Module 6

Sectional Views

AutoCAD 2D-1

Sectional Views

Module Objectives

1. Differentiate between full, half, and rib and web sections.

2. Define hatching and explains its function.

3. Create sectional views from a given isometric drawing.

A video on Cross Sectional View

http://www.youtube.com/watch?v=e5jT5UAq1Q8&list=PLBDFD226C06F3D4

AC&index=11

Sectional Views Introduction to Sectional Views

A sectional view is that view seen beyond an imaginary plane passing through an object at right angles to the direction of sight. Sectional views are used to show the interior construction or details of hidden features that cannot be shown clearly by outside views. The cutting plane on which a section has been taken is indicated by a heavy dash line. Arrow heads at the ends of the cutting plane lines are used to indicate the direction in which the sections are viewed. See Fig 6.1 (a, b). Fig.6.1: Sectional views

Sectional Views 2. Types of sectional views A) Full Section

A full section view is made by passing an imaginary cutting plane fully through an object.

The figure shows an imaginary cutting plane passing fully through an object and half of it being removed.

In a multi-view drawing, a full section view is placed in the same position that a non-sectioned view would normally occupy; that is, a front section view would replace the traditional front view - see Fig. 6.2.

Fig.6.2: Cutting Plane Line.

Sectional Views B. Half Section Half sections are created by passing an imaginary cutting plane halfway through an object and one quarter of it is removed. Hidden lines are omitted on both halves of the section view. External features of the part are drawn on the non- sectioned half of the view. A center line, not an object line, is used to separate the sectioned half from the non sectioned half of the view. Half section views are most often used on parts that are symmetrical, such as cylinders. See Fig. 6.3. Fig.6.3: Half Section

Sectional Views C. Rib and Web Sections

The thin webs are not normally sectioned

even though they lie in the section plane,

according to ISO recommendations.

A good way to accept these exceptions to

the general rule are to imagine how

complicated the drawing would look if they

are sectioned. See Fig 6.4.

The ribs are sectioned when they lie across

the section plane.

Fig.6.4: Rib

Section Technique

Sectional Views 3.Hatching Hatching lines are thin lines and should preferably be inclining at 45 degrees. They should be evenly spaced. If there are two or more adjacent sectioned parts, the hatching lines should either be of different spacing or different direction. (See Fig 6.5.) However, hatching pattern should be the same for separate areas of a single object. Fig.

Fig. 6.5: Hatching pattern

Sectional Views 4. Examples on Sectioning

Different examples of full and half sections are shown in Fig.6.6.

Fig.6.6 a : Three views without sectioning

Sectional Views

Examples on

Sectioning cont’d…

Class Activity 1

Match the correct section view with the

corresponding drawing.

Write the correct sectional view letter beside the drawing number in the space

provided.

Class Activity 2 Using the THIRD angle projection, draw the following

ORTHOGRAPHIC views of component shown below.

1. A complete sectional front view

2. A side view

3. A top view

Use an A3 size drawing sheet to redraw the following views:

1. The top view.

2. The complete sectional side view at

A-A.

3. The front view.

Class Activity 3

Using the THIRD angle projection,

draw the following

ORTHOGRAPHIC views of

component shown below.

1. A complete sectional front view

2. A side view

3. A top view

Homework 6 - at the back of module 6 -

Due next class