet customer due datesMinimise response timeMinimise completion timeMinimise time in the systemMinimise overtimeMinimise work-in-process inventory

Shop Floor Control

LoadingCheck availability of material, machines and labour

SequencingRelease work orders to shop and issue despatch lists for individual machines

MonitoringMaintain progress reports on each job until it is complete

Loading

Process of assigning work to limited resourcesPerform work on most efficient resources

Assignment MethodPerform row reductions

subtract minimum value in each row from all other row values

Perform column reductionssubtract minimum value in each column from all other column values

Cross out all zeros in matrixuse minimum number of horizontal and vertical lines to cover all the 0s

If number of lines equals number of rows in matrix then optimum solution has been found. Make assignments where zeros appearElse modify matrix

subtract minimum uncrossed value from all uncrossed valuesadd it to all cells where two lines intersectother values in matrix remain unchanged

Repeat steps 3 through 5 until optimum solution is reached

Name

Time taken for completing the task

1 2 3 4Duryodhan 10 5 6 10

Dushyasan 6 2 4 6

Jarasandha 7 6 5 6

Jayadratha 9 5 4 10

Example

Name


1 2 3 4Duryodhan 5 0 1 5

Dushyasan 4 0 2 4

Jarasandha 2 1 0 1

Jayadratha 5 1 0 6

Step 1 - Row Reduction

Name


1 2 3 4Duryodhan 3 0 1 4

Dushyasan 2 0 2 3

Jarasandha 0 1 0 0

Jayadratha 3 1 0 5

Step 2 - Column Reduction

Name


1 2 3 4Duryodhan 3 0 1 4

Dushyasan 2 0 2 3

Jarasandha 0 1 0 0

Jayadratha 3 1 0 5

Step 3 - Cover all Zeros

Number of Lines = 3 ; Number of Rows = 4Modify Matrix

NameTime taken for

completing the task

1 2 3 4

Duryodhan

3 0 1 4

Dushyasan

2 0 2 3

Jarasandha

0 1 0 0

Jayadratha

3 1 0 5

Step 4 - Modify the Matrix

Take the lowest value in the ‘uncovered’ cells ( in this case = 2 ) and reduce the column to which it belongsAdd this value to the values of the intersecting cells as shown

Name


1 2 3 4Duryodhan 1 0 1 4

Dushyasan 0 0 2 3

Jarasandha 0 3 2 0

Jayadratha 1 1 0 5

Step 5 - Select the Tasks

Name


1 2 3 4Duryodhan 10 5 6 10

Dushyasan 6 2 4 6

Jarasandha 7 6 5 6

Jayadratha 9 5 4 10

Example

Name


1 2 3 4Savani 20 90 40 10Vidhey

a 40 45 50 35

Antara 30 70 35 25Amala 60 45 70 40

Example

Name


1 2 3 4Savani 10 80 30 0Vidhey

a 5 10 15 0

Antara 5 45 10 0Amala 20 5 30 0

Step 1 - Row Reduction

Name



a 0 5 5 0

Antara 0 40 0 0Amala 15 0 20 0

Step 2 - Column Reduction

Name



a 0 5 5 0

Antara 0 40 0 0Amala 15 0 20 0

Step 3 - Cover all Zeros

Number of lines = Number of Rows

Name



a 0 5 5 0

Antara 0 40 0 0Amala 15 0 20 0

Step 4 - Select the Tasks

Name


1 2 3 4Savani 20 90 40 10Vidhey

a 40 45 50 35

Antara 30 70 35 25Amala 60 45 70 40

Step 5 - Assign Jobs

Sequencing

Prioritise jobs assigned to a resourceStandardised Sequencing Rules

Sequencing Rules

FCFS - first-come, first-servedLCFS - last come, first servedDDATE - earliest due dateCUSTPR - highest customer prioritySETUP - similar required setupsSLACK - smallest slackCR - critical ratioSPT - shortest processing timeLPT - longest processing time

Sequencing Jobs Through Two Serial Processes

Johnson’s Rule

List time required to process each job at each machine. Set up a one-dimensional matrix to represent desired sequence with number of slots equal to number of jobs.

Select smallest processing time at either machine. If that time is on machine 1, put the job as near to beginning of sequence as possible.

If smallest time occurs on machine 2, put the job as near to the end of the sequence as possible.

Remove job from list.

Repeat steps 2-4 until all slots in matrix are filled and all jobs are sequenced.

Machines

Jobs

A B C D E F

M1 4 8 3 6 7 5

M2 6 3 7 2 8 4

C A F E B D

Johnson’s Rule

1 2 3 4 5 6 7 8 91

01

11

21

31

41

51

61

71

81

92

02

12

22

32

42

52

62

72

82

93

03

13

23

33

43

5

Machine 1

C A F E B D

Machine 2

C A F E B

D

Machines

Jobs

A B C D E

M1 10 12 8 15 16

M2 3 2 4 1 5

M3 5 6 4 7 3

M4 14 7 12 8 10

Example

C A E D B

Sequence

Machine 1

Machine 2

Machine 3

Machine 4

IDLE TIME

IN

OUT

IN

OUT

IN

OUT

IN

OUT

M1

M2

M3

M4

C 0 8 81

21

216

16

28 - 81

21

6

A 81

81

82

12

126

28

42 - 6 5 -

E1

83

43

43

93

942

42

52 -1

31

3-

D3

44

94

95

05

057

57

65 -1

08 5

B4

96

16

16

36

369

69

76 -1

16 4

N

IL4

84

42

5

MachinesJobs

A B C D

M1 4 3 1 3

M2 3 7 2 4

M3 7 2 4 3

M4 8 5 7 2

The Heuristic Method

Add the time taken on Machines 1 and 2 to create a ‘new’ MachineCompute similarly for Machines 3 and 4

