1. Sectioning ERT 243/3 CAD IN BIOSYSTEM ENGINEERING SITI KAMARIAH BINTI MD SA’AT SCHOOL OF BIOPROCESS ENGINEERING, UNIMAP

2.  Page 2 Sectioning  There are many times when the interior details of an object cannot be seen from the outside.

3.  Page 3  It should not really be a surprise that a convention is required to give additional details about the interior of an object. Many common examples can be seen every day - items that look as though they may be constructed In similar ways when viewed solely with the information available from the outer surface.

4.  Page 4  We can get around this by pretending to cut the object on a plane and showing the "sectional view". The sectional view is applicable to objects like engine blocks, where the interior details are intricate and would be very difficult to understand through the use of "hidden" lines (hidden lines are, by convention, dotted) on an orthographic or isometric drawing.  Imagine slicing the object in the middle

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9.  Page 9 Take away the front half and what you have is a full section view

10. Cross Sectioning Views

11.  Page 11  A cross-sectional view portrays a cut-away portion of the object and is another way to show hidden components in a device.  Imagine a plane that cuts vertically through the center of the pillow block. Then imagine removing the material from the front of this plane.

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13.  Page 13 This is how the remaining rear section would look. Diagonal lines (cross-hatches) show regions where materials have been cut by the cutting plane.

14.  Page 14  This cross-sectional view (section A-A) one that is orthogonal to the viewing direction, shows the relationships of lengths and diameters better.  The top "outside" view of the bearing is shown in next fifure. It is an orthogonal (perpendicular) projection. Notice the direction of the arrows for the "A-A" cutting plane.

15.  Page 15 The top "outside" view of the bearing

16.  Page 16 Half-Sections  A half-section is a view of an object showing one- half of the view in section.  The diagonal lines on the section drawing are used to indicate the area that has been theoretically cut.

17.  Page 17 Half-Sections  These lines are called section lining or cross- hatching. The lines are thin and are usually drawn at a 45-degree angle to the major outline of the object.  The spacing between lines should be uniform. A second, rarer, use of cross-hatching is to indicate the material of the object. One form of cross- hatching may be used for cast iron, another for bronze, and so on.

18.  Page 18 Full and sectioned isometric views

19.  Page 19 Front view and half section

20.  Page 20 Cross section

21.  Page 21 EXAMPLE 1:

22.  Page 22 EXAMPLE 2:

23.  Page 23 EXAMPLE 3:

24.  Page 24 EXAMPLE 4: