Lect 13 P. 1

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Section Views

Lecture 13

Lect 13 P. 2

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Topics For Today

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

Lect 13 P. 3

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Section Views

• Goals– Recognize various kinds of section views,

make full and half section views.– Improve visualization of interior features.

Lect 13 P. 4

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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.

Section Views

Lect 13 P. 5

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Types Of Section Views

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

Lect 13 P. 6

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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

Lect 13 P. 7

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Section Lines

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

Lect 13 P. 8

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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

Hidden Lines are Visible

Lect 13 P. 9

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Full Section View

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

Lect 13 P. 10

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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.

Visible lines omitted

Incorrect

Correct

Lect 13 P. 11

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Multiple Sectioned Views

SECTION A-A

AA

SECTION B-B

B

B

Lect 13 P. 12

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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.

Lect 13 P. 13

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• Half Section used mainly for symmetric objects

Half Section View

Lect 13 P. 14

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Revolved Sections

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

Lect 13 P. 15

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Removed Sections

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

A

A

Section A-A

C CSection C-C

B

B

Section B-B

Lect 13 P. 16

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Broken Out Sections

Lect 13 P. 17

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Offset Sections

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

Lect 13 P. 18

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Offset Sections

Lect 13 P. 19

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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

Lect 13 P. 20

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Conventional Hole Revolutions

• Note no hidden lines

Lect 13 P. 21

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Conventional Rib Revolutions

• Note: Ribs not crosshatched

Lect 13 P. 22

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Conventional Spoke Revolution• Note: Spokes not crosshatched

Lect 13 P. 23

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Holes and Ribs in Combination

Lect 13 P. 24

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Assignment

• Dwg 25 – F18-A – Complete section views– Due at end of today’s lecture

• Dwg 26 – SECT 1-N– Sketch Section Views– Due at beginning of next lecture