Plate Rolling Machine: Types and Operation

Plate rolling machines are a type of metal forming equipment that uses work rollers to generate sheet metal round processing and forming. Plate rolling machines are often referred to as plate bending rollers. This machine is a type of machine tool used for making continuous point metal sheet bending. The plate rolling machine is crucial in the sheet metal industry. This machine can be used to make cylindrical parts, conical parts, and various arc-shaped parts.

Plate Rolling Machine Operation Principle

The operation of a symmetrical plate rolling machine is driven by hydraulic oil in the cylinders, which moves the upper roller vertically between two lower rollers. This vertical movement is central to the machine's function. The main reducer’s final reduction gear powers the two lower rollers, generating the necessary torque for rolling plates.

As the flattened metal sheet passes between the upper roller and the two lower rollers, the combined forces of the upper roller's downward pressure and the lower rollers' rotational motion facilitate a continuous bending process. During this process, the sheet metal undergoes plastic deformation: the outer layer stretches, the inner layer compresses, and the middle layer remains unchanged. This consistent deformation allows the metal sheet to be rolled into various shapes such as cylinders or cones, depending on the specifications.

This operation is particularly effective with large roll bending machines designed for handling thick plates, typically 50 mm or more. To enhance precision and overall performance, the plate rolling machine features a row of fixed steel rollers at the base of the lower roller. These rollers reduce the gap between the two lower rollers, resulting in more accurate and efficient rolling.

Plate Rolling Machine Classification

Plate rolling machines are classified into different types based on their application sectors and the number of rollers they utilize. They are primarily divided into three-roller and four-roller variations. The main categories of three-roller bending machines include:

- Hydraulic bending machines

- Arc downward-adjusting plate bending machines

- Horizontal downward-adjusting three-roller bending machines

- Symmetrical three-roller bending machines

- Universal three-roller bending machines with an upper roller

1. Mechanical

Mechanical three-roller bending machines come in both symmetrical and asymmetrical versions:

- Mechanical Symmetrical Three-Roller Machine:  

  This machine features a symmetrical three-roller frame where the upper roller moves vertically at the center between two lower rollers. This movement is controlled by a worm and screw nut transmission system. The rotational motion needed to roll the metal sheet is generated by the output gear of the reducer, which meshes with the gear of the lower roller. One limitation of this design is the need to pre-bend the ends of the sheet metal plate using additional equipment.

- Mechanical Asymmetrical Three-Roller Machine:  

  In this design, the three rollers are arranged asymmetrically. The top roller serves as the primary drive, while the lower roller moves vertically to securely hold the plate. The lower roller also meshes with the upper roller gear through its gear, enabling the rolling process.

2. Hydraulic

The hydraulic three-roller symmetrical plate rolling machine offers the key advantage of enabling vertical movement of the upper roller. This vertical lifting is powered by hydraulic transmission, where hydraulic oil in the cylinders acts on the piston rod to achieve the desired motion. The lower roller is driven by an output gear that meshes with the machine's reducer, facilitating the rotational movement necessary for rolling.

An adjustable idler positioned under the bottom roller provides the necessary torque for coiling the sheet. The upper roller, designed with a drum shape, enhances the straightness of the final product, making this machine particularly well-suited for producing long tanks with large cross-sectional shapes. The machine can efficiently roll and shape metal sheets into circular, arc-shaped, and conical workpieces, offering versatility within a specific range.

In this design, one of the lower rollers acts as the driving roller, while the other serves as the driven roller, contributing to the machine's overall functionality.