Dimensioning & Lettering. A comprehensive approach .pptx

A comprehensive presentation on Drawing and Lettering

1. Engineering Drawing

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

3. Basic Knowledge for Drafting Graphics language Word language Line types Geometric construction Lettering Projection method

4. Drawing Standard

5. Introduction Standards are set of rules that govern how technical drawings are represented. Drawing standards are used so that drawings convey the same meaning to everyone who reads them.

6. ISO I nternational S tandards O rganization Standard Code ANSI A merican N ational S tandard I nstitute USA JIS J apanese I ndustrial S tandard Japan BS B ritish S tandard UK AS A ustralian S tandard Australia D eutsches I nstitut f ü r N ormung DIN Germany Country Code Full name

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

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

9. SAMPLE OF DRAWING SHEET

10. Drawing Scale

11. Drawing Scales Scale is 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 Length, size :

12. Drawing Scales Designation of a scale consists of the word “ SCALE ” followed by the indication of its ratio , as follow SCALE 1:1 for full size SCALE X :1 for enlargement scales (X > 1) SCALE 1: X for reduction scales (X > 1) 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.

13. Dimensioning

14. LECTURE OBJECTIVES Introduction Dimensioning Components Dimensioning Object ’ s Features Placement of Dimensions .

15. Example : Line conventions in engineering drawing

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

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

18. Introduction

19. Shape Multiview Drawing Dimensioning Design a part 1. Size, Location ENGINEERING DESIGN 2. Non-graphic information TRANSFERRED INFORMATION Create drawings Manufacture RESULT Sketches of ideas PROCESS

20. DEFINITION Dimensioning is the process of specifying part’ s information by using of figures , symbols and notes . This information are such as: 1. Sizes and Locations of Features 2. Material’s Type 3. Number Required 4. Kind of surface finish 5. Manufacturing process 6. Size and geometric tolerances This course

21. DIMENSIONING SYSTEM 1. Metric system : ISO and JIS standards 2. Decimal-inch system 3. Fractional-inch system , 0.25 (not .25) , 5.375 etc. Examples Examples 32, 32.5, 32.55, 0.5 (not .5) etc. Examples etc. This course

22. Dimensioning Components

23. DIMENSIONING COMPONENTS Extension lines Dimension lines (with arrowheads) Leader lines Dimension figures Notes : - local note - general note Drawn with 4H pencil Lettered with 2H pencil.

24. indicate the location on the object’s features that are dimensioned. EXTENSION LINES

25. DIMENSION LINES indicate the direction and extent of a dimension, and inscribe dimension figures . 10 27 43 13 123 o

26. indicate details of the feature with a local note. LEADER LINES 10 27 43 13 123 o 10 Drill, 2 Holes R16

27. Recommended Practices

28. EXTENSION LINES Leave a visible gap (≈ 1 mm) from a view and start drawing an extension line. Visible gap COMMON MISTAKE

29. Do not break the lines as they cross object lines. COMMON MISTAKE Continuous EXTENSION LINES

30. Dimension lines should not be spaced too close to each other and to the view. 11 34 Leave a space at least 2 times of a letter height. 16 35 DIMENSION LINES Leave a space at least 1 time of a letter height.

31. DIMENSION FIGURES The height of figures is suggested to be 2.5~3 mm. Place the numbers at about 1 mm above dimension line and between extension lines . COMMON MISTAKE 11 11 34 34

32. 16.25 16.25 or DIMENSION FIGURES When there is not enough space for figure or arrows, put it outside either of the extension lines. 1 Not enough space for figures Not enough space for arrows 1 1

33. The JIS and ISO standards adopt the unit of Angular dimension in degree with a symbol “ o ” ( and if necessary minutes and seconds may be used together). DIMENSION FIGURES : UNITS Length dimension in millimeters without specifying a unit symbol “mm”.

34. 1. Aligned method 2. Unidirectional method The dimension figures are placed so that they are readable from the bottom and right side of the drawing. The dimension figures are placed so that they can be read from the bottom of the drawing. Do not use both system on the same drawing or on the same series of drawing (JIS Z8317) DIMENSION FIGURES : ORIENTATION

35. 30 30 30 30 30 30 30 30 EXAMPLE : Dimension of length using aligned method.

