Product Design (Part 4)
Engineering Drawing
Chapter 16
Drawing Standards
Line conventions and letteringANSI/ASME Y14.2M-1992
Multiview and sectional view drawingsANSI/ASME Y14.3M-1994
Pictorial drawing-ANSI/ASME Y14.4M1989(1994)
Dimensioning and tolerancingANSI/ASME Y14.5M-1994
Line Types
Line Types
F 16-1
Engineering Drawing
Multiview Projection
F 16-2 Standards
Projection Symbols
F 16-3 Symbols
Third Angle Projection
F 16-4 Six principal views
Primary Auxiliary View
F 16-5 Auxiliary view
Full Section
Half Section
This side drawn in section
Imagine this place of
the part removed.
This side drawn as exterior view
Offset Section
Offset Section
Cutting plane
Do now show bends
in the cutting plane
Dimensioning
F 16-8 Basic dimension
Dimensioning
F 16-9 Reference dimension
Dimensioning
F 16-10 Types of dimensioning
Tolerancing
F 16-11 Mating parts (inches)
Tolerancing
F 16-12 Mating parts (inches)
Tolerancing
F 16-13 Tolerances (inches)
System of Fits
Hole basis: The system of fits where the
minimum hole size is the basic size.
Shaft basis: The system of fits where the
minimum shaft size is the basic size
Fit Types
Clearance: Gap between mating parts
Interference: No clearance, force required
for assembly
Transition: Result in either a clearance or an
interference fit
Types of Fits
RC-running and sliding fits
LC-clearance locational fits
LT-transition locational fits
LN-interference locational fits
FN-force and shrink fits
Hole Basis
Shaft Basis
Description
H11/c11
C11/hll
Loose running fit for wide commercial tolerances or
allowances on external members.
H9/d9
D9/h9
Free running fit for running accurate machines and
for accurate location at moderate speeds and journal
pressures.
H8/f7
F8/h7
Close running fit for running on accurate machines
and for accurate location at moderate speeds and
journal pressures.
H7/g6
G7/h6
Sliding fit not intended to run freely, but to move and
turn freely and locate accurately.
H7/h6
H7/h6
Locational clearance fit provides snug fit for locating
stationary parts: but can freely assembled and
disassembled.
Hole Basis
Shaft Basis
Description
H7/n6
N7/h6
Location transition fit for more accurate location
where greater interference is permissible.
H7/p6
P7/h6
Locational interference fit for parts requiring rigidity
and alignment with prime accuracy of location but
without special bore pressure requirements.
H7/s6
P7/h6
Medium drive fit for ordinary steel parts or shrink fits
on light sections, the tightest fit usable with cast iron.
H7/u6
U7/h6
Force fit suitable for parts which can be highly
stressed or for shrink fits where the heavy pressing
forces required are impractical.
Symbols and Their Definitions as Applied Holes and Shafts
Basic Size
HOLE
Tolerance Grade
40 H8
Fundamental Deviation
IT Grade
Basic Size
Tolerance Grade
SHAFT
40 F7
Fundamental Deviation
IT Grade
Basic Size
FIT
Hole Tolerance
Fit
40 H8/f7
Shaft Tolerance
Tolerances for Interchangeability
F 16-14 Car knob assembly
Surface Texture
F 16-15 Criteria
Surface Symbols
F 16-16 Standard lay Designations
Surface Symbols
F 16-17 Applications
Geometric Dimensioning
and Tolerancing
Chapter 17
F 17-1 ASME Y14.5M-1994
F 17-2 GD&T Tolerances and Symbols
F 17-3 Feature control frame
F 17-4 Flatness
F 17-5 Surface Straightness
F 17-6 Axis straightness
F 17-7 Axis straightness
F 17-8 Circularity
F 17-9 Cylindricity
F 17-10 Parallelism
F 17-11 Perpendicularity
F 17-12 Angularity
F 17-13 Circular runout
F 17-14 Total runout
F 17-15 Profile of a line
F 17-16 Profile of a surface
F 17-17 Concentricity
F 17-18 Symmetry
F 17-19 Tolerance of position
Computer-Aided Design
Chapter 18
3D Modeling Methods
1. Wire Frame
2. Surface Modeling
3. Solid Modeling
Wire Frame
A. Advantages
1. Easiest to construct
2. Infinite number of views possible
B. Disadvantages
1. Difficult to visualize complex objects
2. Mass properties cannot be calculated
Surface Modeling
A. Advantages
1. Better representation of object compared to
wire frame
2. Can be used to determine machine tool paths
B. Disadvantages
1. Not a complete representation of real object
2. Cannot be sectioned
Solid Modeling
A. Advantages
1. True 3D object
2. Elimination of ambiguity in viewing model
3. Section cuts can be produced and displayed
4. Mass properties may be calculated
B. Disadvantages
1. Software more expensive
2. More memory is required
Modeling Uses
Circuit Board Layout
CAD software designed for printed circuit
boards (PCB) has features unique to that
application.
