IE 271Operations Analysis and Design

Lecture 1

Introduction

What is Production?

Production is transformation of inputs into outputs

ProductionInputs Outputs

- Raw Materials- Labor- Energy- Machines- Money- Information

- Goods Produced (Manufacturing)- Services Provided (Service)

Production

Cutting Drilling Casting Molding Assembling Painting ...

Production is transformation of inputs into outputs

Some examples of the transformation processes in manufacturing systems.

Car Manufacturers: The whole production system consists of manufacture and assembly of cars together with services like sales, distribution, marketing etc.

Production vs Manufacturing?

Production is a broader term that corresponds to all activities required in a transformation process until a valuable good or service is obtained

Production and Manufacturing are not equivalent terms

Manufacturing

Production

Manufacturing and Production Systems Manufacturing is the ability to make goods and services to

satisfy societal needs Manufacturing processes are strung together to create a

manufacturing system (MS) Production system is the total company and includes

manufacturing systems

The manufacturing system converts inputs to outputs using processes to add value to the goods for the external customer.

Manufacturing - Technologically

The functions and systems of the production system, which includes (and services) the manufacturing system.

Manufacturing Systems

Raw MaterialInventory

Finished GoodsInventory

. . .

Work - In - Process

Suppliers

Customers

Raw material can be stored in the warehouse (Raw Materials Inventory)

Subparts can be stored during the process, between the departments (Work-In-Process Inventory)

Finished Goods can be stored at the warehouse (Finished Goods Inventory)

Types of Manufacturing

Manufacturing can be discrete or continuous.

Continuous process industries involve the continuous production of product, often using chemical rather than physical or mechanical means, e.g. sugar, paper, glass

Discrete parts production involves the production of individual items, e.g. cars, appliances, etc.

Discrete Manufacturing Layout Product Layout (Flow Shop): arrange activities in a

line according to the sequence of operations that need to be performed to assemble a particular product

Process Layout (Job Shop): group similar activities, together in departments or work centers according to the process or function they perform

Project Shop: Immobile item being manufactured (e.g planes, ships, etc)

P - Q Relationship in Plant Layout

Process Layout

Layout in which equipment is arranged according to function

Suited to low and medium production quantities and medium to high product variety

Different parts or products are processed through different operations in batches Each batch follows its own routing

No common work flow followed by all work units Material handling activity is significant

Process Layout

Process Layout (Job Shop)

Product Layout

Layout in which workstations and equipment are located along the line of flow of the work units

Suited to high production quantities and low product variety

Work units typically moved by powered conveyor At each workstation, a small amount of the total

work content is accomplished on each work unit Each station specializes in its task, thus achieving high

efficiency

Product Layout for Assembled Product

Product Layout (Flow Shop)

Flow Shop

Figure 1-8 The moving assembly line for cars is an example of the flow shop.

Assembly workers on an engine assembly line (photo courtesy of Ford Motor Company).

Product Layout Process Layout

Description Sequential arrangement of activities Functional grouping of activities

Type of Process Continuous, mass production, assembly Intermittent, job shop, batch production

Product Standardized, made to stock Varied, made to order

Demand Stable Fluctuating

Volume High Low

Equipment Special Purpose General Purpose

Workers Limited Skills Varied Skills

Inventory Low WIP, High FG High WIP, Low FG

Storage Space Small Large

Material Handling Fixed Path (conveyor) Variable Path (Forklifts)

Aisles Narrow Wide

Scheduling Part of Balancing Dynamic

Layout Decisions Line Balancing Machine Location

Goal Equalize work at each station Min. Mat. Handling Costs

Advantage Efficiency Flexibility

Fixed-Position Layout

Layout in which product remains in one location during fabrication, and workers and equipment are brought to the product

Suited to low production quantities and high product variety

Reason for keeping product in one location: Product is big and heavy

Typical plants: assembly and fabrication Much manual labor Equipment is portable or mobile

Fixed-Position Layout

Assembly operations on the Boeing 777 (photo courtesy of Boeing Commercial Airplane Co.).

