Facility Layout: Manufacturing and Services

1

2

Facility Layout: Manufacturing and Services

The aim of layout design

is to organize the

physical arrangement of

economic activity

centers

within a facility so that a process

can be as efficient as possible.

An

economic activity center

can be anything that

consumes space:

a person, or group of people, a teller window, a

m achine, a workbench or work station, a

departm ent, a stairway or an aisle, a tim ecard-rack,

a cafeteria, or storage room , and so on.

Facility layout means:

Planning for the location of all machines, utilities,

employee-workstations, customer-service-areas,

material-storage-areas, aisles, restrooms, lunchrooms,

internal walls, offices, and computer rooms

Planning for the flow patterns of materials and people around,

into, and within buildings

The Need for Layout Decisions

Inefficient operations

For Example:

High Cost

Bottlenecks

Changes in the design

of products or services

The introduction of new

products or services

Accidents

The Need for Layout Designs (Cont’d)

Changes in

environmental

or other legal

requirements

Changes in volume of

output or mix of

products

Changes in methods

and equipment

Morale problems

Objectives of Facility Layout

Minimize material handling costs

9

Utilize space efficiently

Utilize labor efficiently

Eliminate bottlenecks

9

Facilitate communication and interaction between

workers, between workers and their supervisors,

or between workers and customers

9

Reduce manufacturing cycle time or customer

Objectives of Facility Layout (Contd.)

Eliminate waste or redundant movement

9

Facilitate the entry, exit, and placement of

material, products, or people

9

Incorporate safety and security measures

Promote product and service quality

9

Encourage proper maintenance activities

9

Provide a visual control of operations or activities

Provide flexibility to adapt to changing conditions

Increase capacity

8

The overall Objectives of Layout Design

To arrange the facilities needed by a process so that desired

output is achieved with minimum resources.

OR

To lay out available facilities so that the maximum output is

achieved.

These objectives must be met without breaking a number constraints which result from Product Design

Planned capacity Process Used Space available

Constraints of the building Other site constraints

Appropriate material handling

Capital investment available Service areas needed

Communications and information flows Requirements of employees

Safety

●

Proper layout enables:

●

Higher utilization of space, equipment, and

people

●

Improved flow of information, materials, or

people

●

Improved employee morale and safer working

conditions

●

Improved customer/client interaction

Flexibility

●

an understanding of capacity and space requirements

selection of appropriate material handling equipment

decisions regarding environment and aesthetics

●

identification and understanding of the requirements for

information flow

●

identification of the cost of moving between the various

work areas

Characteristics of the Facility Layout Decision

●

Location of various economic activities center areas and its impacts

of the flow through the system.

●

The layout can affect productivity and costs generated by the

system.

●

Layout alternatives are limited by

●

the amount and type of space required for the various areas

the amount and type of space available

●

the operations strategy

●

Layout decisions tend to be

Infrequent

●

Expensive to implement

●

Studied and evaluated extensively

Long-term commitments

Materials Handling

●

The

central focus

of most manufacturing layouts is to

minimize (a) the cost of processing, (b) transporting, and (c)

storing materials throughout the production system.

●

Materials used in manufacturing include:

●

Raw material

●

Purchased components

Work-in-progress

●

Finished goods

●

Packaging material

Materials Handling

A

materials-handling system is the entire network of

transportation

that:

●

Receives material

●

Stores material in inventories

●

Moves material between processing points

●

Deposits the finished products into vehicles for

Materials Handling

Material-Handling Principles

●

Move directly (no zigzagging/backtracking)

Minimize human effort required

●

Move heavy/bulky items the shortest distances

Minimize number of times same item is moved

Material handling systems should be flexible

Mobile equipment should carry full loads

Materials Handling

Material-Handling Equipment

●

Automatic transfer devices

Containers/pallets/hand carts

Conveyors

Cranes

Elevators

Pipelines

Turntables

AGVS

Process Layout

Machines grouped by process they perform [ deals with low- volum e,

high-variety production ( “ j ob shop” , interm ittent production)] – Exam ple: Job shops, hospitals, kitchen.

Product Layout

Linear arrangem ent of w orkst at ions t o produce a specific

product [ seeks the best personnel and m achine use in repetitive or continuous production] – Exam ple: electronic assem ble, m ilk bottling.

