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 Through Apex Section Plane Through Generators Section Plane Parallel to end generator. Section Plane Parallel to Axis. Triangle Ellipse Parabola Hyperbola Ellipse Cylinder through generators. generators. Sq. Pyramid through all slant edges Trapezium Typical Section Planes & Typical Shapes Of Sections.

ILLUSTRATION SHOWING IMPORTANT TERMS IN SECTIONING. xy SECTIONPLANE TRACE LINE (egde view) SECTION LINES (45 0 to axis or outline, preferably not parallel to an outline) Apparent Shape of section SECTIONAL T.V. Direction 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 a d c b a’, b’ c’, d’ 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: Usually hidden lines behind the section are not drawn

FRONT VIEW SIDE VIEW SECTIONAL SIDE VIEW Section plane Section lines at 45 o 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 A AA

9 Ribs (used for strengthening, positioning) Rib B B B B TV Full FV Sectioned 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