1

Views using first angle projection;

used in Europe.

Views using third angle projection;

used in North America

DRAWINGS

2Customary views using first angle projection

DRAWINGS

3Customary views using third angle projectionbracket 01.sldprt

DRAWINGS

4Automatic dimensions are most often not acceptable

DRAWINGS

5

Dimensions must either modified or created

DRAWINGS

6first third angle EXAMPLE part.sldprt

7

8

9Automatic dimensions are most often not acceptable

DRAWINGS

10

Dimensions must either modified or created

DRAWINGS

11

DRAWINGS

BOM

TOC

12

DRAWINGS

Learn to use all types of views in drawings

Learn BOM

Learn TOC

Learn dimensioning

…

…

Learn fits and GD&T; we’ll cover this later in the course

13

DESIGN FOR MANUFACTURING PROCESS

MATERIAL SELECTION

14

Concurrent* Engineering Using DFM

[Bakerjian 1992]

Design concept

Design for Assembly (DFA)

Selection of materials and processes; early cost

estimates

Best design concept

Design for manufacture (DFM)

Prototype

Production

Suggestions for simplification of product

structure

Suggestions for more economic materials and

processes

Detail design for minimum manufacturing

costs

We are here

*Concurrent:

Occurring or operating at the same time; "a series of coincident events".

15

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

16

Materials and Manufacturing

In many manufacturing operations the cost of materials may account for more than 50% of the total cost

• automobiles : 70% of manufacturing cost

• shipbuilding : 45% of manufacturing cost

Note: 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

17

Most Commonly Used MaterialsSteels and Irons

1. 1020

2. 1040

3. 4140

4. 4340

5. S30400 (stainless)

6. S316 (stainless)

7. O1 tool steel

8. Grey cast iron

Aluminum and copper

9. 2024

10. 3003 or 5005

11. 6061

12. 7075

13. C268 (copper)

Other metals

14. Titanium 6-4

15. Magnesium AZ63A

Plastics

16. ABS

17. Polycarbonate

18. Nylon 6/6

19. Polypropylene

20. Polystyrene

Ceramics

21. Alumina

22. Graphite

Composite materials

23. Douglas fir (wood)

24. Fiberglass

25. Graphite/epoxy

18

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

19

Materials Used in Common Items

[Ullman 1992]

20

Materials Used in Common Items

21

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

22K IC plane strain fracture toughnessK ISCC threshold stress intensity factor

FAILURE MODES AND MATERIAL PROPERTIES

23

Thomas Young (1773 - 1829)

Modulus of Elasticity

24

Modulus of Elasticity

Stress-Strain Relations

Steel

Aluminum

Wood

Strain

Str

ess

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)

25

Approximate Moduli of Elasticity of Various Solids

MaterialYoung's modulus E

[GPa]Young's modulus E

[psi]

Rubber (small strain) 0.01-0.1 1,500-15,000

Low density polyethylene 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) 11 1,600,000

High-strength concrete (under compression) 30 4,350,000

Magnesium metal 45 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

Carbon fiber reinforced plastic (unidirectional, along grain)

150 21,800,000

Wrought iron and steel 190-210 30,000,000

Tungsten (W) 400-410 58,000,000-59,500,000

Silicon carbide (SiC) 450 65,000,000

Tungsten carbide (WC) 450-650 65,000,000-94,000,000

Single Carbon nanotube [1] approx. 1,000 approx. 145,000,000

Diamond 1,050-1,200 150,000,000-175,000,000

http://en.wikipedia.org/wiki/Young's_modulus

26

Approximate Moduli of Elasticity of Various Solids

27

Stress-Strain Curves

Yield Strength (or Yield Stress) - Stress at which a permanent deformation has occurredTensile 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).

28

STRAIN

ST

RE

SS

Linear material model

Non linear material model

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 ]

Linearrange

Linear vs. nonlinear material models

α

tanα = E

29

Simeon Poisson (1781 – 1840)

Poisson’s ratio

30

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.

Poisson’s ratio

31

Yield Strength

[Ullman 1992]

32

Tensile Strength

33

Elongation ( or Plastic Strain) - Strains that go beyond the elastic limit and result in residual strains after unloading are called inelastic or plastic strains.

f 0

0

f

0

L - Lplastic strain = elongation =

L

L - finallength

L - original length

Elongation

34

Elongation

35

Scratch hardnessPrimarily used in mineralogy.

Indentation hardnessPrimarily 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:

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 hardnessAlso 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

Hardness

σTS = 500 x HB

36

Hardness

37

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.

38

Endurance (Fatigue) Limit

39

Melting Temperature

40

Thermal Conductivity and Thermal Expansion

41

Thermal Conductivity

42

Coefficient of Thermal Expansion

43

Density

44

Cost per units of mass

45

Cost per Volume

46

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.

47

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

48

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.

49

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

EXAMPLE OF MATERIAL SELECTION

50

To find out which material properties really matter

EXAMPLE OF MATERIAL SELECTION

51

To find out which material will be the best from the point of view of the required properties (decision matrix)

EXAMPLE OF MATERIAL SELECTION