Hybrid ( including group) Layout

Exam ple: fast- food restaurants, airport passenger term inals

Fixed Posit ion Layout

Layout in w hich t he product or proj ect rem ains st at ionary, and

w orkers, m at erials, and equipm ent are m oved as needed [ large bulky proj ects such as ships and buildings] – Exam ple: Shipbuilding, road laying

Specialized Layout

Exam ple: offices, warehouses, retails

Process (Job Shop) Layouts

●

Equipment that perform similar processes are

grouped together

●

Used when the operations system must handle a

wide variety of products in relatively small

volumes

(i.e., flexibility is necessary)

18

Manufacturing Process Layout

L

L

L

L

L

L

L

L

L

L

M

M

M

M

D

D

D

D

D

D

D

D

G

G

G

G

G

G

A

A

A

Grinding Department

P

P

19

L

L

L

L

L

L

L

L

L

L

M

M

M

M

D

D

D

D

D

D

D

D

G

G

G

G

G

G

A

A

A

Grinding Department

P

P

20

L

L

L

L

L

L

L

L

L

L

M

M

M

M

D

D

D

D

D

D

D

D

G

G

G

G

G

G

A

A

A

Grinding Department

P

P

Characteristics of Process Layouts

General-purpose equipment is used

●

Changeover is rapid

●

Material handling equipment is flexible

Operators are highly skilled

●

Technical supervision is required

Production time is relatively long

●

In-process inventory is relatively high

Designing Process Layouts

An Important Objective

: Minimize the costs associated with

movement of materials, people, etc.

9

Block Diagramming

Minimize nonadjacent loads

Use when quantitative data is available

Addresses a single criteria/objective [generally minimizing

transportation costs or distance traveled]

9

Relationship Diagramming - Systematic Layout Planning

Based on location preference between areas

Use when quantitative data is not available

Designing Process Layouts [Contd.]

There are three steps in the overall design:

(1) Collect relevant information concerning:

(a) space required for each area

(b) quantities moved between area

(c) number of trips between areas

(d) and so on.

(2) Build a general

Block Plan

[

Block Diagram

] and try to

minimize the total movement

(3) Add details to the Block Plan to give a final layout (using

architects, engineers, consultants and other expertise).

Note: The key step of this process is the second, where a general block

plan is produced. Further, this block plan has to be evaluated to finalize.

Designing Process Layouts [Contd.]

A Procedure to evaluate the Block Plan

1) List the separate areas or departments to be located and determine the space needed by each one.

2) Build a “from-to” matrix. This records the number of trips directly between each pair of areas, and can usually be found by observation over some representative period. 3) Use logical or sensible arguments to develop an initial schematic diagram for the

layout (perhaps based on the current layout).

4) Determine a cost for this layout. This can be phrased in terms of total meters moved

(= Σ movements * distance); kilogram-meters moved ( = Σ movements * distance * weight) or some other convenient measure. If this solution is acceptable go to Step 6, otherwise continue to Step 5.

5) Improve the initial layout. This may be done by trial and error, some algorithm (such as minimizing non-adjacent loads) , or experience. Go back to Step 4.

6) Complete the block plan by including details of cost, additional constraints, preferred features, problems, and so on.

25

Block diagramming - Example

1 2 3 4 5 Department Department 1 2 3 4 5 1 100 50 2 200 50 3 60 40 50 4 100 60 5 50

Load Summary Chart

50 employees, 5 departments (cutting, sheet metal, machining, painting, assembly)

•Evaluate the current layout.

Example : Process Layout [Contd.]

Department 1

2

3

4

5

Load Summary Chart

FROM/TO DEPARTMENT

1

—

100

50

2

—

200

50 50

3

60

—

40

50

4

100

—

60

5

50

—

Composite

Movements

Composite

Movements

2

l

3

200 loads

4

l

5

60 loads

2

l

4

150 loads

2

l

5

50 loads

1

l

3

110 loads

3

l

4

40 loads

1

l

2

100 loads

1

l

4

0 loads

Example 1: Process Layout [Contd.]