Example

C A B D

Machines

Jobs

A B C D

M1 7 10 3 7

M2 15 7 11 5

Sequence

Machine 1

Machine 2

Machine 3

Machine 4

IDLE TIME

IN

OUT

IN

OUT

IN

OUT

IN

OUT

M1

M2

M3

M4

C 0 1 1 3 3 7 7 14 - 1 3 7

A 1 5 5 8 8 151

523 - 2 1 1

B 5 8 81

51

517

23

28 - - - -

D 81

11

51

91

922

28

30 - - 2 -

N

IL3 6 8

The following 6 jobs have the following Processing Times and Due Dates . Compare which of the following sequencing methods will be best suited for these jobs : FCFS , LCFS , DDATE , SPT

Example

Jobs

Processing Time

Due Date ( from now )

A 2 6

B 5 9

C 3 8

D 4 12

E 1 10

F 7 11

G 6 13

Jobs

Processing Time

Due Date ( from

now )

Total Flow Time

Delay

A 2 6 2 0

B 5 9 7 0

C 3 8 10 2

D 4 12 14 2

E 1 10 15 5

F 7 11 22 11

G 6 13 28 15

Solution

FCFS – First Come First Served

Average Flow Time = 14Average Delay = 5

Jobs

Processing Time

Due Date ( from

now )

Total Flow Time

Delay

G 6 13 6 0

F 7 11 13 2

E 1 10 14 4

D 4 12 18 6

C 3 8 21 13

B 5 9 26 17

A 2 6 28 22

Solution

LCFS – Last Come First Served

Average Flow Time = 18Average Delay = 9.14

Jobs

Processing Time

Due Date ( from

now )

Total Flow Time

Delay

A 2 6 2 0

C 3 8 5 0

B 5 9 10 1

E 1 10 11 1

F 7 11 18 7

D 4 12 22 10

G 6 13 28 15

Solution

DDATE – Earliest Due Date

Average Flow Time = 13.7Average Delay = 4.85

Jobs

Processing Time

Due Date ( from

now )

Total Flow Time

Delay

E 1 10 1 0

A 2 6 3 0

C 3 8 6 0

D 4 12 10 0

B 5 9 15 6

G 6 13 21 8

F 7 11 28 17

Solution

SPT – Shortest Processing Time

Average Flow Time = 12Average Delay = 4.42

Comparing the Methods of Sequencing with their Average Flow Time and Average Delays we get :

FCFS – 14 , 5LCFS – 18 , 9.14DDATE – 13.7 , 4.85SPT – 12 , 4.42

SPT , with the least Average Flow Time and Least Average Delay , is the chosen method .

Material Handling

Definition of Material Handling

The efficient and effective method of facilitating a controlled flow of product between locations and storing thereafter constitutes the activity of Material Handling

* the term product includes hardware , software , a combination thereof , people and information

Objectives of Material Handling

• To eliminate product damage• To enhance product flow• To optimise operating costs ( high volumes at lower

time frames )• To ensure asset protection• To ensure safety

Anatomy of Material Handling

The Logical flow of materials in a facility

Receiving Sorting Storage Pick-up

Packaging

Processing

Shipping

Important terms in Material Handling

• Distribution – The function of transporting finished goods in a safe condition to a separate storage facility or to the customer

• Storage – The act of safekeeping of goods and preserving them in a usable condition until they are required by another facility , workstation or the Customer

• Logistics – Combines the above activities and includes the flow of related information

Types of Product Movement ( flow )

Horizontal Product MovementThis movement takes place at a single level or elevation

• between workstations • between functional areas• between adjacent structures• within a warehouse

either at floor level , above floor level or overhead in the same facility or location

Types of Product Movement ( flow )

Vertical Product MovementThis movement takes place at multiple levels or elevations

• between workstations • between functional areas• between adjacent structures• within a warehouse

either at floor level , above the floor level , or overhead at the same facility location

Types of Transportation Concepts

The different types of Transportation Concepts are based on the following

• The Power Source• Weight and Load Carrying Capacity• Required Travel Space or Path• Volume handled• Ability to load and unload the goods


Above Floor Non powered Transportation Concept

These require Gravity Force or Human Power to facilitate product flow between locationsHorizontalThis concept is applied at a single level or elevation . Commonly used methods are

• Gradients ( from a higher level to lower level )• Ropeways• Chain-Pulley Blocks• Movable Frames• Weight Differentials• Wheels


Above Floor Non powered Transportation Concept

VerticalThis concept is applied at multiple levels or elevations . Commonly used methods are

• Gradients ( from a higher level to lower level )• Ropeways• Chain-Pulley Blocks• Weight Differentials• Wheels

Types of Transportation ConceptsAbove Floor Powered Transportation

Concept

These require an Electric Motor , Fuel Powered Motor , Air Pressure or Vacuum to propel a load carrying surface or product to facilitate product flow between locations

Horizontal

This concept is applied at a single level or elevation . Commonly used methods are

•Trolleys ( Electric Powered , Air Cushioned , Pneumatic , Hydraulic )

•Caddie Cars ( usually Electric Powered )•Pipes ( Vacuum powered )


Above Floor Powered Transportation Concept

VerticalThis concept is applied at multiple levels or

elevations . Commonly used methods are•Lifts ( Electric Powered , Pneumatic , Hydraulic )•Cable Cars ( usually Electric Powered )•Pipes ( Vacuum powered )


In Floor Non Powered Transportation Concept

These have a travel path that is embedded in the floor and utilise Gravity or Human Power to facilitate product flow between locations

HorizontalThis concept is applied at a single level or elevation . Commonly used methods are

•Trolleys on Rails•Cars on Specially Designed trenches•Gradient enabled Conduits


In Floor Non Powered Transportation Concept

VerticalThis concept is applied at multiple levels or elevations . Commonly used methods are

•Light Trolleys with Wall Scaling Rails•Gradient enabled Conduits


In Floor Powered Transportation Concept

These have a travel path that is embedded in the floor and require Electric Powered Motor and Fuel Powered Motor Trolleys besides Air Pressure to facilitate product flow between locations.

