Rolls and Roll Design
Rolls are one of the oldest and most versatile pieces of equipment used in manufacturing and process industries. Rolls are used in a variety of processes to shape, compress, heat, and rotate materials such as powders, slugs, pastes, and sheets. They are also used as feeders, conveyors, idlers, and as roll stands for assembling operations.
Rolls are typically round and consist of a stationary or rotating shaft supporting a cylindrical or conical shell or assembly. The force generated from the rolling process is greatly determined by the design and diameter of the rolls.
Rolls are designed and manufactured in a variety of shapes, sizes, and configurations, depending on the material being processed, the number of product rolls, and the power requirements. Rolls can be designed as single-roll, multi-roll, or stacked-roll arrangements.
Single-roll systems are typically used in applications involving high torque and conveying and are usually made up of one solid cylinder, usually two to five-inches in diameter. Multi-roll systems are typically used in applications requiring higher loading and more accurate control of pressure and velocity. Stacked-roll systems are commonly used for process applications such as rolling, stretching, and crushing.
The primary design considerations for roll design are the type of material to be processed, the number of product rolls, the power requirements and the desired roll diameter.
The overall roll size and roll geometry depend on the application and the type of material to be processed. For example, thin materials may require narrower rolls or concentric rolls to reduce wear on the material and prevent breakage. Larger, thicker materials may require wider rolls or larger diameter rolls to reduce material damage or feed problems.
The number of product rolls also affects roll design. Single-roll systems are typically used when only one product roll is required, while stacked-roll systems are used when processing multiple product rolls.
The power requirements and desired roll diameter also influence the design of a roll. The diameter of the roll is typically determined by the force needed to compress or stretch the material, while the power requirements are based on the amount of force required to move the material. This is determined by a combination of factors such as the material’s elasticity, tensile strength, and moisture content.
The materials used to construct rolls are chosen based on the material being processed and the desired characteristics of the roll. Common materials used to construct rolls include plastic, rubber, and metal.
Plastics are used for roll construction when non-corrosive properties, temperature resistance, and electrical insulation characteristics are essential.
Rubber is used for roll construction when the material needs to have a high coefficient of friction or when the material is particularly abrasive or corrosive.
Metal is used for rolls that need to withstand high temperatures and high pressures or when wear resistance is essential.
Rolls are one of the most versatile pieces of equipment used in industrial and process manufacturing operations. They are available in a variety of shapes, sizes, and configurations, depending on the material being processed and the power requirements and desired roll diameter. The materials used to construct rolls must be chosen based on the material being processed and the desired characteristics of the roll.
