Lean Built-Up Panel Assembly in a Newbuilding Shipyard

Abstract

The main shipbuilding assembly processes greatly influence the flow of interim products in a newbuilding shipyard. The panel assembly line is a major process located upstream of all the other shipyard assembly processes. In a previous paper, the application of lean principles enabled a balanced and smaller takt time along the workstations and yielded significant savings in man-hours. Although a panel consists of butt-welded steel plates with multiple fillet-welded longitudinal stiffeners, a built-up panel is this same panel fitted with longitudinal and transverse steel elements. Since there are many internal structural elements, the man-hours along a traditional built-up panel assembly line are multiple times greater than that of panel assembly. Therefore, it is necessary to analyze and map built-up panel assembly in an actual newbuilding shipyard. Using value stream mapping along with kaizen principles of continual improvement to determine the transformative steps to make the traditional built-up panel assembly line leaner. This enables significant man-hour reductions of about 60%, which yields remarkable cost savings to the shipyard. 1. Introduction The built-up panel assembly line process is located downstream to the panel assembly process, and in most shipyards, half of all steel panels become built-up panels. It is very labor intensive since there are many steel elements that need to be joined in both longitudinal and transverse directions and there are both fillet and vertical welding jobs to be done. The joining of built-up panels to panels yields large three-dimensional blocks. Although in past papers (Kolich et al. 2017, 2015a) a lean value stream mapping methodology to transform panel assembly was developed, it makes sense to develop a methodology for the more complex and man-hour intensive built-up panel assembly process as well. The transformed built-up panel assembly process will further reduce bottlenecks in the shipyard and improve flow bringing down man-hours, which translates to critical savings for the shipyard.