![ADDIS ABABA SCIENCE AND
TECHNOLOGY
UNIVERSITY
Collage of Electrical and Mechanical
Engineering
Department of Mechanical Engineering
COURSE :ENGINEERING DRAWING [Meng1011]](https://image.slidesharecdn.com/chapter3-240208075437-425c36cd/85/CHAPTER-3-MULTI-VIEW-DRAWING-2-pptx-1-320.jpg)
CHAPTER 3. MULTI-VIEW DRAWING (2).pptx
- 1. ADDIS ABABA SCIENCE AND TECHNOLOGY UNIVERSITY Collage of Electrical and Mechanical Engineering Department of Mechanical Engineering COURSE :ENGINEERING DRAWING [Meng1011]
- 3. TOPICS SYSTEM OF PROJECTION CHOICE OF VIEWS LAYING OUT DRAWINGS AND RELATION BETWEEN HEIGHT, DEPTH AND WIDTH ONE VIEW, TWO VIEW AND THREE VIEW DRAWINGS PROJECTION OF CURVE ,INCLINDE, OBLIQUE AND INTERSECTION AND TANGENTS LINE CONVENTION
- 5. SYSTEM OF PROJECTION A plane of projection (POP) is a plane on which a particular view is projected. Three such planes, perpendicular to each other, are called principal planes or reference planes (RP). When the observer looks at the object from the front, the view obtained is called the front view or elevation and is seen on the vertical plane (VP)/ frontal plane (FP). When the observer looks at the object from above, the view obtained is called top view or plan and is seen on the horizontal plane (HP). When the observer looks at the object from side, i.e., from his left-hand side or right-hand side, the view obtained is called side view and is seen on the profile plane (PP).
- 8. First Angle Projection: the object is placed in the first quadrant. This means that the Vertical Plane is behind the object and the Horizontal Plane is underneath the object. The object lies in between the observer and the planes of projection. SYSTEM OF PROJECTION Third Angle Projection: The Object is placed in the Third Quadrant. This means that the Vertical Plane is in front of the object and the Horizontal Plane is above the object. The Plane of projection lie between the object and the observer.
- 9. SYSTEM OF PROJECTION 1. First angle system 2. Third angle system First Quadrant Third Quadrant - European country - ISO standard - Canada, USA, Japan, Thailand
- 10. 1st angle system 3rd angle system SYSTEM OF PROJECTION
- 11. 1st angle system 3rd angle system Folding line Folding line Folding line Folding line SYSTEM OF PROJECTION
- 12. 1st angle system 3rd angle system Front View Front View Right Side View Right Side View Top View Top View SYSTEM OF PROJECTION
- 13. First angle system Third angle system SYSTEM OF PROJECTION Projection Symbols
- 14. SYSTEM OF PROJECTION d 1.7d 2.2d Suggested proportion Projection Symbols
- 16. CHOICE OF VIEWS 16 Most commonly used views Front View Top View Right Side View Steps for Choice of views Orient the object to the best position Select the front view Select adjacent views
- 17. STEP 1 : Orient the Object The object should be placed in its natural position. NO ! The object should presents its features in actual size and shape in orthographic views. GOOD 17 CHOICE OF VIEWS
- 18. STEP 2 : Select a Front View The object’s longest dimension should be presented as a width. Inappropriate First choice GOOD Second choice Waste more space 18 CHOICE OF VIEWS Most descriptive view is typically designated as the Front View
- 19. Inappropriate The adjacent views that are projected from the selected front view should appear in its natural position. STEP 2 : Select a Front View 19 CHOICE OF VIEWS
- 20. STEP 2 : Select a Front View Choose the view that have the fewest number of hidden lines. GOOD Inappropriate 20 CHOICE OF VIEWS
- 21. STEP 3 : Select an Adjacent View GOOD Inappropriate Inappropriate GOOD Choose the view that have the fewest number of hidden lines. 21 CHOICE OF VIEWS
- 22. Choose the minimum number of views that can represent the major features of the object. STEP 3 : Select an Adjacent View Necessary Necessary Hole’s location can be specified on the same view. Difficult to interprete. Easy to understand 22 CHOICE OF VIEWS
- 23. Choose the views that are suitable to a drawing space. STEP 3 : Select an Adjacent View POOR Not enough space for dimensioning. 23 CHOICE OF VIEWS
- 24. Choose the views that are suitable to a drawing space. STEP 3 : Select an Adjacent View GOOD 24 CHOICE OF VIEWS
- 25. Example : View selection Shape description Size description F.V. W D W H D mislead to… F.V. & T.V. Three views F.V. & R.S.V. H 25 CHOICE OF VIEWS
- 26. 3.3 ONE VIEW, TWO VIEW AND THREE VIEW DRAWINGS
- 27. ONE-VIEW DRAWING Thin objects can be described with only one view: Depth is given in a note eg. Flat part having a uniform thickness. Unnecessary These 2 views provide only information about the part thickness ! 1 Thick 27
- 28. ONE-VIEW DRAWING Simple objects can be described with one views eg. Cylindrical-shaped part. Unnecessary Repeat ! Unnecessary 28
- 29. TWO-VIEW DRAWING There exists an identical view. Repeat ! Unnecessary 29
- 30. The 3rd view has no significant contours of the object. TWO-VIEW DRAWING Unnecessary 30
- 31. TWO-VIEW DRAWING Unnecessary The 3rd view has no significant contours of the object. 31
- 32. 32 Necessary Necessary Hole’s location can be specified on the same view. Difficult to interprete. Easy to understand THREE-VIEW DRAWING Complex objects require three views to describe its shape