HorizontalThis concept is applied at a single level or elevation . Commonly used methods are

•Mini Trains on Rails•Cars on Specially Designed trenches•Vacuum Conduits


In Floor Powered Transportation Concept

VerticalThis concept is applied at multiple levels or elevations .

Commonly used methods are•Elevators•Escalators•Vacuum Conduits


Overhead Non Powered Transportation Concept

These are unique in characteristics in this that the travel path is above the floor level . These require Gravity or Employee power to facilitate product flow between locations. The support for the travel path is from the ceiling , the wall or from the floor with stands or racks . These facilitate movement from a higher to a lower gradient only .

•Slides•Tubes or pipes•Suspended Platforms


Overhead Powered Transportation Concept

These also have the travel path above the floor level . These require Electric Power , Air Pressure or vacuum to propel the load carrying surface or the product to facilitate flow between locations.

Horizontal Used for a single level or elevation•Conveyor Belts or Lines•Tubes or pipes ( vacuum powered )•Powered Platforms ( suspended )


Overhead Powered Transportation Concept

VerticalUsed for multiple levels or elevations•Conveyor Belts or Lines•Tubes or pipes ( vacuum powered )•Powered Platforms ( suspended )


Fixed Travel Path Transportation Concept

These are Load Carrying Surfaces that follow an orderly sequence or travel path through the facility . These are powered by an Electric Motor , air pressure or vacuum or computerised .

• Assembly lines• Trains or Cars• Fork lifts


Variable Travel Path Transportation Concept

These are Load Carrying Surfaces that do not follow an orderly sequence or travel path through the facility . These are powered by an Electric Motor or Fuel Powered Motors and are driven by employees .

•Cars•Fork lifts

Types of Activities

There are two types of activities in each of the Product Transportation concepts

•Static Activities•Dynamic Activities

Static ActivitiesStatic activities occur at a Workstation ( either at origination or at the culmination ) before the load carrying surface or the load is readied for transportation

Types of Activities

Dynamic ActivitiesDynamic activities occur at a workstation ( as before ) and during the transportation process ( as found fit ) at the instant the load carrying surface or the load is readied for transportation

Types of Activities

Static ActivitiesThese activities include•Compiling necessary information•Presenting the information in a comprehendible form

( to a person or a machine )•Issuing Authorisations accordingly

Types of Activities

Dynamic ActivitiesThese activities include• Readying the Product and / or the Load Carrying

Surface• Loading the Product / Surface• Despatching the Product / Surface

• manually• mechanised• automated

• Traversing the Path• Diverting wherever necessary• Ensuring correct halts• Unloading• Run Out

Concept Design Parameters

These Parameters include• Product Dimensions ( length , width , height , weight

, shape )• Product Quantities ( Volumes )• Product Mix ( based on processing , shapes ,

dimensions , despatch )• Open Space required for the Product or Load

Carrying Surface• Customer or Workstation ‘working’ space• Fragility of the Product• Crushability of the Product

Concept Design Parameters

• Transportation or traversed distance• Orientation of Traversed Distance• Goodness of Traversed Distance• Effort of the Traversed Distance• Number of Pickup and Delivery Points• Location of Pickup and Delivery Points• Loading and Unloading Methods• Production Method• Number of trips in a defined time bucket• Geographic Location of Facility and Safety

Measures

What is Quality ?

Usual Responses

• Inspection• Responsibility of the Quality Control Department• Measurement Activity• Statistics• Technical Activity• Support Function

The total composite product and service characteristics of marketing , engineering , manufacture , and maintenance through which the product and the service in use will meet the expectations of the customer - Armand V. Feigenbaum

A product or a service possesses Quality if it helps someone live better materially and /or otherwise and enjoys a large and sustainable market

- W. Edwards Deming

Quality is defined as fitness for purpose . To be fit for purpose , the product/service must have features that satisfy customer needs and must be delivered free of deficiencies. - Joseph M. Juran

Quality is conformance to requirements - Phillip B. Crosby

Different Definitions of Quality

...degree to which a set of inherent characteristics fulfils requirements- ISO 9000 : 2008

“ A people focussed management system that aims at continual increase in customer satisfaction at continually lower cost , working horizontally across functions and departments , involving all employees and processes , top to bottom , extending forwards and backwards to include the Supply chain as well as the Customer chain . ”

Quality Management

SP

EC

IFICA

TIO

NPRODUCTION

INS

PE

CTI

ON

SHEWHART CYCLE

Specification

A commitment that has to be met implying “satisfied requirements”

Production

An effort that is carried out to meet these requirements

InspectionAn act carried out to assess the effectiveness of the

efforts to meet these requirements

1. Idea for placing importance on Quality2. Responsibility for Quality3. Research4. Standards for Designing and Improvement of Products5. Economy of Manufacturing6. Inspection of Products7. Expansion of Sales Channels8. Improvement

Customer

1.Design the Product (with appropriate Tests)

2.Make it, test it in the Production Line and in the Laboratory

3. Put it on the Market

4.Test it in Service, through Market Research, find out what the user thinks of it, and why the non-user has not bought it

THE DEMING WHEEL

manufacturerthe user andthe non user

Plan a change or a test aimed at improvement

Do - Carry out the change or test ( preferably on a small scale )

Study the results . What went wrong? What did we learn?

