A drawing is a graphic representation of a real thing. To draw something as a figure by means of lines expressing some ideas on the paper is known as a drawing. The purpose of the drawing is to define and specify the shape and size of a particular object by means of lines and other information about the object. A good drawing gives full information about the object in the shortest and simplest way.
A drawing worked out by an engineer, having engineering ideas, for engineering purpose, is known as Engineering Drawing. It is the universal graphic language of engineers. Every language has its own rules of grammar. Engineering Drawing also has been devised according to certain rules. It has its own conventions in the theory of projection, the types of lines, its abbreviations, symbols and its description. The knowledge of the drawing is the most important requirement of all the technical persons to work in an engineering occupation.
A technician expresses his ideas on the paper through the medium of drawing. A complete working drawing of a job is prepared in brief. It is then followed up by the workers who give accurate shape to the raw materials according to the drawing. If technician commits a little error in the initial drawing work, it is carried over in the practical work by the workers resulting in the loss of time, money, material and labour. As a result, the production efficiency of the factory decreases. Therefore, it is extremely important for the engineers, designers, supervisors, draftsmen, mechanics and other workers engaged in production to have a thorough knowledge of engineering drawing.
The ability to read drawing is the most important requirement of all technical people in engineering profession. The potentialities of drawing as an engineer’s language may be made use of, as a tool for imparting knowledge and providing information on various aspects of engineering.
Engineering drawing is a two dimensional representation of a three dimensional object. It is the graphic language from which a trained person can visualize the object. As an engineering drawing displays a precise picture of the object to be produced, it conveys the same picture to every trained eye. Drawings prepared in one country may be utilized in any other country, irrespective of the language spoken there. Hence, engineering drawing is called the universal language of engineers.
By means of drawing, the shape, size, finish, color and construction of any object can be described accurately and clearly in the simplest and shortest way. The quality of any engineering drawing depends on the following factors:
- Ability to visualize the job in three dimensions.
- A clear conception and appreciation of the shape, size, proportion and design.
- Clarity of Expression of ideas on the paper by sketches.
- Speed and accuracy of the drawing work.
- Interest in the drawing works.
The numerous utilities of engineering drawing are as follows:
- As it is the representation of an object on a single plane, even a huge object can be drawn on a small piece of paper with all the necessary details of the object.
- It precisely and fully gives shape of an object and contains all the information required for its manufacture, inspection or maintenance.
- It also supplies the information regarding the exact size, material, the relative position, finish, accuracy and method of securing of the parts.
- Even large machining operations can be represented by small symbols.