Materials and processes in manufacturing

7.9 The Role of Processing on Cast Properties 179Chapter 8 Nonferrous Metals and Other Materials Designed for Chapter 9 Nonmetallic Materials: Plastics, Elastomers, Ceramics, Chapter 10

Missouri University of Science & Technology

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It’s a world of manufactured goods Whether we like it or not, we all live in a cal society Every day we come in contact with hundreds of manufactured items, madefrom every possible material From the bedroom to the kitchen, to the workplace, weuse appliances, phones, cars, trains, and planes, TVs, cell phones, VCRs, DVD’s, furni-ture, clothing, sports equipment, books and more! These goods are manufactured infactories all over the world using manufacturing processes

technologi-Basically, manufacturing is a value-adding activity, where the conversion of rials into products adds value to the original material Thus, the objective of a companyengaged in manufacturing is to add value and to do so in the most efficient manner, withthe least amount of waste in terms of time, material, money, space, and labor To mini-mize waste and increase productivity, the processes and operations need to be properlyselected and arranged to permit smooth and controlled flow of material through thefactory and provide for product variety Meeting these goals requires an engineer whocan design and operate an efficient manufacturing system Here are the trends that areimpacting the manufacturing world

mate- Manufacturing is a global activityManufacturing is a global activity with companies sending work to other countr-ies (China, Taiwan, Mexico) to take advantage of low-cost labor Many US compa-nies have plants in other countries and foreign companies have built plants in theUnited States, to be nearer their marketplace Automobile manufacturers from allaround the globe and their suppliers use just about every process described in thisbook and some that we do not describe, often because they are closely held secrets

 It’s a digital worldInformation technology and computers are growing exponentially, doubling inpower every year Every manufacturing company has ready access to world-wide dig-ital technology Products can be built by suppliers anywhere in the world workingusing a common set of digital information Designs can be emailed to manufacturerswho can rapidly produce a prototype in metal or plastic in a day

 Lean manufacturing is widely practicedMost (over 60%) manufacturing companies have restructured their facto-ries (their manufacturing systems) to become lean producers, making goods ofsuperior quality, cheaper, faster in a flexible way (i.e., they are more responsive

to the customers) Almost every plant is doing something to make itself leaner.Many of them have adopted some version of the Toyota Production System.More importantly, these manufacturing factories are designed with the internalcustomer (the workforce) in mind, so things like ergonomics and safety are keydesign requirements So while this book is all about materials and processes formaking the products, the design of the factory cannot be ignored when it comes

to making the external customer happy with the product and the internal tomer satisfied with the employer

cus- New products and materials need new processesThe number and variety of products and the materials from which they aremade continues to proliferate, while production quantities (lot sizes) have becomesmaller Existing processes must be modified to be more flexible, and new processesmust be developed

 Customers expect great qualityConsumers want better quality and reliability, so the methods, processes, andpeople responsible for the quality must be continually improved The trend toward(improving) zero defects and continuous improvement requires continual changes tothe manufacturing system

iii

 Rapid product development is requiredFinally, the effort to reduce the time-to-market for new products is continuing.Many companies are taking wholistic or system wide perspectives, including concur-rent engineering efforts to bring product design and manufacturing closer to the cus-tomer There are two key aspects here First, products are designed to be easier tomanufacture and assemble (called design for manufacture/assembly) Second, themanufacturing system design is flexible (able to rapidly assimilate new products), sothe company can be competitive in the global marketplace.

E Paul DeGarmo was a mechanical engineering professor at the University of nia, Berkley when he wrote the first edition of Materials and Processes in Manufactur-ing, published by Macmillan in 1957 The book quickly became the emulated standardfor introductory texts in manufacturing Second, third, and fourth editions followed in

Califor-1962, 1969, and 1974 DeGarmo had begun teaching at Berkeley in 1937, after earninghis M.S in mechanical engineering from California Institute of Technology DeGarmowas a founder of the Department of Industrial Engineering (now Industrial Engineer-ing and Operations Research) and served as its chair from 1956–1960 He was alsoassistant dean of the College of Engineering for three years while continuing his teach-ing responsibilities

Dr DeGarmo observed that engineering education had begun to place moreemphasis on the underlying sciences at the expense of hands on experience Most of hisstudents were coming to college with little familiarity with materials, machine tools, andmanufacturing methods that their predecessors had acquired through the old‘‘shop’’classes If these engineers and technicians were to successfully convert their ideas intoreality, they needed a foundation in materials and processes, with emphasis on theiropportunities and their limitations He sought to provide a text that could be used ineither a one-or two-semester course designed to meet these objectives The materialssections were written with an emphasis on use and application Processes and machinetools were described in terms of what they could do, how they do it, and their relativeadvantages and limitations, including economic considerations Recognizing that manystudents would be encountering the material for the first time, clear description wasaccompanied by numerous visual illustrations

Paul’s efforts were well received, and the book quickly became the standard text inmany schools and curricula As materials and processes evolved, advances were incorpo-rated into subsequent editions Computer usage, quality control, and automation wereadded to the text, along with other topics, so that it continued to provide state-of-the-artinstruction in both materials and processes As competing books entered the market,their subject material and organization tended to mimic the DeGarmo text

Paul DeGarmo retired from active teaching in 1971, but he continued hisresearch, writing, and consulting for many years In 1977, after the publication of thefourth edition of Materials and Processes in Manufacturing, he received a letter fromRon Kohser, then an assistant professor at the University of Missouri-Rolla who hadmany suggestions regarding the materials chapters DeGarmo asked Ron to rewritethose chapters for the upcoming fifth edition After the 5th edition DeGarmo decided

he was really going to retire and after a national search, recruited J T Black, then aProfessor at Ohio State, to co-author the book with Dr Kohser

For the sixth through tenth editions (published in 1984 and 1988 by Macmillan,

1997 by Prentice Hall and 2003 and 2008 by John Wiley & Sons), Ron Kohser and

J T Black have shared the responsibility for the text The chapters on engineeringmaterials, casting, forming, powder metallurgy, additive manufacturing, joining andnon-destructive testing have been written or revised by Ron Kohser J T Black hasresponsibility for the introduction and chapters on material removal, metrology,surface finishing, quality control, manufacturing systems design, and lean engineering.DeGarmo died in 2000, three weeks short of his 93rd birthday His wife Mary died

in 1995; he is survived by his sons, David and Richard, and many grandchildren For the

10th edition, which coincided with the 50th anniversary of the text, we honored ourmentor with a change in the title to include his name—DeGarmo’s Materials and Pro-cesses in Manufacturing We recognize Paul for his insight and leadership and are for-ever indebted to him for selecting us to carry on the tradition of his book for this, the11th edition!

The purpose of this book is to provide basic information on materials, manufacturingprocesses and systems to engineers and technicians The materials section focuses onproperties and behavior Thus, aspects of smelting and refining (or other material pro-duction processes) are presented only as they affect manufacturing and manufacturedproducts In terms of the processes used to manufacture items (converting materialsinto products), this text seeks to provide a descriptive introduction to a wide variety ofoptions, emphasizing how each process works and its relative advantages and limita-tions Our goal is to present this material in a way that can be understood by individualsseeing it for the very first time This is not a graduate text where the objective is to thor-oughly understand and optimize manufacturing processes Mathematical models andanalytical equations are used only when they enhance the basic understanding of thematerial So, while the text is an introductory text, we do attempt to incorporate newand emerging technologies like direct-digital-and micro-manufacturing processes asthey are introduced into usage

E Paul DeGarmo wanted a book that explained to engineers how the things theydesigned are made DeGarmo’s Materials and Processes in Manufacturing is stillbeing written to provide a broad, basic introduction to the fundamentals of man-ufacturing The book begins with a survey of engineering materials, the ‘‘stuff’’that manufacturing begins with, and seeks to provide the basic information thatcan be used to match the properties of a material to the service requirements of

a component A variety of engineering materials are presented, along with theirproperties and means of modifying them The materials section can be used incurricula that lack preparatory courses in metallurgy, materials science, orstrength of materials, or where the student has not yet been exposed to thosetopics In addition, various chapters in this section can be used as supplements to

a basic materials course, providing additional information on topics such as heattreatment, plastics, composites, and material selection

Following the materials chapters are sections on casting, forming, powder lurgy, material removal, and joining Each section begins with a presentation of the fun-damentals on which those processes are based The introductions are followed by adiscussion of the various process alternatives, which can be selected to operate individ-ually or be combined into an integrated system

metal-The chapter on rapid prototyping, which had been moved to a web-based ment in the 10th edition, has been restored to the print text, significantly expanded, andrenamed Additive Processes: Rapid Prototyping and Direct-Digital Manufacturing, toincorporate the aspects of rapid prototyping, rapid tooling, and direct-digital manufac-turing, and provide updated information on many recent advances in this area

supple-Reflecting the growing role of plastics, ceramics and composites, the chapter onthe processes used with these materials has also been expanded

New to this edition is an Advanced Topic section on lean engineering The leanengineer works to transform the mass production system into a lean production system

To achieve lean production, the final assembly line is converted to a mixed model ery system so that the demand for subassemblies and components is made constant Theconveyor type flow lines are dismantled and converted into U-shaped manufacturingcells also capable of one-piece flow The subassembly and manufacturing cells arelinked to the final assembly by a pull system called Kanban (visible record) to form anintegrated production and inventory control system Hence, economy of scale of the

mass production system changed to the‘‘Economy of Scope’’, featuring flexibility,small lots, superior quality, minimum-inventory and short throughput times.

