GRAPHIC LANGUAGE

 

A technical person can use the graphic language as powerful means of communication with

others for conveying ideas on technical matters. However, for effective exchange of ideas with

others, the engineer must have proficiency in (i) language, both written and oral, (ii) symbols

associated with basic sciences and (iii) the graphic language. Engineering drawing is a suitable

graphic language from which any trained person can visualise the required object. As an

engineering drawing displays the exact picture of an object, it obviously conveys the same

ideas to every trained eye.

Irrespective of language barriers, the drawings can be effectively used in other countries,

in addition to the country where they are prepared. Thus, the engineering drawing is the

universal language of all engineers.

Engineering drawing has its origin sometime in 500 BC in the regime of King Pharos of

Egypt when symbols were used to convey the ideas among people.

IMPORTANCE OF GRAPHIC LANGUAGE

The graphic language had its existence when it became necessary to build new structures and

create new machines or the like, in addition to representing the existing ones. In the absence

of graphic language, the ideas on technical matters have to be conveyed by speech or writing,

both are unreliable and difficult to understand by the shop floor people for manufacturing.

This method involves not only lot of time and labour, but also manufacturing errors. Without

engineering drawing, it would have been impossible to produce objects such as aircrafts,

automobiles, locomotives, etc., each requiring thousands of different components.

NEED FOR CORRECT DRAWING

The drawings prepared by any technical person must be clear, unmistakable in meaning and

there should not be any scope for more than one interpretation, or else litigation may arise. In

a number of dealings with contracts, the drawing is an official document and the success or

failure of a structure depends on the clarity of details provided on the drawing. Thus, the

drawings should not give any scope for mis-interpretation even by accident.

It would not have been possible to produce the machines/automobiles on a mass scale

where a number of assemblies and sub-assemblies are involved, without clear, correct and

accurate drawings. To achieve this, the technical person must gain a thorough knowledge of

both the principles and conventional practice of draughting. If these are not achieved and or

practiced, the drawings prepared by one may convey different meaning to others, causing

unnecessary delays and expenses in production shops.

Hence, an engineer should posses good knowledge, not only in preparing a correct drawing

but also to read the drawing correctly. The course content of this book is expected to meet

these requirements.

The study of machine drawing mainly involves learning to sketch machine parts and to

make working and assembly drawings. This involves a study of those conventions in drawings

that are widely adopted in engineering practice.

CLASSIFICATION OF DRAWING