Introduction
Mechanical parts rolling is the process of plastically deforming metal by an arrangement of rolls.It is also referred to as roll forming. The rolls must be arranged so that the metal is drawn in, reduced in thickness and then rolled to the desired shape. Rolling is used mainly to produce strip, sectional, and sheet metal and is used when large quantities of parts having the same cross-section are required. In modern manufacturing, sheet-metal rolling processes are the most common, used for practically all metal products from the lightest to heaviest.
Process
Rolling involves passing the metal between two or more rollers, reducing the thickness in the process. If the rollers move quite fast, then an additional force, called roll separating force, must be applied to prevent the rollers from sticking together. This force is produced by additional rollers, or by means of a pressure mechanism.
During the rolling process, the amount of material being rolled is continuously monitored. In some cases, the metal material is cut to the desired length with a circular saw blade positioned within the machine. If the material is too wide, the metal which is outside of the desired size can be discarded.
The metal is then heated until it is malleable and then sent through a series of rollers of varying sizes. These rollers shape the metal into the desired shape and, using hydraulic pressure, bond the finished product together.
If the material is too small to be rolled, it must be rejected and reworked. This can cause delays in manufacturing and lead to increased costs as more material needs to be purchased and extra man-hours are needed to manufacture the parts.
Advantages
One of the most significant advantages of roll forming is its ability to produce parts with very tight tolerances. This is because once a forming profile has been established, it is very easy to replicate it exactly with very minor adjustments in the roll gap. This leads to improved product quality.
The process also uses less material than other forms of manufacturing as the material being formed is reduced in thickness, resulting in less material wastage.
This method of manufacturing is cost effective as only a few rollers are required and the process is relatively fast as the fabrication can be carried out in a single pass.
Limitations
Roll forming is limited to the production of simple shapes and is not suitable for more complex product forms.
Roll forming cannot be used to produce parts with a large cross section as the rolls cannot apply enough power and force to the metal to shape it.
Conclusion
Roll forming is a popular form of metal fabrication and is used to form sheet metal, strip and sectional metal in large quantities. The process is a cost effective way of forming parts with tight tolerances and is capable of producing parts with excellent surface finish.
However, the process is limited to simple shapes and is not suitable for more complex geometries. The process also cannot be used to produce parts with large cross-sections.
