So, what is roll forming? It is the process of gradually bending a flat strip or coil of metal into a longitudinally uniform profile. To obtain the desired shape, the operator passes the workpiece through a series of mating dies.
Roll forming is a cold forming process that does not require heating of the metal. Special equipment for high temperatures is not required to produce cold rolled shapes. The difference between hot and cold forming affects the properties of the final part.
The raw material can be flat or coiled sheet. Cold roll forming machine can use hot rolled steel in sheet form as the raw material. You just don't "press it on the press", so to speak - by the time the roll forming machine is used, the room temperature will have lasted several days.
Roll forming is a flexible and cost effective process for forming metal into customised cross-sectional profiles. Often referred to as "cold roll forming" because the metal is formed in its hardened state, roll forming is used in a wide variety of industries to produce parts and components, ranging from metal forming in automobiles to household appliances, aircraft and houses.
For products that can be roll formed, the method offers many advantages and benefits over other methods.
Most roll forming is done using long rolls of metal strip, so the process is high speed, low labour requirements and more efficient for mass production of most products compared to press brake or stamping. Other processes such as stamping or slotting can be combined into the roll forming line, thus further reducing labour requirements and outputting a complete product for distribution. Bending machines require separate punching, slotting or perforating processes which can add time, labour and expense.
Roll forming is an unheated system - reducing energy costs - by passing the metal through a series of custom-designed rolls that gradually bend the metal into its final shape in stages. Roll forming does not cause tool wear as stamping does, and the process eliminates the need for machining, such as deburring, which is normally required for bending machines. Identical parts cut from long strips mean that there is no wasted scrap, and roll-formed parts can be almost any length, whereas press brakes limit the length to the size of the machine. Batch production of roll-formed metal parts is almost always more cost effective than plastic or extruded products.
Even complex cross-sectional profiles, which are difficult to stamp and form, can be easily created by roll forming, including round, closed and C-shaped profiles. Almost all metals (ferrous or non-ferrous) can be roll formed, whereas extrusion is limited to aluminium or brass. Roll forming can also be performed on metals that have been painted, plated or coated, whereas extrusion is only suitable for unfinished, unplated blanks, and press braking of finished metals requires additional handling and processes, thus wasting time and money.
Roll forming can be designed to meet very tight tolerances. The consistency and uniformity of the product throughout the run is greater than with press braking, simplifying easy-to-use applications such as assembly line manufacturing where components must be installed correctly every time. Roll forming can produce higher quality products and components than extrusion.