COMPUTER AIDED DRAFTING AND SOLID MODELING

   

Drawing has been an integral part of engineering for many years. It is the link between the engineering design and manufacturing. Information regarding the size, shape, dimensions, tolerances and other manufacturing/construction details are quickly communicated to the production construction personnel in the form of drawings prepared according to prescribed drafting standards. These drafting standards are specified for understanding and interpreting the drawings in the same way by various designers and manufacturing personnel. An engineering drawing may be prepared by means of conventional tools such as drafting board, pencil or ink on the tracing paper or alternatively, with the aid of a computer. The method of preparing the drawings by computers is known as Computer Aided Drafting (CAD) or Computer Aided Design and Drafting (CADD).

Concept of computer aided drafting

Computer aided drafting is the creation, storage and manipulation of models of objects and their pictures via computers. Interactive computer graphics is the important case in which a user dynamically controls the picture content, format, size or colours on a video display by means of interaction devices such as key board, mouse etc. Graphics display on a monitor can be converted into hard copy with a plotter or a printer. In computer aided design interactive graphics is used to design components and systems of civil, mechanical, and electronic devices. These systems include structures (buildings. automobile bodies. airplanes and ships, chemical and power plants), optical systems, computer networks etc. The emphasis in computer aided drafting is only on producing precise drawings of components and assemblies.

Advantages and Disadvantages of CAD

A CAD system should be thought of as a tool at your disposal for making drawings. It is a tool used to make the drawings at a higher speed and more accurately. Drawings can be revised and changed much more quickly and accurately than by hand. The storage of drawings is very easy. Employees of an organization  using CAD are likely to follow a set of company standards as they produce drawings. These drawings accumulate in the database which can be utilized for quick accession by all other authorized personnel and can be used for manufacturing.  Hence it is economically sound to let a drawing be prepared by a computer.

There are some negative aspects of computer aided drafting. At certain times you may not be able to use the system due to its overload by simultaneous requests for use. It also may be due to a component being out of service. This may last for several hours or even days until service person can repair the system. This is called as "down-time". The initial investment on a CAD system is high. As the computers are faster in makings the drawings, the manpower requirement automatically comes down and it may lead to social problems.