Current surface mount technology (SMT)
and the continued miniaturization of
integrated-circuit products makes the
design of most PCBs a complex task
PCB Design Considerations
The number of layers in a final board
assembly (single-sided, double sided, and
multilayered)
The miniaturization of components and
the effect on pin spacing and number of
pins in a conductor
Conductor routing and board layers
Design Considerations Contd.
The frequency of the current in the
different circuits and the resulting
inductance
Heat dissipation
The placement of similar types of
components
Rapid Prototyping Methods
Stereolithography apparatus (SLA)
Solid ground curing (SGC)
Laminated object manufacturing (LOM)
Fused deposition modeling (FDM)
Selective laser sintering (SLS)
Ballistic particle manufacturing (BPM)
Advantages of Rapid
Prototyping
Produce three dimensional parts within hours
Create masters and patterns
Accelerate prototype production
Achieve major savings in production of soft and
hard tooling
Increase manufacturing capabilities with low
volume production runs
Add impact to marketing concept presentations
with hands-on models
Improve the accuracy of vendor bid response
Disadvantages of Rapid
Prototyping
Parts typically cannot be used for physical
testing
Parts have surface finish quality and
tolerance limitations
Special techniques and materials are
required of some systems
Equipment is expensive
Product Design Tools
Chapter 19
Manufacturing Strategies
Customer Response
Entrepreneurial Manufacturing
Time Based Strategy
Managing For Speed Product
Customer Responsive
Targets quality improvement and customer
service
Uses short-run manufacturing via the work
cell concept
Entrepreneurial Manufacturing
Requires flexible system capable of
shifting from one product to another on
short notice
Success is dependent upon a companys
capacity to create new markets for
specialized high-value-added products.
Time Based Strategy
Organization of process components and
standardization
Length of production run
Complexity of scheduling procedures
Favors smaller increments of improvement in
new products, but introduces them more often
Managing for Speed Product
Depends on:
Organizing product development for speed
Organizing product manufacturing for speed
Using miscellaneous techniques for speed
Using computer-aided technology for speed
Manufacturing Strategies
Customer
Responsive
Entrepreneurial
Manufacturing
All strategies focus on delivering a quality product at a
competitive price simultaneously responding to customer
needs, and striving for continuous improvement.
Time Based
Strategy
Managing For
Speed Product
Concurrent Engineering Principles
T 19-1
Understand your customer
Use product development teams
Integrate process design
Involve suppliers and subcontractors early
Use digital product models
Integrate CAE, CAD, and CAM tools
Use quality engineering and reliability
techniques
Create an efficient development approach
Improve the design process continuously
F 19-1 Process failure mode and analysis
Quality Function Deployment
(QFD)
A strategy/technique of listening to the
voice of the customer
Benefits of Using a Quality Function
Deployment Strategy
T 19-6
Earlier determination of key product characteristics
Documentation of actual customers needs rather than
decisions based on opinions
Reduction in product development costs
Reduction in time required to bring a new product to
market
Greater customer satisfaction due to lower costs and
improved responsiveness
Reduction in number of engineering changes across the
products life cycle
Quality Function Deployment (QFD)
F 19-2 Four stages of QFD
F 19-3 House of quality
F 19-4 QFD matrices
Group Technology (GT)
An approach to reduce manufacturing
system information content by identifying
and exploiting the sameness or similarity of
parts based on their geometrical shape
and/or similarities in their production
process.
Part Families
Design-oriented: Have similar design
feature, such as geometric shape
Manufacturing-oriented: Can be based on
any number of different considerations,
such as parts manufactured by the same
plant or same materials
Methods of Grouping Parts
Visual inspection
Production flow analysis (PFA)
Classification and coding
(Most effective and widely used)
Two Main Coding Systems
1. Attribute-based (polycodes)
2. Hierarchical-based (monocodes)
F 19-5 Attribute-based coding
F 19-6 Hierarchical-based coding
