Roll forming machines manufacture specific configurations from long strips of metal, most commonly coiled steel. In most applications, the desired cross-sectional profile of the workpiece is specifically designed for the machine to bend the metal as needed. In addition to roll forming, these machines perform many metalworking tasks, including material cutting and roll stamping. In most cases, roll formers can work in a continuous cycle. The material is fed into the machine, where it continuously passes through each operational stage, culminating in the final product.
Roll formers bend metal at room temperature using multiple stations where stationary rollers both guide the metal and perform the necessary bending. As the metal strip passes through the roll former, each set of rolls bends slightly more metal than the rolls in the previous station. This progressive method of bending metal ensures that the correct cross-sectional configuration is obtained while maintaining the cross-sectional area of the workpiece. Typically operating at speeds of 30 to 600 feet per minute, roll formers are ideal for making large numbers of parts or very long parts.
Roll forming machines are also suitable for making precision parts that require little, if any, finishing work. In most cases, depending on the molding material, the final product has an excellent finish and very fine detail.
The roll forming machine has a production line that can be divided into four main parts. The first part is the inlet part of the loaded material. The material is usually inserted in sheet form or fed from a continuous roll. The next part, the station rolls, is where the actual roll forming takes place, where the stations are, and where the metal is formed throughout the process. Station rolls not only shape the metal, but are the main driving force of the machine. The next part of the roll forming machine is the cut-off press, which cuts the metal into predetermined lengths. Due to the speed at which the machine works and it is a continuous machine, fly cutting technology is not uncommon. The last part is the exit station, where the finished parts leave the machine to a roller conveyor or table, where they are moved manually.
The dimensional variation of parts made by roll forming depends on the type of material used, the roll forming machine and the actual application. Tolerances can be affected by variations in metal thickness or width, material springback during production, tool quality and wear, actual machine conditions, and the operator's experience level.
