Table Of ContentEngineering Design and Rapid Prototyping
Ali K. Kamrani Emad Abouel Nasr
●
Engineering Design
and Rapid Prototyping
Ali K. Kamrani Emad Abouel Nasr
Industrial Engineering Department Fatimah Alnijris’s Research Chair
University of Houston for Advanced Manufacturing Technology
Houston, TX, USA Industrial Engineering Department
and Faculty of Engineering
Fatimah Alnijris’s Research Chair King Saud University
for Advanced Manufacturing Technology Riyadh, Saudi Arabia
Industrial Engineering Department and
King Saud University Mechanical Engineering Department
Riyadh, Saudi Arabia Faculty of Engineering
akamrani@uh.edu Helwan University
Helwan, Egypt
emadsamir60@helwan.edu.eg
ISBN 978-0-387-95862-0 e-ISBN 978-0-387-95863-7
DOI 10.1007/978-0-387-95863-7
Springer New York Dordrecht Heidelberg London
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To my wife Sonia and sons Arshya
and Ariya
Ali Kamrani
To my parents, wife, and children Nada,
Haidy, and Amr
Emad Abouel Nasr
Preface
Engineering design process consists of a set of activities arranged in a specific order
with the clearly identified inputs and outputs. The process of engineering design is
an iterative that supports the decision-making activities involved. Each activity in
the process takes an input and transforms it into an output of some value defined by
design specifications and objectives. The output of the process is either a product,
a process, or a service. The objective of the process is to satisfy customer require-
ments and management objectives. This process is considered efficient when the
output of the process satisfies general customers and defined requirements, meets
management objectives and customer deadlines, and all these with less costs and
resources. Establishing objectives and criteria, synthesis, analysis, construction,
testing, and evaluation are considered as fundamental elements within the design
process. Steps in the Engineering design process are illustrated in Fig. 1.
These steps and further described below:
1. Identify the Need/Problem: This step is not always realized by engineers.
Problems are typically identified by the market and customers and then passed
on to the engineering group to search and develop solutions.
Engineering
Design
Process
Select Best
Possible
Solu(cid:31)on
Fig. 1 Engineering design process
vii
viii Preface
2. Research the Need/Problem: This step is of importance since a solution to the
defined problem or portion of the problem may have already existed. Through
proper research, time and money can be easily saved.
3. Develop Possible Solutions: In this step, the engineering group will propose
different solution alternatives that will solve the problem. These possible solu-
tions are made while taking into consideration the information found in the pre-
vious steps.
4. Select Best Possible Solution: The engineering group will then use the defined
criteria and other methodologies to select the best possible solution. The param-
eters on which the engineering group determine if it is the best possible solution
may vary depending on the defined constrains and/or the design criteria estab-
lished at the beginning of the engineering design process.
5. Construct a Prototype: In this step, the engineering group proceeds to con-
struct a prototype of the selected solution. Once the prototype is built, testing is
performed to validate the proposed design solution. If the design does not meet
the required performance, the engineering design process is repeated until a sat-
isfactory solution is implemented.
New global economies and global markets changed business practices and
focused on the customer as the major player in the economy. In order to compete
in this fast-paced global market, organizations need to produce products that can be
easily configured to offer distinctive capabilities compared to the competition.
Furthermore, organizations need to develop and implement new engineering meth-
ods (e.g., modularity), and apply advanced techniques in design (e.g., Feature-
Based Design) and technologies (e.g., Rapid Prototyping) to react rapidly to
required changes in products and market trends and to shorten the product develop-
ment cycle, which will enable them to gain more economic competitiveness. This
requires that the tasks needed to develop products be made in parallel, starting at
the early stages of product development. By developing such techniques, organiza-
tions will be able rapidly to design changed or new products, to change parts of a
product, or to change manufacturing facilities to a new version of a product.
The concept of modularity can provide the necessary foundation for organiza-
tions to design products that can respond rapidly to market needs, and allow the
changes in product design to happen in a cost-effective manner. Modularity can be
applied to the engineering design processes to build modular products. An impor-
tant aspect of modular products is the creation of a basic core unit to which different
components (modules) can be fitted, thus enabling a variety of versions of the same
module to be produced. The core should have sufficient capacity to cope with all
expected variations in performance and usage. Components used in a modular
product must have features that enable them to be coupled together to form a new
product. Figure 2 illustrates the scope of modular design methodology.
Computer-aided design (CAD) and manufacturing (CAM) systems are based on
modeling geometric data. The main advantage of CAD/CAM systems is the ability
to visualize product design, and support design analysis and manufacturing acti-
vates. CAD/CAM systems need the standardization that gives them the ability
Preface ix
Design Concept
(Re)Formulation
Optimization Models
Design for
and Sub-System
Modularity (DFMo)
Generation
Design for Simplification of
Assembly (DFA) Product Structure
y
arit Selection of Material Knowledge-Based
ul and Primary Process D Engineering and
d
o for Near Net Shape Decision Trees
M
n for FDeaessiibglne /COopnticmeupmt F MaMteorriael sE, cPornoocmesicses
g and Machines
si
e
D Design for
Manufacture M
Template-Based Decision Trees and
Process Planning Group Technology
Optimization Models
Modular
and Manufacturing
Manufacturing Cells
Cells Generation
Fig. 2 Design for modularity life cycle
to communicate to each other. Different CAD or geometric modeling packages
store the information related to the design in their own databases, and the structures
of these databases are different from each other. As a result, no common or standard
structure has been developed that can be used by all CAD/CAM packages.
Therefore, a feature-based approach using IGES standard will provide the required
standardization to achieve the integration between CAD and CAM. Figure 3 illus-
trates the stages that CAD/CAM and other advanced tools and technologies are
used to support, and integrated and intelligent engineering design life cycle.
Rapid Prototyping (RP) is a technique for direct conversion of three—dimen-
sional CAD data into a physical prototype. RP allows for automatic construction of
physical models and has been used to significantly reduce the time for the product
development cycle and to improve the final quality of the designed product. Before
the application of RP, computer numerically controlled (CNC) equipments were
used to create prototypes either directly or indirectly using CAD data. In RP pro-
cess, thin-horizontalcross-sections are used to transform materials into physical
prototypes. Steps in RP process cycle are illustrated in Fig. 4.
In the RP process, CAD data are interpreted into the Stereolithography (stl) data
format. The stl is the standard data format used by all RP machines. By using “stl”,
the surface of the solid is approximated using triangular facets, with a normal vec-
tor pointing away from the surface in the solid. Within the last few years, corpora-
x Preface
s
si
y
al
An Manufacturing and
g Production
n
uri
ct
ufa Process Planning
n and CAPP
a
M
d Variety and
an CAD/CAE Complexity
gn Design for Manufacture Analysis
esi and Assembly Analysis
D Analysis and
Re-Design
Specifications
Rapid Prototyping
and Concepts
CAD
Time
Fig. 3 CAD/CAM application for EDP
Functional & Physical Specifications
Tools for
CAD Tool for Decomposition
Sculptural
Geometric Design &
Design and Modular
3D Model
Styling Components
and
Subassemblies
Rapid
STL File Analysis Prototyping
& Editing
Testing
Product Product
Mfg. &
Planning & Process & Process
Assembly
Development Testing
Fig. 4 Generic RP process cycle
