It is a kind of machine that manufactures steel (metal) products. Custom roll forming machine is the roll former for industrial application, instead of daily purposes. A regular roll former produces steel building materials, while custom roll forming machine works for something else.
Roll forming, also spelled rollforming, is a continuous bending operation in which a long strip of metal sheet (usually steel coils, like PPGI, GI, PPGA, Aluminum etc) passes through sets of rolls mounted on consecutive stands, each set performing only an incremental part of the bend, until the desired cross-section profile is obtained. Roll forming is ideal for producing constant-profile parts with long lengths and in large quantities.