Sectional view of a centrifugal pump

Radial section

Axial section

Sectional view of a leaf

SECTIONAL VIEWS

TO VIEW FEATURES THAT ARE HIDDEN IN AN UN-SECTIONED

VIEW

Section Plane Section Plane Through ApexThrough Apex

Section PlaneSection PlaneThrough GeneratorsThrough Generators

Section Plane Parallel Section Plane Parallel to end generator.to end generator.

Section Plane Section Plane Parallel to Axis.Parallel to Axis.

TriangleTriangle EllipseEllipse

Para

bola

Para

bola

HyperbolaHyperbola

EllipseEllipse

Cylinder throughCylinder through generators.generators.

Sq. Pyramid through Sq. Pyramid through all slant edgesall slant edges

TrapeziumTrapezium

Typical Section Planes Typical Section Planes &&

Typical Shapes Typical Shapes Of Of

SectionsSections..

ILLUSTRATION SHOWING ILLUSTRATION SHOWING IMPORTANT TERMS IMPORTANT TERMS

IN SECTIONING.IN SECTIONING.

xx yy

SECTION SECTION PLANEPLANETRACETRACE LINE LINE (egde view)(egde view)

SECTION LINESSECTION LINES(45(4500 to axis or outline, to axis or outline,

preferably not parallel to preferably not parallel to an outline)an outline)

Apparent Shape Apparent Shape of sectionof section

SECTIONAL T.V.SECTIONAL T.V.

Direction of viewing for TVDirection of viewing for TV

The section is drawn by projecting the points where the section plane intersects the edges of the solid and joining them

ad

cb

a’, b’

c’, d’

F.V.F.V.

Notations for cutting planes

Ref: Fundamentals of Engg. Drawing, Luzadder

Section plane denoted by different methods Arrows point towards

the remaining part

End point of object

Section more than one component in the same drawing

(e.g. concentric cylinders)

Section lines of adjacent components are drawn in different directions

Section lines for alternate components can be drawn in the same direction but with different spacing between section lines

Sectioning a solid• It is required to see features that are not clear in an

unsectioned view

REF: http://www.tpub.com/content/draftsman/14276/css/14276_190.htm

Usually hidden lines behind the section are not drawn

FRONT VIEW SIDE VIEW SECTIONAL SIDE VIEW

Section plane

Section lines at 45o to adjacent axis, lighter than the outlines

8

Ribs (used for strengthening, positioning)

Rib

Rib not sectioned even though cutting plane passes through it

A

AA A

9

Ribs (used for strengthening, positioning)Rib

B

B

B

B

TV

Full FVSectioned SV

Viewing direction

10

Types of sectional views(Used for showing outer and inner features on the same figure)

“It is considered good practice to omit all hidden lines unless such lines are necessary to clarify the representation.”

“Good practice dictates that hidden lines be omitted from both halves of the view unless they are absolutely necessary to explain the object.”

EXAMPLE TAKEN FROM BOOK BY LUZADDER AND DUFF

11

Full section

Offset full section

13

Section B-B

Section A-A

15

C

C Section A-A

Rib not sectioned

Section B-B

Section C-C

Each section has been drawn separately

Draw orthographic views showing

sections P-P and R-R

Draw orthographic views showing the section indicated