DRAWINGS
Views using first angle projection;
Views using third angle projection;
used in Europe.
used in North America
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first third angle EXAMPLE part.sldprt
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3
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DRAWINGS
Customary views using third angle projection
bracket 01.sldprt
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DRAWINGS
Customary views using first angle projection
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DRAWINGS
Automatic dimensions are most often not acceptable
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DRAWINGS
Dimensions must either modified or created
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DRAWINGS
BOM
TOC
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DRAWINGS
Learn to use all types of views in drawings
Learn BOM
Learn TOC
Learn dimensioning
…
…
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ON LINE MODELS
http://www.3dcontentcentral.com/
Great site for selection design
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ON LINE MODELS
http://www.3dcontentcentral.com/3DContentCentral/
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ON LINE RESOURCES
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ON LINE RESOURCES
http://www.solidworks.com/
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DESIGN FOR MANUFACTURING PROCESS
MATERIAL SELECTION
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Concurrent* Engineering Using DFM
Design concept
Design for Assembly
(DFA)
We are here
Selection of materials
and processes; early cost
estimates
Suggestions for
simplification of product
structure
Suggestions for more
economic materials and
processes
Best design concept
Design for manufacture
(DFM)
Detail design for
minimum manufacturing
costs
Prototype
*Concurrent:
[Bakerjian 1992]
Occurring or operating at the same
time; "a series of coincident events".
Production
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Factors that Influence Manufacturing Process Selection
• Cost of manufacture
• Material
• Geometric shape
• Tolerances
• Surface finish
• Quantity of pieces required
• Tooling, jigs, and fixtures
• Gages
• Avaliable equipment
• Delivery date
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Materials and Manufacturing
In many manufacturing operations the cost of materials may account for more than
50% of the total cost
• automobiles :
• shipbuilding :
Note:
70% of manufacturing cost
45% of manufacturing cost
The higher the degree of automation (lower labor costs), the greater the % of the total
cost is due to materials.
Variety of Materials in a Product
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Most Commonly Used Materials
Steels and Irons
1.
1020
Plastics
2.
1040
16.
ABS
3.
4140
17.
Polycarbonate
4.
4340
18.
Nylon 6/6
5.
S30400 (stainless)
19.
Polypropylene
6.
S316 (stainless)
20.
Polystyrene
7.
O1 tool steel
8.
Grey cast iron
Ceramics
Aluminum and copper
21.
Alumina
9.
2024
22.
Graphite
10.
3003 or 5005
11.
6061
Composite materials
12.
7075
23.
Douglas fir (wood)
13.
C268 (copper)
24.
Fiberglass
25.
Graphite/epoxy
Other metals
14.
Titanium 6-4
15.
Magnesium AZ63A
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Performance Characteristics of Materials
The performance requirements of a material are expressed in terms of physical,
mechanical, thermal, electrical, or chemical properties.
Characteristics of Material Classes
Metals
Ceramics
Polymers
Strong
Strong
Strong
Stiff
Stiff
Compliant
Tough
Brittle
Durable
Electrically conducting
Electrical insulating
Electrically insulating
High thermal conductivity
Low thermal conductivity
Temperature sensitive
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Materials Used in Common Items
[Ullman 1992]
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Materials Used in Common Items
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SUMMARY OF IMPORTANT MATERIAL PROPERTIES
Modulus of elasticity
MPa
Poisson’s ratio
1
Yield strength (stress)
MPa
Ultimate strength (stress)
MPa
Elongation
%
Hardness
HB, HV, …
Melting temperature
K
Thermal expansion
%/ K
Thermal conductivity
W/(m K)
Density
kg/m3
Cost/unit of mass
$ / kg
Cost/volume
$ / m3
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FAILURE MODES AND MATERIAL PROPERTIES
K IC
K ISCC
plane strain fracture toughness
threshold stress intensity factor
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MATERIAL SELECTION
Materials
selection
is
based
on
material
properties
(part
performance) and material processing (part manufacturing). Most
material selection is based on past experiences (but doesn't
necessarily produce optimal solutions).
There are a large number of materials available (eg. over 40,000
metallic alloys alone).
An improperly chosen material can lead to:
• failure of the part or component
• unnecessary costs
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BASIC STEPS IN MATERIALS SELECTION
1. Analyze material requirements - determine the conditions of service and
environment that the product must withstand.
2. Screen candidate materials - compare the needed properties with a large
materials property data-base to select the most promising materials for the
application.
3. Select candidate materials - analyze candidate materials in terms of trade -offs of:
product performance, cost, fabrication, availability, etc..
4. Develop design data – if necessary, determine experimentally the key material
properties for the selected material to obtain statistically reliable measures of the
material performance under specific conditions expected to be encountered in
service.
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EXAMPLE OF MATERIAL SELECTION
Problem:
Select a material suitable for designing the core of an automobile radiator.
Material Performance Requirements: ( What the material should do)
Rapid Heat Transfer
Does not melt
Does not deform
Long lasting
Light Weight
Inexpensive
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EXAMPLE OF MATERIAL SELECTION
To find out which material properties really matter
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EXAMPLE OF MATERIAL SELECTION
To find out which material will be the best from the point of
view of the required properties (decision matrix)
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Modulus of Elasticity
Thomas Young (1773 - 1829)
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Modulus of Elasticity
Stress
Steel
Aluminum
Wood
Strain
Stress-Strain Relations
Young's Modulus of Elasticity is a "measure of stiffness" and is high for metals and low for
plastics and rubber.
The Modulus of elasticity is the stress caused by 100% strain which is doubling the length of a
tensile sample (even though most materials would not survive this test)
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Approximate Moduli of Elasticity of Various Solids
Young's modulus E
[GPa]
Young's modulus E
[psi]
0.01-0.1
1,500-15,000
0.2
30,000
Polypropylene
1.5-2
217,000-290,000
Polyethylene terephthalate
2-2.5
290,000-360,000
Polystyrene
3-3.5
435,000-505,000
Nylon
2-4
290,000-580,000
Oak wood (along grain)
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1,600,000
High-strength concrete (under compression)
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4,350,000
Magnesium metal
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6,500,000
Aluminum alloy
69
10,000,000
Glass (all types)
72
10,400,000
Brass and bronze
103-124
17,000,000
Titanium (Ti)
105-120
15,000,000-17,500,000
150
21,800,000
Wrought iron and steel
190-210
30,000,000
Tungsten (W)
400-410
58,000,000-59,500,000
450
65,000,000
450-650
65,000,000-94,000,000
approx. 1,000
approx. 145,000,000
1,050-1,200
150,000,000-175,000,000
Material
Rubber (small strain)
Low density polyethylene
Carbon fiber reinforced plastic (unidirectional, along
grain)
Silicon carbide (SiC)
Tungsten carbide (WC)
Single Carbon nanotube [1]
Diamond
http://en.wikipedia.org/wiki/Young's_modulus
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Approximate Moduli of Elasticity of Various Solids
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Stress-Strain Curves
Yield Strength (or Yield Stress) - Stress at which a permanent deformation has occurred
Tensile Strength -The maximum nominal stress a specimen supports in a tension test prior to failure.
Nominal Stress -Approximate value of stress calculated using the original area Ao or length Lo (instead of
the actual values which change during testing).
Stress-strain curves illustrating the meaning of yield strength and tensile
strength for two types of deformational behavior (steel and polyethylene).
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Linear vs. nonlinear material models
Linear material model
tanα = E
Linear
range
Non linear material model
α
STRAIN
The linear material behavior complies with Hooke’s law:
= E
in tension
=  G
in shear