Later chapters provide an introduction to surface engineering, measurements andquality control Engineers need to know how to determine process capability and if theyget involved in six sigma projects, to know what sigma really measures There is alsointroductory material on surface integrity, since so many processes produce the finishedsurface and residual stresses in the components

With each new edition, new and emerging technology is incorporated, and ing technologies are updated to accurately reflect current capabilities Through its 50-plus year history and 10 previous editions, the DeGarmo text was often the first intro-ductory book to incorporate processes such as friction-stir welding, microwave heatingand sintering, and machining dynamics

exist-Somewhat open-ended case studies have been incorporated throughout the text.These have been designed to make students aware of the great importance of properlycoordinating design, material selection, and manufacturing to produce cost competi-tive, reliable products

The text is intended for use by engineering (mechanical, lean, manufacturing, andindustrial) and engineering technology students, in both two-and four-year under-graduate degree programs In addition, the book is also used by engineers and technolo-gists in other disciplines concerned with design and manufacturing (such as aerospaceand electronics) Factory personnel will find this book to be a valuable reference thatconcisely presents the various production alternatives and the advantages and limita-tions of each Additional or more in-depth information on specific materials or pro-cesses can be found in the expanded list of references that accompanies the text

For instructors adopting the text for use in their course, an instructor solutions manual isavaila ble through the book webs ite: ww w.wiley.c om/go/glo bal/degarm o Also available

on the website is a set of PowerPoint lecture slides created by Philip Appel

Two additional chapters, as well as three Advanced Topic sections, are available

on the book website These chapters cover: measurement and inspection, destructive inspection and testing, lean engineering, quality engineering, and the enter-prise (production system) The registration card attached on the inside front coverprovides information on how to access and download this material If the registrationcard is mi ssing, access can be pu r chased directly on the w ebsite www w iley.com /go/glob al/de garm o, by clicki ng on ‘‘ studen t compa nion site ’’ and then on the lin ks to thechapter titles

The authors wish to acknowledge the multitude of assistance, information, and tions that have been provided by a variety of industries, professional organizations, andtrade associations The text has become known for the large number of clear and helpfulphotos and illustrations that have been graciously provided by a variety of sources Insome cases, equipment is photographed or depicted without safety guards, so as toshow important details, and personnel are not wearing certain items of safety apparelthat would be worn during normal operation

illustra-Over the many editions, there have been hundreds of reviewers, faculty, and dents who have made suggestions and corrections to the text We continue to be grate-ful for the time and interest that they have put into this book For this edition webenefited from the comments of the following reviewers:

stu-Jerald Brevick, The Ohio State University; Zezhong Chen, Concordia University;Emmanuel Enemuoh, University of Minnesota; Ronald Huston, University ofCincinnati; Thenkurussi Kesavadas, University at Buffalo, The State University of NewYork; Shuting Lei, Kansas State University; Lee Gearhart, University at Buffalo,The State University of New York; ZJ Pei, Kansas State University; Christine Corum,

Purdue University; Allen Yi, The Ohio State University; Stephen Oneyear, NorthCarolina State; Roger Wright, Rennselaer Polytechnic Institute.

The authors would also like to acknowledge the contributions of Dr Elliot Sternfor the dynamics of machining section in Chapter 20, Dr Memberu Lulu for inputs

to the quality chapter, Dr Lewis Payton for writing the micro manufacturing chapter,

Dr Subbu Subramanium for inputs to the abrasive chapter, Dr David Cochran for hiscontributions in lean engineering and system design, and Mr Chris Huskamp of theBoeing Company for valuable assistance with the chapter on additive manufacturing

As always, our wives have played a major role in preparing the manuscript CarolBlack and Barb Kohser have endured being‘‘textbook widows’’ during the time whenthe book was being were written Not only did they provide loving support, but Carolalso provided hours of expert proofreading, typing, and editing as the manuscript wasprepared

J T Black received his Ph.D from Mechanical and Industrial Engineering, University

of Illinois, Urbana in 1969, an M.S in Industrial Engineering from West Virginia versity in 1963 and his B.S in Industrial Engineering, Lehigh University in 1960 J T isProfessor Emeritus from Industrial and Systems Engineering at Auburn University Hewas the Chairman and a Professor of Industrial and Systems Engineering at The Uni-versity of Alabama-Huntsville He also taught at The Ohio State University, the Uni-versity of Rhode Island, the University of Vermont, and the University of Illinois Hetaught his first processes class in 1960 at West Virginia University J T is a Fellow in theAmerican Society of Mechanical Engineers, the Institute of Industrial Engineering andthe Society of Manufacturing Engineers J loves to write music (mostly down homecountry) and poetry, play tennis in the backyard and show his champion pug dog VBo.Ron Kohser received his Ph.D from Lehigh University Institute for Metal Form-ing in 1975 Ron is currently in his 37th year on the faculty of Missouri University ofScience & Technology (formerly the University of Missouri-Rolla), where he is a Pro-fessor of Metallurgical Engineering and Dean’s Teaching Scholar While maintaining afull commitment to classroom instruction, he has served as department chair and Asso-ciate Dean for Undergraduate Instruction He currently teaches courses in Metallurgyfor Engineers, Introduction to Manufacturing Processes, and Material Selection, Fabri-cation and Failure Analysis In addition to his academic responsibilities, Ron and hiswife Barb operate A Miner Indulgence, a bed-and-breakfast in Rolla, Missouri, andthey enjoy showing their three collector cars

Chapter 1 Introduction to DeGarmo's

Materials and Processes in

Chapter 2 Manufacturing Systems

Chapter 3 Properties of Materials 59

Chapter 4 Nature of Metals

4.15 Cold Working, Recrystallization, and

4.18 Atomic Structure and Electrical

Chapter 6 Heat Treatment 121

Chapter 7 Ferrous Metals and

7.9 The Role of Processing on Cast Properties 179

Chapter 8 Nonferrous Metals and

Other Materials Designed for

Chapter 9 Nonmetallic Materials:

Plastics, Elastomers, Ceramics,

Chapter 10 Material Selection 248

10.2 Material Selection and Manufacturing

10.9 Effect of Product Liability on Materials

Chapter 12 Expendable-Mold Casting Processes 291

12.4 Other Expendable-Mold Processes with

Case Study Movable and Fixed Jaw Pieces for a

Chapter 13 Multiple-Use-Mold Casting Processes 323

Chapter 14 Fabrication of Plastics, Ceramics, and Composites 345

Case Study Automotive and Light Truck Fuel Tanks 378

16.8 Cold Forming, Cold Forging, and Impact

16.11 Surface Improvement by Deformation

17.5 Alternative Methods of Producing Sheet-Type

Chapter 18 Powder Metallurgy 481

18.4 Microcrystalline and Amorphous Material

18.11 Other Techniques to Produce High-Density

18.12 Metal Injection Molding or Powder Injection

18.17 Advantages and Disadvantages of Powder

Case Study Steering Gear for a Riding Lawn

Chapter 19 Additive Processes:

Rapid Prototyping and Digital Manufacturing 507

Chapter 20 Fundamentals of Machining/Orthogonal

Case Study Orthogonal Plate Machining

Chapter 21 Cutting Tools for

Case Study HSS versus Tungsten

Chapter 25 NC/CNC Processes and

Adaptive Control: A(4) and A(5)

Levels of Automation 686

Chapter 27 Workholding Devices for Machine Tools 745

Case Study Fixture versus No Fixture

Chapter 28 Nontraditional Manufacturing Processes 771

Chapter 29 Fundamentals

29.2 Classification of Welding and Thermal

30.9 Metallurgical and Heat Effects in

Case Study Bicycle Frame Construction and Repair 842

Chapter 31 Resistance- and

Case Study Manufacture of an Automobile

32.3 Surface Modification by Welding-Related

Chapter 34 Surface Engineering 912

Chapter 35 Microelectronic Manufacturing and Electronic

35.6 Fabricating Integrated Circuits on Silicon

Chapter 36 Micro/Meso/Nano Fabrication Processes 986

37.4 Inspection Methods for

Chapter 38 Nondestructive

Inspection and Testing 1041

(Web Based Chapter)

(www.wiley.com/go/global/DeGarmo)

