Roll forming is a metal forming process in which metal strips and coils are fed into rolls of different configurations successively until parts of the required shape, thickness and uniform cross section are produced. Roll forming is used to produce various types of shapes and forms such as: angles, channel shapes like C, U, T, Z, special forms like hat sections, round, square, and rectangular tubes, and hexagonal, pipes, etc. Roll forming is commonly used in metal for roofing and siding, home appliances, heating, ventilation, and air conditioning (HVAC) systems, and in the automotive and rail industries. Rolling may be either hot rolling or cold rolling methods. In hot rolling, the material is heated and passed through the rolls.
There are two steel rolls, the top and bottom, which are firmly fixed on high-class bearings. The rolls are rotated by an electric motor, usually in a clockwise direction. Sheet metal is fed into the rolls by conveyor systems or conveyor belts and the rolls apply pressure to the metal to compress and lengthen it and to bend and form it. A special type of industrial software called Profil is used to program the machinery to produce the desired cross-section profiles. The belts may be powered to move the sheets or the rolls themselves may pull the sheet metal through.
Roll forming can be done on any type of metal that can be bent without breaking. However, generally, the more ductile the metal is the better. Ferrous and nonferrous metals can both be roll formed along with hot and cold metal, polished, plated, and painted metals. Roll forming is often used in the fabrication of steel, aluminum, stainless steel, sheet metal and galvanized steel metal products. However, the process is ideal for lightweight metals such as tin, zinc, copper, titanium, and lead.
Roll forming is a high volume, industrial production process which may use other supporting processes such as: sheet embossing, annealing, powder coating, slitting, corrugating, bending, painting, machining, in-line notching and punching, pre/post notching and punching, press braking, skiving, welding, drilling and metal stamping.
The rolls have to be grinded periodically to remove any dents and nicks or oxidation layers by using precision roll grinding machines.