Understanding Section Views in Technical Drawing: Cutting Planes and Types of Sections, Slides of Computer Graphics and Animation

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Section Views

Objective

• To demonstrate the proper use of section views which show internal features of objects that are not easily understood in standard multiview drawings
• To demonstrate the use of CAD tools in generating section views

Sectioned Drawings

• Definition: A multiview technical drawing that reveals details about internal features by displaying the part as if cut by an imaginary cutting plane
• Objective: To make the drawing more understandable, especially the internal details of the part
• Since the sectioned drawing shows internal features there is generally no need to show hidden lines
• Especially helpful for assembly drawings

The Cutting Plane

• An imaginary plane that defines where the object is cut
• Shown in drawing adjacent to the sectioned drawing
• Drawn with the PHANTOM line type
• Arrows at the end of the cutting plane line indicate the direction of view for the sectioned drawing. - The arrows point toward the part of the object that is visible in the sectioned drawing. - A sectioned drawing follows the general rules of any view in a multiview drawing Docsity.com

Section Lines

• Section lines are drawn where the object passes through the cutting plane
• If a saw was used to cut the part then section lines represent the cutting marks left by the saw blade
• Different materials may be represented by the use of different section line types
• The general section line type which may be used for any material is the line type for iron

Section Lines

• Section lines should not be parallel or perpendicular to object lines
• Section lines are generally drawn at 45 degrees unless this conflicts with other rules
• Section lines should be oriented at different angles for separate parts
• Occasionally section lines are only drawn on the perimeter of large areas
• Section lines are not used for thin parts rather they are filled in solid (Do not use closely spaced section lines)

Full Section

• The cutting plane passes completely through the part as a single flat plane

Half Section

• The cutting plane only passes half way through the part
• The other half is drawn as usual
• Hidden lines are not shown on either half of the part
• A center line is used to separate the two halves
• Mostly used on cylindrical parts

Assembly Section

• Cut each part of the assembly and section each part with the appropriate section line type
• Put the parts together in their assembled position

Assembly Section

• The shaft is not sectioned because it is a standard part and section lines would provide no additional information
• The other two part are made from the same material
• The orientation of section lines clearly shows the location of the different parts

Offset Section

• The internal features of many part can not be shown using a single straight cut to create the sectioned drawing
• An offset section is used for such parts

Offset Section

• The multiview drawing is often difficult to interpret when there are several hidden features on the object
• Look at the figure in your text and try to picture the part in your mind
• A sectioned view makes the object much easier to understand
• Use either drawing for your homework

Offset Section

• The actual part would show a new visible line at the bend in the cutting plane
• Since the cutting plane bend is arbitrary, do not show the line representing this bend in the sectioned drawing

Offset Section

• The sectioned view does not show the bend in the cutting plane
• Hidden lines are not shown
• Be sure to include object lines that are behind the cutting plane