Chap006_Process Selection & Facility Layout

7/28/2019 Chap006_Process Selection & Facility Layout

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6-1 Process Selection and Facility Layout

CHAPTER

6

Process Selectionand Facility Layout


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Process selection Deciding on the way production of goods or

services will be organized

Major implications Capacity planning

Layout of facilities

Equipment Design of work systems

Introduction


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Forecasting

Product and

Service Design

Technological

Change

Capacity

Planning

ProcessSelection

Facilities and

Equipment

Layout

Work

Design

Figure 6.1

Process Selection and System Design


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Key aspects of process strategy Capital intensive equipment/labor

Process flexibility

Adjust to changes

Design

Volume

technology

Process Strategy


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Job shop Small scale

Batch

Moderate volume

Repetitive/assembly line

High volumes of standardized goods or services

Continuous

Very high volumes of non-discrete goods

Process Types


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Process Type

Job Shop Appliance repairEmergency

room

Not

feasible

Batch Commercial

bakeryClassroom

Lecture

Repetitive Automotiveassembly

Automatic

carwash

Continuous

(flow)

Not

feasible

Oil refinery

Water purification

Figure 6.2

ProductProcess Matrix


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Dimension

Job variety Very High Moderate Low Very low

Process

flexibility

Very High Moderate Low Very low

Unit cost Very High Moderate Low Very low

Volume of

output

Very High Low High Very low

Figure 6.2 (contd)

ProductProcess Matrix

6 8 P S l ti d F ilit L t


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Automation: Machinery that has sensing andcontrol devices that enables it to operate

Fixed automation

Programmable automation

Automation



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Computer-aided design andmanufacturing systems (CAD/CAM)

Numerically controlled (NC) machines

Robot Manufacturing cell

Flexible manufacturing systems(FMS)

Computer-integrated manufacturing (CIM)

Automation



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Layout: the configuration of departments,work centers, and equipment, with particular

emphasis on movement of work (customers

or materials) through the system

Facilities Layout



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Requires substantial investments of moneyand effort

Involves long-term commitments

Has significant impact on cost and efficiencyof short-term operations

Importance of Layout Decisions



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Inefficient operations

For Example:

High Cost

Bottlenecks

Changes in the design

of products or services

The introduction of new

products or services

Accidents

Safety hazards

The Need for Layout Decisions

6 13 Process Selection and Facility Layout


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Changes inenvironmental

or other legal

requirements

Changes in volume of

output or mix of

products

Changes in methodsand equipment

Morale problems

The Need for Layout Design (Contd)



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Product layouts

Process layouts

Fixed-Position layout

Combination layouts

Basic Layout Types



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Product layout Layout that uses standardized processing

operations to achieve smooth, rapid, high-volume flow

Process layout Layout that can handle varied processing

requirements

Fixed Position layout Layout in which the product or project remains

stationary, and workers, materials, andequipment are moved as needed

Basic Layout Types



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Raw

materials

or customer

Finished

item

Station

2

Station

3

Station

4

Material

and/or

labor

Station

1

Material

and/or

labor

Material

and/or

labor

Material

and/or

labor

Used for Repetitive or Continuous Processing

Figure 6.4

Product Layout



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High rate of output Low unit cost

Labor specialization

Low material handling cost

High utilization of labor and equipment

Established routing and scheduling

Routing accounting and purchasing

Advantages of Product Layout



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Creates dull, repetitive jobs Poorly skilled workers may not maintain

equipment or quality of output

Fairly inflexible to changes in volume Highly susceptible to shutdowns

Needs preventive maintenance

Individual incentive plans are impractical

Disadvantages of Product Layout



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Can handle a variety of processingrequirements

Not particularly vulnerable to equipment

failures Equipment used is less costly

Possible to use individual incentive plans

Advantages of Process Layouts



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In-process inventory costs can be high Challenging routing and scheduling

Equipment utilization rates are low

Material handling slow and inefficient

Complexities often reduce span of supervision

Special attention for each product or customer

Accounting and purchasing are more involved

Disadvantages of Process Layouts



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Line Balancing is the process of assigning

tasks to workstations in such a way that

the workstations have approximately

equal time requirements.

Design Product Layouts: Line Balancing



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Cycle time is the maximum time

allowed at each workstation tocomplete its set of tasks on a unit.

Cycle Time



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Percent idle time =Idle time per cycle

(N)(CT)

Efficiency = 1 Percent idle time

Calculate Percent Idle Time



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Assign tasks in order of most following

tasks.

Count the number of tasks that follow

Assign tasks in order of greatest positional

weight.

Positional weight is the sum of each tasks

time and the times of all following tasks.

Some Heuristic (intuitive) Rules:

Line Balancing Rules



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Information Requirements:1. List of departments

2. Projection of work flows

3. Distance between locations

4. Amount of money to be invested

5. List of special considerations

6. Location of key utilities

Designing Process Layouts

Documents

Chap006_Process Selection & Facility Layout