In general, the working ability of the plate rolling machine refers to the thickness of the plate it can roll, that is, the ability to roll the maximum thickness and width of the plate according to the specified yield limit and the minimum diameter of the drum with the plate in the cooling state. Under normal circumstances, the cold rolling ability is about half of the hot rolling ability. But recently, it is cold roll ability in constant development.

To sum up, I have drawn up the following different plans according to the various types of coil boards, and analyzed and proved them separately.

2.1.1 plan 1 double roll bending machine

There are only two rolls in the rolling machine. The upper roll is made of steel and the lower roll is elastic, which can also be used for straight movement. When the plate coiler starts to work, the lower roll starts to rotate, which promotes the plate and upper roll to press the plate into the elastic layer of the lower roll under the action of moving pressure, so as to make the lower roll produce elastic deformation. However, the volume of the lower roll does not change when it changes, so the pressure is transferred to all sides, resulting in a strong and continuous back pressure, which forces the sheet metal to stick closely with the rigid roll, and finally the sheet can be rolled out of the barrel. The depth of the upper roller pressing into the lower roller, that is, the deformation of the elastic layer, is the primary technological parameter determining the tortuous radius. It is concluded that the greater the reduction, the smaller the bending radius of sheet metal; but when the reduction reaches a certain value, the bending radius tends to be stable, which has little to do with the reduction. This is an important feature of the technology of double roll bending machine.

The double roll plate rolling machine has the advantages that other plate rolling machines don't have: 1. The processed plates don't need to be pre bent and can be processed directly, so the production speed is very fast; 2. The structure of the plate rolling machine is simple and the price is low; 3. All kinds of materials can be processed. Disadvantages of double roll plate rolling machine: 1. Each bending product has a corresponding upper roll for processing, so it is not suitable for products with different bending requirements in small batch production; 2. Generally, it can only be used for processing the thickness of plate below 10 mm, and the processing effect of too thick plate is very poor.

2.1.2 plan 2 three roll bending machine (1) symmetrical three roll bending machine

The upper roll is symmetrically located in the center of the two lower rolls. It is simple and compact in structure, easy to manufacture and repair, light in weight, small in investment, accurate in forming, and less in force on the roller. However, it can't bend all the length of the plate. The two ends of the plate are slightly less than half of the distance between the two lower rolls, which is straight, that is, the remaining straight side is large. It needs to be equipped with pre bending equipment, as shown in Figure 5

Rolling process (2) asymmetric three roll rolling machine

The upper roll is located above the lower roll and slightly deviates. The structure is relatively simple, and there are few straight edges left. However, the sheet metal needs to turn around and bend, so the operation is not convenient. The roller has a large force, and the bending ability is small. It is commonly used to roll thin and short light-duty tube sections, and the operation ability is generally below 32 × 3000mm, as shown in Figure 6

Unsymmetrical coiler 2.1.3 plan 3 four roll coiler

Four roll rolling machine four roll rolling machine has four rolls, the upper roll is automatic roll, the lower roll can move up and down, two side rolls can rise and fall along the oblique direction.