Act - Adopt the change , or abandon it , or run through the cycle again

What is a Control Chart?A Control Chart is a statistical tool used to distinguish between process variation resulting from common causes and variation resulting from special causes.

Statistical Methods

What Are the Control Chart Types?

• X-Bar and R Chart

• Individual X and Moving Range Chart

Other Control Chart types:

• nP Chart

• c Chart

• p Chart

• u Chart

Statistical Methods

Are youchartingattributedata?

Data arevariables

Data

Is sampleSize equal

to 1?

Use XmRchart forvariables

data

Use XmR for Attributes data or

other control chart types

For sample sizebetween 2 and15, use X-Barand R Chart

NO

YES

YES

NO

Control Chart Decision Tree

Control Chart used where the Sample size is the Same

nP Chart

UCL = nP + 3

LCL = nP - 3

nP = Average Number of Rejections

P = Overall Proportion of Rejects

Example

A lot of 50 pieces were being produced per worker per day in a factory . The following rejects were observed every day for each worker . Draw a Control Chart and state your conclusions .

WorkersDay

1 2 3 4

Worker 1 9 11 7 8

Worker 2 6 11 11 9

Worker 3 12 7 5 5

Worker 4 11 10 13 9

Worker 5 14 8 9 11

Worker 6 4 11 12 12

nP = Average Rejections = Total number of Rejections / Total number of attempts = 225 / 24 = 9.38

P = Overall Proportion of Rejects = Total number of Rejections / total number produced = 225 / 24*50 = 225 / 1200 = 0.188

Now

UCL = nP + 3 LCL = nP - 3

= 9.38 + 3

= 9.38 + 3(2.76)

= 9.38 + 8.27

= 17.66

= 9.38 - 3

= 9.38 - 3(2.76)

= 9.38 - 8.27

= 1.11

Control Chart used where the Bulk Sample is the Samec Chart

UCL = c + 3 LCL = c - 3

c = Average Number of Blemishes

An officer from the NHAI provided the following data for the number of potholes found for every 10 kilometres over a stretch of 150 kilometres on the Mumbai Nasik Highway . Draw a c Chart and state your conclusions

Sample

1 2 3 4 5 6 7 8 91

01

11

21

31

41

5

Potholes

2 4 1 1 4 5 2 1 2 3 4 3 5 2 1

c = Average Number of Blemishes = Total number of blemishes / Total number of Samples

= 40 / 15 = 2.667

UCL = c + 3 LCL = c - 3

= 2.667 + 3

= 2.667 + 4.889

= 7.567

= 2.667 - 3

= 2.667 – 4.889

= -2.222 LCL = 0

Steps in drawing an XmR Chart

• Decide what are the data to be collected

• Collect Data

• Arrange data in their chronological sequence

• Calculate Average ( X bar )

• Compute Moving Range ( MR )

• Calculate Average Moving Range ( MR bar )

• Substitute in the formulae

• UCL = Xbar+2.66(MRbar)

• LCL = Xbar-2.66(MRbar)

XmR Chart

XmR Chart

Example

Date1

/82

/83

/84

/85/

86/

87/

88

/89/

81

0/8

Minutes

19

22

16

18

19

23

18

15

19

18

Calculating MR bar

Compute differences between successive values arranged in their chronological sequence and take the modulus of those values ( MR )

Calculate the average of the differences (MR bar)

Example

XmR Chart

Date1

/82

/83

/84

/85/

86/

87/

88

/89/

81

0/8

Minutes

19

22

16

18

19

23

18

15

19

18

Ranges

3 6 2 1 4 5 3 4 1Average = 187 / 10 = 18.7 ; MRbar = 29 / 9 = 3.2

Steps in drawing an XmR ChartSubstituting in the formulaeUCL = Xbar+2.66(MRbar) = 18.7+2.66(3.2) = 27.27LCL = Xbar-2.66(MRbar) = 18.7-2.66(3.2) = 10.13Plotting the Chart we get…

XmR Chart

Constructing an X – bar and R Chart

Step 1 - Determine the data to be collected.Step 2 - Collect and enter data by subgroupStep 3 - Calculate and enter subgroup averagesStep 4 - Calculate and enter subgroup rangesStep 5 - Calculate grand meanStep 6 - Calculate average of subgroup rangesStep 7 - Calculate UCL and LCL for subgroup averagesStep 8 - Select scales and plotStep 9 - Document the chart

Average X = X1 + X2 + X3 +…..+Xn

nWhere X is the averageand X1… are the individual values in the subgroupn is the total values in the subgroup

X = X1 + X2 + X3 + ……+Xn nRange R = Largest value in each Subgroup – Smallest value in each Subgroup

Average R = R1 + R2 + R3 +…..+Rn

n

Where R is the average Range and R1… are the individual Ranges of the subgroups n is the total number of Subgroups

UCL = Xdbar + A2 Rbar

LCL = Xdbar – A2 Rbar

Use value of A2 based on number of

values in subgroup = n

n A2

3 1.023

4 0.729

5 0.577

6 0.483

7 0.419

8 0.373

9 0.337

10

0.308

11

0.285

12

0.266

13

0.249

14

0.235

Subgroup

1 2 3 4 5 6 7 8 9

X115

.314

.41

5.315

.01

5.314

.915

.61

4.014.

0

X214

.915

.51

5.114

.81

6.415

.316

.41

5.815.

