7 Manufacturing

5/22/2018 7 Manufacturing

1/442007 John Wile & Sons Inc. M P Groover

INTRODUCTION AND

OVERVIEW OF MANUFACTURING

1.What is Manufacturing?2.Materials in Manufacturing

3.Manufacturing Processes4.Production Systems



Manufacturing is Important

Technologically

Economically



Manufacturing - Technologically

Important

Technology - the application of science toprovide society and its members with thosethings that are needed or desired

Technology provides the products that help our

society and its members live better

What do these products have in common?

They are all manufactured Manufacturing is the essential factor that makes

technology possible



Manufacturing - Economically Important

Manufacturing isone way by which

nations creatematerial wealth

U.S. economy:

Sector% of

GNP

Manufacturing 20%

Agriculture, minerals, etc. 5%

Construction & utilities 5%

Service sectorretail,

transportation, banking,

communication, education, and

government

70%



Manufacturing - Technologically

Manufacturing

as a technical

Process:

Application of physical and chemical processesto alter the geometry, properties, and/orappearance of a starting material to make parts or

products

Manufacturing also includes assembly

Almost always carried out as a sequence of

operations



Manufacturing - Economically

Manufacturing

as an economic

process

Transformation of materials into items of greatervalue by means of one or more processing and/orassembly operations

Manufacturing adds valueto the material by

changing its shape or properties, or by combiningit with other materials



Manufacturing Industries

Industry consists of enterprises andorganizations that produce or supplygoods and services

Industries can be classified as:

1.Primary industries - those that cultivate andexploit natural resources, e.g., farming,

mining

2.Secondary industries - take the outputs ofprimary industries and convert them intoconsumer and capital goods -

manufacturing is the principal activity

3.Tertiary industries - service sector



Manufacturing Industries - continued Secondary industries include

manufacturing, construction, and electric

power generation

Manufacturing includes several industries

whose products are not covered in this

book; e.g., apparel, beverages,

chemicals, and food processing

For our purposes, manufacturing means

production of hardware

Nuts and bolts, forgings, cars, airplanes, digitalcomputers, plastic parts, and ceramic products


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Methods of Manufacture

FIGURE 1.6 Various methods of making a simple part: (a) casting or powder metallurgy, (b) forging or

upsetting, (c) extrusion, (d) machining, (e) joining two pieces.



Manufacturing Processes

Two basic types:1. Processing operations - transform a work

material from one state of completion to a

more advanced state

Operations that change the geometry, properties, orappearance of the starting material

2.Assembly operations - join two or morecomponents to create a new entity



Figure 1.4 Classification of manufacturing processes



Processing Operations

Alters a materials shape, physicalproperties, or appearance in order to addvalue

Three categories of processing operations:

1. Shaping operations - alter the geometry of thestarting work material

2. Property-enhancing operations - improve physicalproperties without changing shape

3. Surface processing operations - to clean, treat,coat, or deposit material on exterior surface of the

work



Shaping ProcessesFour Categories

1. Solidification processes - starting material isa heated liquid or semifluid2. Deformation processes - starting material is

a ductile solid (commonly metal)3. Particulate processing - starting material

consists of powders

4. Material removal processes - startingmaterial is a ductile or brittle solid



Solidification Processes - Casting

Starting material is heated sufficiently totransform it into a liquid or highly plastic

state

Examples:metalcasting, plastic molding



Open Molds and Closed Molds

Figure 10.2 Two forms of mold: (a) open mold, simply acontainer in the shape of the desired part; and (b) closed

mold, in which the mold geometry is more complex and

requires a gating system (passageway) leading into the

cavity.



Figure 11.1 A large sand casting weighing over 680 kg (1500 lb)

for an air compressor frame (photo courtesy of Elkhart Foundry).



Shell MoldingCasting process in which the mold is a thin shell of sand

held together by thermosetting resin binder


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Expanded Polystyrene Process


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Investment Casting



Permanent Mold Casting



Die Casting

-



Centrifugal Casting



Forming Processes: Deformation

Starting workpart is shaped by application offorces that exceed the yield strength of the

material

Examples: (a) forging, (b) extrusion


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Forming Processes: Deformation

Bulk Deformation

Sheet Metal Forming


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Bulk Deformation Processes

Rolling

ExtrusionDrawing

Forging



Figure 19.2 Some of the steel products made in a rolling mill.

Rolled Products Made of Steel


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Cutting

Deep

Drawing

Sheet Metal Forming Processes

V-Bending


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Presses

Figure Schematic representation of the

various types of press drive mechanisms.


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Types of Press Frame

Figure 17-61(Right) A 200-ton

(1800-kN) straight-sided press.

(Courtesy of Rousselle

Corporation, West Chicago,

IL.)

Figure 17-60(Left) Inclinable

gap-frame press with sliding

bolster to accommodate two

die sets for rapid change of

tooling. (Courtesy of Niagara

Machine & Tool Works, Buffalo,

NY.)


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2007 John Wile & Sons Inc. M P Groover

Figure 19.20 Diagram showing details of a drop hammer

for impression-die forging.

Drop Hammer Details


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Figure 20.32 Components of a typical mechanical drive stamping press

Stamping Press


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Forming: Particulate Processing

Starting materials are powders of metals orceramics

Usually involves pressing and sintering, in

which powders are first compressed and

then heated to bond the individual particles


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Forming: Material Removal Processes

-Machining

Excess material removed from thestarting piece so what remains is the

desired geometry

Examples: machining such asturning, drilling, and milling; also

grinding and nontraditional

processes

Turning: Machining

of cylindrical partsDrilling Milling


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Forming: Material Removal Processes

-Machining

Turning examples

Standard Turning Facing

Threading:


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Figure 21.3 Two forms of milling: (a) peripheral milling, and (b)

face milling.

Two Forms of Milling


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Turning Machine:

Lathe

Milli M hi


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Milling Machine:


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Figure 31.1 Basic configuration of an arc welding process.

Joining Processes:

Welding, a Permanent Joining Process


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A pool of molten metal is formed near electrode tip,and as electrode is moved along joint, molten

weld pool solidifies in its wake

Figure 31.1 Basic configuration of an arc welding process.

Arc Welding


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31.4 Gas metal arc welding (GMAW).

Gas Metal Arc Welding

R i t S t W ldi


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Resistance welding,

showing the components inspot welding, the main

process in the RW group.

Resistance Spot Welding


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Figure 31.21 A typical oxyacetylene welding operation (OAW).

Oxyacetylene Welding

Brazing - Soldering: Permanent


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Figure 32.4 Several techniques for applying filler metal in brazing:(a) torch and filler rod. Sequence: (1) before, and (2) after.

Brazing - Soldering: Permanent

Joining ProcessesWeak Bonding,

Lower Temperatures


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Figure 32.10 Types of stresses that must be

considered in adhesive bonded joints: (a) tension, (b)

shear, (c) cleavage, and (d) peeling.

Joining Process: Adhesive Bonding

7 Manufacturing

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