Department 1 2 3 4 5

Load Summary Chart

FROM/TO DEPARTMENT 1 — 100 50 2 — 200 50 50 3 60 — 40 50 4 100 — 60 5 50 — Department 1 2 3 4 5

Load (two-way) Summary Chart

FROM-TO DEPARTMENT 1 — 100 110 2 — 200 150 50 3 — 40 100 4 — 60 5 —

Department 1

2

3

4

5

Load Summary Chart

FROM/TO DEPARTMENT

1

—

100

50

2

—

200

50 50

3

60

—

40

50

4

100

—

60

5

50

—

1

2

3

4

5

Example 1: Process Layout [Contd.]

Composite

Movements

Composite

Movements

2

l

3

200 loads

4

l

5

60 loads

2

l

4

150 loads

2

l

5

50 loads

1

l

3

110 loads

3

l

4

40 loads

1

l

2

100 loads

1

l

4

0 loads

Department 1

2

3

4

5

Load Summary Chart

FROM/TO DEPARTMENT

1

—

100

50

2

—

200

50

3

60

—

40

50

4

100

—

60

5

50

—

Composite

Movements

Composite

Movements

2

l

3

200 loads

4

l

5

60 loads

2

l

4

150 loads

2

l

5

50 loads

1

l

3

110 loads

3

l

4

40 loads

1

l

2

100 loads

1

l

4

0 loads

3

l

5

100 loads

1

l

5

0 loads

1

2

3

4

5

Department 1

2

3

4

5

Load Summary Chart

FROM/TO DEPARTMENT

1

—

100

50

2

—

200

50

3

60

—

40

50

4

100

—

60

5

50

—

Composite

Movements

Composite

Movements

2

l

3

200 loads

4

l

5

60 loads

2

l

4

150 loads

2

l

5

50 loads

1

l

3

110 loads

3

l

4

40 loads

1

l

2

100 loads

1

l

4

0 loads

3

l

5

100 loads

1

l

5

0 loads

1

2

3

4

5

Example 2: Process Layout

A company wants to arrange the six departments of its factory in a way that will

minimize interdepartmental material handling costs. They make an initial

assumption (to simply the problem) that each department is 20x20 feet and that

the building is 60 feet long and 40 feet wide. A from-to matrix of the current

layout [the following figure shows the current layout] is given in the next slide.

For this problem, the company assumes that a forklift carries all

interdepartmental loads. The cost of moving one load between adjacent

department is estimated to be $1. Moving a load between nonadjacent

departments costs $2.

With the above information, improve the given layout.

Assembly Department 1 Receiving Department 4 Printing Department 2 Shipping Department 5 Machine shop Department 3 Testing Department 6

Example 2: Interdepartmental Flow of Parts

1

2

3

4

5

6

1

2

3

4

5

6

50

100

0

0

20

30

50

10

0

20

0

100

50

0

0

Example 2: Interdepartmental Flow Graph

Showing Number of Weekly Loads

100

50

30

10

20

50

20

100

50

Example 2: Current Layout 1

Assembly

Department

(1)

Printing

Department

(2)

Machine Shop

Department

(3)

Receiving

Department

(4)

Shipping

Department

(5)

Testing

Department

(6)

Room 1

Room 2

Room 2

Room 4

Room 5

Room 6

60’

35

20

100

50

30

50

50

10

20

Schematic Diagram

& Cost Solution

Dept.

Dept.

Cost

1

3

$ 200

1

2

$ 50

1

6

$ 40

4

2

$ 50

4

3

$ 40

4

5

$ 50

2

5

$ 10

2

3

$ 30

3

6

$ 100

Total Cost

$570

1

2

3

6

4

5

100

36

Solution

Can we get a layout cheaper than $570? There are 6! or

720 possibilities. Putting departments 1 & 3 adjacent to

each other gives a total cost of $480.

60 ft.

40 ft.

Room 1

Room 2

Room 3

Dept. 1

Dept. 3 Dept. 2

Dept. 4

Dept. 5

Dept. 6

37

20

30

50

100

50

50

10

20

Schematic Diagram

& Cost Solution

Dept.

Dept.