2

X315

.014

.81

5.316

.01

7.214

.915

.31

6.413.

6

X415

.215

.61

8.515

.61

5.516

.515

.31

6.415.

0

X516

.414

.91

4.915

.41

5.515

.115

.01

5.315.

0

Averages

15.36

15.04

15.82

15.36

15.98

15.34

15.52

15.58

14.56

Ranges

1.5

1.2

3.6

1.2

1.9

1.6

1.42.

41.6

Grand Average = 15.40Range Average = 1.82

Factors in Job Design

Task analysis• how tasks fit together to form a job

Worker analysis• determining worker capabilities and responsibilities

for a job

Environment analysis• physical characteristics and location of a job

Ergonomics• optimising number of limb and eye movements to

complete the task

Technology and automation• replacing the human element in the task to be

performed

Task Analysis

• Description of tasks to be performed• Task sequence• Function of tasks• Frequency of tasks• Criticality of tasks• Relationship with other jobs/tasks• Performance requirements• Information requirements• Control requirements• Error possibilities• Tasks duration(s)• Equipment requirements

Worker Analysis• Capability requirements• Performance requirements• Evaluation• Skill level• Job training• Physical requirements• Mental stress• Boredom / Fatigue• Motivation• Number of workers• Level of responsibility• Monitoring level• Quality responsibility• Empowerment level

Environmental Analysis

• Workplace location• Process location• Temperature and humidity• Lighting• Ventilation• Safety• Logistics• Space requirements• Noise• Vibration

Three Aspects of Job Instructions

• Knowledge of “Supposed to do”• Knowledge of “Is Doing”• Knowledge of “Regulating the Process”

Different Types of Process Charts

• Outline Process Chart• Flow Process Chart ( Man , Material , Equipment )• Two Handed Process Chart• Multiple Activity Chart

Worker-Machine Multiple Activity Chart

Job : Photo ID CardsJob : Photo ID Cards Date : 3/2/2013Date : 3/2/2013

Operator Time (min)Time (min) Photo Machine

Key in Customer Data on Card

2.6 minutes Idle

Feed Data Card in 0.4 minutes Accept Card

Position Customer for photo

1.0 minutes Idle

Take Picture 0.6 minutesBegin Photo

process

Idle 3.4 minutes3.4 minutesPhoto / Card

processed

Inspect Card and Trim edges 1.2 minutes1.2 minutes Idle

Worker-Machine Time Chart

SummarySummary

Operator Time

%Photo

Machine Time%

WorkWork 5.8 63 4.8 52

IdleIdle 3.4 37 4.4 48

TotalTotal 9.2 100 9.2 100

Work Measurement

• Determining how long it takes to do a job ( in manufacture and in service )

• Time studies• Standard time

• is time required by an average worker to perform a job once

• incentive piece-rate wage system was based on time study ( now used for improvement purposes only )

1. Establish standard job method2. Break down job into elements3. Study job4. Rate worker’s performance (RF)5. Compute average time (t)

Work Measurement

6.Compute normal time

7.Compute standard time

Normal Cycle Time = NT = ΣNt

Normal Time = (Elemental average) x (rating factor)

Nt = (t )(RF)

ST = (NT)(1 + AF)

Standard Time = (normal cycle time) x (1 + allowance factor)

Work Measurement

Computation of Standard Time

Observed Time

Rating Factor

Normal Time

Process Allowance

Relaxation Allowance

Contingency Allowance

Special Allowance

Policy Allowance

Standard Time

Performing a Time Study

Time Study Observation Sheet

Identification of operation Sandwich Assembly Date 6/2

Operator Approval Observer

Cycles Summary

1 2 3 4 5 6 7 8 9 10 Σ t NtRFt

Place ham, cheese, and lettuce on bread

1

2

3

4

Grasp and lay out bread slices

Spread mayonnaiseon both slices

Place top on sandwich,Slice, and stack

t

t

t

t

R

R

R

R

.11 .44 .79 1.13 1.47 1.83 2.21 2.60 2.98 3.37

.04 .05 .05 .04 .06 .05 .06 .06 .07 .05 .53 .053 1.05 .056

.04 .38 .72 1.05 1.40 1.76 2.13 2.50 2.89 3.29

.07 .06 .07 .08 .08 .08.07 .07 .10 .09 .77 .077 .0771.00

.11.12 .14 .12 .12.13.13.13 .14 .14 1.28 1.28 1.10 .141

.93.23 .55 1.25 1.60 1.96 2.34 2.72 3.12 3.51

.12.10 .08 .09 .12 .10.11 .11 .10.10 1.03 1.03 1.10 .113

.33 .67 1.01 1.34 1.71 2.07 2.44 2.82 3.24 3.61

Normal time = (Elemental average)(rating factor)Nt = ( t )(RF) = (0.053)(1.05) = 0.056

Normal Cycle Time = NT = Σ Nt = 0.387

ST = (NT) (1 + AF) = (0.387)(1+0.15) = 0.445 min

Average element time = t = = = 0.053 Σt10

0.5310


How many sandwiches can be made in 2 hours?

= 269.7 or 270 sandwiches120 min0.445 min/sandwich


Performing a Time StudyExample

Operator is Rated at 110 %Allowable Factor is 9.1 %Fatigue Factor is 10 %

Compute Standard TimeCompute Output in 8 hours

Job Element

Cycles

1 2 3 4

1 0.160.

120.

330.

15

2 0.60.

60.

590.

61

3 0.330.

370.

350.

35

4 0.50.

50.

490.

51

Learning CurvesIllustrates improvement rate of workers as a job is repeatedProcessing time per unit decreases by a constant percentage each time output doubles

Units produced

Pro

cess

ing

tim

e p

er u

nit

Learning Curves

tn = t1nbTime required for the nth unit =

where:

tn = time required for nth unit producedt1 = time required for first unit producedn = cumulative number of units produced

b = where r is the learning curve percentage (decimal coefficient)

loger

loge2

Learning Curve Example

A Process designed to assemble Computers had the following attributes.t1 = 18 hourslearning rate = 80%What is time taken for 9th, 18th, 36th units?

t9 = (18)(9)ln(0.8)/ln 2 = (18)(9)-0.322

= (18)/(9)0.322 = (18)(0.493) = 8.874hrst18= (18)(18)ln(0.8)/ln 2 = (18)(0.394) = 7.092hrst36= (18)(36)ln(0.8)/ln 2 = (18)(0.315) = 5.674hrs

Learning Curve for Mass Production Job

Standard time

End of improvement

Units produced

Pro

cess

ing

tim

e p

er u

nit

I

Element

Elemental Average Time in

minutes

Rating Factor

Step 1

0.20 5 %

Step 2

0.08 10 %

Step 3

2.20 7.5 %

Step 4

0.05 12.5 %

Step 5

0.10 20 %

ExampleThe following times in minutes were observed for different steps carried out to complete a job . The following factors were considered besides the Rating factors mentioned in the table . Relaxation Allowance was 10 % . Special Allowance was 5 % . Calculate Standard time . Calculate standard output in 8 hours . Suppose one of the operators makes 100 jobs in 6 hours – what is his efficiency ?

Maintaining and Improving Equipment

Maintenance• Often viewed as an ‘Overhead Cash

Pit’• Largely : Breakdown Repair• Highly understaffed• Carried out in haste

Maintaining and Improving Equipment

Breakdown Maintenance• Finding the Breakdown• Remedying the Breakdown• Shuffling to make up for lost time

Outcomes :• Unnecessary Capital Investment• Large Inventories of finished / semi-finished

product• Large Inventories of Spares

Equipment Problems

Machine Malfunction• Machine Deterioration resulting in

shortened machine life• Machine Inefficiency resulting in eventual

high costs• Incorrect output – Scrap and Rework

Equipment Problems

Machine Breakdown• Safety Hazards resulting in Injuries• Idled workers resulting in High

Inventories• Idled Facilities resulting in Schedule

delays

Preventive Maintenance

The practice of tending to equipment so that it is never idle because of a malfunction or a breakdown thus being in a state of optimal operation at all times

Maintainability

Maintainability is the effort and cost of performing maintenance . There are two measures of maintainability

• Mean Time To Repair ( MTTR )• Mean Time Between Failures ( MTBF )

Mean Time To Repair ( MTTR )

MTTR = Σ ( Downtime for Repair ) / Number of Repairs

Downtime for repair includes :

• Waiting for repair Personnel• Diagnose Problem• Locate necessary Spares• Remedy the problem ( Repair )• Test the Equipment• Handover to owner

Mean Time Between Failures ( MTBF )

MTBF = Total Running Time / Total Number of Failures

MTBF is used to estimate Reliability of an item expressed as a function of time

So Reliability R(t) = e-λT

where

λ = 1 / MTBF ( failure rate )T = Specified timee = Naperian Logarithm ( 2.718 )

ExampleTwenty Machines are operated for 100 hours . One Machine fails at 60 hours and another machine fails at 70 hours . The rest of the eighteen machines run for the complete 100 hours . Calculate MTBF .

Total Running Time for the machines is

18 ( 100 ) + 60 + 70 = 1930 hours

Total Number of Failures = 2

So MTBF = 1930 / 2 = 965 hours

Example

For the same example what would be the reliability of the machine ata)500 hoursb)900 hours

λ = 1 / MTBF = 1 / 965 = 0.0010362

So by the formula

R ( 500 ) = e -0.0010362(500) = 0.596 or 60 %

And

R ( 900 ) = e -0.0010362(900) = 0.394 or 40 %

ExampleFor the same example suppose there is a component that helps the machine revert to a reliability of 100 % , when should it be replaced so that the machine performance does not slip below 90 %

Reliability R(t) = e-λT where

R(t) = 0.9

So , substituting we get

0.9 = e -0.0010362(T)

Solving by transposing , T = 109.2 hours(101.7)

AvailabilityAvailability is the proportion of time the equipment is actually available to perform work out of the time it should be available to perform work

Taking into account MTBF and MTTR

The total time of running of a machine in a given period of time is MTTR + MTBFTime it is available is MTBF

So Availability ( A ) = MTBF / ( MTBF + MTTR )

MTTR MTBF

MTTR = 5 ; MTBF = 15 ; A = 75%

MTTR MTBF

MTTR = 5 ; MTBF = 20 ; A = 80%

MTTR MTBF

MTTR = 2 ; MTBF = 20 ; A = 90%

Relationship between Availability and MTTR + MTBF

AvailabilityAvailability can also be given asA = Actual Running Time / Planned Running Time

where

Planned Running Time = Total Plant Time – Planned Downtime

Actual Running Time = Planned Running Time – All other Downtime

AvailabilityPlanned Downtime includes

• Meals• Rest Breaks• Scheduled Preventive Maintenance

All other Downtime includes• Setup Time• Equipment Breakdown• Unavailability of Material

ExampleA plant working in 2 shifts of 8 hours each has 2 hours of planned downtime per shift . On an average it has been observed that 110 minutes are consumed for set up of the machine and 75 minutes for breakdown / malfunction . Calculate Availability

Planned Running Time = 16 – 2(2) hours = 12 hours = 720 minutes

Actual Running Time = 720 – 110 – 75 = 535 minutes

A = 535 / 720 = 0.7431 = 74 %

Efficiency

Efficiency is a measure of how well an equipment performs when it’s running . There are two components of efficiency

Rate EfficiencySpeed Efficiency

Rate Efficiency =

Actual Production Volume x Actual Cycle Time / Actual Running Time

Example

If in 535 minutes it has been observed that 830 units have been produced but the actual cycle time for each unit is 0.6 what is the rate efficiency of the equipment ?