Hybrid Layouts

Cellular - attempts to combine the best features of process and product layouts

Combinations of fixed position and either Process layout or Product layout

Cellular Layout

Layout in which work units flow between stations, as in a production line, but each station can cope with a variety of part styles without the need for time-consuming changeovers

Combination of product and process layouts Tries to combine efficiency of product layout with versatility

of process layout Neither objective is achieved perfectly, but it is more efficient

than a process layout and more versatile than a product layout

Based on principles of group technology

Cellular Layout

A machining cell consisting of two horizontal machining centers supplied by an in-line pallet shuttle (photo courtesy of Cincinnati Milacron).

Cellular Layout

A robotic arm performs unloading and loading operation in a turning center using a dual gripper (photo courtesy of Cincinnati Milacron).

Other Combination Layouts

Fixed-position and process layout Shipyard - ships made in modules

Parts fabricated in process layout Modules built in fixed-position layout

Fixed-position and product layout Commercial airplanes (e.g., Boeing 747)

Fabrication begins with fuselage and proceeds through 7 or so stations where specialized workers assemble parts and modules to airplane

Layout Types for P-Q Combinations

Project Layout

Usually refers to construction project Work teams and equipment are brought to the work

site Layout is temporary because project has scheduled

completion date Project layout vs. fixed-position layout:

Product is large and heavy In fixed-position layout, when product is completed, it is

transported away In project layout, product remains, workers and equipment

are transported away

Mass Production to Lean Production

The traditional subassembly lines can be redesigned into U-shaped cells as part of the conversion of mass production to lean production.

New Manufacturing Systems

Toyota Production System Lean manufacturing system 100% good units flow without interruption Integrated quality control Responsibility for quality is given to manufacturing Constant quality improvement

Order Driven vs. Stock Driven Manufacturing Systems Make to stock (MTS) Assemble to order (ATO) Make to order (MTO) Engineer to order (ETO)

Order and Stock Driven Systems Make to Stock (MTS)

Customer demand is forecasted for future periods. Finished goods are produced in large quantities and stored in a

warehouse. When customer order is received, the item is sold from the stocks

(warehouse). When the quantity remaining in the stocks falls down under

critical levels, the item is produced again. Suitable when the demand is large and more or less predictable. Delivery of the product to the customer is determined by the

availability in the warehouse and the stock replenishment mechanism.

Order and Stock Driven Manuf. Systems

Make to Order (MTO) Products are selected by the customers based on

a catalog of available designs Manufacturing of the finished good starts only

after the customer order is received Generally, there are time lags between the

delivery time of the product to the customer and the time order is placed

Kitchen Furniture

Order and Stock Driven Systems Assemble to Order (ATO)

Similar to MTO Products are configured or assembled to

customer order from a set of core subassemblies or components

Customer makes a contact with the manufacturer through their sales organization

Laptop computer

Order and Stock Driven Systems

Engineer to Order (ETO) Customer order requires that a new engineering

design be developed The product is designed specifically for the needs

of the customer ETO products are one of a kind products

New Manufacturing Environment

Increased product diversity

Greatly reduced product life cycles

Environmental impact of manufacturing systems

Changing cost patterns

Changing social expectations

Industrial Revolution

Mechanization is the replacement of human labor by machine

Automation is replacement of human control of machines by automatic control CNC (Computer Numerical Control) Machines

Performs computerized manufacturing operations Computer Aided Drawing (CAD) ERP Systems:

Very large scaled information system software which automates various operational activities in the production system

Robots Reprogrammable multi-functional manipulator, designed to move

material, parts, tools or specialized devices through variable programmed motions for the performance of a variety of tasks.

Industrial Engineering - Definitons “The engineering approach applied to all factors,

including the human factor, involved in the production and distribution of products or services”

“Industrial Engineering is concerned with the design, improvement and installation of integrated systems of people, material, equipment and energy. It draws upon specialized knowledge and skills in the mathematical, physical and social sciences together with the principles and methods of enginering analysis and design to specify, predict and evaluate the results to be obtained from such systems”

Industrial Engineering

Finding ways of utilizing input resources in a more cost-effective manner

Has been originated out of the need of businesses and military organizations.

