Commercial filters come in many shapes and sizes. The filter media is often encapsulated by plastic or metal to give the assembly rigidity. Some are surrounded by frames and others, such as the one depicted here, are supported by two different roll formed shapes and plastic end caps. The two roll formed parts are two unique profiles that are called Steg and Profile. The assembly consists of seven roll formed Stegs and two roll formed Profiles that Samson Roll Formed Products Company roll forms for a major commercial filter manufacturer. (Please go to the pdf document if you would like to see dimensioned drawings of these parts.)
Roll forming is the manufacturing method of choice for these two metal shapes because the economics of roll forming favor large lot sizes. Roll forming typically competes with braking and extruding at lower volumes. Because roll form tooling is generally the most expensive tooling relative to these processes, roll forming does not compete favorably with these processes at lower volumes, but the difference in tooling cost becomes moot as the volume increases because the difference in per unit cost among these processes increases at an incrementally larger rate per unit.