文档介绍：英文正文资料
英文正文资料
ABSTRACT
Design and manufacturing are the core activities for realizing a marketable and profitable product. A number of evolutionary changes have taken place over the past couple of decades in the areas of both design and manufacturing. First we explore the developments in what is called CAD. The major focus in CAD technology development has been on advancing representation completeness. First there was the development of a two-dimensional (2D) drafting system in the 1960s. Then the extension of 2D drafting systems to three-dimensional (3D) models led to the development of wire frame-based modeling systems. However, it was not possible to represent higher order geometry data such as surface data. To bridge this gap, surface based models were developed in the early 1970s. Even though the surface models provided some higher level information, such as surface data for boundary representation, this was still not sufficient to represent solid or volume enclosure information. The need for solid modeling intensified with the development of application programs such as numerical control (NC) verification codes and automation mesh generation. A volume representation of the part is needed for performing topological validity checks. The solid modeling technology has evolved only since the mid-1970s. A large number of comprehensive software products are now available that enable integration of geometric modeling with design analysis and computer aided manufacturing .
The latest evolutionary development in the CAD/CAM industry has been knowledge-based engineering systems that can capture both geometric and nongeometric product information, such as engineering rules, part dependences, and manufacturing constraints, resulting in more informationally complete product definitions.
Optimum Design
In the design of any component , there are always associate with the design certain desirable and undesirable effects. It is possible to obtain design solutions without