4. Manufacturing Industries
ď§ Industries can be classified as:
1. Primary industries - those that exploit natural resources,
e.g., mining, farming, fishing, petroleum
2. Secondary industries - automotive, computers,
electronics
3. Tertiary industries - service sector
e.g., banking, education, communication, hotels
5. Manufacturing Processes
⢠Two basic types:
1. Processing - transform a work material from
one state of completion to a more advanced
state
2. Assembly - join two or more components to
create a new entity
7. Processing Operations
ď§ Three categories of processing operations:
1. Shaping - alter the geometry of the starting work
material
2. Property enhancing - improve physical
properties
⢠Heat treatment of metals & glass
3. Surface processing â
⢠Cleaning
⢠Surface treatments
⢠Coating and thin film deposition
26. Figure Shows Some of the steel products made in a rolling mill.
Rolled Products Made of Steel
27.
28. (a) forge hot billet to max diameter
(b) âfuller: tool to mark step-locations
(c) forge right side
(d) reverse part, forge left side
(e) finish (dimension control)
t
Stages in Open die forging
41. Material Removal Processes -
Machining
⢠Excess material removed from the
starting piece so to get the desired
geometry
ď§ Examples: machining such as
turning, drilling, and milling; also
grinding and nontraditional
processes
Turning: Machining
of cylindrical parts
Drilling Milling
49. Surface Processing Operations
⢠Cleaning - chemical and mechanical processes to
remove dirt, oil, and other surface contaminants
⢠Surface treatments - mechanical working such as
sand blasting, and physical processes like diffusion
⢠Coating and thin film deposition - coating exterior
surface of the work part. Examples:
ď§ Electroplating
ď§ Physical vapor deposition
ď§ Painting
54. Types of Welding Processes
⢠Solid state welding processes
⢠Liquid state welding processes
⢠Solid / Liquid state bonding processes
55. Solid State Welding Processes
Steps Solid State:
⢠Heating the surfaces without causing melting
and applying normal pressure
⢠Providing relative motion between the two
surfaces and applying light normal pressure
⢠Applying high pressure without melting
56. Forge Welding
⢠Surfaces to be joined are heated till they
are red hot and then forced together by
hammering.
58. Friction Stir Welding
⢠Friction-stir welding joins metal with heat and high
pressure.
ď§ A constantly rotated non consumable cylindrical-shouldered tool
with a profiled nib is transversely fed at a constant rate into a
butt joint between two clamped pieces of butted material
ď§ Frictional heat is generated between the wear-resistant welding
components and the work pieces
59. Explosive Welding
⢠Very high contact pressure developed by detonating a thin
layer of explosive.
⢠The detonation imparts high kinetic energy
⢠No filler material is used and no diffusion takes place.
61. Arc Welding
⢠In Electric Arc Welding a sustained arc provides the heat
required for melting the parent as well as filler material.
62. Figure 31.1 Basic configuration of an arc welding process.
Arc Welding
⢠When the electrode and work piece are in contact, current flows and
when they are separated an arc is generated and the current continues
to flow.
⢠The arc is generated by the electrons liberated form cathode and
moving towards anode.
⢠The arc changes electrical energy into heat and light.
Liquid State Welding
63. Shielded Arc Welding
⢠Consumable Electrode
⢠Slag
ď Proctective Cover
ď Slow down Cooling rate
Liquid State Welding
64. Gas Metal Arc Welding
⢠Gas Metal Arc Welding(GMAW) is also known as MIG welding.
⢠A Continuous wire if fed into welding gun
Liquid State Welding
65. Submerged Arc Welding
⢠Submerged Arc Welding (SAW) is only performed by automatic or
semiautomatic methods
⢠Uses a continuously fed filler metal electrode
⢠Weld pool is protected from the surrounding atmosphere by a blanket
of granular flux fed at the welding gun
Liquid State Welding
70. Figure Shows Several techniques for applying filler metal in
brazing: (a) torch and filler rod. Sequence: (1) before, and
(2) after.
Brazing - Soldering: Permanent
Joining Processes â Weak Bonding,
Lower Temperatures
71. Brazing
⢠The filler metals are generally
copper alloys.
⢠Cu-Zn and Cu-Ag alloys are used
for brazing
72. Brazing methods
ďTorch and filler rods
ďRing of filler metal at entrance of gap
ďFoil of filler metal between flat part
surfaces
Brazing
76. Types of stresses that must be considered in
adhesive bonded joints: (a) tension, (b) shear, (c)
cleavage, and (d) peeling.
Joining Process: Adhesive Bonding
79. Threaded Fasteners
⢠Bolt - externally threaded fastener inserted through
holes and "screwed" into a nut on the opposite side
⢠Nut - internally threaded fastener having standard
threads that match those on bolts of the same
diameter, pitch, and thread form
⢠Screw - externally threaded fastener generally Assemble into
blind threaded hole
80. Bolt Specification
A bolt consists of three parts:
⢠a head
⢠a shank (optional)
⢠a thread
T. Thread Diameter
S. Shank Diameter
R. Root Diameter
a b
c
a. Shank length
b. Thread length
c. Nominal length
shank thread
head
81. Nut Specification
Parts:
⢠a body
⢠a thread
⢠a hole
⢠Diameters
⢠Height
⢠Thread Type
⢠Right handed unless otherwise stated is the norm
⢠Thread specification
⢠Will be discussed in the thread specification section
R
T
T Thread Diameter
R Root Diameter
height
82. Types of Bolts
⢠Carriage bolt
⢠Usually used to attach a wooden part to
metal.
⢠Machine bolt
⢠Used for precision attachment using
threads to secure materials together.
⢠Tap bolt
⢠Similar to a machine bolt but the whole
body is threaded.
⢠Stove bolt
⢠General purpose fastener used when
precision fit is not necessary.
⢠Stud bolt
⢠One end is driven into material & the other
end is left exposed so that other parts can
be fastened to it.
83. Types of Machine Screws
⢠Machine & cap screws
⢠Used for precision fit into thread
holes in metal.
⢠Setscrew
⢠Typically used for safety reasons
to hold a sleeve, collar or gear on
a shaft to prevent relative motion.
⢠Thumbscrews
⢠Used where a screw must be
turned by hand using the thumb
and a finger.
84. Rivets
⢠Most widely used permanent fastening method
⢠Typically a pneumatic hammer delivers a succession of blows to
upset the rivet
Types: (a) solid, (b) tubular, (c) semitubular, (d) bifurcated, and (e) compression.
(a) solid, (b) tubular, (c) semitubular, (d) bifurcated, and
(e) compression