COMPUTER AIDED DESIGN
The 21st century business environment can be characterized by expanding global competition and produce of increasing variety and lower demand.
CAD / CAM / CIM are considered as a key component strategy for manufacturing enterprises to achieve this. During the last twenty years the CIM technology is undergone considerable changes.
The CAD /CAM technology has become more sophisticated and seamless integrations between different applications is no longer an issue. The intranet and wide web can now help to achieve significant time compression in product developments.
The display of the drawing or the geometric models of the component in CAD uses the technology of computer graphics.
The techniques of raster technology scan conversion, clipping, removal of hidden lines and hidden surfaces, coloring, and texture are briefly dealt in this unit.
Concept of CAD;
Computer-aided design (CAD) is the use of computer systems to assist in the creation, modification, analysis, or optimization of a design. CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing. CAD output is often in the form of electronic files for print, machining, or other manufacturing operations.
Computer-aided design is used in many fields. Its use in designing electronic systems is known as Electronic Design Automation, or EDA. In mechanical design it is known as Mechanical Design Automation (MDA) or computer-aided drafting (CAD), which includes the process of creating a technical drawing with the use of computer software.
CAD software for mechanical design uses either vector-based graphics to depict the objects of traditional drafting, or may also produce raster graphics showing the overall appearance of designed objects. However, it involves more than just shapes. As in the manual drafting of technical and engineering drawings, the output of CAD must convey information, such as materials, processes, dimensions, and tolerances, according to application-specific conventions. CAD may be used to design curves and figures in two-dimensional (2D) space; or curves, surfaces, and solids in three-dimensional (3D) space.
Computer-aided manufacturing (CAM) is the use of computer software to control machine tools and related machinery in the manufacturing of work pieces. This is not the only definition for CAM, but it is the most common; CAM may also refer to the use of a computer to assist in all operations of a manufacturing plant, including planning, management, transportation and storage.
Its primary purpose is to create a faster production process and components and tooling with more precise dimensions and material consistency, which in some cases, uses only the required amount of raw material (thus minimizing waste), while simultaneously reducing energy consumption.
CAM is now a system used in schools and lower educational purposes. CAM is a subsequent computer-aided process after computer-aided design (CAD) and sometimes computer-aided engineering (CAE), as the model generated in CAD and verified in CAE can be input into CAM software, which then controls the machine tool.
CAD, CAM and CIM ;
· CAD/CAM involves the use of computers to make Design and Manufacturing more profitable.
· Parts of CIM use CAD/CAM techniques and products to try and make the factory fully connected using computers.
· The essential difference is CAD/CAM provides the tools, CIM is the philosophy which is used when organizing the computers, programs, etc. and all the information that flows between them. CIM focuses on connecting the various CAD/CAM modules.
The cad system consists of two basic components; they are
· Computer Hardware;
- It consists of graphic workstations,
- Graphic input devices like keyboard, mouse etc.,
- Graphic output devices like printer and plotters.
· Computer Software;
- It consists of operating system for basic operations,
- Software package used for geometric modeling,
- Application software for design, analysis and synthesis.
Elements of CAD; (or) Various phases of CAD;
The design process in a CAD system consists of 4 stages / phases, they are;
§ Geometric modeling,
§ Design analysis and optimization,
§ Design review and evaluation,
§ Documentation and drafting.