Rolling operations

Rolling machines are commonly used for batch blending very viscous materials, and the method of operation is shown in Fig. 8.32. The preferential adherence of the extruded film to one of the rollers can be obtained with a small speed differential. The viscosity of the fluid is high enough to prevent centrifugal forces throwing it clear of the roller, and it returns to the feed 

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The rolling operations that foUow take place first on hot (95°C) differential-speed roUs which dry and coUoid the paste and convert it iato sheet form, and then on even-speed roUs which produce smoothly surfaced propellant sheets ia which all iagredients have been uniformly iacorporated. The roU gap ia the differeatial roUs is adjustable to produce sheets of various thicknesses, and rolling is continued until the moisture is reduced to a predetermined level, usually less than 0.5%. The sheet is then cut off the roU. Differential rolling is potentially hazardous, and fires are not uncommon, although detonations are not apt to occur. Operations are conducted by remote control. 

The component materials comply with apphcable ASTM specifications, but alter manufacture the outer component may increase in hardness beyond specification limits, and special care is required during the tube-rolling operation. When the harder material is on the outside, precautions must be exercised to expand the tube properly. When the inner material is considerably softer, rolling may not be practical unless ferrules of the soft material are used. 

Paint-grinding roller mills (Fig. 20-52) consist of two to five smooth rollers (sometimes caUed rolls) operating at differential speeds. A paste is fed between the first two, or low-speed, rollers and is discharged from the final, or high-speed, roller by a scraping blade. The paste passes from the surface of one roller to that of the next because of the differential speed, which also apphes shear stress to the film of... 

No other evidence of deterioration, such as corrosion, was apparent on either surface. The cracks are probably material defects. They may be laps or seams that were present on the external surface prior to the fin-rolling operation and were exaggerated during the rolling process. 

There is one obvious drawback of high-hysteresis rubber. In normal rolling operation, considerable elastic deformations still take place in the tyre wall, and high-loss tyres will consume fuel and generate considerable heat. The way out is to use a low-loss tyre covered with a high-loss tread - another example of design using composite materials (Fig. 26.9). 

Fig. 14.9. (a) In order to minimise the effects of friction, rolling operations should be carried out with minimum values of w/d. (b) Small rolls give small w/d values, but they may need to be supported by additional secondary rolls. 

Rolling operations that use oil-in-water emulsions as coolants and lubricants are found in 27 plants of the aluminum forming industry. Table 5.5 summarizes the classical and toxic pollutant data for the rolling with emulsions subcategory. 

Calculate pressures and identify the neutral point in rolling operations. 

Fig. 256. General view of rolling operations (Courtesy Olin Industries, Inc. [29]).

Compn A-3 is produced in a similar manner but without the final rolling operation. A water slurry of RDX heated to about 90° has the... 

Hot and cold rolling operations for steel and aluminum strip utilize oil-water emulsions for both lubrication and cooling. 

Note Coating with a deterrent not only modifies the rate of burning of the propint, but it also renders the grains waterproof c)The slurry of coated grains is pumped to the feed tank from where it can be sent either to the rolls(if the grain web is to be reduced in size) or directly to the top-feed filters(if the rolling operation is considered unnecessary)... 

Mixt of NC 46.5, NG (or DEGDN) 33.5, PETN (or RDX) 16, St w-insol soap 4% is blended under w and centrifuged to lower the w-content to ca 30%. The soap consists of Caoleate 88, Mg stearate 10 St A1 stearate 2%. The blend is then treated as in Example 1A, but not to complete removal of w. Then, in the middle of rolling operation, some powdered oxidizer (such as Amm or K perchlorate) is incorporated and the material is continued to be rolled to completion of dehydration and gelatinization. The amt of oxidizer is 5 to 45% of dried sheet Example 3 ... 

Metal forming / ss Rollers for cold rolling operations Punches, dies, plugs, mandrels (Fe Al Cu)... 

The rolling operation (Figure 7.12) is one of plane-strain that is, that material deforms in the x and z directions, but does not deform appreciably in the y or... 

This procedure identifies plastisols that are spread-coated on different substrates such as paper, aluminum foil, wood, and plastic sheet or film. Application is by doctor blade, direct roll, or reverse roll operations (Chapter 10). As an example plastisols are roll coated on adhesively primed metal for house sidings, conveyor belts, cloth fabrics, wood panels, and so on. 

The desired shortening flake product dictates the chill roll operating conditions and additional treatment necessary before and after packaging. However, some generalizations relative to chill roll operations and product quality can be made. 

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