The way forward in rotary draw bending: a review

Abstract

Presently, Rotary Draw Bending (RDB) process is one of the most common tube bending techniques used in industrial production around the world. The process is executed on a specially designed machine being fitted with specific forming tools. The quality of final products in RDB largely depends on process parameters being selected by the machine operator. These process parameters are selective balance of movements and effect of forming tools on the tubes. Substantial development has been done in identification of optimum process parameters for improving the quality of bent tubes. Each process parameter has a unique and versatile effect on quality aspects like ovality, wrinkling and fracture of the tubes. This reviewbased research is focused on gathering published information on so-far identified process parameters in RDB and their eventual effect on the tube’s quality. In the end, authors present their own perspective about the future of a RDB process. The authors perspective suggests merging of AM (Additive Manufacturing) with conventional RDB process to impart enhanced efficiency and improved quality to forming tools and bent products respectively. Apropos, a concept of hybrid pressure die is presented which encompasses manufacturing of a fundamental forming tool (pressure die) using AM techniques. The suggested model of hybrid forming tools opens a new avenue for industrialists to manufacture more flexible, cost effective and substantially beneficial tools for the RDB process in future.