Pictorial Drawings. DFTG-1305 Technical Drafting Prepared by Francis Ha, Instructor

Transcription

1 DFTG-1305 Technical Drafting Prepared by Francis Ha, Instructor Pictorial Drawings Geisecke s textbook for reference: 14 th Ed. Ch. 15: p. 601 Ch. 16: p th Ed. Ch. 14: p. 518 Ch. 15: p. 552 Update:

2 Key points: They are used to aid visualization. A pictorial is a 2-D pseudo 3-D drawing. What will we learn in this Chapter? Pictorial Drawings How to create a pictorial drawing.

3 Contents Pictorials Introduction Isometric Pictorial Axes Oblique Pictorials Overview Drawing Linear Features Drawing Circles and Radii Drawing Cylinders

4 Draw an Isometric Drawn in 2-D. Looks like a 3-D.

5 Two types of pictorials: Isometric Oblique

6 Isometric Pictorial

7 Isometric Pictorial Axes Isometric pictorials are drawn in a coordinate system where the axes are 60 degrees apart.

8 Drawing Linear Features Step 1 - Draw the three construction lines that represent the isometric axes.

9 Isometric Pictorials Scale The linear features on, or parallel, to these three axes are drawn at between 50-80% (recommended) scale to represent true size. Isometric pictorials may be drawn at any scale (between 50%-80% normally) as long as the scale is uniform on all axes.

10 Isometric How do we draw an isometric pictorial?

11 Isometric How do we draw an isometric pictorial?

12 Isometric How do we draw an isometric pictorial?

13 Isometric How do we draw an isometric pictorial?

14 Isometric How do we draw an isometric pictorial?

15 Exercise1 Creating an Isometric Pictorial In-class Practice

16 Drawing Linear Features How do we draw an isometric pictorial?

17 Isometric Procedures Drawing Linear Features Step 1 - Draw a defining box (Side dimensions = the height, width and depth of the object)

18 Drawing Linear Features Step 2 Sketch the based lines a reduced scale, 80% isometric pictorial of the following object.

19 Drawing Linear Features Step 3 - Draw the lines of the object that are parallel to the axes.

20 Drawing Linear Features Step 4 - Add the lines of the object that are not parallel to one of the axes.

21 Drawing Linear Features Step 4 (cont.)- Add the lines of the object that are not parallel to one of the axes.

22 Drawing Linear Features Step 4 (cont.)- Add the lines of the object that are not parallel to one of the axes.

23 Drawing Linear Features Step 5 - Erase or remove the construction lines.

24 Drawing Linear Features Step 5 - Erase or remove the construction lines.

25 Oblique Pictorials

26 Oblique Pictorials In the oblique pictorials coordinate system, only one axis is at an angle. The angle may range between 1 and 89 degrees; however, the most commonly used angle is 45 degrees.

27 Oblique Pictorials The features drawn on the plane defined by the vertical and horizontal axes are drawn at full scale and true shape. The front view should be squared

28 Oblique Pictorials The linear features drawn on the angled axis may be full scale (cavalier projection) or may be drawn foreshortened. The most common, is half scale (cabinet projection).

29 Oblique Pictorials

30 Oblique Pictorials

31 Oblique How do we draw an oblique pictorial?

32 Oblique How do we draw an oblique pictorial?

33 Oblique How do we draw an oblique pictorial?

34 Oblique How do we draw an oblique pictorial?

35 Oblique How do we draw an oblique pictorial?

36 COMPARISON Oblique vs. Isometric What differences can you see?

37 COMPARISON

38 COMPARISON

39 How to draw Circles and Radii in pictorial?

40 How to draw an ellipse?

41 Drawing Isometric Circle and Radii Circular features of an object appear as ellipses on an isometric pictorial.

42 Drawing Circle and Radii Step 1: Draw the linear features of the object using the procedure previously described. Squares become rhombuses. Reduced scale to 50% isometric pictorial of the following object.

43 Drawing Circles and Radii Step 2: Draw diagonals and ellipses in boxes that define the beginning and end of the cylinder.

44 Drawing Circles and Radii Step 3: Draw an ellipse in the box whose major axis is aligned with the long diagonal of the box. The ellipses touch the box at the midpoint of its sides. The same procedure is used for creating radii except that the unwanted part of the ellipse is erased or trimmed. Major Axis

45 Drawing Circles and Radii Step 4: Erase or remove the construction lines Erase or remove the lines of behind cylinder.

46 How to Draw Cylinders

47 Drawing Cylinders Step 1: Draw a defining box and first ellipse a defining box. The height is equal to the height of the cylinder and the width and depth are equal to the diameter of the cylinder.

48 Drawing Cylinders Step 2: Draw diagonals and second ellipses a defining box. The height is equal to the height of the cylinder and the width and depth are equal to the diameter of the cylinder.

49 Drawing Cylinders Step 3: Draw diagonals and ellipses in boxes that define the beginning and end of the cylinder. Major Axis

50 Drawing Cylinders Step 4: Erase or remove the construction lines.

51 Drawing Cylinders Step 5: Erase or remove the lines of behind cylinder.

52 Drawing Cylinders Cylinders in an isometric pictorial is a drawing with two circles and adding some connecting lines.

53 Exercise 2 Creating an Isometric Pictorial In-class Practice

54 Step 1: Draw three construction lines that represent the isometric axes. The grid spacing is 0.25 inch.

55 To do: Create a reduced scale, say, 50% isometric pictorial of the following object (4 steps)

56 Step 2: Draw a box whose sides are parallel to the three axes and whose lengths are ½ (50%) the maximum height, width and depth dimension of the object.

57 Step 3: Draw the lines of the object that are parallel to the axes.

58 Step 4: The lines of the object that are not parallel to one of the axes are added by connecting the ends of existing lines.

59 Continue Step 4

60 Continue Step 4

61 Step 5: Erase or remove the construction lines. Done.

62 Exercise 3 Creating an Isometric Pictorial In-class Practice

63 Skip to next part of the exercise Exercise 2 Create a reduced scale, say, 50% isometric pictorial of the following object. The grid spacing is 10 mm.

64 Step 1: Draw the linear features of the object using the procedure previously described.

65 Step 2: Draw a box whose diagonals meet at the center of the radius and the length of the sides are equal to the 2R.

66 Step 3: Draw an ellipse in the box whose major axis is aligned with the long diagonal of the box. The ellipses touch the box at the midpoint of its sides.

67 Step 4: Repeat for the bottom radius.

68 Step 5: Use a vertical line to connect the ellipses.

69 Step 6: Erase half of ellipses.

70 Step 7: Draw the defining boxes for the cylindrical feature on the top of the part.

71 Step 8: Draw ellipses in the defining boxes for the cylindrical feature on the top of the part.

72 Step 9: Draw and connect the ellipses.

73 Step 10: Draw the ellipse that represents the thru hole.

74 Step 11: Draw the defining box and cylinder that defines the counterbore.

75 Step 12: Draw the ellipse representing the drill. Only a small piece shows.

76 Step 13: Erase all construction and unwanted lines.

77 Isometric Assembly

78 Isometric Mechanical Assembly Pictorials are very effective at illustrating assemblies.

79 Pictorials are very effective at illustrating assemblies.

80 Isometric Mechanical Assembly

81 Isometric Assembly of a PC Board

82 The End