- 33. 33 THREE-VIEW DRAWING Complex objects require three views to describe its shape
- 35. 35 LAYING OUT DRAWINGS Hand Layout of a metric three-view drawing
- 36. 36 LAYING OUT DRAWINGS Views should be visually balanced within the working space Draw border (20mm from left and 5 mm from each 3 sides) and title block using light construction lines STEP 1 A4 Border line 20 5 28 5 5
- 37. 37 Determine space desired between the front and right-side views (C), and front and Top views (C) say 20 or 30 mm. Add STEP 2 To set equal distances to the paper edge, subtract this total from the sheet width (Ws=185), and height (Hs=259) then divide the remaining number by two. A = (Ws - H)/2 B = (Hs - V)/2
- 38. 38 1st Angle Projection Set off vertical and horizontal spacing measurements with light tick marks along the edge of the sheet and draw construction lines STEP 3 Dimension take from the object
- 39. 39 STEP 3 Set off vertical and horizontal spacing measurements with light tick marks along the edge of the sheet and draw construction lines Dimension take from the object 3rd Angle Projection
- 40. 40 Construct the views : add hidden lines and darken final lines. STEP 4 1st Angle Projection
- 41. 41 Construct the views : add hidden lines and darken final lines. STEP 4 3rd Angle Projection
- 42. 1st Angle Projection LAYING OUT DRAWINGS
- 43. 3rd Angle Projection LAYING OUT DRAWINGS
- 44. 44 The three-view drawing is the standard used in engineering, as normally other three principal views are mirror images. The standard views – TOP, FRONT and RIGHT. All objects have 3 dimensions Height : Distance from top to bottom Width : Distance from side to side Depth: Distance from the front to back R/N B/N HEIGHT, DEPTH AND WIDTH
- 45. The width dimensions are aligned between the front and top view using vertical projection lines. The height dimensions are aligned between the front and side views, using horizontal projection lines. The depth dimensions are aligned between top and side views, using scale, miter line or compass. 45 R/N B/N HEIGHT, DEPTH AND WIDTH
- 46. 46 Top View Front View RS.View Width Height Depth Width Height Depth R/N B/N HEIGHT, DEPTH AND WIDTH
- 48. PRECEDENCE OF LINE Visible line Order of importance Hidden line Center line
- 49. HIDDEN LINE PRACTICE Hidden line should join a visible line, except it extended from the visible line. Correct No ! Join Leave space
- 50. Correct No ! Hidden line should join a visible line, except it extended from the visible line. Leave space Leave space HIDDEN LINE PRACTICE
- 51. Hidden line should intersect to form L and T corners. Correct No ! L T HIDDEN LINE PRACTICE
- 52. Hidden arcs should start on a center line. HIDDEN LINE PRACTICE
- 53. Make a hidden line “jump” a visible line when possible. Draw parallel hidden lines so that the dashes are staggered, as in bricklaying. HIDDEN LINE PRACTICE
- 54. When two or three hidden lines meet at a point, join the dashes, as shown for the bottom of this drilled hole. The same rule of joining the dashes when two or three hidden lines meet at a point applies for the top of this countersunk hole.. HIDDEN LINE PRACTICE
- 55. CENTER LINE PRACTICE In circular view, short dash should cross at the intersections of center line. For small hole, center line is presented as thin continuous line. Center line should not extend between views. Leave space Leave space
- 56. Leave the gap when centerline forms a continuation with a visible or hidden line Leave space Leave space Leave space Leave space Center line should always start and end with long dash. CENTER LINE PRACTICE
- 57. 3.6. PROJECTION OF CURVE ,INCLINDE, OBLIQUE AND INTERSECTION AND TANGENTS
- 58. PROJECTION OF CURVED EDGES • Curved edges project as straight lines on the plane to which they are perpendicular • Curved edges project as curved lines on the planes to which they are parallel or inclined
- 59. PROJECTION OF NORMAL SURFACES Normal surfaces appear as an edge in two opposite principal views, and appear a surface in all other principal views. 59
- 60. PROJECTION OF INCLINED SURFACES • Inclined surfaces appear as an edge in two opposite principal views, and appear foreshortened (not true size) in all other principal views. 60
- 61. PROJECTION OF OBLIQUE SURFACES • Oblique surfaces do not appear either as an edge or true size in any principal view. 61
- 62. NO LINE NO LINE PROJECTION OF INTERSECTIONS & TANGENCIES • Where a curved surface is tangent to a plane surface, no line should be shown where they join
- 63. PROJECTION OF INTERSECTIONS & TANGENCIES • Where a plane surface intersects a curved surface, an edge is formed LINE LINE
- 64. PROJECTION OF INTERSECTIONS & TANGENCIES • Where the plane surface is horizontal or vertical, exceptions to these rules may occur LINE VERTICAL SURFACE
- 65. Example 1. Using the first angle projection system, draw the three principal view of the object whose pictorial drawings are given below.
- 67. Example 2. Using the first angle projection system, draw the three principal view of the object whose pictorial drawings are given below.