Process Selection and Facility Layout McGraw-Hill/Irwin Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved

Process Selection

and Facility Layout

Chapter 6

McGraw-Hill/Irwin Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved.

Chapter 6: Learning ObjectivesYou should be able to:

1. Explain the strategic importance of process selection

2. Describe the influence that process selection has on the organization

3. Compare the basic processing types4. Explain the need for management of technology5. List some reasons for redesign of layouts6. Describe the basic layout types, and the main

advantages and disadvantages of each7. Solve simple line-balancing problems

Instructor Slides 6-2

I. Process SelectionProcess selection

Refers to deciding on the way production of goods or services will be organized. How will we produce?

It has major implications forCapacity planningLayout of facilitiesEquipmentDesign of work systems


Process Selection and System Design

Forecasting

Product andService Design

TechnologicalChange

CapacityPlanning

ProcessSelection

Facilities andEquipment

Layout

WorkDesign


Process StrategyKey Aspects of Process Strategy:

Capital IntensityThe mix of equipment and labor that will be used by

the organization Process flexibility

The degree to which the system can be adjusted to changes in processing requirements due to such factors asProduct and service design changesVolume changesChanges in technology


Process choice is demand driven:1. Variety

How much?

2. Equipment flexibility To what degree?

3. Volume Expected output?

Process Selection

Job Shop

Repetitive

Batch

Continuous


1. Job shopSmall scale; customizable; craft

2. BatchModerate volume of related items.

3. Repetitive/assembly lineHigh volumes of standardized goods or services

4. ContinuousVery high volumes of non-discrete goods

Process Types

Job Shop BatchRepetitive/Assembly

Continuous

Description Customizedgoods orservices

Semi-standardizedgoods or services

Standardizedgoods orservices

Highly standardized

Goods or services

Advantages Able to handle a wide variety of work

Flexibility; easy to add or change products or services

Low unit cost, high volume, efficient

Very efficient, very high volume

Disadvantages

Slow, high costper unit,complexplanning andscheduling

Moderate costper unit,moderateschedulingcomplexity

Low flexibility,high cost of downtime

Very rigid, lack of variety, costly to change, very high cost of downtime

Types of Processing


Product-Process Matrix


Process Choice EffectsActivity/Function Job Shop Batch Repetitive

Continuous Projects

Cost estimation

Difficult Somewhat routine Routine Routine Simple to complex

Cost per unit High Moderate Low Low Very high

Equipment used

General purpose

General purpose Special purpose Special purpose Varied

Fixed costs Low Moderate High Very high Varied

Variable costs High Moderate Low Very low High

Labor skills High Moderate Low Low to high Low to high

Marketing Promotecapabilities

Promotecapabilities; semi-standardized goods and services

Promotestandardized goods/services

Promotestandardized goods/services

Promotecapabilities

Scheduling Complex Moderately complex

Routine Routine Complex, subject

to change

Work –in-processinventory

High High Low Low VariedInstructor Slides 6-10

Product and Service ProfilingProcess selection involves

Substantial investment in equipment Has a very specific influence on layout

Product or service profiling Linking key product or service requirements to process

capabilities Key dimensions relate to

Range of products or services that will be processed Expected order sizes Pricing strategies Expected frequency of schedule changes Order-winning requirements


Selecting a ProcessSelecting your process depends upon the

characteristics of your product. For the following examples, what is the BEST process? Why?(1)Upscale, gourmet restaurant serving French cuisine, each meal prepared by hand by the Chef.

(2)Cheesecake company specializing in 13 varieties of cheesecakes, shipped to individual customers and restaurants.

TechnologyTechnological Innovation

The discovery and development of new or improved products, services, or processes for producing or providing them

TechnologyThe application of scientific discoveries to the

development and improvement of products and services and/or the processes that produce or provide them


AutomationMachinery that has sensing and control devices

that enable it to operate automaticallyFixed automationProgrammable automationFlexible automation

Automation


Programmable AutomationProgrammable Automation

Involves the use of high-cost, general-purpose equipment controlled by a computer program that provides both the sequence of operations and specific details about each operationComputer-Aided Manufacturing (CAM)

The use of computers in process control, ranging from robots to automated quality control

Numerically Controlled (N/C) Machines Machines that perform operations by following mathematical

processing instructionsRobot

A machine consisting of a mechanical arm, a power supply, and a controller


Flexible AutomationFlexible automation

evolved from programmable automation. It uses equipment that is more customized than that of programmable automation. A key difference between the two is that flexible automation requires significantly less changeover time. FMS (Flexible Manufacturing System)

A group of machines designed to handle intermittent processing requirements and produce a variety of similar products

CIM (Computer Integrated Manufacturing) A system for linking a broad range of manufacturing activities

through an integrated computer system


II. Facilities LayoutLayout

the configuration of departments, work centers, and equipment, with particular emphasis on movement of work (customers or materials) through the system

Facilities layout decisions arise when:Designing new facilitiesRe-designing existing facilities


Does Layout Matter? Read……

“Designing Supermarkets”, page 258/186.

