Engineering Graphics - mechanical engineering

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1. Engineering Graphics Course material prepared by Mr. S.Sathyaraj , M.E Assistant Professor Depart. of Mechanical Engineering SSCET

2. Why Engineering Design for CSE, IT? “ Language of design " used by engineers to visually represent ideas, objects, or structures. T o show how things are built or how they work. D rawings are precise and detailed so that anyone can understand how to construct, assemble, or use the object or system. Ex: D esign of robotic systems .

3. Why Engineering Design for CSE, IT? Imagine you’re developing software for a robotic arm that picks and places objects. While you may be focused on programming the robot’s movements, the engineers who design the robot's hardware (the arm, motors, and joints) will create detailed engineering drawings that show how these parts fit together.

4. D rawing instruments Pencil T-Square Ruler (or Scale) Compass Set Square (Triangle) Protractor

5. Types of pencils

6. Sizes of sheets

7. Drawing board

8. Types of lines

9. Dimensioning T he process of adding numerical values to a drawing to indicate the size and location of parts. Aligned dimensioning Unidirectional dimensioning

10. GENERAL RULES OF DIMENSIONING Dimension lines and projection lines are drawn as continuous thin lines . Projection lines should extend slightly beyond the dimension line approximately to 3mm.  Numerals and letters should be bold and large enough to ensure easy readings.  Dimension values should be placed approximately at the middle unless unavoidable due to lack of space.  Dimensions should not be placed within a view.

11. Dimension lines should be placed at sufficient distance from the parts being dimensioned, preferably at a distance of 6 to 10 mm. Extension and projection lines should not cross other.

12. For this condition, smaller dimensions should be placed near the view and larger dimensions should be placed away from the view.  Dimensions are to be given from visible outlines rather than from hidden lines. GENERAL RULES OF DIMENSIONING

13. Each end of dimension line should be defined by an arrow head, proportional to the line thickness and size of the drawing. The ratio of length to width of arrow head should be 3: 1.

14. Each dimension should be given only once . For this condition, a dimension given in one view (say height in front view) should not be repeated in another view (the same height in side view).

15. Two systems of dimensioning should not be mixed up in one drawing . Dimensions in one particular drawing should be expressed in one unit only . A dimensional line should be shown unbroken even if the feature is broken

16. A centre line, an outline or an extension line should not be used as a dimension line.

17. Exercise Redraw the figure to full size and dimension it in ( i ) Aligned system and (ii) Unidirectional system as per Bureau of Indian standards. Take all the dimensions are in mm.