Graphics lecture#4 section view
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The document provides an extensive overview of section views in technical drawing, outlining their purpose, types, and common practices, including methods for dimensioning. It details various forms of section views, such as full, half, offset, broken-out, and revolved sections, along with guidelines for drawing techniques and dimensional standards. Additionally, it emphasizes the significance of clear dimensioning methods and the representation of features like ribs and lugs for effective manufacturing communication.
Graphics lecture#4 section view
- 2. Sectioning image NO information about Cutting the apple with knife apple inside After cutting we get information about in side
- 3. Sectioning image Information about color NO information about Cutting the watermelon by knife inside Watermelon Information about taste Information about seeds
- 4. PURPOSES OF SECTION VIEWS Clarify the views by reducing or eliminating the hidden lines. revealing the cross sectional’s shape. Describing the material Facilitate the dimensioning.
- 5. EXAMPLE : Advantage of using a section view.
- 6. CUTTING PLANE Cutting plane is a plane that imaginarily cuts the object to reveal the internal features. Cutting plane Cutting plane line Section lines
- 7. CUTTING PLANE LINE Cutting plane line is an edge view of the cutting plane. Indicate the path of cutting plane.
- 8. CUTTING PLANE LINESTYLES Thick line ANSI Viewing standard direction Thick line Viewing direction JIS & ISO Thin line standard Viewing direction
- 9. SECTION LINING Section lines or cross-hatch lines are used to indicate the surfaces that are cut by the cutting plane. Section lines Drawn with 4H pencil.
- 10. SECTION LINES SYMBOLS The section lines are different for each of material’s type. For practical purpose, the cast iron symbol is used most often for any materials. Cast iron, Steel Concrete Sand Wood Malleable iron
- 11. SECTION LINING PRACTICE The spaces between lines may vary from 1.5 mm for small sections to 3 mm for large sections. COMMON MISTAKE
- 12. SECTION LINING PRACTICE It should not be drawn parallel or perpendicular to contour of the view. COMMON MISTAKE
- 14. KIND OF SECTIONS 1. Full section 2. Offset section 3. Half section 4. Broken-out section 5. Revolved section (aligned section) 6. Removed section (detailed section)
- 15. FULL SECTION VIEW The view is made by passing the straight cutting plane completely through the part.
- 16. OFFSET SECTION VIEW The view is made by passing the bended cutting plane completely through the part. Do not show the edge views of the cutting plane.
- 17. TREATMENT OF HIDDEN LINES Hidden lines are normally omitted from section views.
- 18. HALF SECTION VIEW The view is made by passing the cutting plane halfway through an object and remove a quarter of it.
- 19. HALF SECTION VIEW A center line is used to separate the sectioned half from the unsectioned half of the view. Hidden line is omitted in unsection half of the view.
- 20. BROKEN-OUT SECTION VIEW The view is made by passing the cutting plane normal to the viewing direction and removing the portion of an object in front of it.
- 21. BROKEN-OUT SECTION VIEW A break line is used to separate the sectioned portion from the unsectioned portion of the view. Break line is a thin continuous line (4H) and is drawn freehand. There is no cutting plane line.
- 22. EXAMPLE : Comparison among several section techniques
- 23. REVOLVED SECTION VIEW Revolved sections show cross-sectional features of a part. No need for additional orthographic views. This section is especially helpful when a cross-section varies.
- 24. REVOLVED SECTION VIEW Basic concept
- 25. REVOLVED SECTION VIEW Basic concept
- 26. REVOLVED SECTION VIEW Steps in construction Given Edge view of cross-section Step 1 a. Assign position of cutting plane. b. Draw axis of rotation in front view.
- 27. REVOLVED SECTION VIEW Steps in construction Given Step 2 a. Transfer the depth dimension to the front view.
- 28. REVOLVED SECTION VIEW Steps in construction Given Step 3 a. Draw the revolved section. b. Add section lines.
- 29. REVOLVED SECTION VIEW Steps in construction Given FINAL PICTURE
- 30. REVOLVED SECTION VIEW Placement of revolved section 1. Superimposed to orthographic view. 2. Break from orthographic view. Break Superimposed
- 31. REMOVED SECTION VIEW 6. Removed section Removed section is revolved section. Section view is shown outside the view. Used where space does not enough for revolved section Can be located elsewhere on a drawing with properly labeled
- 32. REMOVED SECTION VIEW Example : Revolved vs. removed sections. Revolved section Removed section
- 33. REMOVED SECTION VIEW Example : Situation that removed section is preferred. Poor Preferred Too messy !!