38.1 Destructive versus Nondestructive Testing 1041

38.2 Other Methods of Nondestructive Testing

A1.4 Linked-Cell Manufacturing System

A1.6 Preliminary Steps to Lean

A1.7 Methodology for Implementation of

A1.13 Machine Tool Design for Lean

Advanced Topic 2 Quality

(Web Based Chapter)

(www.wiley.com/go/global/DeGarmo)

Advanced Topic 3 The Enterprise (Production Systems) A79 (Web Based Chapter)

(www.wiley.com/go/global/DeGarmo)

A3.4 Functional Areas in the

A3.5 Human Resources (Personnel)

CHAPTER 1

1.1 MATERIALS, MANUFACTURING,

AND THESTANDARD OFLIVING1.2 MANUFACTURING AND

PRODUCTION SYSTEMSProduction System––TheEnterprise

Manufacturing SystemsManufacturing ProcessesJob and Station

OperationTreatments

Tools, Tooling, and WorkholdersTooling for Measurement andInspection

Integrating Inspection into theProcess

Products and FabricationsWorkpiece and its ConfigurationRoles of Engineers in

ManufacturingChanging World CompetitionManufacturing System Designs

Basic Manufacutring ProcessesOther Manufacturing OperationsUnderstand Your ProcessTechnology

Product Life Cycle andLife-Cycle CostComparisons of ManufacturingSystem Design

New Manufacturing SystemsCase Study: Famous ManufacturingEngineers

AND THE STANDARD OFLIVING

Manufacturing is critical to a country’s economic welfare and standard of living becausethe standard of living in any society is determined, primarily, by the goods and servicesthat are available to its people Manufacturing companies contribute about 20% of theGNP, employ about 18% of the workforce, and account for 40% of the exports of theUnited States In most cases, materials are utilized in the form of manufactured goods.Manufacturing and assembly represent the organized activities that convert raw materialsinto salable goods The manufactured goods are typically divided into two classes: pro-ducer goods and consumer goods Producer goods are those goods manufactured for othercompanies to use to manufacture either producer or consumer goods Consumer goodsare those purchased directly by the consumer or the general public For example, someonehas to build the machine tool (a lathe) that produces (using machining processes) thelarge rolls that are sold to the rolling mill factory to be used to roll the sheets of steel thatare then formed (using dies) into body panels of your car Similarly, many service indus-tries depend heavily on the use of manufactured products, just as the agricultural industry

is heavily dependent on the use of large farming machines for efficient production.Processes convert materials from one form to another adding value to them Themore efficiently materials can be produced and converted into the desired products thatfunction with the prescribed quality, the greater will be the companies’ productivity andthe better will be the standard of living of the employees

The history of man has been linked to his ability to work with tools and materials,beginning with the Stone Age and ranging through the eras of copper and bronze, theIron Age, and recently the age of steel While ferrous materials still dominate the man-ufacturing world, we are entering the age of tailor-made plastics, composite materials,and exotic alloys

A good example of this progression is shown in Figure 1-1 The goal of the turer of any product or service is to continually improve For a given product or service,this improvement process usually follows an S-shaped curve, as shown in Figure 1-1a,often called a product life-cycle curve After the initial invention/creation and develop-ment, a period of rapid growth in performance occurs, with relatively few resourcesrequired However, each improvement becomes progressively more difficult For a delta

manufac-1

gain, more money and time and ingenuity are required Finally, the product or serviceenters the maturity phase, during which additional performance gains become very costly.For example, in the automobile tire industry, Figure 1-1b shows the evolution ofradial tire performance from its birth in 1946 to the present Growth in performance is actu-ally the superposition of many different improvements in material, processes, and design.These innovations, known as sustaining technology, serve to continually bringmore value to the consumer of existing products and services In general, sustainingmanufacturing technology is the backbone of American industry and the ever-increasing productivity metric.

Although materials are no longer used only in their natural state, there is ously an absolute limit to the amounts of many materials available here on earth There-fore, as the variety of man-made materials continues to increase, resources must beused efficiently and recycled whenever possible Of course, recycling only postponesthe exhaustion date

obvi-Like materials, processes have also proliferated greatly in the past 50 years,with new processes being developed to handle the new materials more efficiently andwith less waste A good example is the laser, invented around 1960, which now findsmany uses in machining, measurement, inspection, heat treating, welding, and more.New developments in manufacturing technology often account for improvements inproductivity Even when the technology is proprietary, the competition often gainsaccess to it, usually quite quickly

Starting with the product design, materials, labor, and equipment are interactivefactors in manufacturing that must be combined properly (integrated) to achieve lowcost, superior quality, and on-time delivery Figure 1-2 shows a breakdown of costs for a

Product Development S-Curve

Growth

Time resource

Maturity Design optimization

Run flat

Development Creation/invention

Silica

Computer modeling

Belt architectures Synthetic rubber

2010

FIGURE 1-1 (a) A product development curve usually has an ‘‘S’’-shape (b) Example of the S-curve forthe radial tire (Courtesy of Bart Thomas, Michelin)

FIGURE 1-2 Manufacturing

cost is the largest part of the

selling price, usually around

40% The largest part of the

manufacturing cost is materials,

usually 50%

Engineering cost, 15%

Manufacturing cost, 40%

Profit,

≅ 20%

Admin.

sales marketing, 25%

Equipment plant energy, 12%

Indirect labor, 26%

Direct labor, 10–12%

Subassemblies component parts and other materials

product (like a car) Typically about 40% of the selling price of a product is the facturing cost Because the selling price determines how much the customer is willing topay, maintaining the profit often depends on reducing manufacturing cost The internalcustomers who really make the product are called direct labor They are usually thetargets of automation, but typically they account for only about 10% of the manufactur-ing cost, even though they are the main element in increasing productivity In Chapter 2,

manu-a mmanu-anufmanu-acturing strmanu-ategy is presented thmanu-at manu-attmanu-acks the mmanu-aterimanu-als cost, indirect costs, manu-andgeneral administration costs, in addition to labor costs The materials costs include thecost of storing and handling the materials within the plant The strategy depends on anew factory design and is called lean production

Referring again to the total expenses shown in Figure 1-2 (selling price less profit),about 68% of dollars are spent on people, but only 5 to 10% on director labor, the break-down for the rest being about 15% for engineers and 25% for marketing, sales, andgeneral management people The average labor cost in manufacturing in the United States

is around $15 per hour for hourly workers (2010) Reductions in direct labor will have onlymarginal effects on the total people costs The optimal combination of factors for produc-ing a small quantity of a given product may be very inefficient for a larger quantity of thesame product Consequently, a systems approach, taking all the factors into account, must

be used This requires a sound and broad understanding on the part of the decision makers

on the value of materials, processes, and equipment to the company, and their customers,accompanied by an understanding of the manufacturing systems Materials, processes, andmanufacturing systems are what this book is all about

Manufacturing is the economic term for making goods and services available to satisfyhuman wants Manufacturing implies creating value by applying useful mental or physi-cal labor The manufacturing processes are collected together to form a manufacturingsystem (MS) The manufacturing system is a complex arrangement of physical elementscharacterized by measurable parameters (Figure 1-3) The manufacturing system takesinputs and produces products for the external customer

The entire company is often referred to as the enterprise or the productionsystem The production services the manufacturing system, as shown in Figure 1-4 Inthis book, a production system will refer to the total company and will include within itthe manufacturing system The production system includes the manufacturing systemplus all the other functional areas of the plant for information, design, analysis, and con-trol These subsystems are connected by various means to each other to produce eithergoods or services or both

Goods refers to material things Services are nonmaterial things that we buy tosatisfy our wants, needs, or desires Service production systems include transportation,banking, finance, savings and loan, insurance, utilities, health care, education, commu-nication, entertainment, sporting events, and so forth They are useful labors that donot directly produce a product Manufacturing has the responsibility for designing

FIGURE 1-3 The

manufacturing system design

(aka the factory design) is

composed of machines, tooling,

material handling equipment,

and people

Component supplies

Inputs include

Internal customers

Raw materials

External customer (consumer goods)

A Flow Shop Manufacturing System

processes (sequences of operations and processes) and systems to create (make ormanufacture) the product as designed The system must exhibit flexibility to meetcustomer demand (volumes and mixes of products) as well as changes in product design.Advanced Topic 3 on the Web provides more detailed discussions of the productionsystem beyond what is presented here.

