Introduction
Rolling mills are essential components in many metal forming processes. While typically used in the manufacturing of steel products, rolling mills can also be used to roll other materials such as aluminum or copper. The process of shaping a workpiece by repeatedly rolling it through rolls is known as roll forming. A roll forming mill consists of a set of rollers, each with its own roll space. These rollers are arranged so that the material to be formed passes between each roller and can be manipulated in order to achieve the desired shape.
Roll forming mills are often referred to as multi-stand rolling mills or mandrel rolling mills. This type of mill is composed of two or more stands with each stand consisting of at least two rolls. The material to be shaped is continually passed between the stands and the shape is created incrementally from one stand to the next.
Multi-Stand Rolling Mill
When forming metal shapes, the rolling mill is most often equipped with a multi-stand roll set. The roll set consists of several rolls that are arranged in-line. This arrangement allows for multiple rolling passes, each one adjusting the shape of the metal slightly. The gap between each set of rolls is called the ‘form’ or ‘mandrel’. This form creates the desired shape as the metal is passed through the rolls.
Since the mandrel affects the finished shape of the workpiece, it can be adjusted to accommodate different shapes and designs. Each pass reduces the thickness of the material, culminating in the finished shape. This makes multi-stand rolling mills ideal for producing complex shapes and sizes.
In addition to their ability to form complex shapes, multi-stand rolling mills also offer high accuracy and reliability. This is due to their precise roll alignment and precise roll geometry. The roll alignment is adjusted to ensure that the roll faces are parallel to one another. This transfers the pressure evenly across the total width of the workpiece. In addition, precise roll geometry provides support for the metal sheet as it passes between the stands, preventing it from jamming or wrinkling.
Types of Multi-Stand Rolling Mills
Multi-stand rolling mills come in a variety of types, each with its own unique set of features and benefits. Here are the most common types of rolling mills:
Two-High Mills
Two-high mills are the most basic type of multi-stand rolling mills. They consist of two stands, each with two rolls. The metal is passed between the two stands continuously. This type of mill is used to produce basic shapes such as rod, wire, and tubing.
Four-High Mills
Four-high mills consist of four stands, each with their own sets of two rolls. This arrangement increases the number of passes and the number of possible shapes that the mill can form. These mills are used to produce intricate shapes such as I-beams and complicated shapes.
Six-High and Eight-High Mills
Six-high and eight-high mills are an expansion of the four-high type mills. These mills also have four stands, but with an additional two or four stands. This allows for an even larger number of passes and a greater range of possible shapes.
Conclusion
Rolling mills are essential components for many metal forming processes. Multi-stand rolling mills, or mandrel rolling mills, are most often used for forming complicated shapes and sizes. These mills consist of multiple stands, each with its own sets of rolls. The metal is passed between the stands, incrementally reducing its thickness and forming it into the desired shape.
The types of multi-stand rolling mills vary, ranging from two-high mills to eight-high mills. The number of stands and rolls determine the number of passes, as well as the type of shapes that the mill can form. Multi-stand rolling mills offer high accuracy and reliability due to their precise roll alignment and geometry.