History of Industrial Engineering Matthew Bolton and James Watt (around

1795) Modern, closely integrated factory to produce

steam engines Standards for detecting waste and inefficiency Used methods for forecasting, plant location and

layout, wage incentives 100-150 years ahead of their time

History of Industrial Engineering Applied economists and industrialists in

England around 1800 Adam Smith – specialization of labor

Development of new skills when a single task is performed

Saving of time lost in changing from one task to another Invention of new, special-purpose tools and equipment

Charles Babbage Not necessary to pay for skill levels used only during a

fraction of the total job

History of Industrial Engineering Developments in America

Frederick W. Taylor (early 1900s) The Principles of Scientific Management

Frank and Lillian Gilbreth Henry Gantt

Gantt chart still used by today as a preliminary scheduling aid.

History of Operations Research World War II

Groups of mathematicians, economists and other scientists formed in England and in the US

Navy employing more than 70 scientists Variety of problems such as

radar installations,

search for enemy submarines,

deploy aerial mines in the seas around Japan,

determining optimal size of merchant convoy fleets,

development of maneuver strategies for ships under attack

...

History of Operations Research

After World War II Industrial firms in England and the US

attempting to apply it to their operational and managerial problems

Issues attacked by people such as Taylor and Gantt being addressed using more quantitative and systems-oriented procedures

George Dantzig Development of linear programming

IE – OR

Traditional IE and OR can be considered as a continuum where IE is at one end and OR is at the other

Traditional IE tends to be more applicable to problems in a manufacturing environment

OR has a broader scope OR has more mathematical approaches than

traditional IE

IE vs OR

Somewhat separate histories Common mission

Providing effective, efficient answers to questions relating to design, analysis and evaluation.

N. Barish says OR is the applied science for managerial systems,

whereas IE is the engineering of managerial systems. Each student will develop their own philosophy of

the relationship between the two areas in time.

Description Activity Courses

Determining the most appropriate manufacturing operations and tooling to use to produce a particular product

Manufacturing

Processes

IE262

Setting time standards for various manufacturing jobs, such as welding two plates together

Work Measurement

IE271

Designing efficient and effective methods for work tasks Work Methods IE271

Evaluating the economic costs and benefits of one or more investment alternatives

Engineering Economy

IE342

Designing the best layout of a facility so that travel distances are minimized

Facility Layout IE271 + El

Determining the location of fewest number of fire stations required to provide a response time of no greater than 5 minutes

Facility Location Elective

Determine how much to produce and when to produce Production Planning

IE375

Examples of IE/OR Activities

Examples of IE/OR ActivitiesDetermining the best system for moving goods within a set of

facilitiesMaterial Handling

IE271

Mathematical modeling of decision problems involving allocation of scarce resources, finding optimal solutions

Mathematical Programming

IE202 – IE303

Estimation of average waiting times in front of a bank teller Queueing IE325

Determining optimal reorder and order quantities of inventories Inventory IE325 + El

Forecasting future demand figures Forecasting IE375

Determining the sequence of jobs in order to meet due dates Scheduling IE375 + El

Designing acceptance tests to ascertain a quality level Quality Control IE380

Determining the method of cutting the maximum number of shirt patterns from a large piece of cloth to minimize scrap

Cutting Stock IE202 + Elective

Determining the most efficient procedures of assembling a bicycle Methods Improvement

IE271

Industrial Engineering

IE uses engineering concepts, mathematics, economics, and principles of human behavior to design and implement more efficient, more productive systems.

What is more efficient? What is more productive? How can you quantify them?