Rate Efficiency = Actual Production Volume x Actual Cycle Time / Actual Running time

= 830 x 0.6 / 535 = 498 / 535 = 0.9308

= 93 %

EfficiencySpeed Efficiency

The Ratio of Designed Cycle Time to Actual Cycle Time is called as Speed Efficiency of the Equipment

Speed Efficiency = Designed Cycle Time / Actual Cycle Time

ExampleIf designed cycle time is 0.5 per unit for previous example

Speed Efficiency = 0.5 / 0.6 = 0.833 = 83%

Efficiency

Performance Efficiency

Performance Efficiency = RE x SE

= 0.9308 x 0.8333 = 0.7756 = 77 %

Yield

Yield is also termed as Quality Rate and is expressed as a ratio of

Good Units Produced / Total Units Produced

Example

If the equipment under consideration produces 800 good units out of 830 units , Yield is given as

800 / 830 = 0.9639 = 96 %

Overall Equipment Effectiveness ( OEE )

OEE = Availability x Performance Efficiency x Yield

Example

For the equipment under consideration , OEE

= 0.7431 x 0.7756 x 0.9639 = 0.55

55 %

The Need for something "New"

• Operators accepted chronic stoppages as ‘inevitable’

• Operators suffered from an attitude of “I operate – you clean and fix”

• The relation between the chronic stoppages and equipment components was not explored fully

• Maintenance Operators were not trained in the Science of Investigation and Remedy of Equipment Problems

• Slight Defects were often ignored

TPM = Total Productive Maintenance

TPMFirst implemented at Toyota Motor Company in 1962

The MissionAdvanced Products for an Advancing Society

The Policy

• Aim for World-class Quality• Corporate Growth through Product Leadership• Product Development through Technological

Research• Greater Efficiency through Greater Flexibility• Revitalise the Corporation through Employee

Talent

The Need for TPMThe Purpose

The purpose of TPM is not only to keep the equipment in a state of optimal operation at all times – but also to tailor the equipment so that it becomes robust enough to withstand any changes in it’s vicinity and flexible enough to be adaptable in the wake of technological advances

The Philosophy

We are all responsible for our Equipment

TPM Policy and Objectives

• To Maximise Overall Equipment Effectiveness through Total Employee Involvement

• To continually improve reliability and maintainability of equipment resulting in higher productivity and Quality

• To maximise economy of operation for the entire life of the Equipment

• To continually enhance skills and expertise of all employees ( with relation to their equipment )

• To continually enhance the work environment and enrich jobs

Eight Steps to TPM

1. Conduct Initial Cleaning2. Address causes of Dirty Equipment3. Reduce the number of ‘Hard-to-Clean’ areas4. Document and Standardise Maintenance

Activities5. Familiarise Operators with Optimal operating

conditions6. Develop Diagnostic Skills and Cultivate

Autonomy7. Organise and Manage the entire Workspace8. Strive for Continual Improvement

Conduct Initial Cleaning

• Get rid of all debris and prevent accelerated deterioration

• Identify hidden problems made apparent by cleaning and correct them

• Familiarise Operators with the nuances of equipment operation

Cleaning is Inspection

Causes of Dirty Equipment

• Prevent Scattering of dust and contaminants wherever possible

• Prevent dirt from adhering to different parts of the equipment

• Work on Improving Equipment

Localise scattering of Debris

Work on Hard-to-Clean Areas

• Design better methods for continual cleaning• Work on creating ‘Visual Controls’• Make equipment more ‘transparent’

Hard to Clean is Hard to Inspect

Standardise Maintenance Activities

• Enlist factors of Deterioration• Draft provisional standards of cleaning , inspecting

and maintenance• Study the structure and function of the Equipment

thoroughly

Adhere and Empower

Develop Operating Conditions

• Learn of Equipment Optimal Performance Parameters• Work with experts to learn of Equipment Deterioration• Document relationship of deterioration to

surroundings and effects of deterioration• Work on establishing early warning signals

Establish Conditions

Develop Diagnostic Skills

• Create Checklists and Use them appropriately• Improve Operational Reliability and Clarify Abnormal

conditions• Establish and Document appropriate Corrective and

Preventive Measures

Control Conditions

Manage Entire Workspace

• Standardise and Document Workshop Housekeeping Procedures

• Facilitate an All-encompassing Companywide Maintenance Programme

• Establish the 5S System• Cover all areas and all assets in the organisation

Manage Conditions

Improve Continually

• Train each and every person in the organisation in TPM

• Record and Analyse Equipment Data continually and facilitate organised feedback

• Relate Maintenance Goals to Company Goals• Integrate Equipment Management into Long term and

Annual Organisational Plans

Transcend Performance Standards

5 S Technique5 S Process

The 5 - S practice is a technique used to maintain a “Quality Culture” in an organisation.

The name stands for 5 Japanese words

•Seiri•Seiton•Seiso•Seiketsu•Shitsuke

5 S Process

整理 – Seiri = Sort

Arrange and discard unnecessary items

• Have all unnecessary items been removed ?• Is it clear why the unnecessary items were there in

the first place ? • Are all loose wires tied up and bundled ? • Have all hoses / pipes been grouped ? • Are all walkways clearly outlined ?

