The Principle of Plate Rolling Machine

1. Classification of Plate Rolling Machine

The plate bending machine is a general-purpose equipment for bending metal sheet into cylindrical, curved or other shaped workpieces. According to the principle of three points forming a circle, using the relative position change and rotational movement of the workpiece to produce continuous plastic deformation of the sheet to obtain a workpiece of a predetermined shape. The product is widely used in boiler, shipbuilding, petroleum, woodworking, metal structure and other machinery manufacturing industries.

● Three-roller rolling machine: including symmetrical three-roller rolling machine, asymmetrical three-roller rolling machine, horizontal down-regulating three-roller rolling machine, inclined down-regulating three-roller rolling machine, curved down-regulating three-roller rolling machine and vertical roll-down three-roller rolling machine etc.

● Four-roller rolling machine: divided into side-roller tilt-adjusting four-roller rolling machine and side-roller arc-adjusting four-roller rolling machine.

● Special-purpose plate rolling machine: vertical plate rolling machine, marine plate rolling machine, double roll plate rolling machine, cone plate rolling machine, multi-roll plate rolling machine and multi-purpose plate rolling machine, etc.

2. The Principle of Plate Rolling Machine

● The movement form of the plate rolling machine

The movement form of the plate rolling machine can be divided into two forms of main movement and auxiliary movement. The main motion refers to the movement of the upper and lower rollers constituting the plate rolling machine to rotate and bend the processed plate, and the main motion completes the processing tasks of the plate rolling machine. Auxiliary movement is the form of movement of the loading, unloading and lifting of the upper roller, the lifting and the turning of the headstock during the rolling process of the plate bending machine.

The mechanism is a three-roller symmetrical type. The upper roll is vertically moved at the symmetrical position of the two lower rolls. It is obtained by the screw and screw worm drive. The two lower rolls are rotated. Engagement to provide torque for rolled sheet.

Working principle diagram of three-roller rolling machine

The main motion refers to the upper roller around 01 and the lower roller around 02 and 03 for clockwise or counterclockwise rotation. Auxiliary movement refers to the upward or downward movement of the upper roller, as well as the upward roll and flanging movement of the upper roller in the 01 vertical plane.

● Processing method of bending

In the manufacture of steel structures, the bending process is mainly several processing methods such as coiling (rounding), bending (simmering) hemming, and die pressing. The bending process is completed by hot or cold processing.

Spheronization is to make the outer fiber of the steel plate elongate under the action of external force, and the inner fiber shortens to produce bending deformation (the middle fiber does not change). When the radius of the cylinder is large, it can be rolled at room temperature. For example, when the radius is small and the steel plate is thick, the steel plate should be heated and rolled. There are three processing methods for round steel plate at room temperature: mechanical rounding, tire mold pressing and manual production. Mechanical spheronization is carried out on a plate rolling machine (also called a plate rolling machine or a rounding machine).

The bending of the plate on the plate rolling machine is achieved by the pressure generated when the upper roller moves downward. Their working principle is as shown.

Schematic diagram of rounding machine

With three-roller bending machine, the two ends of the plate need to be pre-bent, and the length of the pre-bend is 0.5L + (30 ~ 50) mm (L is the center distance of the lower roller). The pre-bending can be pre-bending with press molding or with a pallet in the rounding machine.

Schematic diagram of steel plate pre-bending