Work

Is our primary means of livelihood Serves an important economic function in

the global world of commerce Creates opportunities for social

interactions and friendships Provides the products and services that

sustain and improve our standard of living

The Nature of Work

Work is an activity in which one exerts physical and mental effort to accomplish a given task or perform a duty

Task or duty has some useful objective Worker applies skills and knowledge for

successful completion The activity has commercial value The worker is compensated

The Pyramidal Structure of Work Work consists of tasks

Tasks consist of work elements Work elements consist of basic motion elements

Task

An amount of work that is assigned to a worker or for which a worker is responsible

Repetitive task – as in mass production Time required = 30 seconds to several minutes

Non-repetitive task – performed periodically, infrequently, or only once Time required usually much longer than for

repetitive task

Work Element

A series of work activities that are logically grouped together because they have a unified function in the task

Example: assembling a component to a base part using several nuts and bolts

Required time = six seconds or longer

A Work System as a Physical Entity

Productivity

The level of output of a given process relative to the level of input

Process can refer to Individual production or service operations A national economy

Productivity is an important metric in work systems because Improving productivity is the means by which worker

compensation can be increased without increasing the costs of products and services they produce

Labor Productivity

The most common productivity measure is labor productivity, defined by the following ratio:

LPR =

where LPR = labor productivity ratio, WU = work units of output, LH = labor hours of input

LH

WU

Labor Factor in Productivity Labor itself does not contribute much to

improving productivity More important factors:

Capital - substitution of machines for human labor

Technology - fundamental change in the way some activity or function is accomplished

Measuring Productivity

Not as easy as it seems because of the following problems: Non-homogeneous output units Multiple input factors

Labor, capital, technology, materials, energy Price and cost changes due to economic forces Product mix changes

Relative proportions of products that a company sells change over time

Labor Productivity Index

Measure that compares input/output ratio from one year to the next

LPI =

where LPI = labor productivity index,

LPRt = labor productivity ratio for period t, and

LPRb = labor productivity ratio for base period

b

t

LPR

LPR

Example: Productivity Measurement During the base year in a small steel mill,

326,000 tons of steel were produced using 203,000 labor hours. In the next year, the output was 341,000 tons using 246,000 labor hours.

Determine: (a) the labor productivity ratio for the base year, (b) the labor productivity ratio for the second year, and (c) the productivity index for the second year.

Example: Solution

(a) In the base year, LPR = 326,000 / 203,000= 1.606 tons per labor hour

(b) In the second year, LPR = 341,000 / 246,000

= 1.386 tons per labor hour(c) Productivity index for the second year

LPI = 1.386 / 1.606 = 0.863 Comment: No matter how it’s measured,

productivity went down in the second year.

Productive Work Content

A given task performed by a worker can be considered to consist of

Basic productive work content Theoretical minimum amount of work required to

accomplish the task Excess nonproductive activities

Extra physical and mental actions of worker Do not add value to the task Do not facilitate the productive work content Take time

Excess Nonproductive Activities Can be classified into three categories:

Excess activities due to poor design of product or service

Excess activities caused by inefficient methods, poor workplace layout, and interruptions

Excessive activities cause by the human factor

Productivity

Productivity measures the capability of processing inputs to convert to outputs.

It simply measures how much output is produced relative to the inputs of labor, capital (plant and equipment), and technology

A process may be productive but may not be efficient

Efficiency

Efficiency denotes the maximum utilization on one’s given resources

Efficiency is generally a relative term, used for comparison. Its focus is on the best utilization of resources.

Elimination of some adjacent bank branches as a result of merge of two banks would attain greater efficiency, while a termination of employment due to teller machines would cause greater productivity.

Standard Time-Based Performance Index

100 employees produce 5000 units of a given product in one day. The productivity is 50 units/employee per day.

Standard time to assemble:

a grinder=2min/unit;

an operator assembles 275 grinders/day,

work duration is 8 hrs/day (480 min/day).

Performance Index = (2*275)/480 = 114.6 %

Factors that facilitate productivity improvement: Technological Innovation:

faster machines, eliminate heavy physical work and repetitive operations

increased capital investment, complex machinery, skilled operators

Effective Management Employee motivation, better marketing, etc.

Questions we will deal with in this course: How is work done? What is a better way of doing it? (Setup times,

loading/unloading, inspection, actual operations) How long does the work take to complete? What is the frequency of work? We will use

Work Study: Time Study (Taylor) and Motion Study (Gilbreths)

Plant Layout

Work Study for Increased Productivity Motion Study

Eliminate unnecessary work Design efficient and effective methods and

procedures most suitable to the employees

Time Study Measurement of work to determine standard

times.