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IEEM 215: Manufacturing Processes Introduction and Agenda

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Title: IEEM 215: Manufacturing Processes Introduction and Agenda


1
IEEM 215 Manufacturing Processes
2
Introduction and Agenda
Outcome(s)
Materials Properties - helps to determine how to
make things with it - helps to determine the
processing conditions - helps and constrains
process optimization
1.0 1.1
3.0 3.1
Processes - forming, cutting, non-traditional,
joining, surface treatments, electronics
components,
2.0 2.1 7.0
4.0
Process Planning
6.0, 6.1
CNC programming
5.0, 8.0, 8.1
Process Evaluation and Quality control
5.0
Process Economics and Optimization
9.0
Product design and Fabrication
3
Motivation (1)
A bottle of Watsons water (HK6)
Four components (bottle, cap, label, water) -
How are each of these manufactured? - What does
the equipment cost?
4
Motivation (2)
Stapler (HK 45)
Approx. 15 components - How do we select the
best material for each component? - How are
each of these manufactured?
Car 15,000 parts Boeing 747 plane 6 million
parts Intel core 2 duo processor 65 nm feature
size, 291 million transistors
5
Materials
Ferrous metals carbon-, alloy-, stainless-,
tool-and-die steels
Non-ferrous metals aluminum, magnesium, copper,
nickel,
titanium, superalloys, refractory metals,
beryllium, zirconium,
low-melting alloys,
gold, silver, platinum,
Plastics thermoplastics (acrylic, nylon,
polyethylene, ABS,) thermosets
(epoxies, Polymides, Phenolics, )
elastomers (rubbers, silicones, polyurethanes, )
Ceramics, Glasses, Graphite, Diamond, Cubic Boron
Nitride
Composites reinforced plastics, metal-, ceramic
matrix composites
Nanomaterials, shape-memory alloys,
superconductors,
6
Properties of materials
Mechanical properties of materials Strength,
Toughness, Hardness, Ductility, Elasticity,
Fatigue and Creep
Physical properties Density, Specific heat,
Melting and boiling point, Thermal expansion and
conductivity, Electrical and magnetic properties
Chemical properties Oxidation, Corrosion,
Flammability, Toxicity,
7
Mechanical properties Stress analysis
stress s Force/Area
Why do we need stress/strain (not just force,
elongation) ?
Tensile, compressive and shear stresses
Stresses in an infinitesimal element of a beam
8
Stress Analysis Principal directions in 2D case
- principal directions are orthogonal to each
other - 0 shear stress along PDs
9
Stress Analysis Principal shear stress in 2D case
10
Failure in Tension, Youngs modulus and Tensile
strength
Engineering stress s P/Ao
Engineering strain e (L Lo)/Lo d/Lo
11
Failure in Tension, Youngs modulus and Tensile
strength..
Original
12
Failure in Tension, Youngs modulus and Tensile
strength
In the linear elastic range Hookes law s E e
or, E s/e E Youngs modulus
13
Elastic recovery after plastic deformation
14
True Stress, True Strain, and Toughness
Engg stress and strain are gross measures
s F/A gt s is the average stress ? local
stress e d/Lo gt e is average strain
Toughness energy used to fracture
area under true stress-strain curve
15
Ductility
Measures how much the material can be stretched
before fracture
Ductility 100 x (Lf Lo)/Lo
High ductility platinum, steel, copper Good
ductility aluminum Low ductility (brittle)
chalk, glass, graphite
- Walkman headphone wires Al or Cu?
16
Hardness
resistance to plastic deformation by indentation
17
Shear stress and Strain the torsion test
Angle of twist q TL/GJ Shear stress t
Tr/J Maximum shear stress tmax TR/J Shear
strain g rq/L
T torque, J polar moment of inertia J ?
r2 dA Cylindrical shell J p( D4-d4)/32
t G g
G Modulus of rigidity
18
Shear strength and Tensile strength
approximate relation between shear and tensile
strengths
Ultimate Tensile Strength Su Ultimate Shear
Strength Ssu Tensile Yield Strength Syp
Shear yield point Ssyp
References Machine design Theory and Practice
.A.D.Deutschman, W.A Michels C.E. Wilson..
MacMillan Publishing 1975.
19
Fatigue
Fracture/failure of a material subjected cyclic
stresses
S-N curve for compressive loading
20
Failure under impact
Application Drop forging
Testing for Impact Strength
21
Strain Hardening
- Metals microstructure crystal-grains - Under
plastic strain, grains slipping along
boundaries - Locking up of grains gt increase in
strength - We can see this in the
true-stress-strain curve also
Applications - Cold rolling, forging part is
stronger than casting
22
Residual stresses
Internal stresses remaining in material after it
is processed
Causes - Forging, drawing, removal of
external forces - Casting varying rate of
solidification, thermal contraction
Problem warping when machined, creep
Releasing residual stresses annealing
23
Physical Properties
24
Summary
Materials have different physical, chemical,
electrical properties
Knowledge of materials properties is required
to Select appropriate material for design
requirement Select appropriate manufacturing
process Optimize processing conditions for
economic manufacturing
Reference Chapter 2, Chapter 3, Mfg Engg Tech,
Kalpakjian Schmid
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