The Basic Theory of Crowning Industrial Rollers（最高工业辊的基本理论）.pdf

The Basic Theory of Crowning Industrial Rollers Written by Matthew Menges Javier Carreon Please visit us at 260 Industrial Dr., Wauconda, Il 60084-1077 ▼ (847) 487-8877 Fax (847) 487-8897 The Basic Theory of Crowning Industrial Rollers Rollers that are crowned are utilized by many industrial manufacturers. These companies are in the paper, film and foil converting industry. As a roller manufacturer, specifying a crown on a roller has to be taken with caution. Failure to do so may lead to problems and costly errors. Let us first establish the definition of a crown with respect to the roller industry. A crown is a shape or diameter profile necessary to compensate for deflection in order to obtain a uniform nip pressure distribution. (See Figure 1). ¥Crown/2 FIGURE 1 ¢ Roll crowning is intended to ensure proper web alignment and mainly to count- er the effects of deflection. In a simple nip system, roller deflection is one of the main reasons for nip variations across the width of the roll face. This is primarily evident in all end loaded rollers. The roll will deflect or bend away from the nip, which causes pinching at the ends as seen in Figure 2. FIGURE 2 ¥ ¥ ¢ ¢ Roller deflection is bending due to its dimensions, material, and the load being applied to the roll in its particular application. Therefore, roll crowning is one common method of reducing the nip variation caused by roller deflection. The other benefit of crowning a roll is that it will yield improved product quality. And more importantly crowning helps the roll covering last longer, increases the rubber life and helps reduce machine down time. As discussed earlier, specifying a crown on a roller has to be taken with caution. Th