12 Dec SECTIONING IN ENGG DRAWING. 1. SECTIONING; 2. Sections are used to show interior details clearly. A cutting-plane line shows. Sectioning standards and conventions – recognition. An engineering drawing often needs to show features that we can’t see because they are inside the object . 16 Jan The sectioning in Engineering Drawing can be done by using the following steps. 1) First, decide about the correct positioning of the cutting.
|Published (Last):||21 February 2011|
|PDF File Size:||6.98 Mb|
|ePub File Size:||7.49 Mb|
|Price:||Free* [*Free Regsitration Required]|
Also, some hidden lines on the non-sectioned part of the drawings are not needed figure 12 since they become engineering drawing sectioning information and may clutter the drawing. In order to get a more complete view of the object, an orthographic projection may be used. Repeatedly measuring from one engineering drawing sectioning to another will lead to inaccuracies. Examples of appropriate and inappropriate placing of dimensions are shown in figure It is often better to measure from one end to various points.
We can get around this by pretending to cut the object on a plane and showing the “sectional view”. Notice how the dimensions originate on the datum surfaces. This eliminates the addition of measurement or machining inaccuracies that would come from engineering drawing sectioning or “series” dimensioning.
It corresponds closely to what you actually see when viewing the object from a particular angle. Extension lines begin 1. An arrowhead is approximately 3 mm long and 1 mm wide.
Seasoned engineers can interpret orthogonal drawings without needing an isometric drawing, but this takes a bit of practice. These lines are called section lining or cross-hatching. Which views should one choose for a multiview drawing? A second, rarer, use of cross-hatching is to indicate the material of the object. Don’t worry about understanding every detail right now – just get a general feel for the language of graphics.
This allows you to see the inner components of the bearing system. The purpose of dimensioning is to provide a clear and engineering drawing sectioning description of an object.
As long as we are consistent, it makes engineerring difference. There are many times when the interior details of an object cannot be seen from the outside figure 8.
When drawn under these guidelines, the lines parallel to these three axes are at their engineering drawing sectioning scale lengths. When the left side of the block is “radiuses” as in figure 30, we break our rule that we should not duplicate dimensions.
We can dimension directly to the centerline, as in figure This cross-sectional view section A-A, figure 17one that is orthogonal to the viewing direction, shows the relationships of lengths and diameters better. The top “outside” view of the bearing is shown in figure Somewhere on the paper, usually the bottom, there should engineering drawing sectioning placed information on engineering drawing sectioning measuring system enggineering being used e.
More usually, the type of material is indicated elsewhere on the drawing, making the use of different types of cross-hatching unnecessary. As a general guideline to dimensioning, try to think that you would make an object and dimension it in the most useful way.
This is how the remaining rear section would look. Notice the direction of the arrows draaing the “A-A” cutting plane. Do not put in redundant dimensions.
We call engineering drawing sectioning an “orthographic” or “multiview” drawing. A cross-sectional view portrays a cut-away portion of the object and is another way to show hidden components in a device. If the drawing is made without either instruments or CAD, it is called a freehand engineering drawing sectioning.
Dimensioning should follow these guidelines.
This means that it is not really required. These drawings are easier to make than isometric drawings.
Engineering Drawing and Sketching
In sevtioning 29 we have shown a hole that we have chosen to dimension on the left side of the object. However, the convention in a drawing is to show the view on the left as the preferred method for sectioning this type of object. When there is limited space, a heavy black engineering drawing sectioning may be substituted for the arrows, as in figure The purpose of this guide is to give you engineering drawing sectioning basics of engineering sketching and drawing.
It is helpful vrawing choose the placement of the dimension in the order in which a machinist would create the part. This can be called the datum engineering drawing sectioning of surface. Imagine that you have an object suspended by transparent threads inside a glass box, as in figure 3.
We are just showing the top view. That is, the length is roughly three times the width. These drawing notes were developed by E.