As shown in Table 1-1, production terms have a definite rank of importance,somewhat like rank in the army Confusing system with section is similar to mistaking acolonel for a corporal In either case, knowledge of rank is necessary The terms tend tooverlap because of the inconsistencies of popular usage

An obvious problem exists here in the terminology of manufacturing and tion The same term can refer to different things For example, drill can refer to themachine tool that does these kinds of operations; the operation itself, which can be

produc-Distribution centers, warehouses

Inspection (quality control)

% of scrap Iosses

Recommend changes in design

to improve manufacturing

R&D

MSD manufacturing department process design

External customer of goods

Marketing department (Estimate price and volume forecasts)

V

end

ors

Production and inventory control (schedules)

Purchasing department

Material requisitions

Material delivery

Issue materials Work schedules Manufacturing

system (see figure 1-7)

Inspect products

Finished products

Receiving shipping Final assembly

Production budget

Drawings, specifications, and standards

How to make the product

Design and test and redesign new products

Recommend design changes

Predict demand (Q)

Market information Deliver

products

Finance department

Product design engineering

Instructions or orders Feedback

Material flow

FIGURE 1-4 The production system includes and services the manufacturing system The functionaldepartments are connected by formal and informal information systems, designed to service themanufacturing that produces the goods

done on many different kinds of machines; or the cutting tool, which exists in many ferent forms It is therefore important to use modifiers whenever possible:‘‘Use theradial drill press to drill a hole with a 1-in.-diameter spade drill.’’ The emphasis of thisbook will be directed toward the understanding of the processes, machines, and toolsrequired for manufacturing and how they interact with the materials being processed.

dif-In the last section of the book, an introduction to systems aspects is presented

PRODUCTION SYSTEM—THE ENTERPRISEThe highest-ranking term in the hierarchy is production system A production systemincludes people, money, equipment, materials and supplies, markets, management, andthe manufacturing system In fact, all aspects of commerce (manufacturing, sales,advertising, profit, and distribution) are involved Table 1-2 provides a partial list of

TABLE 1-1 Production Terms for Manufacturing Production Systems

Production system; the

enterprise

All aspects of workers, machines, and information, considered collectively, needed to manufacture parts or products; integration of all units of the system is critical.

Company that makes engines, assembly plant, glassmaking factory, foundry; sometimes called the enterprise or the business.

Rolling steel plates, manufacturing of automobiles, series of connected operations or processes, a job shop,

a flow shop, a continuous process.

Machine or machine tool or

manufacturing process

A specific piece of equipment designed to accomplish specific processes, often called a machine tool; machine tools linked together to make a manufacturing system.

Spot welding, milling machine, lathe, drill press, forge, drop hammer, die caster, punch press, grinder, etc Job (sometimes called a station;

a collection of tasks)

A collection of operations done on machines or a collection of tasks performed by one worker at one location on the assembly line.

Operation of machines, inspection, final assembly; e.g., forklift driver has the job of moving materials Operation (sometimes called

Tools or tooling Refers to the implements used to hold, cut, shape, or

deform the work materials; called cutting tools if referring to machining; can refer to jigs and fixtures in workholding and punches and dies in metal forming.

Grinding wheel, drill bit, end milling cutter, die, mold, clamp, three-jaw chuck, fixture.

TABLE 1-2 Partial List of Production Systems for Producer and Consumer Goods

Aerospace and airplanes Foods (canned, dairy, meats, etc.)

Automotive (cars, trucks, vans, wagons, etc.) Furniture

Building supplies (hardware) Hospital suppliers

Chemicals and allied industries Marine engineering Clothing (garments) Metals (steel, aluminum, etc.) Construction Natural resources (oil, coal, forest, pulp and paper) Construction materials (brick, block, panels) Publishing and printing (books, CDs, newspapers)

Electrical and microelectronics Retail (food, department stores, etc.) Energy (power, gas, electric) Ship building

Equipment and machinery (agricultural, construction and electrical products, electronics, household products, industrial machine tools, office equipment, computers, power generators)

Tire and rubber Tobacco Transportation vehicles (railroad, airline, truck, bus) Vehicles (bikes, cycles, ATVs, snowmobiles)

production systems Another term for them is‘‘industries’’ as in the

‘‘aerospace industry.’’ Further discussion on the enterprise is found inAdvanced Topic 3, on the Web

Much of the information given for manufacturing systems is vant to the service system Most require a service production system[SPS] for proper product sales This is particularly true in industries,such as the food (restaurant) industry, in which customer service is asimportant as quality and on-time delivery Table 1-3 provides a shortlist of service industries

rele-MANUFACTURING SYSTEMS

A collection of operations and processes used to obtain a desiredproduct(s) or component(s) is called a manufacturing system Themanufacturing system is therefore the design or arrangement of themanufacturing processes in the factory Control of a system applies to overall control

of the whole, not merely of the individual processes or equipment The entire facturing system must be controlled in order to schedule and control the factory—allits inputs, inventory levels, product quality, output rates, and so forth Designs orlayouts of factories are discussed in Chapter 2

manu-MANUFACTURING PROCESSES

A manufacturing process converts unfinished materials to finished products, often usingmachines or machine tools For example, injection molding, die casting, progressivestamping, milling, arc welding, painting, assembling, testing, pasteurizing, homogeniz-ing, and annealing are commonly called processes or manufacturing processes.The term process can also refer to a sequence of steps, processes, or operations forproduction of goods and services, as shown in Figure 1-5, which shows the processes tomanufacture an Olympic-type medal

A machine tool is an assembly of related mechanisms on a frame or bed thattogether produce a desired result Generally, motors, controls, and auxiliary devicesare included Cutting tools and workholding devices are considered separately

A machine tool may do a single process (e.g., cutoff saw) or multiple processes, or

it may manufacture an entire component Machine sizes vary from a tabletop drill press

to a 1000-ton forging press

JOB AND STATION

In the classical manufacturing system, a job is the total of the work or duties a workerperforms A station is a location or area where a production worker performs tasks

or his job

A job is a group of related operations and tasks performed at one station or series ofstations in cells For example, the job at a final assembly station may consist of four tasks:

1 Attach carburetor

2 Connect gas line

3 Connect vacuum line

4 Connect accelerator rod

The job of a turret lathe (a semiautomatic machine) operator may include thefollowing operations and tasks: load, start, index and stop, unload, inspect The opera-tor’s job may also include setting up the machine (i.e., getting ready for manufacturing).Other machine operations include drilling, reaming, facing, turning, chamfering, andknurling The operator can run more than one machine or service at more than onestation

The terms job and station have been carried over to unmanned machines A job

is a group of related operations generally performed at one station, and a station is aposition or location in a machine (or process) where specific operations are performed

A simple machine may have only one station Complex machines can be composed of

TABLE 1-3 Types of Service Industries

Advertising and marketing

Communication (telephone, computer networks)

Education

Entertainment (radio, TV, movies, plays)

Equipment and furniture rental

Financial (banks, investment companies, loan companies)

Health care

Insurance

Transportation and car rental

Travel (hotel, motel, cruise lines)

CAM

Cavity in die forms medal

Bottom CNC machine tool

Computer

(3) The computer has software to produce a program to drive numerical control machine to cut a die set.

How an olympic medal is made using the CAD/CAM process

(1) An oversized 3D plaster model is made

from the artist’s conceptual drawings.

(2) The model is scanned with a laser to

produce a digital computer called a computer-aided design (CAD).

Additional finishing steps in the process include chemical etching;

gold or silver plating; packaging

Blanks are cut from bronze metal sheet stock using an abrasive water jet under 2-axis CNC control.

The blanks are heated and placed between the top die and bottom die Very high pressure is applied by a press

at very slow rates

The blank plastically deforms into the medal This press

is called hot isostatic pressing.

Air supply port valve

High-pressure water inlet

Abrasive

feed line

Abrasive metering system

Sheet stock (bronze)

Blank

Blank

Formed medal

FIGURE 1-5 The manufacturing process for making Olympic medals has many steps or operations, beginning with designand including die making (Courtesy J T Black)

many stations The job at a station often includes many simultaneous operations, such

as‘‘drill all five holes’’ by multiple spindle drills In the planning of a job, a processplan is often developed (by the engineer) to describe how a component is made using asequence of operation The engineer begins with a part drawing and a piece of rawmaterial Follow in Figure 1-6 the sequence of machining operations that transformsthe cylinder in a pinion shaft This information can be embedded in a computer pro-gram, in a machine tool called a lathe

OPERATION

An operation is a distinct action performed to produce a desired result or effect Typicalmanual machine operations are loading and unloading Operations can be divided intosuboperational elements For example, loading is made up of picking up a part, placingpart in jig, closing jig However, suboperational elements will not be discussed here.Operations categorized by function are:

1 Materials handling and transporting: change in position of the product

2 Processing: change in volume and quality, including assembly and disassembly; caninclude packaging

External cylindrical

Raw material bar stock cylinder with flat ends

Cut bar stock to length;

centerdrill ends.

(saw and drill press)

Turn and face rough turn and finish turn (Lathe)

Turn the smaller external cylindrical surfaces.

