Page 32 - 04. Subyek Engineering Materials - Manufacturing, Engineering and Technology SI 6th Edition - Serope Kalpakjian, Stephen Schmid (2009)

General Introduction

ensure that the product will still meet all specified requirements and will function
satisfactorily. A later change from, say, a forged to a cast component will likewise
necessitate a repeat analysis. Such iterations obviously waste both time and the
resources of a company.

Concurrent Engineering. Driven primarily by the consumer electronics industry, a
continuing trend is taking place to bring products to the marketplace as rapidly as
possible, so as to gain a higher percentage share of the market and thus higher prof-
its. An important methodology aimed at achieving this end is concurrent engineer-
ing, which involves the product-development approach shown in Fig. I.3b. Note
that, although this concept, also called simultaneous engineering, still has the same
general product-flow sequence as in the traditional approach (Fig. I.3a), it now con-
tains several deliberate modifications. From the earliest stages of product design and
engineering, all relevant disciplines are now simultaneously involved. As a result,
any iterations that may have to be made will require a smaller effort and thus result
in much less wasted time than occurs in the traditional approach to design. It should
be apparent that a critical feature of this approach is the recognition of the impor-
tance of communication among and within all disciplines.
Concurrent engineering can be implemented in companies large or small, which
is particularly significant because 98% of all U.S. manufacturing companies have fewer
than 500 employees. Such companies are generally referred to as srnall businesses. As
an example of the benefits of concurrent engineering, one automotive company re-
duced the number of components in one of its engines by 30%, decreased the engine
weight by 25%, and reduced its manufacturing time by 50%.

Life Cycle. In concurrent engineering, the design and manufacture of products are
integrated with a view toward optimizing all elements involved in the life cycle of
the product (see Section 1.4). The life cycle of a new product generally consists of the
following four stages:
l. Product start-up
2. Rapid growth of the product in the marketplace
3. Product maturity
4. Decline.
Consequently, life-cycle engineering requires that the entire life of a product be consid-
ered, beginning with the design stage and on through production, distribution, prod-
uct use, and, finally, recycling or the disposal of the product.

Role of Computers in Product Design. Typically, product design first requires the
preparation of analytical and physical models of the product for the purposes of
visualization and engineering analysis. Although the need for such models depends
on product complexity, constructing and studying these models have become highly
simplified through the use of computer-aided design (CAD) and computer-aided
engineering (CAE) techniques.
CAD systems are capable of rapid and complete analyses of designs, whether it
be a simple shelf bracket or a shaft in large and complex structures. The Boeing 777
passenger airplane, for example, was designed completely by computers in a process
known as paperless design, with 2000 workstations linked to eight design servers.
Unlike previous mock-ups of aircraft, no prototypes or mock-ups were built and the
777 was constructed and assembled directly from the CAD/CAM software that had
been developed.
Through computer-aided engineering, the performance of structures subjected,
for example, to static or fluctuating loads or to temperature gradients also can be