Engineering Drawing Lines its types and uses
Engineering drawings use different types of lines to represent various features, dimensions, and details of an object. These lines help in conveying accurate information about the design, structure, and function of components. Here are the main types of lines used in engineering drawing along with their uses:
1. Object (Visible) Line
- Description: Thick and continuous.
- Use: Represents the visible edges and contours of an object.
2. Hidden Line
- Description: Dashed line (short dashes).
- Use: Represents edges or surfaces that are not visible from the current viewpoint.
3. Center Line
- Description: Long and short alternating dashes.
- Use: Indicates the center of circles, arcs, and symmetrical objects.
4. Construction Line
- Description: Very light and thin continuous line.
- Use: Used as a guide for constructing other lines and shapes.
5. Dimension Line
- Description: Thin continuous line with arrowheads at both ends.
- Use: Shows the measurement of an object.
6. Extension Line
- Description: Thin continuous line extending from an object to indicate the start and end of a dimension.
- Use: Helps in defining the points between which dimensions are measured.
7. Leader Line
- Description: Thin line with an arrow or dot at one end.
- Use: Used for annotations, notes, and symbols.
8. Cutting Plane Line
- Description: Thick dashed line with long dashes and short dashes.
- Use: Represents an imaginary plane where a sectional view is taken.
9. Section Line (Hatching Line)
- Description: Thin diagonal lines.
- Use: Represents the surfaces of an object that have been cut in a sectional view.
10. Break Line
- Description: Zig-zag or wavy continuous line.
- Use: Indicates that a part of an object is removed for clarity.
11. Phantom Line
- Description: Alternating long and double short dashes.
- Use: Represents alternative positions of moving parts or repeated details.
In engineering drawing, different types of lines are categorized into Type A, Type B, Type C, etc., as per BIS (Bureau of Indian Standards) IS 10714 or ISO 128. These classifications define the thickness, style, and purpose of lines in technical drawings.
Types of Lines in Engineering Drawing (A-Type, B-Type, etc.)
| Line Type | Description | Use in Drawing |
|---|---|---|
| Type A | Thick continuous line | Used for visible outlines and edges |
| Type B | Thin continuous line | Used for dimension lines, projection lines, hatching, and short center lines |
| Type C | Thick dashed line | Used for hidden edges and outlines |
| Type D | Thin dashed line | Used for hidden edges when clarity is needed |
| Type E | Thin continuous line with freehand zigzag | Used for break lines in long objects |
| Type F | Thin continuous line with curve | Used for limits of partial views and sections |
| Type G | Chain line (long dash and dot) | Used for center lines and symmetry axes |
| Type H | Chain line (long dash, two short dashes) | Used for cutting plane lines |
| Type K | Thick continuous with freehand | Used for irregular boundaries or breaks |
Key Points:
- Thick Lines are used for visible objects, cutting planes, and break lines.
- Thin Lines are used for dimensioning, projection, and hatching.
- Dashed Lines represent hidden features.
- Chain Lines are used for center lines, cutting planes, and special limits.
