CHAPTER 7 SECTIONAL VIEWES INSTRUCTOR M YAQUB Sectional
CHAPTER 7 SECTIONAL VIEWES INSTRUCTOR M. YAQUB
Sectional view • External features of the object can be described by multi-view drawing. • Internal features by hidden lines but sometime not clear. • To show these features, cut the object like apple, and cut way view of the part is drawn. • Such views are called Sectional view or Sections.
A cutting plane is used to cut the object.
Full Sections • Comparison of left side view and section view, section view is clear, omit left side view. • Cutting plane appears as a cutting plane line indicating direction of sight. • Direction of sight and the view must be on opposite side. • The area which is in contact with the cutting plane should be cross hatched by section lines. • Visible part should not cross hatched.
A correct front view and sectional view
In general, all visible edges and contours behind the cutting plane should be shown: otherwise view will be disconnected and unrelated parts.
Sections are used to replace hidden lines. Therefore no hidden lines in section view. Show only when necessary for clarity.
A sectioned lined area is always completely bounded by a visible outline – never by hidden line. A visible line can never cut across a section-lined area.
Section lines in all sectioned areas must be parallel. Opposite direction means two different parts.
Section lines must not be parallel or perpendicular to the visible line.
In general, hidden lines should be omitted on both halves, can be shown in un-sectioned view when required for dimensioning. A center line is used to separate the halves of the half section (ANSI standard).
If only partial section of a view is needed, it will be shown by broken out section.
Cut the object and rotate 90 and show
Remove original lines covered by Revolved sections.
Removed Sections • A section which is not in direct projection from the view containing the cutting plane and not positioned in agreement with standard view. • Represented by A-A or B-B.
Removed section is a partial section and drawn on a large scale.
Placement of the Removed sections on center lines extended from the section cut
- Slides: 50