When the subjects for Engineering curriculum were thought of and designed, importance to the “power of imagination” was given preference. This requirement gave birth to the subject “Engineering Drawing”. Over a period of time though the content underwent modifications, the basic ideas/requirements were retained. With the introduction of super specialities in engineering specializations, new subjects were introduced in the place of existing ones, as latest inventions were to find place in the curriculum. However, the subject Engineering Drawing could not be touched/replaced because of its importance to the engineer.
The purpose of any language is to communicate and therefore, drawing should also serve this purpose. The engineers express/explain their ideas or concepts effectively through the medium of drawing.
The subject drawing is, therefore, included in the engineering curriculum to train the students to draw in a manner which is easily understood by others and also to help them understand the drawings made by others in the profession. It is obvious that, an engineer must be wellversed in this language and hence, it forms a very basic and important component of any engineering curriculum.
The subject engineering drawing is introduced in the curriculum to enhance the imagination power of the engineering student and to communicate with other engineers.
With the realization of the importance of the subject, standards both at international and national level are produced so that the drawings prepared based on the standards could be understood by everyone, irrespective of the language of their country. Thus, drawing is the source of communication for engineers.
An important function of the drawing of a component is, to help its production in the shop/construction/design of a machine tool. Thus, drawing is an important auxiliary of production.
The subject engineering drawing is introduced at the first year of study of the engineering course to provide a basic knowledge of the subject and contribute to the power of imagination.
The various drawings that are included in the branches of engineering are: Civil engineering drawing / Building drawing; Mechanical engineering / Machine drawing, Production drawing; Electrical engineering drawing; Architectural drawing, Design and drawing and so on.
When a machine has to be produced or a structure has to be constructed, the first step is, it should be imagined by the engineer. Then a rough sketch is made to explain its function / working to a layman. Through these rough sketches, the ideas are conveyed. Later, changes are made to these sketches if required to overcome any limitations or to introduce any required modifications. Preparation of a sketchy idea needs basic training which is provided at the first year level of engineering with the introduction of the subject Engineering Drawing.
The subject engineering drawing deals with “Plane geometrical drawing - dealing with the representation of two dimensional objects and “Solid geometrical drawing”- dealing with the representation of objects having three dimensions.
A language, to be communicative, should follow certain rules so that it conveys the same meaning to all. Similarly, drawing practice also should follow certain rules and Bureau of Indian standards (BIS) adopting the international standards on code of practice for drawing. Every student of engineering should be familiar with these rules while dealing with the subject “drawing”, in general.
Part of the subject ’Plane geometrical drawing’ familiarizes the student of engineering with various curves used in engineering practice, projection of points, lines and planes. This forms the basis for the ultimate requirement of representation of solids.
Part of the subject ‘Solid geometrical drawing’ provides [1], [2], [3], [4] training so that the student learns to represent regular solids under the topics such as orthographic projections, projections of solids and sections of solids. This forms the basis for learning the method of representation of engineering objects.
Part of the subject ’Development of the surfaces and intersection of surfaces’ familiarises the students and provides them the ability to represent the combination of two or more solids.
The principles of orthographic projection are meant to train the student to visualize and interpret the shape of an object from the multi-view drawings.
However, persons who cannot visualise the object from its multi-view drawing, the engineer should be able to convey the information about the object by pictorial drawings. Isometric projections and perspective projections will help the engineer in this regard, which fall under pictorial projections.
By the time the students undergo training in engineering drawing (plane and solid geometrical drawing), they will be familiar with the basics of the engineering drawing- the stepping stone for understanding the representation of engineering objects.
The starting point for the representation of engineering objects is through machine drawing[5].
Machine drawing is the indispensable communicating medium employed in industries, to furnish the basic information required for the manufacture and, assembly of the components of a machine.
When a machine has to be produced or a structure has to be constructed, first of all the engineer should imagine the same. Next, he should be able to convey his ideas by sketches and to make a sketch, a basic training is needed. This basic training is provided at the first year level by the subject Engineering Drawing.
A design engineer will be able to convey his ideas about a machine by sketching various parts individually and assembling the same. This enables him to check its satisfactory working. Otherwise, modifications are made to the sketches and checked. This process may continue till a satisfactory result is obtained. However, this is not the end of the process. Machines cannot be produced from these sketches as these drawings will only give an idea of the principle of working of a machine.
The contents under “Machine drawing” will be such that, the students can learn well about the drawing practice of most of the important mechanical engineering components and sub-assemblies they will be studying through various courses.
The topics included in machine drawing are,
Sub-assemblies pertain to engine parts, machine tool parts, valves and boiler mountings.
The above topics will cover most of the engineering components one will come across in the various industrial products. Once the student is familiar with these components they will be in a position to understand any other engineering component because, the basics of representation are the same.
Machine drawing of components are not suitable for fabrication purpose because in these drawings only nominal sizes of the components are presented.
The development of a new machine starts from the preparation of its design assembly drawings. After analysing these drawings thoroughly, final assembly drawings are made. The production of a machine consists of the individual parts of the unit being produced first. To facilitate this, the preparation of the working drawings is to be made from the assembly drawing. The production drawings, also called as working drawings of each component, should provide all the information required, such as size and shape description, dimensions, notes, material, tolerances, surface finish values, manufacturing methods, etc.
The production drawing[6] of a component is usually accompanied by a sheet, known as process planning sheet or process sheet indicating the sequence of operations recommended for manufacturing it. It should contain every act or event necessary, including operations, which change the shape or dimensions of a part, its surface finish or material characteristics (i, e., hardness, etc.), verifying its accuracy or performance (inspection), and specifying its movement or storage. It should also list the machinery, tooling and skills for each act or event. It is forwarded to the production shop by the process planning section for carrying out manufacturing of the component.
The authors thank all faculty members concerned with the study of Engineering Drawing for their contribution in preparing the students of Engineering in enhancing their power of imagination.
The subject is designed to enhance the ability to convey their ideas to all concerned. May be, it is necessary to design some such subjects to all the students seeking higher education, so that they derive pleasure in both learning the subject and able to utilize the same to the maximum extent. The paper gives an idea to the reader, how effectively the course content of engineering curriculum is designed.