How to reduce deflection of upper work roll?

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The rolling machine is professional equipment for shaping the plate. The upper work roll is the core component to complete the rolling. When the force in the rolling is very large, it will produce deflection and uneven pressure distribution on the steel plate, resulting in defective products.

How to reduce deflection? At present, the main methods are as follows:

Designed the upper work roll as a waist drum


In the design, the diameter of the working part of the work roll is gradually reduced from the middle to both ends. The bending deformation of the upper roll due to the upward rolling force just counteracts with the middle part of the waist drum shape, which makes the upper roll tend to be flat.

This method is widely used in the bending machine and is adopted by most designers. Although the design can play a certain compensation effect, it is difficult to calculate and manufacture.

 

Support the upper work roll


The supporting beam and supporting roll are added for the upper work roll. By adjusting the height of the back-up roll, a certain pre deformation of the upper work roll can be produced downward, which is just offset by the upward deformation of the upper work roll during plate rolling, so as to achieve the purpose of deflection compensation.

This method is mostly used in the rolling machine with a large width, such as marine rolling machine and oil storage and transportation tank. And it can only roll the arc plate or the workpiece with a larger diameter of the drum.

Set up lifting support


In this method, the lifting support beam and support roll is set for the upper work roll. When the plate end is pre-bent, the force is large, and the work roll will produce bending deformation. At this time, the support beam is lowered, and the upper work roll is supported to reduce its deformation. After the pre-bending, when the roll is round, the support beam is raised, and the cylinder can pass through the middle of the upper work roll and the support roll.

This method is suitable for the workpieces with small drum diameter and pre-bending at the plate end.

Using backpressure

 

In this method, the deflection of the upper work roll is reduced by backpressure. Two hydraulic cylinders are installed on the outside of the frame to vertically apply back pressure on both ends of the upper roll, so as to make the middle section of the upper roll bend downward and eliminate the deformation caused by insufficient deflection of the upper roll.
The above methods have their own advantages and disadvantages. In the actual design, it should be combined with the working condition and manufacturing cost of the bending machine to select the appropriate scheme.

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