normal stress
[ N / m2 ]

strain
[1]

shear angle
[rad]
E
modulus of elasticity
[ N / m2 ]
G
shear modulus
[ N / m2 ]
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Poisson’s ratio
Simeon Poisson (1781 – 1840)
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Poisson’s ratio
When a sample of material is stretched in one direction, it tends to
get thinner in the other two directions. Poisson's ratio (ν), named
after Simeon Poisson, is a measure of this tendency.
It is defined as the ratio of the strain in the direction of the applied
load to the strain normal to the load. For a perfectly
incompressible material, the Poisson's ratio would be exactly 0.5.
Most practical engineering materials have ν between 0.0 and 0.5.
Cork is close to 0.0, most steels are around 0.3, and rubber is
almost 0.5.
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Yield Strength
[Ullman 1992]
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Tensile Strength
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Elongation
Elongation ( or Plastic Strain) - Strains that go beyond the elastic limit and result in residual
strains after unloading are called inelastic or plastic strains.
plastic strain = elongation =
Lf - L0
L0
Lf - finallength
L0 - original length
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Elongation
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Hardness
Scratch hardness
Primarily used in mineralogy.
Indentation hardness
Primarily used in metallurgy, indentation hardness seeks to characterise a material's resistance to
permanent, and in particular plastic, deformation. It is usually measured by loading an indenter of
specified geometry onto the material and measuring the dimensions of the resulting indentation.
There are several alternative definitions of indentation hardness, the most common of which are:
σTS = 500 x HB
Brinell hardness test (HB)
Janka hardness, used for wood
Knoop hardness test (HK) or micro hardness test, for measurement over small areas
Meyer hardness test
Rockwell hardness test (HR), principally used in the USA
Shore hardness, used for polymers
Vickers hardness test (HV), has one of the widest scales
There is, in general, no simple relationship between the results of different hardness tests. Though
there are practical conversion tables for hard steels, for example, some materials show qualitatively
different behavior under the various measurement methods.
Rebound hardness
Also known as dynamic or absolute hardness, rebound hardness measures the height of rebound of
an indenter dropped onto a material using an instrument known as a scleroscope
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Hardness
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Endurance (Fatigue) Limit
Endurance Limit – is a limiting value of stress such that fatigue failure does not occur
regardless of the number of cycles of loading (i.e. the maximum repetitive stress a material can
with stand without fracturing)
Fatigue Data for a Composite
Note: This composite is fiberglass embedded in phenolic resin.
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Endurance (Fatigue) Limit
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Melting Temperature
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Thermal Conductivity and Thermal Expansion
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Thermal Conductivity
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Coefficient of Thermal Expansion
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Density
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Cost per units of mass
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Cost per Volume
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TYPICAL STEELS AND ALUMINUM ALLOYS USED FOR
WELDMENTS AND SHEET METAL
Steel sheets
1010-1020
Structural steels – tubes
1018
Structural Steel Beams - I-beam and channel
1018?
Steels - Hot and cold rolled bars
1010?
Steel shafts/rods
1010, 1045
Aluminum Sheets
6061, 6065 (not bendable without heat)
3003 (utility grade- great for bending, machines very
poorly-sticky and clogs cutters)
1000 series (poor quality aluminum, good for bending)
Aluminum shapes and beams
T6061 (T designates temper)
Aluminum billets, bars and rods
T6061, T7075 (T designates temper).
Both have good machine-ability - 7075 machines better
and will polish better too.
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