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Plate bending: plate roll forming process

Four-roller plate bending machine


Roll forming is a method in which the sheet material is placed in 2-4 rollers of the plate bending machine, and the sheet material is bent and formed along the roller as the roller rotates.

As shown below:

Bending process of plate bending machine

Scope of application

Roll forming is generally suitable for parts with large bending radius, and is widely used in the processing of cylindrical and conical parts.

In addition, because the position of the roller of the plate bending machine can be changed appropriately with respect to the feeding amount of the sheet material, it can be used not only for circular and non-circular cross-section cylindrical parts, but also for circular and non-circular cross-sections. Flange parts of cylindrical parts with circular cross-section, etc.

As the picture shows:

Roll forming process

Pre-bending of the Plate bending machine

Why do you want to pre-bend?

On the three-roller and four-roller, when the flat sheet is bent into a cylindrical shape, the flat part is left at the entrance and exit ends of the sheet due to insufficient deformation. Straight edges are difficult to completely eliminate when rounding. Therefore, the end of the sheet should generally be pre-bent to eliminate straight edges.

Common pre-bending methods are shown in the figure below:

Common pre-bending methods of plate bending machine
  • Suitable for various board thickness;
  • Suitable for t0≥2t, t≤24, not exceeding 60% of the equipment capacity;
  • Suitable for t0≥2t, t≥24, not exceeding 60% of the equipment capacity;
  • Suitable for thin plates.


The bending process of various plate rolling machines is shown in the following figure:

The bending process of various plate bending machines

a) Symmetrical three-roller plate bending machine with flanged backing plate;

b) Asymmetric three-roller plate bending machine;

c) Four-roller bending machine;

d) Eccentric three-roller plate bending machine;

e) Symmetrical downward adjustment type three-roller bending machine;

f) Horizontal downward adjustment type three-roller plate bending machine


Method: Adjust the roller of the plate bending machine to the position of the required maximum correction curvature, roll 1-2 turns to make the curvature of the entire circle uniform, and then gradually remove the load, so that the workpiece is rolled several times under the gradually reduced correction load Roll and round.