Continuous four-roll plate bending: a production process for the manufacture of single seamed tubes of large and medium diameters

Continuous roller bending of plates is an effective process in the production of single seamed tubes of large and medium diameters. The process is capable of a wide range of various tube diameters from the smallest of just larger than the diameter of the top roller to the largest limited only by the handling capacity of the bender. It requires less investment in toolings compared to other bending processes. Relevant researches on roller-bending are reviewed and referred to. Current roller-bending machines are discussed. In particular, the versatility of the four-roll bender and its ability to generate better circularity, thereby helping to reduce material wastage and amount of subsequent machining, are examined. This paper discusses not only the design considerations, but also the working principles and some relevant bending mechanisms of the process.