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Dr Simin Nasseri Southern Polytechnic State University 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter.

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Presentation on theme: "Dr Simin Nasseri Southern Polytechnic State University 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter."— Presentation transcript:

1 Dr Simin Nasseri Southern Polytechnic State University 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 7 Engineering Graphics I Dr Simin Nasseri Southern Polytechnic State University

2 Dr Simin Nasseri Southern Polytechnic State University 2 Figure 7.40 Multiview drawing

3 Dr Simin Nasseri Southern Polytechnic State University 3 Question: The choice of a front view orientation is an important first step. Which side of the car should be considered for the front view orientation (which side of the car is most descriptive)?

4 Dr Simin Nasseri Southern Polytechnic State University 4 Figure 7.42 Orthogonal views

5 Dr Simin Nasseri Southern Polytechnic State University 5 Figure 7.43 Principal views These 3 views are most descriptive

6 Dr Simin Nasseri Southern Polytechnic State University 6 Figure 7.44 Multiviews of common objects Practice: Draw multiviews of some simple objects.

7 Dr Simin Nasseri Southern Polytechnic State University 7 Multiview Sketching Techniques: 1.Line conventions: Multiview drawings and sketches require adherence to the proper use of alphabet of lines. These standard line types are shown in the next slide with the recommended line thicknesses.

8 Dr Simin Nasseri Southern Polytechnic State University 8 Alphabet of lines: Visible line: For features of the object that can be seen Hidden line: For features which are not visible in the current view Center line: For showing, circle, arcs and bases of cones and cylinders Dimension and extension line: To show the sizes of features Phantom line: To show a movable feature in its different position Cutting plan lines: These are used in section drawings to show the locations of cutting planes. Construction lines: Thin lines used to roughly lay out some of the details of sketches. Section lines: Used in section views to represent surfaces of an object cut by a cutting plane. Short Break line- Long ruled thin line with zigzags. Used to show where an object is broken to save drawing space or reveal interior features. Chain line -Used to indicate that a surface is to receive additional treatment.

9 Dr Simin Nasseri Southern Polytechnic State University 9 Figure 7.45 Alphabet of lines: For features of the object that can be seen For features which are not visible in the current view For showing, circle, arcs and bases of cones and cylinders To show the sizes of features To show a movable feature in its different position These are used in section drawings to show the locations of cutting planes. Thin line used to roughly lay out some of the details of sketches. Used in section views to represent surfaces of an object cut by a cutting plane.

10 Dr Simin Nasseri Southern Polytechnic State University 10 Visible lines and cutting plane lines are.6 mm thick and the other lines are 0.3 mm thick.

11 Dr Simin Nasseri Southern Polytechnic State University 11 Figure 7.46 Alphabet of lines:

12 Dr Simin Nasseri Southern Polytechnic State University 12 Multiview Sketching Techniques: 2.Circles are used to represent holes and bases of cones and cylinders. Arcs are used to show portions of these elements. Center lines should be used to show these elements.

13 Dr Simin Nasseri Southern Polytechnic State University 13 Figure /8 “ or 3 mm 1- Locate the center of the circles or arcs. 2- Show the axis of the cylinders, cones, etc. Center lines are used to: 3/4 “ to 1 ½ “ or 20 to 40 mm

14 Dr Simin Nasseri Southern Polytechnic State University Represent lines of symmetry. Center lines are used to:

15 Dr Simin Nasseri Southern Polytechnic State University 15 Figure 7.51 Centerlines conventions: They are used both in circular and horizontal views. To show the center of the semi-circles.

16 Dr Simin Nasseri Southern Polytechnic State University 16 Figure 7.51 Phantom lines Centerlines conventions: When the hole is very small, a solid line may be used instead. To locate the centers of holes around a bolt circle. To show the path of motion.

17 Dr Simin Nasseri Southern Polytechnic State University 17 Multiview Sketching Techniques: 3.When two lines in a view coincide, precedence of lines dictates the linetype to draw. Figure 7.48

18 Dr Simin Nasseri Southern Polytechnic State University 18 Draw the right view:

19 Dr Simin Nasseri Southern Polytechnic State University 19 Draw the 3 principal views:

20 Dr Simin Nasseri Southern Polytechnic State University 20 Draw the 3 principal views:

21 Dr Simin Nasseri Southern Polytechnic State University 21 Figure 7.49 A visible line coincides with the hidden line of the hole. How do you want to show the line? You can not show the hidden line! The hidden line of the step is right below the centerline. What happens if you don’t show the hidden line? It is as if there is no step below! Visible line has precedence over a center line! Still you draw the center line out of the body, to show that it exists!

22 Dr Simin Nasseri Southern Polytechnic State University 22 Figure 7.47

23 Dr Simin Nasseri Southern Polytechnic State University 23 Hidden line conventions: When a hidden line intersects a visible line when the feature terminates => No gap Corners on hidden lines => Should be joined A hidden line intersects either a visible corner or visible arc => there should be a gap 3 hidden intersecting corners => No gap

24 Dr Simin Nasseri Southern Polytechnic State University 24 Hidden line conventions: CorrectIncorrect Hidden arcs are started on the center line or the point of tangency => don’t cross Bottom of the drilled hole => should be joined Hidden line passes behind the visible line => Don’t put a hidden line dash on the visible line. One hidden line crosses in front of another hidden line => use a dash for the one in front.

25 Dr Simin Nasseri Southern Polytechnic State University 25 Multiview Sketches: 1- One-view Sketch (The front view is enough) 2- Two-view projection (when the part is symmetrical) FR F T The long dimension of the paper runs horizontally. The long dimension runs vertically.

26 Dr Simin Nasseri Southern Polytechnic State University 26 Figure 7.54

27 Dr Simin Nasseri Southern Polytechnic State University 27 Figure 7.53

28 Dr Simin Nasseri Southern Polytechnic State University 28 Alignments of 3 orthogonal views Miter line

29 Dr Simin Nasseri Southern Polytechnic State University 29 Figure 7.55

30 Dr Simin Nasseri Southern Polytechnic State University 30 Figure 7.56

31 Dr Simin Nasseri Southern Polytechnic State University 31 Figure 7.37 Oblique Pictorials There are parallel projection pictorial The angle that the right face makes with horizontal is between 30 to 45 degrees o The front face is seen in its true shape and is square with the paper. If full-size depth dimensions are used, the sketch is called Cavalier oblique. If depth is one half size, it is called Cabinet oblique.

32 Dr Simin Nasseri Southern Polytechnic State University 32 When do we use oblique projection? When the majority of the features are on the front face of the object. In fact when we have some details on the sides, we have to use the isometric projection

33 Dr Simin Nasseri Southern Polytechnic State University 33 Draw the front face. Scale the depth to half or two third of the of its actual size. Oblique Pictorials

34 Dr Simin Nasseri Southern Polytechnic State University 34 Figure 7.38

35 Dr Simin Nasseri Southern Polytechnic State University 35 Figure 7.39


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