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3 types of plate rolling machine working principle

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3 roll bending machine

Definition of Plate Rolling Machine

The plate rolling machine is also known as a plate bending machine and plate roller. It is a type of sheet metal bending equipment that utilizes work rollers to produce sheet metal round processing and forming. It can form parts of different shapes such as cylindrical parts and conical parts. It is a piece of very important sheet metal bending processing equipment.

Plate rolling machine working principle

Plate rolling machines can be divided into three-roller and four-roller. The three-roll plate rolling machine can be divided into two types: symmetrical and asymmetrical.
bending process of 3-roll section bending machine
3-roll bending machine
bending process of four-roll section bending machine
4-roll bending machine

The working principle of the plate bending machine is the same as that of the profile bending machine is according to the principle of three points forming a circle, the relative position change and rotational motion of the workpiece are used to produce continuous plastic deformation of the plate to obtain a workpiece with a predetermined shape. According to the rotational movement and position changes of work rolls of different shapes, elliptical parts, arc parts, cylindrical parts, and other parts can be processed.

Plate rolling machine working principle
Working principle of plate bending machine: a: symmetric 3-roller plate bending machine; b: asymmetric 3-roller plate bending machine; c: 4-roll plate bending machine

Working principle of symmetrical 3-roll plate rolling machine

In the picture above (a) is a cross-sectional view of the rollers of a symmetrical 3-roll bending machine. The rollers have a certain length in the axial direction so that the entire width of the sheet is bent.

There is an upper roller 1 at a symmetrical position in the middle of the two lower rollers. The upper roller can be adjusted in the vertical direction so that the sheet material 4 placed between the upper and lower rollers can obtain different bending radii. The lower roller 2 is active and is installed in a fixed bearing. The motor rotates in the same direction and at the same speed through a gear reducer. The upper roller is passive and installed in a bearing that can move up and down. The adjustment of the rollers on the large plate rolling machine is mechanical or hydraulic, and manual adjustment is often used in the small plate rolling machine.

When working, the sheet material is placed between the upper and lower rollers, and the upper roller is pressed down to make the sheet material bend between the support points. When the two lower rollers rotate, the sheet material moves due to the action of friction, so that the entire sheet material is evenly bent.

According to the above bending principle, the required bending radius can only be achieved when the part of the sheet material is in contact with the upper roller, so the edges of both ends of the sheet have a length that does not contact the upper roller and does not bend, which is called The remaining straight side, the length of the remaining straight side is about half of the distance between the two lower rollers.

Working principle of asymmetric 3-roll plate rolling machine

Figure 7-1(b) is the bending drum diagram of the asymmetric three-roll plate bending machine. The upper roll 1 is located on the top of the lower roll 2, and the other roll 3 is on the side, which is called the side roll. The upper and lower rollers are rotated by the same motor. The lower roller can be adjusted up and down, and the maximum distance of adjustment is approximately equal to the maximum thickness of the steel plate that can be bent. The side rollers 3 are passive and can be adjusted in the inclined direction.

When bending, the sheet material 4 is fed into the upper and lower rollers, and then the lower roller is adjusted to compress the sheet material to generate a certain frictional force, and then the position of the side rollers is adjusted. When the upper and lower rollers are driven by the motor to rotate, the sheet material is bent.

The advantage of this asymmetric three-roll plate bending machine is that the edges at both ends of the plate can also be bent, and the length of the remaining straight edge is much smaller than that of the symmetrical three-roll plate bending machine, and its value is less than twice the plate thickness. Although the sheet material cannot be bent between the side roll and the lower roll, the whole bending process can be completed as long as the sheet material is taken out from the rolling machine and then turned around and bent.

The working principle of the 4-roll plate rolling machine

Figure (c) is a four-roll plate rolling machine, which is basically similar to the asymmetric three-roll plate rolling machine, except that one side roller 3 is added. It eliminates the trouble of turning around and bending the sheet on the asymmetric three-roll rolling machine.

Radius of curvature

The plate rolling machine basically consists of three parallel steel rollers, arranged similar to the vertices of an isosceles triangle.
The sheet metal when passes between the lower and upper rollers change its shape and undergo a curvature, known as the radius of curvature. This so-called radius depends on the mutual position of the three steel rollers.

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