Chapter 1 Overview of an Engineering Drawing

1. Chapter 1 Overview of an Engineering Drawing

2. Graphics language Engineering drawing Drawing standards TOPICS

3. Traditional Drawing Tools Lettering Freehand Sketching TOPICS Projection methods

4. GRAPHICS LANGUAGE

5. Effectiveness of Graphics Language 1. Try to write a description of this object. 2. Test your written description by having someone attempt to make a sketch from your description. You can easily understand that … The word languages are inadequate for describing the size, shape and featurescompletely as well as concisely.

6. The language is known as “drawing” or “drafting (sketching) ” . A drawing can be done using freehand, instrumentsor computermethods. Composition of Graphic Language Graphic languagein “engineering application” use linesto represent the surfaces, edges and contoursof objects.

7. Example Freehand drawing The lines are sketched without using instruments other than pencils and erasers.

8. Example Instrument drawing Instruments are used to draw straight lines, circles, and curves concisely and accurately. Thus, the drawings are usually made to scale.

9. Example Computer drawing The drawings are usually made by commercial software such as AutoCAD, solid works etc.

10. Engineering Drawing

11. Graphics language Describe a shape(mainly). Word language Describe size, location andspecification of the object. Elements of Engineering Drawing Engineering drawing are made up of graphics language and word language.

12. Geometric Construction العمليات الهندسية Line Types أنواع الخطوط Projection Method طريقة الإسقاط Lettering Basic Knowledge for Drafting Word language Graphics language

13. Drawing Standard

14. Drawing standards are used so that drawings convey توصل the same meaning to everyone who reads them. Introduction Standards are set of rules that govern تحكمhow technicaldrawings are represented.

15. Full name Country Code USA American National Standard Institute ANSI มอก. สำนักงานมาตรฐานผลิตภัณฑ์อุตสาหกรรม Thailand Japanese Industrial Standard Japan JIS British Standard UK BS Australian Standard Australia AS Deutsches Institut fürNormung Germany DIN International Standards Organization ISO Standard Code

16. Drawing Sheet A4 Trimmed paper of a size A0 ~ A4. A3 Standard sheet size A4 210 x 297 A3 297 x 420 A2 420 x 594 A1 594 x 841 A0 841 x 1189 A2 A1 (Dimensions in millimeters) A0

17. Orientation of drawing sheet c d d c c Sheet size c (min) d (min) A4 10 25 A3 10 25 A2 10 25 A1 20 25 A0 20 25 1. Type X (A0~A4) 2. Type Y (A4 only) Drawing space Drawing space Border lines Title block Title block

18. : Drawing Scales Length, size Scaleis the ratio of the linear dimension of an element of an object shown in the drawing to the real linear dimension of the same element of the object. Size in drawing Actual size

19. Designation of a scale consists of the word “SCALE” followed by the indication of its ratio, as follow Dimension numbers shown in the drawing are correspond to “true size” of the object and they are independent of the scale used in creating that drawing. Drawing Scales SCALE 1:1 for full size SCALE X:1 for enlargement scales (X < 1) SCALE 1:X for reduction scales (X > 1)

20. Continuous thick line Visible line Dimension line Extension line Leader line Continuous thin line Dash thick line Hidden line Chain thin line Center line Basic Line Types Name according to application Types of Lines Appearance NOTE : We will learn other types of line in later chapters.

21. Meaning of Lines Visible lines represent features that can be seen in the current view Hidden lines represent features that can not be seen in the current view Center linerepresents symmetry, path of motion, centers of circles, axis of axisymmetrical parts Dimension and Extension linesindicate the sizes and location of features on a drawing

22. Example : Line conventions in engineering drawing

24. Traditional Drawing Tools

25. DRAWING TOOLS

26. DRAWING TOOLS 1. T-Square 2. Triangles

27. DRAWING TOOLS 2H or HB for thick line 4H for thin line 3. Adhesive Tape 4. Pencils

28. DRAWING TOOLS 5. Compass

29. DRAWING TOOLS 6. Pencil Eraser 7. Erasing Shield

30. DRAWING TOOLS 8. Circle Template

31. DRAWING TOOLS 9. Sharpener 10. Clean paper

32. ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEF Lettering ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEF

33. To communicate nongraphic information. As a substitute for graphic information, in those instance where text can communicate the needed information more clearly and quickly. - shape - space between letters and words Legibility وضوح - size- line thickness Uniformity Text on Drawings Text on engineering drawing is used : Thus, it must be written with

34. يجب مراعاة القواعد التالية عند وضع الأبعاد على الرسم:1- أخذ خطوط المرجع التي تؤخذ منها الأبعاد بعناية 2- عدم تكرار الأبعاد على الرسم3- أن توضع جميع الأبعاد الضرورية على الرسم* تنتهي خطوط الأبعاد بأسهم

38. Dimension & Notes Title Block Notes Example Placement of the text on drawing

39. Use only a vertical Gothic text style. Use a Gothic text style, either inclined or vertical. Use both capital and lower-case letters. Use all capital letters. Use 3 mm for most text height. Same. For letters in title block it is recommend to use 5~8 mm text height Space between lines of text is at least 1/3 of text height. Follows ANSI rule. Lettering Standard ANSI Standard This course

40. Basic Strokes Straight Slanted Horizontal Curved Examples : Application of basic stroke 4 5 1 “I” letter “A” letter “B” letter 1 2 1 6 3 3 2

41. Suggested Strokes Sequence Upper-case letters & Numerals Straight line letters Curved line letters Curved line letters & Numerals

42. Suggested Strokes Sequence Lower-case letters The text’ s body height is about 2/3 the height of a capitalletter.

43. Stroke Sequence T F L I E H

44. Stroke Sequence V X W

45. Stroke Sequence Z M K N 4 Y A

46. Stroke Sequence G Q C O

47. Stroke Sequence U P B D R J 1 2

48. Stroke Sequence 7 5

49. Stroke Sequence 6 0 3 S 8 9

50. Stroke Sequence i l