Dimension lines

Various ISO standards are concerned with dimensioning. They are under the heading of the ISO 129 series. The basic standard is ISO 129:1985 but it has various parts to it. A dimensioning 'instruction' must consist of at least four things. Considering the 50mm width of the jaw and the 32mm spacing of the holes of the movable jaw drawing in Figure 3.15, these are" Two projection lines which extend from the part and show the beginning and end of the actual dimension. They are projected from the part drawing and show the dimension limits. In Figure 3.15, the width is 50mm and the projection lines for this dimension show the width of the part. They are type B lines (thin, continuous and straight). These lines touch the outline of the part. The projection lines for the hole-centre spacing dimension of 32mm are centre lines. They are type G lines (thin, discontinuous, chain) which pass through the drawing just past where the holes are located. A dimension line which is a type B line (thin, continuous and straight). In Figure 3.15, these dimension lines are the length of the dimension itself, i.e. '50' or '32' mm long. A numerical value which is a length or an angle. In the Figure 3.15 example the dimensions are the '50mm' and '32mm' values. If a part is not drawn full size because it is too small or too large with respect to the drawing sheet, the actual dimension will be the value which it is in real life whereas the dimension line is scaled to the length on the drawing. Two terminators to indicate the beginning and end of the dimension line. The terminators of '50' and '32' dimensions in Figure 3.15 are solid, narrow arrowheads. Other arrowhead types may be used. There are four types of arrowhead allowed in ISO, as shown in Figure 3.16. These four are the narrow/open (15~ the wide/open (90~ the narrow/closed (15 ~ and the narrow/solid (15~ An alternative to an arrowhead is the oblique stroke. When several dimensions are to be projected from the same position, the 'origin' indication is used, consisting of a small circle. These drawings are shown in Figure 3.16. An example of an origin indicator is shown in the movable jaw detailed drawing. Many dimensioning examples can be seen in the movable jaw and hardened insert detail drawings. The dimensions in these two drawings follow the following convention. All terminators are of the solid arrow type, all projection lines touch the outside of the part outline, all dimension numerical values are placed above the dimension lines and all dimension values can be read from the lefthand bottom corner of the drawings. 
Engineering Drawing for Manufacture
by Brian Griffiths
Publisher: Elsevier Science & Technology Books

The bed LATHE

Description and functions of lathe parts Following are the principal parts: 1 Bed. 2.Headstock. 3.Tailstock. 4.Carriage. 5.Feed mechanism. 6.Screw cutting mechanism. The bed The lathe bed forms the base of the machine. The headstock and the tailstock are located at either end of the bed and carriage rests over the lathe bed and slides on it. The bed should be seasoned naturally to avoid distortion or warp that may develop when it is cooled after the bed is cast. The guide ways of the lathe may be flat and inverted- v having included angle of 90. The bed material should have high compressive strength, should be wear resistance and absorb vibration cast iron alloyed with nickel and chromium forms a good material suitable for lathe.




fr. NTTF ( NETTUR TECHNICAL TRAINING FOUNDATION)

Sistem Stripper - Ejector

The principle of this system is that the initial release of the product is driven by a stripper and ejectors simultaneously. This system can solve problems of the emergence of large deformation on the product due to stripping of the stripper system or due to the ejection of ejector system above. But in fact this system is mainly used in products where the wall or double wall inner wall has a snap. The principle mechanism of product release. aiming to achieve the distance along the mold opening delimiter pos1, where the stripper plate postal 2 no longer move backwards are other parts of the mold such as male (core) headings 3, 4 male, pos5 support plate, the runner heading pin 6 etc., will continue to move backwards until the composition range of mold. In this position ejector plate and post plate rentainer 7 does not come to move backwards because of the nylon tip shaft 8 which entered the post stripper plate press in post 2. In this position the product has been separated from male post 4, is a wall that has a snap in the end of the ejector pin is still mencengkaram post 9. In a subsequent retreat, nylon ripped from the stripper plate 2 so that the ejector plate post and retainer plate 7 with post-sam ejector pin 9 post interesting in retreat, the product apart from the tip ejector pin post 9. Ejector plate and the retainer plate with ejector pin post 7 post 9 held not come to move backward, it can happen with nylon at the end of the shaft of the post 8. Nylon TSB entered the press with the press can be adjusted by adjusting the bolt conical body. If the bolt rotated to right, in this case the right threaded bolts, then the tuner will sink bolts and nylon will enlarge, press the stripper plate style will grow. This press style that causes the ejector pin go stuck. At the next retreat, ejector plate and the retainer plate 7 will be heading in the push back by the support plate heading 5, where the impetus is greater than the style press nylon, making nylon uprooted from the stripper plate ejector pin which then come to move backward. In addition to nylon, or the opening sequence of movements can also be made of them by wearing jiffy lock.

Design Process - Service design

Design Process Effective design can provide a competitive edge matches product or service characteristics with customer requirements ensures that customer requirements are met in the simplest and least costly manner reduces time required to design a new product or service minimizes revisions necessary to make a design workable Design Process (cont.) Product design defines appearance of product sets standards for performance specifies which materials are to be used determines dimensions and tolerances Service design specifies what physical items, sensual benefits, and psychological benefits customer is to receive from service defines environment in which service will take place