- 34. REMOVED SECTION VIEW Example : Multiple removed section views A B B A SECTION B – B SECTION A – A
- 35. Section view representation of rib, web, spoke and lug
- 36. TERMINOLOGY Rib and Web are thin, flat feature of an object that acts as a structural support. Web Rib Rib
- 37. TERMINOLOGY Spoke is the rod radiating from the hub to the rim of a wheel. Hub Hub Spoke Rim Spoke Rim
- 38. TERMINOLOGY Lug is an ear which is built as portion of an object for attachment.
- 39. CONVENTIONAL PRACTICE Omit the section lines on the section view of Rib, Web and Lug, if the cutting plane is passed flatwise through. Spoke, if the cutting plane is passed longwise through.
- 40. EXAMPLE : RIB Normal multiview drawing Normal section view Section view drawing with convention
- 41. EXAMPLE : WEB : flatwise cut Normal multiview drawing Normal section view Section view drawing with convention
- 42. EXAMPLE : WEB : crosswise cut
- 43. EXAMPLE : WEB : multiple section view
- 44. EXAMPLE : SPOKE Misleading impression
- 45. EXAMPLE : LUG
- 46. Aligned Section
- 47. DEFINITION Aligned section is a section view that is drawn by imaginary rotating the object’s features appeared in a principal view about symmetry axis
- 48. Example : HOLE Gives the impression that this holes are at unsymmetrical position.
- 49. Example : HOLE
- 50. Example : RIB
- 51. Example : Aligned section of lug
- 53. CONVENTIONAL PRACTICE For long objects that have to draw in a small scale to fit them on the paper, it is recommended to remove its long portion (which contains no important information) and draw the break lines at the broken ends.
- 54. Example SCALE 1:1 2:1
- 55. STANDARD BREAK LINES Wood Rectangular cross section Metal Cylindrical cross section Tubular cross section
- 56. TO DRAW CYLINDRICAL BREAK 30o R 30o R/3 R/3
- 57. TO DIMENSION A BROKEN PART f16 Typical method 800 f16 800 Use not to scale dimensions
- 58. Dimensioning
- 59. ENGINEERING DESIGN PROCESS RESULT Design a part Sketches of ideas Multiview Create Shape drawings Drawing 1. Size, Location Dimensioning 2. Non-graphic information Manufacture
- 60. 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 This course 3. Number required 4. Kind of surface finish 5. Manufacturing process 6. Size and geometric tolerances
- 61. DIMENSIONING SYSTEM 1. Metric system : ISO and JIS standards This course Examples 32, 32.5, 32.55, 0.5 (not .5) etc. 2. Decimal-inch system Examples 0.25 (not .25), 5.375 etc. 3. Fractional-inch system 1 , 3 Examples 5 etc. 4 8
- 63. DIMENSIONING COMPONENTS Extension lines Dimension lines Drawn with (with arrowheads) 4H pencil Leader lines Dimension figures Notes : Lettered with - local note 2H pencil. - general note
- 64. EXTENSION LINES indicate the location on the object’s features that are dimensioned.
- 65. DIMENSION LINES indicate the direction and extent of a dimension, and inscribe dimension figures. 10 27 13 43
- 66. LEADER LINES indicate details of the feature with a local note. 10 27 10 Drill, 2 Holes R16 13 43
- 68. EXTENSION LINES Leave a visible gap (≈ 1 mm) from a view and start drawing an extension line. Extend the lines beyond the (last) dimension line 1-2 mm. COMMON MISTAKE Visible gap
- 69. EXTENSION LINES Do not break the lines as they cross object lines. COMMON MISTAKE Continuous
- 70. DIMENSION LINES Dimension lines should not be spaced too close to each other and to the view. Leave a space at least 2 times of a letter height. 16 34 11 35 Leave a space at least 1 time of a letter height.
- 71. 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 34 11 34 11
- 72. DIMENSION FIGURES When there is not enough space for figure or arrows, put it outside either of the extension lines. Not enough space Not enough space for figures for arrows 16.25 1 16.25 1 1 or
- 73. DIMENSION FIGURES : UNITS The JIS and ISO standards adopt the unit of Length dimension in millimeters without specifying a unit symbol “mm”. Angular dimension in degree with a symbol “o” place behind the figures (and if necessary minutes and seconds may be used together).
- 74. DIMENSION FIGURES : ORIENTATION 1. Aligned method The dimension figures are placed so that they are readable from the bottom and right side of the drawing. 2. Unidirectional method 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)
- 75. EXAMPLE : Dimension of length using aligned method. 30 30 30 30
- 76. EXAMPLE : Dimension of length using unidirectional method. 30 30 30 30 30 30 30 30
- 77. EXAMPLE : Dimension of angle using aligned method. 45o 45o 45o 45o
- 78. EXAMPLE : Dimension of angle using unidirectional method. 45o 45o 45o 45o 45o 45o 45o 45o
- 79. LOCAL NOTES Place the notes near to the feature which they apply, and should be placed outside the view. Always read horizontally. COMMON MISTAKE 10 Drill 10 Drill 10 Drill ≈ 10mm Too far
- 80. THE BASIC CONCEPT Dimensioning is accomplished by adding size and location information necessary to manufacture the object. This information have to be Clear Complete Facilitate the - manufacturing method - measurement method
- 81. EXAMPLE L L Designed part L S L S To manufacture this part S we need to know… 1. Width, depth and S thickness of the part. 2. Diameter and depth of the hole. “S” denotes size dimension. 3. Location of the holes. “L” denotes location dimension.