Cost

1

2

$ 50

1

3

$ 100

1

6

$ 20

4

2

$ 50

4

3

$ 40

4

5

$ 50

2

5

$ 10

2

3

$ 60

3

6

$ 100

Total Cost

$480

2

1

3

6

4

5

100

Example 2: Possible Layout 3

Painting

Department

(2)

Assembly

Department

(1)

Machine Shop

Department

(3)

Receiving

Department

(4)

Shipping

Department

(5)

Testing

Department

(6)

Room 1

Room 2

Room 2

Room 4

Room 5

Room 6

60’

39

EXERCISE

One floor of a building has six office areas, which are all the same size. The current layout is shown in Figure. The company feels that a lot of unnecessary movements are made between areas and would like to reduce this by at least 25%. During a random period records were kept of the number of movements between areas and is given in Table. How might the layout of areas given in the figure be improved?

-140 20 10 40 20 6 120 -0 100 0 0 5 0 100 -0 240 20 4 10 80 0 -0 60 3 0 80 200 0 -40 2 0 0 100 120 160 -1 6 5 4 3 2 1 F R O M TO

Table: Number of Movements between areas

6

3

1

2

5

4

40

Larger Layout Problems

●

Method works fine for small problems

Larger problems require software

●

CRAFT-tries to minimize material handling costs

Rearrange many large departments to reduce costs

Human “judgement calls” impossible to computerize

●

Numerical flow of items between departments

●

Can be impractical to obtain

●

Does not account for the qualitative factors that

41

I t is a heuristic program ; it uses a sim ple rules of thum b

in m aking evaluations:

●

"Com pare two departm ents at a tim e and exchange

them if it reduces the total cost of the layout."

I t does not guarantee an optim al solution

●

CRAFT assum es the existence of variable path m aterial

handling equipm ent such as forklift trucks

Process Layout:

CRAFT (Computerized Relative

Allocation of Facilities Technique Approach)

42

Systematic Layout Planning : Relationship

Diagramming

●

Used when quantitative data is not available

●

Replaced load sum m ary chart with m anagem ent

inputs – Muther’s Grid [ Proposed by Richard

Muther]

●

Coded as A,E,I ,O,U and X. Shown in different

thickness of lines

●

Goal: short heavy lines, thin lengthy lines, no

zigzagged lines

43

Example of Systematic Layout Planning:

Importance of Closeness

Value

A

E

I

O

U

X

Closeness

code

Line

Numerical

weights

Absolutely necessary

Especially important

Important

Ordinary closeness OK

Unimportant

Undesirable

16

8

4

2

0

- 80

44

1. Sharing the same facilities; 2. Sharing the same staff; 3. Ease of supervision;

4. Ease of communications;

5. Sequence of operations in a process; 6. Customer contact;

7. Safety;

8. Unpleasant conditions; and so on

Problem: A new office about to be opened, with six equally sized areas as shown in Figure. The importance that areas are close together is described by the following matrix. Suggest a layout for the office.

Figure: Six areas

Matrix shows the importance of areas

A. Absolutely essential E. Especially important I. Important O. Ordinary importance U. Unimportant X. Undesirable

45

C

F

D

E

A

B

C

E

D

F

A

B

1. Sharing the same facilities; 2. Sharing the same staff; 3. Ease of supervision;

4. Ease of communications;

5. Sequence of operations in a process; 6. Customer contact;

7. Safety;

8. Unpleasant conditions; and so on

Solutions A. Absolutely essential E. Especially important I. Important O. Ordinary importance U. Unimportant X. Undesirable Solution

46

Example of Systematic Layout Planning:

Initial Relationship Diagram

1

2

4

3

5

U

U

E

A

I

The number of lines

here represent paths

required to be taken in

transactions between

the departments. The

more lines, the more

the interaction between

departments.

Note here again, Depts. (1) and

(2) are linked together, and

Depts. (2) and (5) are linked

together by multiple lines or

required transactions.