5 S Process 整頓 – Seiton = Straighten

Everything has a place and everything in it's place

• Have special Areas been designated for different items ?

• Are things put away after use ? • Have all joints been tightened / fastened ? • Are all workstations , drawers , shelves and

cleaning implements kept in an orderly fashion ? • Are any visual indicators used to indicate things

out of place ?

5 S Process 清掃 – Seiso = Scrub

Clean all areas / remove dust and grime

• Are all workstations free from dry dust and wet dust ? • Are all relevant fixtures , jigs , tools clean ? • Are the work areas clean ? • Are suitable ventilation equipment / exhausts clean ?

5 S Process

清潔 – Seiketsu - Standardise

Standardise the above three activities

• Have procedures been written for the above three activities ?

• Have instructions for cleanliness and 'everything in it's place' been given ?

• Are regular checks being carried out ? • Is maintenance a part of activities being carried

out ?

5 S Process

躾 – Shitsuke - Systemise

Systemise all of the above activities

• Have all of these disciplines been extended for personal activities ?

• Have all office spaces been assigned 5S activities ?

• How often are audits carried out companywide ?

• What are the improvements being carried out ?

Seiri

Throw away things that are not neededDeal with causes of dirt leaks and noiseOrganise cleaning the floors and housecleaningTreat defects, leakage and breakageOrganise the storage of parts and filesPolicy of “One-is-best”- one set of tools/stationery- one page form/memo- one day processing- one stop service for customer- one location file

Typical Activities Location Action by

Seiton

Everything has a clearly designated name and place30-second retrieval and storageFiling standards and controlZoning and placement marksEliminate covers and locksFirst in, first out arrangementNeat notice boards (also remove obsolete notices)Easy-to-read notices (including zoning)Straight-line and right angle layoutFunctional placement for materials, parts, tools etc

Typical Activities

Location Action by

Seiso

Individual cleaning responsibility assignedMake cleaning and inspection easierRegular cleaning campaignsCleaning inspections and correct minor problemsClean even the places most people do not notice


Seiketsu

Transparency ( e.g. glass covers for see-through)Inspection “OK” marks or labelsDanger zones marked on meters and switches‘Danger’ warning signs and marksFire extinguisher and ‘Exit’ signsDirectional markings on pipes, gangways etcOpen and shut directional labels on switches etcColour-coded pipesFoolproofing (Poka-yoke) practicesResponsibility labelsElectrical/telephone wire managementColour coding - paper, files, containers etcPrevent noise and vibrationDepartment/office labels and name platesPark-like environment (garden office/factory)


Shitsuke

All-together cleaningPractice pick-up of components and wasteWear your safety helmet/gloves/shoes etcPublic-space 5-S managementPractice dealing with emergenciesExecute in individual responsibilityGood telephone and communication practicesDesign and follow the 5-S manualSeeing-is-believing: check for 5-S environment


Mistake proofing

Mistake proofing is a scientific technique for improvement of operating systems including materials, machines and methods with an aim of preventing problems due to human error

The term “error” means a sporadic deviation from standard procedures resulting from loss of memory, perception or motion.

Defect Vs errors

It is important to understand that defects and errors are not the same thing.

A defect is the result of an error, or an error is the cause of defects as explained below.

Error Defect

Cause Result

Prevention of defects

Machineor

human errorDetect error

Take corrective

action

zerodefect

Analyse for preventive

action

Cause Intermediate result End result

Modify workprocedure to

prevent such errors

WorkProcedure

• Error in memory of PLAN : Error of forgetting the sequence/ contents operations required or restricted in standard procedures.

• Error in memory of EXECUTION : Errors of forgetting the sequence/contents of operations having been finished.

• Error in PERCEPTION of type : Error of selecting the wrong object in type or quantity.

• Error in perception of MOVEMENT : Error of misunderstanding/misjudging the shape, position, direction or other characteristics of the objects.

• Error in motion of HOLDING : Error in failing to hold objects.

• Error in motion of CHANGING : Errors of failing to change the shape , position , direction , or other characteristics of object according to the standard.

Types of Error

Human error provoking situations

• Complex design• Inadequately written standards• Too many parts• Mix up• Too many steps• Specifications or critical conditions• Too many adjustments• Frequent repetition

Finger print ID lock is an excellent example of mistake proofing. There's no need to fumble for your keys in the dark any more. The Fingerprint ID Door Lock is a cylindrical lock combined with a security bolt that will let you into the house using just your finger. It reads your unique fingerprint and only allows entry to prints it recognises.

Examples of mistake proofing


Gas pumps are equipped with hose couplings that break away and quickly shutoff the flow of petrol.


Automobiles controls have a mistake proofing device to ensure that the key in the on position before allowing the driver to shift out of park ( for automatic gears ).The keys can not be removed until the car is in park.


3.5 inch diskette can not be inserted unless diskette is oriented correctly.This is as far as diskette can be inserted upside-down.

The beveled corner of the diskette pushes a stop in the disk drive out of the way allowing diskette to be inserted.This feature,along with the fact that the diskette is not square,prohibit incorrect orientation.


Electronic car locks can have three mistake proofing devices:

• Ensures that no door is left unlocked.

• Door automatically locks when car exceeds a predetermined speed

• Lock won’t operate when door is open and engine is running.


New lawn mowers are required to have a safety bar on the handle that must be pulled back in order to start the engine.If you let go of the safety bar,the mowers blade stops in 3 seconds or less.This is an adaptation of the”dead man switch” from railroad locomotives.


Retail stores use electronic article surveillance to ensure that no one walks away without making payment.

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