12 Dec SECTIONING IN ENGG DRAWING. 1. SECTIONING; 2. Sections are used to show interior details clearly. A cutting-plane line shows. Orthographic Views & Sectioning. Prof Ahmed Kovacevic. Engineering Drawing and Design – Lecture 4. School of Engineering and Mathematical Sciences. 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.
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Dimensioning should follow these guidelines.
A leader may also be used to indicate a note or comment about a specific area. Don’t worry about understanding every detail right now – just get a general feel for the language of drasing.
The dimensions should be placed on the face that describes the feature most clearly. As long as we are consistent, it makes no difference. We call this an “orthographic” or “multiview” drawing.
NPTEL :: Mechanical Engineering – Engineering Drawing
Notice how the dimensions originate on the datum surfaces. The spacing between lines should be uniform. A second, rarer, use of sectionint is to indicate the material of the object.
When there is limited space, a heavy black enginesring may be substituted for the arrows, as in figure This drawing is symmetric about the horizontal centerline. Any engineering drawing should show everything: It is helpful to choose the placement of the dimension in the order in which a machinist would create the part.
Engineering Drawing and Sketching
This cross-sectional view section A-A, figure 17one that is orthogonal to the viewing direction, shows the relationships of lengths and diameters better.
Not only will these clutter the drawing, but if “tolerances” or accuracy levels enfineering been included, the redundant dimensions often lead to conflicts when the tolerance allowances can be added in different ways. The purpose of this guide is to give you the basics of engineering sketching and drawing.
This is how the remaining rear section would look. However, the convention in a drawing is to show the view on the left as the preferred method for sectioning this enginefring of object.
Also, some hidden lines on the non-sectioned part of the drawings are not needed figure 12 since they become redundant information and may clutter the drawing. This eliminates the addition of measurement or machining inaccuracies that would come from “chain” or “series” dimensioning. The views that drawinh every detail about the object. A complete set of dimensions will permit only one interpretation needed to construct the part.
Then imagine removing the material from the front of this plane, as shown in figure These drawing notes were developed by E.
An extension line extends a line on the object to the dimension line. We can dimension directly to the centerline, as in figure Which views should one choose for a multiview drawing? The cross-section on the right of figure 22 is technically correct. Frawing is usually best to dimension from a common line or surface. Unfold the box figure 4 and you have the three views. The diagonal lines on the section drawing are used to indicate the area that has been theoretically cut.
Engineering Drawing and Sketching
We hope you like the object in Figure 1, because you’ll be seeing a lot of it. This convention may take some experience. These drawings are easier to make than isometric drawings.
Then, for clarity, we add the overall length of 60 and we note that it is a reference REF dimension. We have to make some choices when we dimension a block with a notch or cutout figure As a general guideline to dimensioning, try to think that you would make an object and dimension it in the most useful way.
The circular object in figure 6 requires only two views.