Lect 13P. 1

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Section Views

• Lecture 13

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Topics For Today

• Sections Views
• Why section views are needed
• Types of section views
• References
• BTG Chapter 6

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Section Views

• Goals
• Recognize various kinds of section views, make
  full and half section views.
• Improve visualization of interior features.

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Section Views

• Section views are used when important hidden
  details are in the interior of an object. These
  details appear as hidden lines in one of the
  orthographic principal views therefore, their
  shapes are not very well described by pure
  orthographic projection.

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Types Of Section Views

• Full sections
• Half sections
• Offset sections
• Revolved sections
• Removed sections
• Broken-out sections

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Cutting Plane

• Section views show how an object would look if a
  cutting plane (or saw) cut through the object and
  the material in front of the cutting plane was
  discarded

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Section Lines

• Section lines (crosshatching) are used to show
  where the cutting plane passed through solid
  material

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Full Section View

• In a full section view, the cutting plane cuts
  across the entire object
• Note that hidden lines become visible in a
  section view

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Full Section View

• Shows cutting plane in the top view
• Makes a full section on the front view

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Full Section View

• Note how the cutting plane is drawn and how the
  crosshatching lines mark the surfaces of material
  cut by the cutting plane.
• No hidden lines on the section view, if possible.
• Note Interior lines behind cutting plane became
  visible.

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Multiple Sectioned Views
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Half Section View

• The cutting planes do not cut all the way through
  to the object. They cut only half way. They
  intersect at the centerline.

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Half Section View

• Half Section used mainly for symmetric objects

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Revolved Sections

• Revolved sections examples show the shape of an
  objects cross-section superimposed on a
  longitudinal view

15
Removed Sections

• Removed sections are like revolved sections
  but moved aside. Note how they are named.

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Broken Out Sections
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Offset Sections

• Offset sections are used to show interior
  features that do not lie along a straight line

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Offset Sections
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Conventional Revolutions

• Used to make section views clear and avoid
  confusion
• Associated with objects that have holes, ribs,
  spokes, or lugs in any combination equally spaced
  in a circular fashion
• Not projected orthographically to section view
• Examples to follow

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Conventional Hole Revolutions

• Note no hidden lines

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Conventional Rib Revolutions

• Note Ribs not crosshatched

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Conventional Spoke Revolution

• Note Spokes not crosshatched

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Holes and Ribs in Combination
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Assignment

• Dwg 25 F18-A
• Complete section views
• Due at end of todays lecture
• Dwg 26 SECT 1-N
• Sketch Section Views
• Due at beginning of next lecture