| Rollforming (sometimes also termed open section | | | | involves high machinery costs, computer simulation is |
| forming) employs a series of sets of dies in order to | | | | used in order to validate the design of the roll stands |
| bend a sheet of metal little by little until the desired | | | | to make sure that the metal product won't be |
| profile (cross section) is obtained. Rollforming is a | | | | stressed unduly, and also to minimize the total |
| continuous operation of bending in which a long metal | | | | number of rolls required. Examples of rollformed |
| strip or sheet- usually of coiled steel - is passed | | | | applications include automobile chassis sections, |
| through sets of rolls (or stands), each of which | | | | window guides, and impact bars. These can be |
| performs only a small incremental portion of the bend | | | | prepunched, then rollformed, midpierced inline, |
| until the finished cross section profile is achieved. Roll | | | | rollformed some more, and then welded and cut off |
| forming is especially useful in the production of parts | | | | in one continuous operation. |
| of long length, and in large quantities. Metal rollforming | | | | As in pipe and tube mills, rollforming can be used with |
| is quite like traditional pipe and tube making. However, | | | | practically all metals, nonferrous as well as ferrous. |
| rollforming is able to create more complicated profiles. | | | | Coils of stainless steel, high strength and low alloy |
| In both pipe and tube making and in roll forming metal | | | | steel, martensitic steel, as well as aluminum can be |
| sheets are bent with roller dies, in which each roll pair | | | | rollformed. It is possible to emboss coils of aluminum |
| works the sheet progressively until the final shape is | | | | or steel with finishes that simulate wood grain (e.g. |
| obtained. Rollforming differs from the older | | | | for garage doors). When using embossed metals the |
| techniques in that it can be combined with | | | | roller dies must be adjusted so as not to roll out the |
| prepunching, postpunching, and midpiercing inline, | | | | embossment. Prepainted and vinyl laminated sheets |
| together with sweeping prior to cutoff. | | | | can also be rollformed but not welded. Rollforming is |
| Another advantage of rollforming is that the same | | | | a process of great versatility which permits |
| rollforming machinery can be used to produce a wide | | | | innovative design. Setting a rollforming system up |
| variety of cross section profiles. Each different profile | | | | requires a skilled rollform engineer's expertise, as well |
| requires a specially designed set of rolls. The | | | | as considerable collaboration between the |
| fundamental roll design resembles a flower - i.e. a | | | | manufacturer and the vendor in order to develop a |
| sequence of profile cross sections (one for each set | | | | successful product. |
| of rolls). Because rollforming is an exact operation and | | | | |