Development of a cold incremental rolling process using a line array roll set for the manufacture of doubly curved metal plates

Abstract

Doubly curved metal plates are useful in the various industrial fields. Bodies of automobiles, ships and airplanes are composed of many kinds of curved metal plates. For the manufacture of the various doubly curved metals corresponding to the desired uses, a variety of forming processes have been developed and applied. Especially, in a shipbuilding industry, a ship’s hull is composed of many pieces of curved plates that are called curved hull-plates. Therefore, hull forming is an important fabrication process in which flat plates are deformed into singly or doubly curved plates. For the manufacture of doubly curved plates, the line heating process has been used for many years in shipbuilding as it does not require any complex equipment. However, the heating process is done manually based on the experience of craftsmen rather than any systematic approach. Hence, the process in most shipyards is still associated with low productivity. Based on this background, for several decades, researchers in shipbuilding industry have emphasized the necessity of hull forming automation to improve productivity and reduce the cost. The objective of this study is the development of a flexible forming system that uses the principles of the incremental roll forming process in order to effectively manufacture a doubly curved metal plate in shipbuilding. A new forming process for the effective manufacture of doubly curved metal plates is proposed. The suggested process employs a line array roll set (LARS) composed of a pair of upper and lower symmetric roll assemblies. All the rolls, which are equipped with servo control units, can be positioned in a vertical direction in accordance with the user’s commands. The new forming process can improve the productivity more than that in recent incremental roll forming processes, which use deformation in small regions. FEM simulations are carried out for verification of the proposed incremental forming system using the chosen design parame...