module 3 - nptelnptel.ac.in/courses/122106032/pdf/3_2.pdf · facilities planning, location, layout...

Management Science II Dr.T.T.Narendran

Indian Institute of Technology Madras

MODULE 3

Facilities Planning, Location, Layout And Movement Of Materials

Factors To Be Considered For Selection Of Region

• Primary Factors

• Market nearness

• Raw-material availability

• Labour availability

• Transport availability

• Power and fuel supply

• Existence of similar firms

Secondary Facorst

• Climate suitability

• Character of the inhabiting community

• State and local taxation-rates

• Expansion facility

• Decentralization suitability

Selection Of Locality

• City Rural Area

• Cheap land

• Avenue for expansion

• Low taxes

• Buildings less costly



• Fewer operating restrictions

• Simpler labour relations

• Absence of allied industry

• Absence of skilled labour

• Absence of transport & public utility

• Absence of banking (less)

• Restricted local market

Ample Market

Skilled Labour

Nearness to allied industry

Public utility services

Transport

Banking & Finance

Education

Recreation

High cost

High tax

Restrictions



• Suburban – via media

• Industrial Estates

• Selection of site – breakeven analysis

Pic1

Layout – Other Forms

• Cellular Manufacturing Systems

• Fixed Position Layout Pic 2

• What do we see in this figure ?

• Machines arranged like a product

• layout

• Smooth flow of work

• Less movement of materials

The logical question is :

• How do we form groups ?



• Broadly there are three ways to do it

• Visual inspection

• Use your experience, technical knowledge and identify the part families that require the same kind of machines

• Process Flow Analysis (PFA)

• Study the route card and group the machines that process the same parts

• Part Characteristic Analysis (PCA)

• Code and classify parts or

• Analyze part features to form part groups

Numerical Methods For Cell Formation Basis Numerical representation of the processing of a component by a machine in a machine-component incidence matrix (MCIM) Source of data Route card Matrix rows <=> machines columns <=> components. Wherever a component requires processing on an machine, the entry in the matrix is ‘1’, otherwise the entry is ‘0’.



Here is a typical incidence matrix

Numerical methods use the machine - component incidence matrix as the basic input data and proceed to identify cells and component families. Amongst the several methods available, this programme introduces two methods, viz.

• Rank - Order Clustering

• A ‘similarity’ - based method ‘ROC’ works for “perfectly groupable” matrices only

• Rarely found in reality

Hence the need for better methods. These are based on

• Similarities

Components

Machines

1 2 3 4 5 6 7

1 1 0 0 1 1 0 1 2 0 1 1 0 0 1 0 3 1 0 0 1 0 0 1 4 0 1 1 0 1 1 0 5 0 0 0 1 1 0 1



• Cluster Analysis

• Array - Sorting

• Graph Theory

• Mathematical Programming

• Pattern Recognition

Method based on ‘Similarity’ ‘Similarity’ can be measured as the extent to which two machines / parts have common parts to process / machines required. Consider the same example :

s12 = similarity between m/c 1&3 = no. of common elements in 1&3 = 5 Similarities between all pairs of machines are :

1 1 1 1 0 0 1

2 1 0 0 1 1 0 3 0 1 1 0 0 1

4 1 0 0 1 1 0

1 2 3 4 5 6

Components

Machines

1 2 3 4

1

- 1 5 1

2 3

1 5 - 0 0 - 6 0

4

1 6 0 -

Machines

Machines



Start with each m/c. Trace its most similar m/c. Go to that row and repeat until you come back to the starting point This is the result :

Group (2,4) in one machine cell and (1,3) in another machine cell. (2,4) takes part family (1,4,5) and (1,3) takes part family (2,3,6). Here is the solution :

1

2

3

4

1

-

1

5

1

2 3

1 5

- 0

0 -

6 0

4

1

6

0

-

Machines

Machine

s

1 - 3 - 1 2 - 4 - 2

2

4

1

3

1

1

1

1

0

4 5

1 1

1 1

0 0

0 0

2 3

0 0

0 0

1 1

1 1

6

0

0

1

1

Components

Machines



A few “home truths”

Perfectly groupable matrices rarely exist. Intercell moves are inescapable. It is not easy to identify the ‘best’ set of groups. Cell formation using numerical methods with 0-1 matrices are used at a preliminary design stage only. 0-2

• Intercell move :

The processing of a part by a machine outside its group Why do intercell moves happen?

Common facilities :

• Heat treatment, Plating / process shop,

• Painting

Costly machines :

• CNCs, Heavy duty presses

What should we do ?

• Live with them !

• Change technology

• (Laser beam for heat treatment)

• Buy additional machines - (expensive)

• Change process



• Subcontract

• Change product design - (concurrent engg.)

How do we evaluate groups ?

• no. of intercell moves

• no. of 0’s inside a block

• composite measures

e.g., grouping efficiency

Methods For Layout

Qualitative A Absolutely necessary E Especially Important I Important O Ordinary Closeness is OK U Unimportant X Undesirable

Some well-known Qualitative Methods ALDEP Automated Layout Design Program CORELAP Computerized Relationship Layout Planning ALDEP



Steps

• Randomly select 1 dept – place it in the plan

• Scan the rest – select 1 with A/E – place next [No A or E ?......Random !]

Continue…

• Convert ratings, Compute total score

• Repeat, many times, with different starting points

Aldep Generate ‘Good’ Layouts - Not Optimal Fgfgf

Assumption Of Layout Models

• Cost & Flow data exist for unknown conditions

• Material Handling (MH) Costs, linear, incremental, assignable to activities

• MH Cost –the only significant factor

Deterministic flow data

Cost Elements

Purchasing, installing, maintaining

Operating

Difference in WIP due to MHs



Other costs due to differences in MHs

Steps In Layout Design

• Formulation

• Analysis

• Search for alternatives – Selection Guidelines

• Exert effort

• Don’t get bogged down by details too soon

• Question liberally...

• Seek Many alternatives

• Avoid conservatism, premature rejection

• Satisfaction

• Consult others, Think differently, Group approach, Beware of limitations

Plant Layout – Quantitative Approach Quadratic Assignment Problem (Qap)

ij

ij

Minimize

Subject to X 1 j

X 1 i

Ζ =

= ∀

= ∀

∑∑∑∑

∑

∑

ijkl ij kl

i J k l

i

j

C X X



Note: i,k for m/c s j,l for locations Objective function reflects load- distance QAP is an “np-complete” problem Solved by empirical methods, e.g. Computerized Relative Allocation of Facilities CRAFT (1963)..upto 40 depts.

Plant Layout – Quantitative Approach (Cont..)

Inputs: Cost matrix, initial layout Procedure:

• Find distances between centroids

• Compute cost of layout

• Evaluate ‘pair wise exchanges’ – choose the best

• Print result

• Repeat until no further reduction

-is an ‘improvement type’ heuristic -sensitive to initial layout

- Other methods Genetic Algorithm, Simulated Annealing etc

Wimmert’s Method For Plant Layout (Qap) Assumption

• Individual areas interchangeable (not always)

• Distance moved independent of direction (ok)-FMS

• Cost in directly proportional to distance moved



(ok for same type of MH equipment)

Example

Wimmert’s Method For Plant Layout (Qap) (Cont..)

module 3 - nptelnptel.ac.in/courses/122106032/pdf/3_2.pdf · facilities planning, location, layout...

Documents