36. 30 30 30 30 30 30 30 30 EXAMPLE : Dimension of length using unidirectional method.

37. 45 o 45 o 45 o 45 o 45 o 45 o 45 o 45 o EXAMPLE : Dimension of angle using aligned method.

38. 45 o 45 o 45 o 45 o 45 o 45 o 45 o 45 o EXAMPLE : Dimension of angle using unidirectional method.

39. LOCAL NOTES Place the notes near to the feature which they apply, and should be placed outside the view. Always read horizontally . 10 Drill COMMON MISTAKE 10 Drill ≈ 10mm 10 Drill Too far

40. Dimensioning Practices

41. THE BASIC CONCEPT Dimensioning is accomplished by adding size and location information necessary to manufacture the object. Clear Complete Facilitate the - manufacturing method measurement method This information have to be

42. L L S S S Designed part EXAMPLE To manufacture this part we need to know… 1. Width , depth and thickness of the part. 2. Diameter and depth of the hole. 3. Location of the holes. “ S ” denotes size dimension. “ L ” denotes location dimension. S L L

43. ANGLE To dimension an angle use circular dimension line having the center at the vertex of the angle. COMMON MISTAKE

44. ARC Arcs are dimensioned by giving the radius , in the views in which their true shapes appear. R 200 The letter “R” is always lettered before the figures to emphasize that this dimension is radius of an arc. R 200 or

45. ARC The dimension figure and the arrowhead should be inside the arc, where there is sufficient space. R 200 R 62.5 Move figure outside R 6.5 Move both figure and arrow outside Sufficient space for both. Sufficient space for arrowhead only. R 58.5 Insufficient space for both.

46. ARC Leader line must be radial and inclined with an angle between 30 ~ 60 degs to the horizontal. COMMON MISTAKE R62.5 R62.5 R62.5 R62.5 R62.5 30 o 60 o R62.5

47. ARC Use the foreshortened radial dimension line , when arc’ s center locates outside the sheet or interfere with other views. Drawing sheet Method 1 Method 2

48. Dimensioning (cont’d)

49. FILLETS AND ROUNDS Give the radius of a typical fillet only by using a local note. R6.5 If all fillets and rounds are uniform in size, dimension may be omitted, but it is necessary to add the note “ All fillets and round are Rxx. ” NOTE: All fillets and round are R6.5 Drawing sheet R12 unless otherwise specified. NOTE: All fillets and round are R6.5

50. The curve constructed from two or more arcs, requires the dimensions of radii and center’s location . CURVE COMMON MISTAKE Tangent point

51. CYLINDER Size dimensions are diameter and length . Measurement method Location dimension must be located from its center lines and should be given in circular view.

52.  100  70 CYLINDER Diameter should be given in a longitudinal view with the symbol “  ” placed before the figures.

53. HOLES Size dimensions are diameter and depth . Location dimension must be located from its center lines and should be given in circular view. Measurement method

54. f xx Use leader line and local note to specify diameter and hole’s depth in the circular view. HOLES : SMALL SIZE xx Drill, Thru. 1) Through thickness hole f xx Thru. or xx Drill. or or

55. f xx, yy Deep HOLES : SMALL SIZE or xx Drill, yy Deep Hole’s depth Use leader line and local note to specify diameter and hole’s depth in the circular view. 2) Blind hole

56. f xx Use extension and dimension lines Use diametral dimension line Use leader line and note HOLES : LARGE SIZE

57. COMMON MISTAKE f xx f xx f xx Rxx f xx HOLES f xx

58. CHAMFER Use leader line and note to indicate linear distance and angle of the chamfer. S q S q For a 45 o chamfer S S C S or