(Lathe)

Mill the flat on the right end Mill the slot on the left end (Milling Machine)

Drill four holes on left end Tap (internal threads) holes (Drill press)

Simplified Sequence of Operations (Typical Machine Tool Used)

Multiple cylinders made by turning (see Figure 1-12)

Three external cylinders and four flats

Three cylinders and six flats

Holes Internal cylindrical

Four internal holes

FIGURE 1-6 The component called a pinion shaft is manufactured by a ‘‘sequence of operations’’ toproduce various geometric surfaces The engineer figures out the sequence and selects the tooling toperform the steps

3 Packaging: special processing; may be temporary or permanent for shipping.

4 Inspecting and testing: comparison to the standard or check of process behavior

5 Storing: time lapses without further operations

These basic operations may occur more than once in some processes, or they maysometimes be omitted Remember, it is the manufacturing processes that change thevalue and quality of the materials Defective processes produce poor quality or scrap.Other operations may be necessary but do not, in general, add value, whereas opera-tions performed by machines that do material processing usually do add value

TREATMENTSTreatments operate continuously on the workpiece They usually alter or modify theproduct-in-process without tool contact Heat treating, curing, galvanizing, plating,finishing, (chemical) cleaning, and painting are examples of treatments Treatmentsusually add value to the part

These processes are difficult to include in manufacturing cells because they oftenhave long cycle times, are hazardous to the workers’ health, or are unpleasant to

be around because of high heat or chemicals They are often done in large tanks orfurnaces or rooms The cycle time for these processes may dictate the cycle times forthe entire system These operations also tend to be material specific Many manufac-tured products are given decorative and protective surface treatments that control thefinished appearance A customer may not buy a new vehicle because it has a visibledefect in the chrome bumper, although this defect will not alter the operation of the car.TOOLS, TOOLING, AND WORKHOLDERS

The lowest mechanism in the production term rank is the tool Tools are used to hold,cut, shape, or form the unfinished product Common hand tools include the saw,hammer, screwdriver, chisel, punch, sandpaper, drill, clamp, file, torch, and grindstone.Basically, machines are mechanized versions of such hand tools and are calledcutting tools Some examples of tools for cutting are drill bits, reamers, single-pointturning tools, milling cutters, saw blades, broaches, and grinding wheels Noncuttingtools for forming include extrusion dies, punches, and molds

Tools also include workholders, jigs, and fixtures These tools and cutting tools aregenerally referred to as the tooling, which usually must be considered (purchased) sepa-rate from machine tools Cutting tools wear and fail and must be periodically replacedbefore parts are ruined The workholding devices must be able to locate and secure theworkpieces during processing in a repeatable, mistake-proof way

TOOLING FOR MEASUREMENT AND INSPECTIONMeasuring tools and instruments are also important for manufacturing Commonexamples of measuring tools are rulers, calipers, micrometers, and gages Precisiondevices that use laser optics or vision systems coupled with sophisticated electronicsare becoming commonplace Vision systems and coordinate measuring machines arebecoming critical elements for achieving superior quality

INTEGRATING INSPECTION INTO THE PROCESSThe integration of the inspection process into the manufacturing process or the manu-facturing system is a critical step toward building products of superior quality

An example will help Compare an electric typewriter with a computer that does wordprocessing The electric typewriter is flexible It types whatever words are wanted inwhatever order It can type in Pica, Elite, or Orator, but the font (disk or ball that hasthe appropriate type size on it) has to be changed according to the size and face of typewanted The computer can do all of this but can also, through its software, set italics; setbold, dark type; vary the spacing to justify the right margin; plus many other functions

It checks immediately for incorrect spelling and other defects like repeated words Thesoftware system provides a signal to the hardware to flash the word so that the operatorwill know something is wrong and can make an immediate correction If the system

were designed to prevent the typist from typing repeated words, then this would be apoka-yoke, a term meaning defect prevention Defect prevention is better than immedi-ate defect detection and correction Ultimately, the system should be able to forecastthe probability of a defect, correcting the problem at the source This means thatthe typist would have to be removed from the process loop, perhaps by having the sys-tem type out what it is told (convert oral to written directly) Poka-yoke devices andsource inspection techniques are keys to designing manufacturing systems that producesuperior-quality products at low cost.

PRODUCTS AND FABRICATIONS

In manufacturing, material things (goods) are made to satisfy human wants Productsresult from manufacture Manufacture also includes conversion processes such asrefining, smelting, and mining

Products can be manufactured by fabricating or by processing Fabricating isthe manufacture of a product from pieces such as parts, components, or assemblies.Individual products or parts can also be fabricated Separable discrete items such astires, nails, spoons, screws, refrigerators, or hinges are fabricated

Processing is also used to refer to the manufacture of a product by continuousmeans, or by a continuous series of operations, for a specific purpose Continuous itemssuch as steel strip, beverages, breakfast foods, tubing, chemicals, and petroleum are

‘‘processed.’’ Many processed products are marketed as discrete items, such as bottles

of beer, bolts of cloth, spools of wire, and sacks of flour

Separable discrete products, both piece parts and assemblies, are fabricated in aplant, factory, or mill, for instance, a textile or rolling mill Products that flow (liquids,gases, grains, or powders) are processed in a plant or refinery The continuous-processindustries such as petroleum and chemical plants are sometimes called processingindustries or flow industries

To a lesser extent, the terms fabricating industries and manufacturing industries areused when referring to fabricators or manufacturers of large products composed of manyparts, such as a car, a plane, or a tractor Manufacturing often includes continuous-processtreatments such as electroplating, heating, demagnetizing, and extrusion forming

Construction or building is making goods by means other than manufacturing orprocessing in factories Construction is a form of project manufacturing of useful goodslike houses, highways, and buildings The public may not consider construction as man-ufacturing because the work is not usually done in a plant or factory, but it can be There

is a company in Delaware that can build a custom house of any design in its factory,truck it to the building site, and assemble it on a foundation in two or three weeks.Agriculture, fisheries, and commercial fishing produce real goods from usefullabor Lumbering is similar to both agriculture and mining in some respects, and miningshould be considered processing Processes that convert the raw materials from agricul-ture, fishing, lumbering, and mining into other usable and consumable products are alsoforms of manufacturing

WORKPIECE AND ITS CONFIGURATION

In the manufacturing of goods, the primary objective is to produce a component having

a desired geometry, size, and finish Every component has a shape that is bounded byvarious types of surfaces of certain sizes that are spaced and arranged relative to eachother Consequently, a component is manufactured by producing the surfaces thatbound the shape Surfaces may be:

1 Plane or flat

2 Cylindrical (external or internal)

3 Conical (external or internal)

4 Irregular (curved or warped)

Figure 1-6 illustrates how a shape can be analyzed and broken up into these basicbounding surfaces Parts are manufactured by using a set or sequence of processes that

will either (1) remove portions of a rough block of material (bar stock, casting, forging)

so as to produce and leave the desired bounding surface or (2) cause material to forminto a stable configuration that has the required bounding surfaces (casting, forging).Consequently, in designing an object, the designer specifies the shape, size, andarrangement of the bounding surface The part design must be analyzed to determinewhat materials will provide the desired properties, including mating to other compo-nents, and what processes can best be employed to obtain the end product at the mostreasonable cost This is often the job of the manufacturing engineer

ROLES OF ENGINEERS IN MANUFACTURINGMany engineers have as their function the designing of products The products arebrought into reality through the processing or fabrication of materials In this capacitydesigners are a key factor in the material selection and manufacturing procedure

A design engineer, better than any other person, should know what the design is toaccomplish, what assumptions can be made about service loads and requirements, whatservice environment the product must withstand, and what appearance the final prod-uct is to have To meet these requirements, the material(s) to be used must be selectedand specified In most cases, to utilize the material and to enable the product to have thedesired form, the designer knows that certain manufacturing processes will have to beemployed In many instances, the selection of a specific material may dictate what proc-essing must be used On the other hand, when certain processes must be used, the designmay have to be modified in order for the process to be utilized effectively and economi-cally Certain dimensional sizes can dictate the processing, and some processes requirecertain sizes for the parts going into them In converting the design into reality, manydecisions must be made In most instances, they can be made most effectively at thedesign stage It is thus apparent that design engineers are a vital factor in the manufac-turing process, and it is indeed a blessing to the company if they can design for manufac-turing, that is, design the product so that it can be manufactured and/or assembledeconomically (i.e., at low unit cost) Design for manufacturing uses the knowledge ofmanufacturing processes, and so the design and manufacturing engineers should worktogether to integrate design and manufacturing activities

Manufacturing engineers select and coordinate specific processes and equipment

to be used or supervise and manage their use Some design special tooling is used sothat standard machines can be utilized in producing specific products These engineersmust have a broad knowledge of manufacturing processes and material behavior so thatdesired operations can be done effectively and efficiently without overloading or dam-aging machines and without adversely affecting the materials being processed.Although it is not obvious, the most hostile environment the material may ever encoun-ter in its lifetime is the processing environment

Industrial and lean engineers are responsible for manufacturing systems design(or layout) of factories They must take into account the interrelationships of the factorydesign and the properties of the materials that the machines are going to process as well asthe interreaction of the materials and processes The choice of machines and equipmentused in manufacturing and their arrangement in the factory are key design tasks

The lean engineer has expertise in cell design, setup reduction (tool design), grated quality control devices (poka-yokes and decouplers) and reliability (mainte-nance of machines and people) for the lean production system See Advanced Topic 1online for discussion of cell design and lean engineering

inte-Materials engineers devote their major efforts to developing new and bettermaterials They, too, must be concerned with how these materials can be processed andwith the effects that the processing will have on the properties of the materials Althoughtheir roles may be quite different, it is apparent that a large proportion of engineers mustconcern themselves with the interrelationships of materials and manufacturing processes

As an example of the close interrelationship of design, materials selection, andthe selection and use of manufacturing processes, consider the common desk stapler.Suppose that this item is sold at the retail store for $20 The wholesale outlet sold thestapler for $16 and the manufacturer probably received about $10 for it Staplers typically

consist of 10 to 12 parts and some rivets and pins Thus, the manufacturer had to produceand assemble the 10 parts for about $1 per part Only by giving a great deal of attention todesign, selection of materials, selection of processes, selection of equipment used for man-ufacturing (tooling), and utilization of personnel could such a result be achieved.

