es 1 - sectional view

Sectional ViewsES 1 – Engineering Drawing

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1st Semester 2009-2010

SECTIONAL VIEW• Often we need to show the internal features of a part that cannot be shown by hidden lines

• We can show the inside by cutting it with a cutting plane much the same way we could cut an apple with a knife

•The cutaway view is called a sectional view, a cross section or simply a section.

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FULL SECTION• To produce a sectional view, a cutting plane is assumed to pass thru the part.

•The sectional view obtained by passing a plane thru the entire parts is called a full section.

•When cutting a section, the area that is actually cut away is shown in cross-hatched with thin parallel lines.

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FULL SECTION

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CUTTING PLANE

The visible edges of the object behind the cutting plane are generally shown because they are now visible but they are not cross-hatched.

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FULL SECTION

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CUTTING PLANES and SECTIONS

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VISUALIZING A SECTION

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RULES ON SECTIONING

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

• Hidden lines are, generally, omitted in sectional views.• A hatched section is always completely bounded by a visible line –

never a hidden line.• The use of hatching in opposite directions indicates different parts.

This is often done in an assembly drawing.

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SECTION LINE MISTAKES

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SECTION LINE TECHNIQUES

• Uniformly spaced by an interval of about 0.10”

• Uniformly thin, not varying thickness

• Do not run beyond outer edges of the visible lines

• Usually at 45˚ angle

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SECTION LINE TECHNIQUES

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SECTION LINING SYMBOLS

Section lining symbols may be used to indicate specific materials.

Using different section lining patterns helps you distinguish different materials, especially on assembly drawings

It is acceptable to use the general-purpose symbol at different angles for different parts

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SECTION LINING SYMBOLS

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FULL SECTION

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OTHER SECTIONAL VIEWS

• Half Section

• Offset Section

• Aligned/Oblique Section

• Auxiliary Section

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HALF SECTION

• Objects that are symmetric can be shown effectively using a half section

•Half sections expose the interior for one half of the object and the exterior of the other half•One quarter of the object is removed

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HALF SECTION

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HALF SECTION

In general:

•Omit hidden lines from both halves of a half section whenever possible

•Use a center line to divide the sectioned half and the unsectioned half

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OFFSET SECTIONIn sectioning through complex objects, it is often desirable to show features that do not lie in a straight line by offsetting or bending the cutting plane

•Offsets or bends in the cutting plane are all 90•The bends in cutting plane are never shown in the sectional view

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OFFSET SECTION

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ALIGNED SECTION

• An aligned section is used when a part feature is angled.

• The plane and features are then imagined to be revolved into the original plane.

• The section thru the part must be taken in such a way that it shown the maximum amount of information.

• The angle of revolution should always be less then 90 for an aligned section

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ALIGNED SECTION

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REFERENCES

flightline.highline.edu/bkonnur/.../06_Sectional_%20Views

ocw.kfupm.edu.sa/user062/ME21008/Sectional%20Views

fd.valenciacc.edu/file/dolenick/Session%208

-- by Eagleman ^_^

es 1 - sectional view

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