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UNIT 7 :

SECTIONAL VIEW

Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 1

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 2

Section Views

Orthographic views showing all hidden lines may not be

clear enough to describe an objects internal details.

This shortcoming can be overcome by imagining that part

of the object has been cut away and shown in a cross-sectional view. This view is called a section view.

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 3

Type of Section Views

Full section view

Offset section view (multiple offset views)

Half section view Broken section view

Aligned and Revolved section views

Removed view

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 4

Section ViewFull Section

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 5

Section ViewOffset Section

Offset cutting plane

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 6

Section ViewMultiple Offset Sections

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 7

Section ViewHalf Section

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 8

Section ViewBroken Section

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 9

Section ViewAligned & Revolved Section

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 10

Section View

Removed sections placed

outside of the view

Hatch lines

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 11

Section Viewreview

All visible edges and contours behind the cutting plane should be shown.

Hidden lines should be omitted in section views.

A section view should always be bounded by a visible outline.

There should be no lines in the hatched area.

Section lines should be in the same direction.

Use standard section lines (hatch) to show materials.

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 12

Breaks and Sectioning

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 13

ANSI Standard Section Lines

for Various Materials

ANSI-31

ANSI-133

ANSI-134

American

National

Standards

Institute

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Section Lining

Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 14

MaterialsCommon

materials

The symbol for cast iron

can be used for most

section views.

Refer to any common

drafting text for additional

symbols.

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 15

Section Lining

45 degree angle lines should be used.

1/8 between lines.

All lines should be uniformly spaced

Thin sections may be blackened in

completely

Spacing lines by eye increases speed

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Ken Youssefi Mechanical and Aerospace Engineering Dept., SJSU 16

Section LiningLine Placement

Lines should never be parallel or

perpendicular to the object lines.

If the outline of the object has 45 degree

lines, 30 or 60 degree lines should be used.

Assemblies with several parts should be

lined with varying angle section lines.