The stapler is a relatively simple product, yet the problems involved in its facture are typical of those that manufacturing industries must deal with The elements

manu-of design, materials, and processes are all closely related, each having its effect on theperformance of the device and the other elements For example, suppose the designercalls for the component that holds the staples to be a metal part Will it be a machinedpart rather than a formed part? Entirely different processes and materials need to bespecified depending on the choice Or, if a part is to be changed from metal to plastic,then a whole new set of fundamentally different materials and processes would need tocome into play Such changes would also have a significant impact on cost as well as theservice (useful life) of the product

CHANGING WORLD COMPETITION

In recent years, major changes in the world of goods manufacturing have taken place.Three of these are:

1 Worldwide competition for global products and their manufacture

2 High-tech manufacturing or advanced technology

3 New manufacturing systems designs, strategies, and management

Worldwide (global) competition is a fact of manufacturing life, and it will get ger in the future The goods you buy today may have been made anywhere in the world.For many U.S companies, suppliers in China, India, and Mexico are not uncommon.The second aspect, advanced manufacturing technology, usually refers to newmachine tools or processes controlled by computers Companies that produce suchmachine tools, though small, can have an enormous impact on factory productivity.Improved processes lead to better components and more durable goods However, thenew technology is often purchased from companies that have developed the technol-ogy, so this approach is important but may not provide a unique competitive advantage

stron-if your competitors can also buy the technology, provided that they have the capital.Some companies develop their own unique process technology and try to keep it propri-etary as long as they can

The third change and perhaps the real key to success in manufacturing is to ment lean manufacturing system design that can deliver, on time to the customer, super-quality goods at the lowest possible cost in a flexible way Lean production is an effort toreduce waste and improve markedly the methodology by which goods are producedrather than simply upgrading the manufacturing process technology

imple-Manufacturing system design is discussed extensively in Chapter 2 and AdvancedTopic 1 of the book, and it is strongly recommended that students examine this materialclosely after they have gained a working knowledge of materials and processes Thenext section provides a brief discussion of manufacturing system designs

MANUFACTURING SYSTEM DESIGNSFive manufacturing system designs can be identified: the job shop, the flow shop, thelinked-cell shop, the project shop, and the continuous process See Figure 1-7 The con-tinuous process deals with liquids and/or gases (such as an oil refinery) rather than solids

or discrete parts and is used mostly by the chemical engineer

The most common of these layouts is the job shop, characterized by large varieties

of components, general-purpose machines, and a functional layout (Figure 1-8) Thismeans that machines are collected by function (all lathes together, all broachestogether, all grinding machines together) and the parts are routed around the shop insmall lots to the various machines The layout of the factory shows the multiple pathsthrough the shop and a detail on one of the seven broaching machine tools The material

is moved from machine to machine in carts or containers and is called the lot or batch

STA 4

Moving assembly line

Rework line for detects

Work is devided equally into the stations

assembly cell II

Sub-Subassembly

Chassis

(e) Linked-cell

STA 3 STA 2 STA 1

STA 11 STA 12

STA 13 STA 14

STA 10

REPAIR

Job shop makes components for subassembly using a functional layout.

Flow shop uses line balancing

to achieve one piece flow.

Continuous process systems make products that can flow like gas and oil.

Lean production uses manufacturing and subassembly cells linked to final assembly.

Receiving Lathes

Drill process

Presses (sheet Millingmachines

Painting Assembly Storage

A B C Saws

Grinders

treating

Heat-Raw materials

Supplies Labor Equipment

This rack bar machining area is functionally designed so it operates like a jobshop, with lathes, broaches, and grinders lined up.

Flow shops are characterized by larger volumes of the same part or assembly, cial-purpose machines and equipment, less variety, less flexibility, and more mechaniza-tion Flow shop layouts are typically either continuous or interrupted and can be formanufacturing or assembly, as shown in Figure 1-9 If continuous, a production line isbuilt that basically runs one large-volume complex item in great quantity and nothingelse The common light bulb is made this way A transfer line producing an engine block

spe-is another typical example If interrupted, the line manufactures large lots but spe-is ically‘‘changed over’’ to run a similar but different component

period-The linked-cell manufacturing system (L-CMS) is composed of ing and subassembly cells connected to final assembly (linked) using a uniqueform of inventory and information control called kanban The L-CMS is used inlean production systems where manufacturing processes and subassemblies arerestructured into U-shaped cells so they can operate on a one-piece-flow basis,like final assembly

manufactur-As shown in Figure 1-10, the lean production factory is laid out (designed) verydifferently than the mass production system At this writing, more than 60% of allmanufacturing industries have adopted lean production Hundreds of manufacturingcompanies have dismantled their conveyor-based flow lines and replaced them withU-shaped subassembly cells, providing flexibility while eliminating the need for linebalancing Chapter 2 discusses manufacturing system designs Advanced Topic 1discusses subassembly cells and manufacturing cells

The project shop is characterized by the immobility of the item being tured In the construction industry, bridges and roads are good examples In the manu-facture of goods, large airplanes, ships, large machine tools, and locomotives aremanufactured in project shops It is necessary that the workers, machines, and materialscome to the site The number of end items is not very large, and therefore the lot sizes

manufac-of the components going into the end item are not large Thus, the job shop usuallysupplies parts and subassemblies to the project shop in small lots

Continuous processes are used to manufacture liquids, oils, gases, and powders.These manufacturing systems are usually large plants producing goods for other

Floor level

8‘

10‘

Broach stroke 90‘‘

Detail on broach

Raw Material

Finished Parts

Saw Saw Saw Saw

S

S S

375‘

8

Crack Detection (Outsourced)

FIGURE 1-8 The vertical broaching machine is one of seven machines in this production job shop IH ¼ inductionhardening, S ¼ bar strengthening

producers or mass-producing canned or bottled goods for consumers The ing engineer in these factories is often a chemical engineer.

manufactur-Naturally, there are many hybrid forms of these manufacturing systems, but thejob shop is the most common system Because of its design, the job shop has been shown

to be the least cost-efficient of all the systems Component parts in a typical job shopspend only 5% of their time in machines and the rest of the time waiting or being movedfrom one functional area to the next Once the part is on the machine, it is actually beingprocessed (i.e., having value added to it by the changing of its shape) only about 30 to40% of the time The rest of the time parts are being loaded, unloaded, inspected, and so

on The advent of numerical control machines increased the percentage of time that themachine is making chips because tool movements are programmed and the machinescan automatically change tools or load or unload parts

However, there are a number of trends that are forcing manufacturing ment to consider means by which the job shop system itself can be redesigned toimprove its overall efficiency These trends have forced manufacturing companies toconvert their batch-oriented job shops into linked-cell manufacturing systems, with themanufacturing and subassembly cells structured around specific products

manage-Another way to identify families of products with a similar set of manufacturingprocesses is called group technology Group technology (GT) can be used to restructurethe factory floor GT is a concept whereby similar parts are grouped together into partfamilies Parts of similar size and shape can often be processed through a similar set ofprocesses A part family based on manufacturing would have the same set or sequences

of manufacturing processes The machine tools needed to process the part family are

Finish

Conveyor

Lines Flow Lines

Large Storage of Subassemblies

Parts Storage

Subassembly lines make

components and subassemblies

for the installation into the

product, often using conveyors.

These lines are examples of

the flow shop.

