Automated Line Heating for Plate Forming by IHI-ALPHA System and its Application to Construction of Actual Vessels

In many shipyards, shell plates having complex curvature are formed using line heating or a combination of line heating and cold forming. These processes are effective but labor intensive. In this paper, we describe a new system that plans and carries out line heating automatically. This system, called IHI-Alpha, projects the desired curved geometry onto the original flat plate, and calculates a heating plan which includes the travel and heat input rate of the heating head. Once calculated, this heating plan is forwarded to a special shop workstation where the final curved form is then produced directly, with no iteration. This differs from the conventional process which is based on operator experience plus trial-and-error.The IHI-Alpha system has been employed in the construction of a number of vessels including bulk carriers, VLCC's, and containerships. In this paper, we introduce the system, its theoretical foundation, and how it works including both software and hardware aspects. Examples of its use in actual ship production are described. Finally, ideas for future development of this technology are discussed.