8- sectional views

Sectional ViewsSectional ViewsKCEC 1101

Section views are an important aspect of design and documentation and are used to improve clarity and reveal interior features of the parts and structures.

Figure shows a regular multiview drawing and a

sectioned multiviewdrawing of the same part

I the front view; the hidden features can be seen after sectioning.

Cutting plane: Traditional section views are based on used of an imaginary cutting plane that cut through the object to reveal interior features

Sectional views are used in every engineering discipline. In 3D views, sectional technical illustration are used to describe interior features of complicated assemblies (see figure below).

Sectional views

An important reason for using section views is to reduce the number of hidden lines in a drawing.However, when a minimum number of hidden lines are needed to represent features other than primary one shown by the section

Optional use of hidden lines

Visible surfaces and edges that represent a change of plane behind the cutting plane are drawn in section view.

Example of defining a cutting Example of defining a cutting plane on a CAD modelplane on a CAD model

Placement Placement of cutting of cutting

plane linesplane linesThe cutting plane line is placed in the view where the cutting plane appears on edge.

Standard cutting plane line stylesStandard cutting plane line styles

ANSI standard ANSI standard section lines for section lines for various materialsvarious materials

The angle at which section lines are drawn is usually 45 degrees to the horizontal, but this can be changed for adjacent parts shown in the same section (135 degrees)

The sectional lines should be evenly equal space and should be thinner than visible lines

Section view typesSection view typesThere are many different types of section views used on technical drawings:

Full sectionHalf sectionBroken-out sectionRevolved sectionRemoved sectionAssembly sectionAuxiliary section

Full sectionFull section

Haft SectionsHaft Sections

BrokenBroken--out sectionout section

Revolved sectionRevolved section

Removed sectionRemoved section

Removed sectionRemoved section

Offset sectionOffset section

Multiple Multiple offset sectionoffset section

Assembly sectionAssembly section

Auxiliary sectionAuxiliary section

Full auxiliary view Partial auxiliary view

Special sectioning conventionsSpecial sectioning conventionsRibs, webs, and lugs are special types of features commonly found in mechanical components. These types of features require special treatment in section views.Adding section lines to these features would give the false impression that the part is thicker than it really is.

Webs in section viewsWebs in section viewsThin features such as webs, are left unsectioned when cut parallel to the feature by the cutting plane

Aligned sectionsAligned sectionsAligned sections are special types of orthographic drawings used to revolve or align special features of parts in order to clarify them or make them easier to represent in section

Aligning spokes in the section views is the conventional method of representation

Aligning lugs in the section views is the conventional method of representation

Conventional Conventional breaksbreaks

Conventional breaks are used for revolved section views or for

shortening the view of an elongated part, such as a shovel

handle or vehicle axle.

A section view created on 3A section view created on 3--D D CAD modelCAD model

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