Introduction to engineering drawings

Engineering drawing,most commonly referred to as engineering graphics,is the art of manipulation of designs of a variety of components,especially those related to engineering. It primarily consists of sketching the actual component,for example a machine,with its exact dimensions. The scale of dimensions is suitably adjusted so as to properly fit within the contours of the drawing sheet.

Engineering drawing,is the most important aspect of mechanical engineering,as it is the fundamental need to develop the design and assembly of a machine.While,the interpretation of a component in terms of sketching can be done in various methods,the three most necessary techniques of drawing/projection are:-

1)Orthographic Projection : In this method,the object is placed in space,in such a way that the front view of it,is captured in the vertical plane,and the top view of the same,is captured in the horizontal plane. The projections of the object are perpendicular with the planar screen,and hence the name 'orthographic'.

2)Perspective Projection : This is a simple technique, of drawing an object,as how one views it. The observer's eye position,height and the distance from the object,all influence the outcome of the drawing. Two sub-methods are adopted for this projection technique,namely, Visual Ray Method and Vanishing Point Method.

3)Isometric Projection : This form of projection,gives the total detail of the component under consideration. The basic principle behind isometric projection is,it involves the consideration of three axes,that are inclined to each other making equal angles with each other (120 deg). This is followed by transfer of actual dimensions to the isometric scale,involving some basic trigonometric calculations.

Hence,engineering drawing plays a vital role both in manufacture and design,as it not only explains the string of arrangement in a machine,but also tells us about the method to employed,to manufacture the individual blocks.