Manufacturing Workflow and Cost Efficiency of Large-Format Additive Manufacturing for Composite Marine Mould Fabrication

Conventional fabrication of composite moulds for marine structures is labour-intensive and involves multiple manual manufacturing stages. This study investigates large-format additive manufacturing (LFAM) for producing a full-scale mould for a 3 m unmanned surface vessel through two comparative assessments: design optimisation for LFAM and comparison with conventional mould fabrication.

First, a Design for Large-Format Additive Manufacturing (DfLFAM) approach was applied to optimise the mould geometry and printing strategy according to LFAM capabilities and constraints. Compared with the initial design, the optimised design reduced mould weight from 672.83 kg to 59.27 kg, representing a 91% reduction. As part of the optimisation, the bead thickness was reduced from 20 mm to 6 mm, with the corresponding print duration decreasing from 35 to 30 hours (14%). Total LFAM production cost, comprising material and printing costs, decreased from USD 10,523.73 to USD 2,273.00 (78%). These improvements were achieved while maintaining acceptable mould quality and dimensional stability.

Second, the optimised LFAM workflow was compared with conventional composite mould fabrication using manufacturing data provided by Integrated Coating Solutions (ICS), the project’s industry partner with expertise in conventional marine composite fabrication. Conventional mould fabrication comprised approximately 17 work activities and 71 hours, whereas the LFAM workflow comprised three principal activities and required approximately 38 hours, including 30 hours of automated printing and 8 hours of setup and post-processing. This represents an approximately 46% reduction in total fabrication time and an 82% reduction in manufacturing activities. Estimated mould production cost was reduced from USD 8,448.95 to USD 2,273.00 (73%).

Overall, the results demonstrate that DfLFAM enables a more automated and efficient approach to composite mould fabrication, substantially reducing material usage, labour, production time and cost. This provides a pathway towards rapid mould production for composite SeaDrone hulls, supporting faster and more responsive manufacturing of unmanned surface vessels.