Design

By Author: endeavor su
Total Articles: 235
Comment this article

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 latter representation completeness. Fig. 1. 2 show the evolution of mechanical CAD/CAM systems over the past three decades.

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 (NO 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.

These software products include Pro/Engineer from Parametric Technology Corporation, IDEAS from SDRC, Unigraphics from Electronic Data Systems, and MES from Intergraph Corporation, among many others.

The solid modeling schemes provide mechanisms for defining complete informational models. However, these schemes have an inherent weakness because they provide a low level representation of parts.

That means that to model a part, the designer has to provide model description in terms of geometric and topological entities that constitute the model. For example, for a boundary representation of a part model, the designer has to specify curves and surfaces and their corresponding edges and faces or a Boolean combination of primitives for a constructive solid geometry (CSG)-based representation.

For example, a solid model of a rotating shaft with one key stores information in terms of only edges and faces. Further developments in parametric modeling provide scope for a higher level of representation of model. These models provide only a higher level of abstraction of the underlying geometry and fail to capture the methodology used to design, configure, and assemble products.

The latest evolutionary development in the CAD/CAM industry has been knowledge-based engineering systems that can capture both geometric and non-geometric product information, such as engineering rules, part dependences, and manufacturing constraints, resulting in more complete informational product definitions.

The commercial knowledge based system known as Intelligent-CAD (ICAD) is available from ICAD, Cambridge, Massachusetts. Because ICAD is based on the principles of object oriented modeling, technology, it provides a development environment with powerful geometric and artificial intelligence CAD-based tools.

Swiss Breitling Bentley Replica have always been a symbol of success. Perfect gifts for your friends Tag Heuer Carrera Replica Watches Summer Large-scale Promotions Started at here.