Production

Offices

Stockroom

Shipping and

receiving

Locker room

Toolroom

Relationship Diagramming Example

A

A

A

O

O

O

O

O

U

U

U

U

E

X

I

Production

Offices

Stockroom

Shipping and

receiving

Locker room

Toolroom

A

A

A

O

O

O

O

O

U

U

U

U

E

X

I

Production

Offices

Stockroom

Shipping and

receiving

Locker room

Toolroom

Relationship Diagramming Example

● A Absolutely necessary ● E Especially important ● I Important ● O Okay ● U Unimportant ● X Undesirable

50

Computerized Layout Solutions

●

CRAFT - block diagramming

●

PREP - multistory block diagram

●

CORELAP -

relationship

diagramming

●

ALDEP -

multistory relationship

diagramming

Simulation

Service Layouts

●

Usually process layouts due to customers needs

Minimize flow of customers or paperwork

●

Retailing tries to maximize customer exposure to products

[Example is given in the next slide]

●

Computer programs consider shelf space, demand,

profitability

52

Process Layout in Services

Women’s lingerie Women’s dresses Women’s sportswear Shoes Cosmetics and jewelry Entry and display area Housewares Children’s department Men’s department

Product-Oriented Layout

●

Facility organized around product

Design minimizes line imbalance

●

Delay between work stations

●

Types: Fabrication line; assembly line

Product-Oriented Requirements

●

Standardized product

●

High production volume

●

Stable production quantities

54

Product-Oriented Layout - Assumptions

●

Volume is adequate for high equipment utilization

●

Product demand is stable enough to justify high

investment in specialized equipment

●

Product is standardized or approaching a phase of its

life cycle that justifies investment in specialized

equipment

●

Supplies of raw materials and components are

adequate and of uniform quality to ensure they will

work with specialized equipment

55

A Product Layout

In

56

Product (Line Flow) Layout

Finished

Goods

Storage &

Shipping

Raw

Materials

Receiving

& Storage

Cut

Plane

Glue

D

ry

Turn

Pack

Drill

Sand

“Flow”

57

Product-Oriented Layout Types

●

Assembles fabricated parts

Uses workstation

●

Repetitive process

Paced by tasks

●

Balanced by moving tasks

♦

Builds components

♦

Uses series of machines

♦

Repetitive process

♦

Machine paced

♦

Balanced by physical redesign

58

59

Characteristics of Product Layouts

●

Special-purpose equipment are used

Changeover is expensive and lengthy

Material flow approaches continuous

Material handling equipment is fixed

Operators need not be as skilled

●

Little direct supervision is required

●

Production time for a unit is relatively short

In-process inventory is relatively low

●

Planning, scheduling and controlling functions are relatively

straight-forward

60

Comparison Of Product And Process Layouts

Description

Sequential arrangement

Functional grouping

of machines

of machines

2. Type of Process

Continuous, mass

Intermittent, job shop

production, mainly

batch production,

assembly

mainly fabrication

3. Product

Standardized

Varied,

made to stock

made to order

4. Demand

Stable

Fluctuating

5. Volume

High

Low

6. Equipment

Special purpose

General purpose

7. Workers

Limited skills

Varied skills

61

8. Inventory

Low in-process,

High in-process,

high finished goods

low finished goods

9. Storage space

Small

Large

10. Material

Fixed path

Variable path

handling

(conveyor)

(forklift)

11. Scheduling

Part of balancing

Dynamic

12. Layout decision

Line balancing

Machine location

13. Goal

Equalize work at

Minimize material

each station

handling cost

14. Advantage

Efficiency

Flexibility

PRODUCT LAYOUT

PROCESS LAYOUT

62

Comparison of Process and Product Layouts

Low process flexibility

●Process designed for specific product

●Adding/changing products requires

significant changes to process

●Failure of one component of the system

can shut down the entire system

●Not feasible for low volumes

High initial cost

●Specialized equipment, facilities

Low operating cost

●Unskilled labor

●Mechanization and automation

feasible

●Low WIP inventory

Short production lead times

●Little waiting, low WIP

●Dedicated resources

Low planning & control complexity Product Layout

(Flow shop)

High operating cost

●Skilled labor

●High material handling costs

●Low equipment utilization

●High WIP inventory

Long production lead times

●Wait-move-wait

●Competition for key resources

High planning & control complexity Process flexibility

●Accommodates a wide range of

products & services

●Easy to add new products

●Facilitates customization

●Volume flexibility

●Problems easily isolated

Low initial cost

●General purpose equipment

Process Layout (Job shop)

Disadvantages Advantages

63

Combination Layout (Typical)

Raw

Materials

Receiving

& Storage

Finished

Goods

Storage &

Shipping