Receiving Lathe

Start of final assembly

Station

FIGURE 1-9 Flow shops and lines are common in the mass production system Final assembly is usually a moving assembly line.The product travels through stations in a specific amount of time The work needed to assemble the product is distributed into thestations, called division of labor The moving assembly line for cars is an example of the flow shop

gathered into a cell Thus, with GT, job shops can be restructured into cells, each cellspecializing in a particular family of parts The parts are handled less, machine setuptime is shorter, in-process inventory is lower, and the time needed for parts to getthrough the manufacturing system (called the throughput time) is greatly reduced.BASIC MANUFACTURING PROCESSES

It is the manufacturing processes that create or add value to a product The ing processes can be classified as:

manufactur-7

Caulding

6 Fasten screws

8 Main meas- urement

5

Attach frame

3 4 5

1 Polarity check

2 Solder repair

3 Meas- urement

4 Attachand adjust resistor

12 Pack- aging

11 External inspection

9

10 Attachlabel Attach lid

Directly link processes to eliminate in-process inventory

Standing, walking workers

Cells areone-pieceflow

= Manufacturing cell (see detail

below)

Subassembly (Sub A) cells (see detail below)

= Kanban linking of cell

to Sub A or Sub A to Final A

= Direct linking, flow,

or synchronized

conveyor

kk

kk

kk

G

A

RM Manufacturing Cell Subassembly Cell

 Casting, foundry, or molding processes.

 Forming or metalworking processes

 Machining (material removal) processes

 Joining and assembly

 Surface treatments (finishing)

as shearing, which is really metal cutting but is viewed as a (sheet) metal-forming cess Assembly may involve processes other than joining The categories of processtypes are far from perfect

pro-Casting and molding processes are widely used to produce parts that often requireother follow-on processes, such as machining Casting uses molten metal to fill a cavity.The metal retains the desired shape of the mold cavity after solidification An importantadvantage of casting and molding is that, in a single step, materials can be convertedfrom a crude form into a desired shape In most cases, a secondary advantage is thatexcess or scrap material can easily be recycled Figure 1-11 illustrates schematicallysome of the basic steps in the lost-wax casting process, one of many processes used inthe foundry industry

Casting processes are commonly classified into two types: permanent mold(a mold can be used repeatedly) or nonpermanent mold (a new mold must be preparedfor each casting made) Molding processes for plastics and composites are included inthe chapters on forming processes

Forming and shearing operations typically utilize material (metal or plastics) thathas been previously cast or molded In many cases, the materials pass through a series offorming or shearing operations, so the form of the material for a specific operation may

be the result of all the prior operations The basic purpose of forming and shearing is tomodify the shape and size and/or physical properties of the material

Metal-forming and shearing operations are done both‘‘hot’’ and ‘‘cold,’’ a ence to the temperature of the material at the time it is being processed with respect tothe temperature at which this material can recrystallize (i.e., grow new grain structure).Figure 1-12 shows the process by which the fender of a car is made using a series ofmetalforming processes

refer-Metal cutting, machining, or metal removal processes refer to the removal ofcertain selected areas from a part in order to obtain a desired shape or finish Chips areformed by interaction of a cutting tool with the material being machined Figure 1-13shows a chip being formed by a single-point cutting tool in a machine tool called a lathe.The manufacturing engineer may be called upon to specify the cutting parameters such

as cutting speed, feed, or depth of cut (DOC) The engineer may also have to select thecutting tools for the job

Cutting tools used to perform the basic turning on the lathe are shown in Figure 1-14.The cutting tools are mounted in machine tools, which provide the required movements ofthe tool with respect to the work (or vice versa) to accomplish the process desired

In recent years many new machining processes have been developed

The seven basic machining processes are shaping, drilling, turning, milling,sawing, broaching, and abrasive machining Each of these basic processes is extensivelydiscussed Historically, eight basic types of machine tools have been developed toaccomplish the basic processes These machine tools are called shapers (and planers),drill presses, lathes, boring machines, milling machines, saws, broaches, and grinders.Most of these machine tools are capable of performing more than one of the basicmachining processes Shortly after numerical control was invented, machining centers

FIGURE 1-11 Schematic of the

lost-foam casting process

Plastic part

Steam Steam

To make the foam parts, metal molds are used Beads of polystyrene are heated and expanded in the mold to get parts.

Patterns

of plastic parts Sprue and runner Polystyrene pattern

A pattern containing a sprue, runners, risers, and parts is made from single or multiple pieces of foamed

polystyrene plastic

Slurry Dipped in

refractory slurry

The polystyrene pattern is dipped in a ceramic slurry, which wets the surface and forms a coating about 0.005 inch thick

Unbonded sand Flask

Surrounded with loose unbonded sand

The coated pattern is placed in a flask and surrounded with loose, unbonded sand.

Vibration

Compacted by vibration

The flask is vibrated so that the loose sand is compacted around the pattern.

Casting removed and sand reclaimed

The solidified casting is removed from flask and the loose sand reclaimed.

were developed that could combine many of the basic processes, plus other related cesses, into a single machine tool with a single workpiece setup.

pro-Aside from the chip-making processes, there are processes wherein metal isremoved by chemical, electrical, electrochemical, or thermal sources Generally speak-ing, these nontraditional processes have evolved to fill a specific need when conven-tional processes were too expensive or too slow when machining very hard materials.One of the first uses of a laser was to machine holes in ultra-high-strength metals Lasersare being used today to drill tiny holes in turbine blades for jet engines Because of itsability to produce components with great precision and accuracy, metal cutting, usingmachine tools, is recognized as having great value-adding capability

In recent years a new family of processes has emerged called rapid prototyping orrapid manufacturing or free-form manufacturing (see Chapter 19) These additive-typeprocesses produce first, or prototype, components directly from the software using spe-cialized machines driven by computer-aided design packages The prototypes can befield tested and modifications to the design quickly implemented Early versions ofthese machines produced only nonmetallic components, but modern machines can

Metalforming Process for Automobile Fender

Sheet metal bending/forming

Hot rolling

Cold-rolling plate

Rolls

Slab Billet

Sheet metal Slab

Single draw punch and die

Cast billets of metal are passed through successive rollers to produce sheets of steel rolled stock.

The flat sheet metal is “formed” into a fender, using sets of dies mounted on stands of large presses.

Slide

Sheet metal Cushion pin

Upper die

Punch

Punch

Blank holder

Trim punch

Die

Scrap

Fender

Scrap

The fender is cut out of the sheet metal

in the last stage using shearing processes.

Sheet metal shearing processes are like scissors cutting paper.

Next, the sheet metal parts are welded into the body of the car.

Punch

Punch Sheet metal

Metal shearing

Die

Die

2 1

FIGURE 1-12 The forming process used to make a fender for a car

make metal parts In contrast, the machining processes are recognized as having greatvalue-adding capability, that is, the ability to produce components with great precisionand accuracy Companies have sprung up; you can send your CAD drawing over theInternet and a prototype is made in hours.

Perhaps the largest collection of processes, in terms of both diversity and quantity,are the joining processes, which include the following:

Workpiece

Cutting tool

revolution) The desired cutting speed V

determines the rpm of the workpiece.

This process is called turning.

Cutting speed Original

diameter

Final diameter

Feed (inch/rev)

Depth of cut

Workpiece

V

Chip Tool

The workpiece is mounted in a workholding device

in a machine tool (lathe) and is cut (machined) with

a cutting tool.

FIGURE 1-13 Single-point metal-cutting process (turning) produces a chip while creating a newsurface on the workpiece (Courtesy J T Black)

operations to produce a computer Starting in the upper left corner, microelectronicfabrication methods produce entire integrated circuits (ICs) of solid-state (no movingparts) components, with wiring and connections, on a single piece of semiconductormaterial, usually single-crystalline silicon Arrays of ICs are produced on thin, rounddisks of semiconductor material called wafers Once the semiconductor on the waferhas been fabricated, the finished wafer is cut up into individual ICs, or chips Next, atlevel 2, these chips are individually housed with connectors or leads making up‘‘dies’’that are placed into‘‘packages’’ using adhesives The packages provide protectionfrom the elements and a connection between the die and another subassembly calledthe printed circuit boards (PCBs) At level 3, IC packages, along with other discretecomponents (e.g., resistors, capacitors, etc.), are soldered onto PCBs and thenassembled with even larger circuits on PCBs This is sometimes referred to as electronicassembly Electronic packages at this level are called cards or printed wiring assemblies(PWAs) Next, series of cards are combined on a back-panel PCB, also known as amotherboard or simply a board This level of packaging is sometimes referred to ascard-on-board packaging Ultimately, card-on-board assemblies are put into housingsusing mechanical fasteners and snap fitting and finally integrated with power suppliesand other electronic peripherals through the use of cables to produce final commercialproducts See Chapter 35 for more details on electronic manufacturing.

