Requirements of engineering drawings – engineering drawing la gasolina in english


■ The drawing must be complete. The content of an engineering drawing must provide all the information for that stage of its manufacture. There may be several drawings for several phases of manufacture, e.g. raw shape, bent shape and heat-treated. Although each drawing should be complete in its own right, it may rely on other drawings for complete specification, e.g. detailed drawings and assembly drawings.

■ The drawing must be suitable for duplication. A drawing is a specification which needs to be communicated. The information may be communicated electronically or in a hard copy format. mp electricity bill payment online jabalpur The drawing needs to be of a suitable scale for duplicating and of a sufficient scale such that if is micro-copied it can be suitable magnified without loss of quality.

The standard dealing with the sizes and layout of drawing sheets is ISO 5457:1999. If hard copies of drawings are required, the first choice standard sizes of drawings are the conventional ‘A’ sizes of drawing paper. These sizes are illustrated in Figure 1.9. electricity load profile Drawings can be made in either portrait or landscape orientation but whatever orientation is used, the ratio of the two sides is 1:^2, (1:1.414). The basic ‘A’ size is the zero size or ‘0’, known as ‘AO’. This has a surface area of lm2 but follows the 1 :V2 ratio. The relationship is that A1 is half AO, A2 is half Al, etc.

The title block is a specially designated area of the drawing sheet containing information for identification, administration and interpretation of the whole drawing. Irrespective of whether landscape or portrait orientation is used, the title block is normally located in the bottom right-hand corner of the drawing. The information included in the title block can range from the very simple to the exceedingly complex. The manual of British Standards in Engineering Drawing and Design (Parker, 1991) recommends that the following basic information always be included in a title block:

A border should be used to define the edge of the drawing region. It should have a minimum width of 20mm for AO and A1 sizes and 10mm for A2, A3 and A4. The border shows the edge of the drawing area and would therefore reveal the fact that the drawing had, say, a torn-off corner. The drawing frame is the area within the border (see Figure 1.10).

Trimming marks may be added at the edge of the drawing within the border to facilitate trimming of the paper. There should be four trimming marks at each corner. They can be of two types. The first type is in the form of a right-angled isosceles triangle as shown in the top left-hand corner in Figure 1.10. gas leak in house The second alternative trimming mark is an ‘L’ shape shown on the top right-hand side of the drawing shown in Figure 1.10.

Areference metric graduation scale may be provided with a minimum length of 100mm that is divided into 10mm intervals (see Figure 1.10). The reference graduations consist of 10 off 10mm graduations together making a total length of 100mm. From this graduation scale one can conclude that the drawing size is A3. This calculation shows the usefulness of the reference graduation scale and that it still permits scaling of a drawing when it is presented at a different scale than the original.

An alphanumeric grid reference system is recommended for all drawings to permit the easy location of things like details, additions and modifications. The number of divisions should be a multiple of two, the number of which should be chosen with respect to the drawings. Capital letters should be used on one edge and numerals for the other. These should be repeated on the opposite sides of the drawing. ISO 5457:1980 suggests that the length of any one of the reference zones should be not less than 25mm and not more than 75mm. 1.6.2 Types of drawings

6. An arrangement drawing can be with respect to a finished product or equipment. It shows the arrangement of assemblies and parts. gas hydrates It will include important functional as well as performance requirements features. An installation drawing is a particular variation of an arrangement drawing which provides the necessary details to affect installation of typically chemical equipment.

Figures 1.11 and 1.12 show an assembly drawing and a detailed drawing of a small hand vice. The assembly drawing is in orthographic third-angle projection. It shows the layout of the individual parts constituting the assembly. There are actually 14 individual parts in the assembly but several of these are common, such as the four insert screws and two-off hardened inserts such that the number of identifiable separate components numbers 10. On the drawing each of the 10 parts is numbered by a balloon reference system. The accompanying item list shows the part number, the number required and its description. Separate detailed drawings would have to be provided for non-standard parts. la gasolina One such detailed drawing is shown in Figure 1.12, which is the detailed drawing of the movable jaw. This is shown in third-angle orthographic projection with all the dimensions sufficient for it to be manufactured. Tolerances have been left off for convenience. Figure 1.11 An assembly drawing of a small hand vice Figure 1.12 A detailed drawing of the movable jaw of a small hand vice