- 82. ANGLE To dimension an angle use circular dimension line having the center at the vertex of the angle. COMMON MISTAKE
- 83. ARC Arcs are dimensioned by giving the radius, in the views in which their true shapes appear. The letter “R” is always lettered before the figures to emphasize that this dimension is radius of an arc. or
- 84. ARC The dimension figure and the arrowhead should be inside the arc, where there is sufficient space. Sufficient space Sufficient space Insufficient space for both. for arrowhead only. for both. Move figure outside Move both figure and arrow outside R 62.5 R 6.5 R 58.5
- 85. 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 R62.5
- 86. ARC Use the foreshortened radial dimension line, when arc’ s center locates outside the sheet or interfere with other views. Method 1 2 Drawing sheet
- 87. FILLETS AND ROUNDS Give the radius of a typical fillet only by using a local note. 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. ” R6.5 R12 NOTE: NOTE: All fillets and round are R6.5 All fillets and round are R6.5 unless otherwise specified. Drawing sheet
- 88. CURVE The curve constructed from two or more arcs, requires the dimensions of radii and center’s location. COMMON MISTAKE Tangent point
- 89. CYLINDER Size dimensions are diameter and length. Location dimension must be located from its center lines and should be given in circular view. Measurement method
- 90. CYLINDER Diameter should be given in a longitudinal view with the symbol “f ” placed before the figures. f 100 f 70
- 91. 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
- 92. HOLES : SMALL SIZE Use leader line and local note to specify diameter and hole’s depth in the circular view. 1) Through thickness hole f xx f xx Thru. xx Drill. xx Drill, Thru. or or or
- 93. HOLES : SMALL SIZE Use leader line and local note to specify diameter and hole’s depth in the circular view. 2) Blind hole f xx, yy Deep xx Drill, yy Deep or Hole’s depth
- 94. HOLES : LARGE SIZE Use extension and Use diametral Use leader line dimension lines dimension line and note f xx
- 95. HOLES COMMON MISTAKE f xx f xx f xx Rxx f xx f xx
- 96. CHAMFER Use leader line and note to indicate linear distance and angle of the chamfer. S q S For a 45o chamfer or CS S S
- 97. ROUNDED-END SHAPES Dimensioned according to the manufacturing method used. f 12 Center to Center Distance R12 21 5
- 98. ROUNDED-END SHAPES Dimensioned according to the manufacturing method used. R12 12 21 Center to Center Distance 5
- 99. ROUNDED-END SHAPES Dimensioned according to the manufacturing method used. R12 12 16 21
- 100. ROUNDED-END SHAPES Dimensioned according to the manufacturing method used. R12 12 27 Tool cutting distance
- 101. ROUNDED-END SHAPES Dimensioned according to the standard sizes of another part to be assembled or manufacturing method used. Key (standard part) 25
- 102. ROUNDED-END SHAPES Dimensioned according to the standard sizes of another part to be assembled or manufacturing method used. 20
- 104. RECOMMENDED PRACTICE 1. Extension lines, leader lines should not cross dimension lines. POOR GOOD
- 105. RECOMMENDED PRACTICE 2. Extension lines should be drawn from the nearest points to be dimensioned. POOR GOOD
- 106. RECOMMENDED PRACTICE 3. Extension lines of internal feature can cross visible lines without leaving a gap at the intersection point. WRONG CORRECT
- 107. RECOMMENDED PRACTICE 4. Do not use object line, center line, and dimension line as an extension lines. POOR GOOD
- 108. RECOMMENDED PRACTICE 5. Avoid dimensioning hidden lines. POOR GOOD
- 109. RECOMMENDED PRACTICE 6. Place dimensions outside the view, unless placing them inside improve the clarity. POOR GOOD
- 110. RECOMMENDED PRACTICE 6. Place dimensions outside the view, unless placing them inside improve the clarity. JUST OK !!! BETTER
- 111. RECOMMENDED PRACTICE 7. Apply the dimension to the view that clearly show the shape or features of an object. POOR GOOD
- 112. RECOMMENDED PRACTICE 8. Dimension lines should be lined up and grouped together as much as possible. POOR GOOD
- 113. RECOMMENDED PRACTICE 9. Do not repeat a dimension. POOR GOOD