Finishing processes are yet another class of processes typically employed forcleaning, removing burrs left by machining, or providing protective and/or decorativesurfaces on workpieces Surface treatments include chemical and mechanical cleaning,deburring, painting, plating, buffing, galvanizing, and anodizing

Heat treatment is the heating and cooling of a metal for the specific purpose ofaltering its metallurgical and mechanical properties Because changing and controllingthese properties is so important in the processing and performance of metals, heat treat-ment is a very important manufacturing process Each type of metal reacts differently toheat treatment Consequently, a designer should know not only how a selected metalcan be altered by heat treatment but, equally important, how a selected metal will react,favorably or unfavorably, to any heating or cooling that may be incidental to the manu-facturing processes

Level 1

Level 1

Level 4 Level 5

on chip

Microelectronic manufacturing

Packaging

Cover chip

PCB assembly PCB fab

Motherboard

IC Package for connection

Silicon wafer

FIGURE 1-14 How an electronic product is made

OTHER MANUFACTURING OPERATIONS

In addition to the processes already described, there are many other fundamental facturing operations that must be considered Inspection determines whether the desiredobjectives stated by the designer in the specifications have been achieved This activityprovides feedback to design and manufacturing with regard to the process behavior.Essential to this inspection function are measurement activities In the factory, measure-ments are either by attributes or variables (see Chapter 37 online) to inspect the outcomesfrom the process and determine how they compare to the specifications The many aspects

manu-of quality control are presented in Advanced Topic 2 online Chapter 38 (on the Web)covers testing, where a product is tried by actual function or operation or by subjection toexternal effects Although a test is a form of inspection, it is often not viewed that way Inmanufacturing, parts and materials are inspected for conformance to the dimensional andphysical specifications, while testing may simulate the environmental or usage demands to

be made on a product after it is placed in service Complex processes may require manytests and inspections Testing includes life-cycle tests, destructive tests, nondestructivetesting to check for processing defects, wind-tunnel tests, road tests, and overload tests.Transportation of goods in the factory is often referred to as material handling

or conveyance of the goods and refers to the transporting of unfinished goods in-process) in the plant and supplies to and from, between, and during manufacturingoperations Loading, positioning, and unloading are also material-handling opera-tions Transportation, by truck or train, is material handling between factories Propermanufacturing system design and mechanization can reduce material handling incountless ways

(work-Automatic material handling is a critical part of continuous automatic turing The word automation is derived from automatic material handling Materialhandling, a fundamental operation done by people and by conveyors and loaders, oftenincludes positioning the workpiece within the machine by indexing, shuttle bars, slides,and clamps In recent years, wire-guided automated guided vehicles (AGVs) and auto-matic storage and retrieval systems (AS/RSs) have been developed in an attempt toreplace forklift trucks on the factory floor Another form of material handling, themechanized removal of waste (chips, trimming, and cutoffs), can be more difficult thanhandling the product Chip removal must be done before a tangle of scrap chips dam-ages tooling or creates defective workpieces

manufac-Most texts on manufacturing processes do not mention packaging, yet the ing is often the first thing the customer sees Also, packaging often maintains the prod-uct’s quality between completion and use (The term packaging is also used inelectronics manufacturing to refer to placing microelectronic chips in containers formounting on circuit boards.) Packaging can also prepare the product for delivery to theuser It varies from filling ampules with antibiotics to steel-strapping aluminum ingotsinto palletized loads A product may require several packaging operations For exam-ple, Hershey Kisses are (1) individually wrapped in foil, (2) placed in bags, (3) put intoboxes, and (4) placed in shipping cartons

packag-Weighing, filling, sealing, and labeling are packaging operations that are highlyautomated in many industries When possible, the cartons or wrappings are formedfrom material on rolls in the packaging machine Packaging is a specialty combiningelements of product design (styling), material handling, and quality control Some pack-ages cost more than their contents (e.g., cosmetics and razor blades)

During storage, nothing happens intentionally to the product or part except thepassage of time Part or product deterioration on the shelf is called shelf life, meaningthat items can rust, age, rot, spoil, embrittle, corrode, creep, and otherwise change instate or structure, while supposedly nothing is happening to them Storage is detrimen-tal, wasting the company’s time and money The best strategy is to keep the productmoving with as little storage as possible Storage during processing must be eliminated,not automated or computerized Companies should avoid investing heavily in largeautomated systems that do not alter the bottom line Have the outputs improved withrespect to the inputs, or has storage simply increased the costs (indirectly) withoutimproving either the quality or the throughput time?

By not storing a product, the company avoidshaving to (1) remember where the product isstored, (2) retrieve it, (3) worry about its deterio-rating, or (4) pay storage (including labor) costs.Storage is the biggest waste of all and should beeliminated at every opportunity.

UNDERSTAND YOUR PROCESS TECHNOLOGY

Understanding the process technology of thecompany is very important for everyone in the com-pany Manufacturing technology affects the design

of the product and the manufacturing system, theway in which the manufacturing system can be con-trolled, the types of people employed, and thematerials that can be processed Table 1-4 outlinesthe factors that characterize a process technology.Take a process you are familiar with and thinkabout these factors One valid criticism of Americancompanies is that their managers seem to have anaversion to understanding their companies’ manu-facturing technologies Failure to understand thecompany business (i.e., its fundamental processtechnology) can lead to the failure of the company.The way to overcome technological aversion

is to run the process and study the technology.Only someone who has run a drill press can under-stand the sensitive relationship between feed rateand drill torque and thrust All processes havethese‘‘know-how’’ features Those who run theprocesses must be part of the decision making forthe factory The CEO who takes a vacation work-ing on the plant floor and learning the processeswill be well on the way to being the head of a suc-cessful company

PRODUCT LIFE CYCLE AND LIFE-CYCLE COST

Manufacturing systems are dynamic and changewith time There is a general, traditional relation-ship between a product’s life cycle and the kind of manufacturing system used to makethe product Figure 1-15 simplifies the product life cycle into these steps, again using anS-shaped curve

1 Startup New product or new company, low volume, small company

2 Rapid growth Products become standardized and volume increases rapidly pany’s ability to meet demand stresses its capacity

Com-3 Maturation Standard designs emerge Process development is very important

4 Commodity Long-life, standard-of-the-industry type of product or

5 Decline Product is slowly replaced by improved products

The maturation of a product in the marketplace generally leads to fewer tors, with competition based more on price and on-time delivery than on unique prod-uct features As the competitive focus shifts during the different stages of the productlife cycle, the requirements placed on manufacturing—cost, quality, flexibility, anddelivery dependability—also change The stage of the product life cycle affects theproduct design stability, the length of the product development cycle, the frequency of

competi-TABLE 1-4 Characterizing a Process Technology

Mechanics (statics and dynamics of the process)

How does the process work?

What are the process mechanics (statics, dynamics, friction)?

What physically happens, and what makes it happen? (Understand the physics.)

Economics or costs

What are the tooling costs, the engineering costs?

Which costs are short term, which long term?

What are the setup costs?

Time spans

How long does it take to set up the process initially?

What is the throughput time?

How can these times be shortened?

How long does it take to run a part once it is set up (cycle time)?

What process parameters affect the cycle time?

Constraints

What are the process limits?

What cannot be done?

What constrains this process (sizes, speeds, forces, volumes, power, cost)?

What is very hard to do within an acceptable time/cost frame?

Uncertainties and process reliability

What can go wrong?

How can this machine fail?

What do people worry about with this process?

Is this a reliable, stable process?

Skills

What operator skills are critical?

What is not done automatically?

How long does it take to learn to do this process?

Flexibility

Can this process be adapted easily for new parts of a new design or material?

How does the process react to changes in part design and demand?

What changes are easy to do?

Process capability

What are the accuracy and precision of the process?

What tolerances does the process meet? (What is the process capability?)

How repeatable are those tolerances?

engineering change orders, and the commonality of components—all of which haveimplications for manufacturing process technology.

During the design phase of the product, much of the cost of manufacturing andassembly is determined Assembly of the product is inherently integrative as it focuses

on pairs and groups of parts

It is crucial to achieve this integration during the design phase because about 70%

of the life-cycle cost of a product is determined when it is designed Design choicesdetermine materials; fabrication methods; assembly methods; and, to a lesser degree,material-handling options, inspection techniques, and other aspects of the productionsystem Manufacturing engineers and internal customers can influence only a small part

of the overall cost if they are presented with a finished design that does not reflect theirconcerns Therefore, all aspects of production should be included if product designs are

to result in real functional integration

Life-cycle costs include the costs of all the materials, manufacture, use, repair, anddisposal of a product Early design decisions determine about 60% of the cost, and allactivities up to the start of full-scale development determine about 75% Later deci-sions can make only minor changes to the ultimate total unless the design of the manu-facturing system is changed

In short, the concept of product life-cycle provides a framework for thinkingabout the product’s evolution through time and the kind of market segments that are

Manufacturing system design

with some flow

Production job shop with some flow lines and assembly lines

More flow mass-produce

or decline

product innovation great

Increasing standardization;

less variety

Emergence of a dominant standard design

High zation

standardi-"Commodity" characteristics

Industry structure: Many small

competitors

Fallout and consolidation Few large companies "Survivors"

become commodities Form of

competition:

Product characteristics

Product quality, cost, and availability

Price and quality with reliability

Price with sistent quality

e

FIGURE 1-15 Product life-cycle costs change with the classic manufacturing system designs