59. ROUNDED-END SHAPES R12 f 12 21 5 Dimensioned according to the manufacturing method used. Center to Center Distance

60. ROUNDED-END SHAPES R12 21 5 12 Dimensioned according to the manufacturing method used. Center to Center Distance

61. ROUNDED-END SHAPES Dimensioned according to the manufacturing method used. R12 21 12 16

62. ROUNDED-END SHAPES R12 27 12 Dimensioned according to the manufacturing method used. Tool cutting distance

63. ROUNDED-END SHAPES Dimensioned according to the standard sizes of another part to be assembled or manufacturing method used. 20

64. Placement of Dimensions

65. Extension lines, leader lines should not cross dimension lines. POOR GOOD RECOMMENDED PRACTICE

66. 2. Extension lines should be drawn from the nearest points to be dimensioned. POOR GOOD RECOMMENDED PRACTICE

67. 3. Extension lines of internal feature can cross visible lines without leaving a gap at the intersection point. WRONG CORRECT RECOMMENDED PRACTICE

68. 4. Do not use object line , center line , and dimension line as an extension lines. POOR GOOD RECOMMENDED PRACTICE

69. POOR GOOD 5. Avoid dimensioning hidden lines. RECOMMENDED PRACTICE

70. JUST OK !!! BETTER RECOMMENDED PRACTICE 6. Place dimensions outside the view, unless placing them inside improve the clarity.

71. 7. Apply the dimension to the view that clearly show the shape or features of an object. POOR GOOD RECOMMENDED PRACTICE

72. 8. Dimension lines should be lined up and grouped together as much as possible. POOR GOOD RECOMMENDED PRACTICE

73. 9. Do not repeat a dimension. POOR GOOD RECOMMENDED PRACTICE

74. PROJECTION METHOD

75. Orthographic Projection

76. Orthographic Projections Orthographic Projections are a collection of 2-D drawings that work together to give an accurate overall representation of an object.

77. Which Views to Present? General Guidelines Pick a Front View that is most descriptive of object Normally the longest dimension is chosen as the width (or depth) Most common combination of views is to use: Front, Top, and Side View

78. Defining the Six Principal Views or Orthographic Views

79. Glass Box Approach Place the object in a glass box Freeze the view from each direction (each of the six sides of the box) and unfold the box

80. Glass Box Approach

81. Glass Box Approach

82. Glass Box Approach

83. Glass Box Approach

84. Glass Box Approach

85. Glass Box Approach

86. Third-angle Projection First-angle Projection First and Third Angle Projections First Angle Third Angle

87. ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEF ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEF Lettering

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

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

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

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

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

93. The text’ s body height is about 2/3 the height of a capital letter. Lower-case letters

94. Stroke Sequence I L T F E H

95. V X W Stroke Sequence

96. N M K Z Y A Stroke Sequence 4

97. O Q C G Stroke Sequence

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

99. 5 Stroke Sequence 7

100. 6 8 9 Stroke Sequence S 3

101. Stroke Sequence l i

102. Stroke Sequence v w x k z

103. Stroke Sequence j y f r t

104. Stroke Sequence c o a b d p q e

105. Stroke Sequence g n m h u s

106. Word Composition Look at the same word having different spacing between letters. JIRAPONG J I G O R N P A Which one is easier to read ? A) Non-uniform spacing B) Uniform spacing

107. Word Composition JIRAPONG \ / \ | )( ) | ( | Space between the letters depends on the contour of the letters at an adjacent side. Spacing Contour | | | | General conclusions are: Good spacing creates approximately equal background area between letters.

108. 1. Straight - Straight 2. Straight - Curve 3. Straight - Slant 4. Curve - Curve Space between Letters

109. 6. Slant - Slant 5. Curve - Slant 7. The letter “L” and “T” ≡ slant slant ≡ slant straight Space between Letters

110. GOOD Not uniform in style. Not uniform in height. Not uniformly vertical or inclined. Not uniform in thickness of stroke. Area between letters not uniform. Area between words not uniform. Example : Good and Poor Lettering

111. Leave the space between words equal to the space requires for writing a letter “O”. Example Sentence Composition ALL DIMENSIONS ARE IN MILLIMETERS O O O O UNLESS OTHERWISE SPECIFIED. O

112. End !!!