1.1. ENGINEERING DESIGN PROCESS 3
1.1.2 PHASE TWO: DESIGN SPECIFICATIONS
e main tasks in Phase Two are: (1) true understanding of the needs; (2) search existing related
solutions for the needs; and (3) determine design specifications for the needs. e needs in Phase
One, which might come from the sale department, or customers, or society, are generally de-
scribed by general language. ese needs are required to be rephrased by engineering language.
Before this, the first step is to have a true understanding of the needs, and then some primary
criteria are set up. Before we start to search existing solutions or possible solutions, we must
fully and truly understand the need, or the real meanings of the need, or the real requirements
from the customers. For example, if customers require us to design transportation for them. If
we provide the transportation which is driven by gasoline or diesel engine or electrical engine,
we make a big mistake when the power source in that region for the customers is natural gas.
e second step is to search existing or possible solutions for the need by using the primary cri-
teria established in the first step. Do not reinvent the wheel. So, the design project for the needs
should use up-to-date techniques. After lots of background investigation has been done, and
lots of related up-to-date technical information has been collected, the third step is to establish
design specifications for the needs. ere are several common or general design goals that are
usually associated with design projects such as safety, environmental protection, public accep-
tance, reliability, performance, durability, ease of operation, use of standard parts, minimum
cost, minimum maintenance and ease of maintenance, and manufacturability. e design spec-
ifications do not mean these common or general goals, which are certainly considered in detail.
e design specifications properly established in the third step are: (1) any special statement for
the design project and (2) any numerical value related to the design project. Two examples of
design specification are: “e device must work properly in a very moist environment” and “the
factor of safety is 3.5.”
e outcomes of Phase Two are as follows. (1) e needs could be satisfied by an existing
product, or profitable product could not be constructed due to the highly competing market.
So, no further action is required. e design project will not be set up. (2) Proper design speci-
fications have been established and will be satisfied by design. e design project will be set up,
and the project team will be formally formed.
Only after the design specifications are established will the design project and project team
be formally assembled. Now the design project will move to Phase ree: Conceptual Design.
1.1.3 PHASE THREE: CONCEPTUAL DESIGN
e main task in Phase ree is to develop a pool of all possible alternative solutions for the
design project, and then to generate several best alternative solutions for the design project from
the pool of all possible alternative solutions.
Modern design projects are typically complicated with several functions or subsystems.
e following four steps can be used to conduct the conceptual design.
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