1. Does the layout of the supermarket influence customers purchasing habits?

2. Identify specific layout strategies supermarkets use to get you to spend more.

1. What are the most profitable items? 2. Where are they? Why?

3. What is “the prison”?

1. Inefficient operationsHigh costBottlenecks

2. Accidents or safety hazards3. Changes in product or service design4. Introduction of new products or services5. Changes in output volume or product mix6. Changes in methods or equipment7. Changes in environmental or other legal

requirements8. Morale problems

The Need for Layout Planning


Layout Design Objectives Basic Objective

Facilitate a smooth flow of work, material, and information through the system

Supporting objectives1. Facilitate product or service quality2. Use workers and space efficiently3. Avoid bottlenecks4. Minimize material handling costs5. Eliminate unnecessary movement of workers or material6. Minimize production time or customer service time7. Design for safety


Basic Layout Types

1. Product layouts

2. Process layouts

3. Fixed-Position layout

4. Combination layouts


Product layout Layout that uses standardized processing

operations to achieve smooth, rapid, high-volume flow

Repetitive Processing: 1. Product Layouts

Used for Repetitive ProcessingRepetitive or Continuous

Raw materialsor customer Finished

itemStation

2 Station

3Station

4

Material and/or labor




Station 1


Product Layouts: Advantages & Disadvantages

Advantages High rate of output Low unit cost Labor specialization Low material handling cost

per unit High utilization of labor and

equipment Established routing and

scheduling Routine accounting,

purchasing, and inventory control

Disadvantages Creates dull, repetitive jobs Poorly skilled workers may not

maintain equipment or quality of output

Fairly inflexible to changes in volume or product or process design

Highly susceptible to shutdowns

Preventive maintenance, capacity for quick repair and spare-parts inventories are necessary expenses

Individual incentive plans are impractical


Process layoutsLayouts that can handle varied processing

requirements

Non-repetitive Processing: 2. Process Layouts

Used for Intermittent processingJob Shop or Batch

Dept. A

Dept. B Dept. D

Dept. C

Dept. F

Dept. E


Process Layouts: Advantages & Disadvantages

Advantages Can handle a variety of

processing requirements Not particularly vulnerable

to equipment failures General-purpose

equipment is often less costly and easier and less costly to maintain

It is possible to use individual incentive systems

Disadvantages In-process inventories can be

high Routing and scheduling pose

continual challenges Equipment utilization rates are

low Material handling is slow and

inefficient Reduced spans of supervision Special attention necessary for

each product or customer Accounting, inventory control,

and purchasing are more involved


Fixed Position layoutLayout in which the product or project remains

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

3. Fixed Position Layouts


4. Combination LayoutsSome operational environments use a

combination of the three basic layout types: Hospitals Supermarket Shipyards

Some organizations are moving away from process layouts in an effort to capture the benefits of product layouts Cellular manufacturing Flexible manufacturing systems


Service LayoutService layouts can be categorized as:

product, process, or fixed positionService layout requirements are somewhat

different due to such factors as: Degree of customer contact Degree of customization

Common service layouts: Warehouse and storage layouts Retail layouts Office layouts


Cellular LayoutsCellular production

Layout in which workstations are grouped into a cell that can process items that have similar processing requirementsGroupings are determined by the operations

needed to perform the work for a set of similar items, part families, that require similar processing

The cells become, in effect, miniature versions of product layouts


Group TechnologyGroup technology

The grouping into part families of items with similar design or manufacturing characteristicsDesign Characteristics:

SizeShapeFunction

Manufacturing or processing characteristicsType of operations requiredSequence of operations required

Requires a systematic analysis of parts to identify the part families


Service LayoutsTwo key factors:

Customer contactDegree of customization

Layouts:Warehouse and storage layoutsRetail layoutsOffice layouts


III. Line BalancingLine balancing

The process of assigning tasks to workstations in such a way that the workstations have approximately equal time requirements

Goal:Obtain task grouping that represent approximately

equal time requirements since this minimizes idle time along the line and results in a high utilization of equipment and labor

Why is line balancing important?1. It allows us to use labor and equipment more

efficiently.2. To avoid fairness issues that arise when one

workstation must work harder than another.Instructor Slides 6-32

Line Balancing is the process of assigning tasks to workstations in such a way that the workstations have approximately equal time requirements.

Line Balancing

***** Open the Word file on the course website for Chapter 6 for specific notes on line balancing that we will use in class and examples we will work.

Cycle TimeCycle time

The maximum time allowed at each workstation to complete its set of tasks on a unit

Cycle time also establishes the output rate of a line

timeCycle

dayper timeOperating rateOutput

rateoutput Desired

dayper timeOperating timeCycle


How Many Workstations are Needed?

The required number of workstations is a function ofDesired output rateOur ability to combine tasks into a

workstationTheoretical minimum number of

stations

s task timeof Sum

stations ofnumber minimum ltheoretica

where

timeCycle

min

min

t

N

tN


Precedence DiagramPrecedence diagram

A diagram that shows elemental tasks and their precedence requirements


Assigning Tasks to Workstations Heuristic Rules for Line Balancing that

we will use in the class, and must be used on homework and exams:1. Assign task with no predecessors (or where

proceeding tasks have already been assigned).2. Assign tasks in order of most following tasks

1. Count the number of tasks that follow

3. Assign tasks in order of longest processing time.

YOU MUST KNOW THESE RULES.


Measuring EffectivenessBalance delay (percentage of idle time)

Percentage of idle time of a line

Efficiency Percentage of busy time of a line

stations ofnumber Actual

where

100 timeCycle

cycleper timeIdleDelay Balance

actual

actual

N

N

Delay Balance - 100%Efficiency


HomeworkFinish any examples in class notesPage 277, problem 1, a,b,c,d,ePage 278, problem 4, a (1,2,3,4)Page 278, problem 5, a, b, c (based on

min. cycle time), d (use line balancing rules for this class)

Line Balancing Rules for this class1. Assign tasks with no predecessors (or

tasks have been assigned)2. Assign tasks with greatest number of

following tasks3. Assign tasks with longest processing

time.

Documents

Process Selection and Facility Layout McGraw-Hill/Irwin Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved