Compound slide

The top slide shown in Fig. 9.6, often referred to as the compound slide, fits on its slideway and can be adjusted for wear by means of a gib strip and adjusting screws. Movement is transmitted by the leadscrew through a nut on the slideway. A toolpost, usually four-way hand-indexing, is located on the top surface and can be locked in the desired position by the locking handle. Movement of this slide is usually quite short, 92 mm on the machine illustrated, and only hand feed is available. Used in conjunction with the swivel base, it is used to turn short tapers. 

A1. simple compound (sliding or fixed-punch tool) with generously long tool life... 

The method used to turn a taper depends upon the angle of taper, its length and the number of workpieces to be machined. Three methods are commonly used with a form tool, with the top or compound slide and with a taper-turning attachment. 

Place in the tube sufficient organic compound to give subsequently about 0-3 g. of the silver halide, and weigh again. Now allow the small tube to slide carefully down the inclined Carius tube until it finally adopts the position shown in D (Fig. 72). If the compound readily loses halogen in the presence of nitric fumes, the Carius tube should first be rotated in an oblique position to wet the tube for about 10 cm. from the bottom the small tube, if cautiously inserted into the Carius tube, will now come to rest when it first reaches the wet portion of the tube and will thus be held above the main bulk of the acid until the tube is sealed. 

A variety of reaction mixtures can be analyzed by this simple technique, although a suitable solvent or solvent mixture for the development of the slide must be determined for the particular compounds involved. 

The friction coefficient is defined as the tangential force acting on a sliding body to the ground reaction force. For rubbers this is a function of the ground pressure. Its dependence has been discussed sufficiently in the literature where it was shown that this is important for soft rubbers on smooth surfaces [2,3], but is of little influence for tire compounds on roads which are always sufficiently rough for the load dependence to be small if not completely absent [4,5]. 

FIGURE 26.1 Experimental friction data (left) as function log speed at different temperatures and master curve (right) of an acrylate-butadiene rubber (ABR) gum compound on a clean dry silicon carbide 180 track surface referred to room temperature. (From Grosch, K.A., Sliding Friction and Abbrasion of Rubbers, PhD thesis. University of London, London, 1963.)... 

The shape of the maser curve not only depends on the rubber compound, but also on the surface on which it slides. On dry, clean polished glass the friction master curve for gum rubbers rises from very small values at low log ajv to a maximum which may reach friction coefficients of more than 3 and falls at high log ajv to values which are normally associated with hard materials, i.e., 0.3 shown for an ABR gum compound in Figure 26.2. If the position of the maximum on the log a-fV axis for different gum rubbers is compared with that of their maximum log E frequency curves, a constant length A = 6 X 10 m results which is of molecular dimension, indicating that this is an adhesion process [10]. 

FIGURE 26.12 Friction coefficient of a natural rubber (NR) gum compound as function of the ice temperature at three different speeds (left) and friction coefficient of four different gum compounds having different glass transition temperatures as function of the ice track temperature at a constant sliding speed of 0.005 m/s. (From Heinz, M. and Grosch, K.A., ACS Spring Meeting, St Antonio, 2005.)... 

FIGURE 26.20 The log a v speed function of the previous chart is combined with the friction master curves for a natural rubber (NR) and a styrene-butadiene rubber (SBR) gum compound on glass showing the limited range of friction values (and their position on the log a-iv axis for different testing conditions) which are obtained when the sliding speed is increased. 

FIGURE 26.52 Sliding abrasion of three different tread compounds as function of temperature at a sliding speed of 0.01 m/s (a) styrene-butadiene rubber (SBR), (b) ANR, (c) NR,-tread compound, —gum compound. 

FIGURE 26.55 Abrasion surface appearance of a natural rubber (NR) black-fiUed tire tread compound for sliding abrasion at different temperatures. 

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