Parametric design involves finding values for the features that characterize the object being studied.
Consider a simple example –
We want to design a cylindrical storage tank that must hold 4 m3 of liquid.
The volume is given by
V = r2 l
The tank is described by the parameters, radius 'r', and length l.
Given V = 4 m3 = r2 l
r2 l = 1.273
We can see a number of values for the radius and length, that will satisfy this equation। Each combination-values of r and l gives a possible solution for the design problem.
(d) Original Design
As described in an earlier section, an original design in the development of an assembly or component that did not exist before।
(e) Redesign
The redesign is a modification of an existing product to meet new requirements। It is same as adaptive design. Most design problems solved in industry are for the redesign of an existing product. Suppose a manufacturer of hydraulic cylinders makes a product that is 0.25m long. If the customer needs a cylinder 0.3m long, the manufacturer might lengthen the outer cylinder and the piston rod to meet this special need.
2.3. On the basis of the objective or strategy the designs are of following main types.
A. Production Design
B. Functional Design
C. Optimum डिजाईन
A. Production DesignIn production design, the designer designs something in such a way that the cost of producing the product is minimum। That is, the first responsibility of the designer is reduction of production cost. Hence, a production designer is concerned with the ease with which something can be produced, and that at a minimum cost.
B. Functional Design W93
In functional design, the aim is at designing a part or member so as to meet the expected performance level.
Functional design is a way of achieving given requirements।- but the same may the unproducible or costly to produce. A good designer, then, has to consider the production aspects also. A product designed without keeping all these aspects into account, wastes time, money and efforts.
C। Optimum Design [W 95]
It is the best design for given objective function, under the specified constraints।
2.4 On the basis of the field/ area or the domain of design, the following types are important.
1. Mechanical Design
2. Machine Design
3. System Design
4. Assembly/sub-assembly design
5. Computer aided डिजाईन
1. Mechanical Design
It means use of scientific principles, technical information and imagination in the design of a structure,or machine to perform prescribed functions with maximum economy and efficiency।
2. Machine Design
It is the process of achieving a plan for the construction of a machine।
3. System Design
System Design is an iterative decision making process to conceive and implement optimum systems, to solve problems and needs of society।
4. Assembly/sub-assembly design [S 93]In the design of Assembly/sub-assembly the major criterion is the fulfillment of functional requirements. The assembly has to be designed to meet broad technical parameters and purpose for which it was meant.
The characteristic features are:
¬ The total number of parts used in the design must be minimum.
¬ Sub-assemblies should be capable of being built separately in order to give maximum manufacturing flexibility.
¬ Standard parts may be used.
¬ Flexible parts should be avoided, as they are easily damaged during handling and assembly।
5. Computer aided design [CAD]
It is a design methodology in which the designs take the advantages of digital computer to draw concepts, analyze and evaluate data etc. Computers are largely used in a design office for simulation and prototype study. In modern design, computers have become an indispensable tool.
Other types of designs are
Probabilistic Design
Industrial Design
Probabilistic Design [S 96]
It is a design approach in which design decisions are made using statistical tools. Generally, the external load acting on a body, the properties of materials etc are liable to vary. In probabilistic design, the designer takes into account the variations of such parameters.
Industrial Design [W 93]It is the design made by considering aesthetes, ergonomics and production aspects