4. Types of Sectioning.pptx

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1. Types of Sectioning M/C Drawing and CAD Rahul M. Chanmanwar Mechanical Department WCE, Sangli.

2. Sectioning Summary Sectional Views Types of Sections Full section Half section Offset section Aligned section Rib and web sections Broken section Removed section Revolved section

3. Creating a Section View The part is cut using an imaginary cutting plane.

4. Creating a Section View The unwanted portion is mentally discarded exposing the interior construction.

5. Section Example Notice how the cutting plane is indicated. Notice how the cut material is shown. Sectional view label

6. Lines Used in Section Views Cutting Plane Line: Used to show where the object is being cut. (Phantom line type)

7. Lines Used in Section Views Shows where the part is being cut. Arrows point to the portion being kept. Section Lines

8. Lines Used in Section Views Section Lines: Section lines are used to indicate where the cutting plane cuts the material. Section lines are thin lines. Section line symbols are chosen according to the material of the object Section lines are generally drawn at a 45° angle.

9. Lines Used in Section Views Common Section Line Symbols

10. Lines Used in Section Views Common Section Line Symbols

11. Rules of Sectioning Rule 1: A section lined area is always completely bounded by a visible outline.

12. Rules of Sectioning Rule 2: The section lines in all areas should be parallel. Section lines shown in opposite directions indicate a different part.

13. Rules of Sectioning Rule 3: All the visible edges behind the cutting plane should be shown.

14. Rules of Sectioning Rule 4: Hidden features should be omitted in all areas of a section view. Exceptions include threads and broken out sections.

15. Types of Sections The type of section used depends on the situation and what information needs to be conveyed. Types of sections Full Section Half Section Offset Section etc …

16. Full Section To create a full section , the cutting plane passes fully through the object. Used in many cases to avoid having to dimension hidden lines.

17. Half Section A half section exposes the interior of one half of an object while retaining the exterior of the other half.

18. Half Section Half sections are used mainly for symmetric objects or assembly drawings.

19. Half Section A centerline is used to separate the two halves. Hidden lines should not be shown on either half.

20. Offset Section An offset section is produced by bending the cutting plane to show features that don’t lie in the same plane.

21. Aligned Section In order to include angled elements in a section, the cutting plane may be bent so that it passes through those features. Skip advanced topic

22. Conventions of Revolution Features are revolved to the projection plane, and then projected over.

23. Rib and Web Sections To avoid a false impression of thickness and solidity, ribs and webs are not sectioned. Cutting plane passes through the web No section lines in cut area of web

24. Rib and Web Sections If the cutting plane passes crosswise through the rib or web, we include section lines. Cutting plane passes through the web Section lines in cut area of web

25. Broken Section Sometimes only a partial or broken out section is needed. Hidden lines are shown in the non-sectioned area of a broken section.

26. Revolved Section The cross sectional shape of an object may be shown in the longitudinal view by means of a revolved section .