Activity 7.2 Sectional Views

Introduction

Have you ever noticed that some objects have more going on inside than outside? Take an apple, for instance. How would you communicate the intricate details hidden inside an apple’s core? You would have to cut the apple in half in order to show someone that there are spaces inside that house seeds. If you were to make a sketch of the apple, you could show the spaces and the seeds as hidden lines, but too many hidden lines can serve to confuse the issue. Sectional views are another alternative.

The main purpose of a sectional view is to effectively communicate internal information to enhance the viewer’s understanding of the part. There are several different types of section views that engineers use to communicate internal geometry.

In this activity you will visualize and create section views, both by hand sketching and CAD of parts that have interior features not easily documented with orthogonal projections.

Equipment

  • Engineering notebook
  • Pencil
  • Computer with 3D CAD solid modeling software

Procedure

  1. Study the figure below. Use points and construction lines to lay out a section view on the grid provided. The cutting plane line will tell you where the full section is cut. Delineate the visible edges of the sketch with object lines. Use section lines to indicate which surfaces were cut by the cutting plane. DO NOT ERASE YOUR POINTS AND CONSTRUCTION LINES.

  1. Study the figure below. Use points and construction lines to lay out a section view on the grid provided. The cutting plane line will tell you where the full section is cut. Delineate the visible edges of the sketch with object lines. Use section lines to indicate which surfaces were cut by the cutting plane. DO NOT ERASE YOUR POINTS AND CONSTRUCTION LINES.

  1. Study the figures below. Use points and construction lines to lay out a half section view of the object. The cutting plane line will tell you where the section occurs. Delineate the visible edges of the sketch with object lines. Use section lines to indicate which surfaces were cut by the cutting plane. DO NOT ERASE YOUR POINTS AND CONSTRUCTION LINES.

  1. Cut and paste the front and right side views of the drill block below into your engineering notebook. Sketch an isometric view of the object in your notebook. Then create a full scale section view as indicated by the cutting plane line, but do not dimension the section view. Use appropriate object and section lines.Note that the section view will appear larger than the views below (which are not shown to scale).

  1. Create a solid model of drill block in number 4 above. Then create a computer-generated fully dimensioned multi-viewpart drawing showing the front view and full section view (as indicated by the cutting plane line A-A). Save the files and document the file name and location below.

Part file name: / Part file location:
Drawing file name: / Drawing file location:
  1. Make a three-view multi-view sketch of the part (arbor press base) illustrated below in your engineering notebook. You must decide which three views are most appropriate to show. One of these views must be a full section, showing the depth of the two holes. Include a cutting plane line to indicate the location of your section. Use section lines to indicate which surfaces were cut by the cutting plane. Leave space between all of the views for dimensions, but DO NOT DIMENSION THE SKETCH.

  1. Create the object shown (arbor press base) in the drawing in number 6 above as a solid CAD model. Then create a fully dimensioned multi-view drawing to document the part, save the CAD files, and document the file names and locationsin the spaces below.

Part file name: / Part file location:
Drawing file name: / Drawing file location:

Extend Your Learning

  1. Open the part file WindshieldYourInitials.ipt that you created in Activity 5.5 CAD Model Features. Use 3D modeling software to create a multi-view part drawing of the part such that the orthogonal projection shown below is the front view. Include a full section view as indicated by the cutting plane line with coordinate dimensions to specify the curvature of the top surface of the par according to the method presented in Dimensioning Standards.ppt. Also include a detail view as indicated by the detail mark to detail the ribs in the interior shell.

Note that you can dimension the curve on the drawing (within the drawing file) by placing a sketch on the section view, projecting the geometry of the curve, and placing points along the curve. It is best to space the points at a constant interval (say 0.5 in. horizontally).

Part file name: / Part file location:
Drawing file name: / Drawing file location:

Conclusion

1.What do the arrows on a cutting plane line indicate?

2.What is the difference between a half and a full section?

3.Are hidden lines shown in a section view?

4.What conventions are associated with section lines?

© 2012 Project Lead The Way, Inc.

Introduction to Engineering DesignActivity 7.2Sectional Views– Page 1