SECTIONAL VIEW DRAWING

Sectional View Drawing - When orthographic views are correctly chosen, even the most sophisticated objects' external aspects can be revealed. There are, however, some things with complex inner elements that when represented by hidden lines may not effectively to portray the genuine inside details. One way to get around this is to portray one or more of the views 'in section.'

A sectional view is obtained by imagining the object, as if cut by a cutting plane and the portion between the observer and the section plane being removed. Figure 1.a depicts an object with the cutting plane running through it, and Figure 1.b depicts the two sides of the object being drawn apart to reveal the inside details.

Figure 1. Principles Of Sectioning

Sectional view has several types will be explained in the explanation below.

Full Section

A full section or sectional view is a sectional view derived by assuming that the item is totally cut by a plane. In full section, Figure 2a depicts the view from the right of the object seen in Figure 1. The sectioned view, which is superior to the unsectioned view with dotted lines for inner details, provides all of the interior details (Fig. 2b). The cutting plane is represented by its trace (V.T) in the front view (Fig. 2c), and the arrows represent the direction of sight to obtain the sectional view.

Figure 2. Sectioned And Un-Sectioned Views

It should be noticed that only one half of the object is assumed to be removed in order to achieve a sectional view, but it is not actually shown removed anywhere except in the sectional view. In addition, section line or hatching is used to indicate the areas of the item that have been cut by the plane in a sectional view. The visible elements behind the cutting plane should likewise be included in the picture.

The acceptable and inappropriate approaches of displaying a sectional view are shown in Figure 3. Hidden lines are typically deleted in sectional views since sections are generally used to replace hidden line representation.

Figure 3. Incorrect And Correct Section

Half Section

For symmetrical objects, a half sectional view is ideal. The cutting plane only removes one quarter of an object for a half section. A half sectional view is used to show both internal and external details in the same view for a symmetrical object. Omitting the concealed lines is a recommended practice even in half sectional views. Figure 4a depicts an object with the cutting plane set up for a half-sectional view from the front, with the top half cut out. Figure 4b depicts two portions that have been drawn apart to reveal the inner details of the sectioned piece. The half sectional view from the front is shown in Figure 4c. It's worth noting that the halves of the half section are divided by a center line. In order to acquire the half sectional view from the front, students should take note of the representation of the cutting plane in the view from above.

Figure 4. Methode Of Obtaining Half Sectional View

Auxilary Section

Auxiliary sections can be utilized to supplement the orthographic projections' main views. The cross-sectional shapes of features such as arms, ribs, and so on are shown in a sectional view projected on an auxiliary plane inclined to the major planes of projection. The auxiliary section X-X is obtained using the auxiliary cutting plane X-X in Figure 5.

Figure 5. Auxilary Section

Sectional View Drawing Examples

Machine Block

Shaft Support

Machine Component

Sliding Block

Yoke

Bearing Bracket

Bearing Bracket Contd.