3D printing comes to the use in the marine industry through OCore, an enterprising Italian society under the leadership of Daniel Cevola, Francesco Belvisi and Mariga Perlongo, three young men already engaged in the design of boats with each other their company Livrea Yacht, and thanks also to multinational agreements able to support the project, such as Lehvoss Group, Autodesk, Kuka Robotic which for some has been transformed into a project of technical sponsorships. Lehvoss also accepted the competition challenge by sponsoring sporting activity, as well as providing the print material with a formulation that fully meets the required structural requirements.
A project based on fractal structures
The Mini 650 is the first fully 3D sailboat designed by Livrea Yacht and built by OCore, a racing boat made of nylon and carbon. The boat is 6 meters and 50 centimeters long, almost 3 meters wide, created with the new 3D printing technology using a robot 2 meters and a half high that prints the whole hull without models or dies and follows the strategy dictated by a patented algorithm based on fractals. Exploring the fractal in 3D printing was the starting point of a study in the early activities developed in collaboration between OCore and Autodesk. Fractals are hierarchical structures that are very common in nature and have the great advantage of generating a complex and efficient structure with a simple and light algorithm. This is a great advantage, not only to generate files to print, but also to predict the structural and thermal properties of the object.
A slimmer and faster process
In addition to the hull, rudders and other components of the boat will also be printed. Until now, for the construction of the competition rudders, following the traditional process, it was necessary to build moulds on which composite leathers were stratified, after which the components were joined, the finishing operations were carried out. The realization of an adequate rudder to the Mini Transat generally requires a full week of machining in order to obtain the moulds and to complete the subsequent processing.
With the OCore system, however, the processing is much slimmer and faster, managing to generate a self-supporting structure in about two hours. In the specific case it is a piece of 1.3 meter long by 30 centimeter wide and 3 centimeter thick which has an internal structure suitable to support the cutting efforts to which the rudder is subject. The wall thickness is 1 millimeter and the 3D printed component weighs 1.5 chilogram. Once the moulded piece has been ready, they have been stratified under a one-way carbon vacuum for a total weight of about 1 chilogram, then proceed to a surface finish.
The artifact consists of about 780 layers superimposed by a thickness of 0.6 millimeter with a polyamide based material loaded with 25% carbon. Lehvoss has created the formulation that satisfies the structural requirements of the rudder for the Mini 650 very well. The great advantage of this innovative procedure is the speed of production and automation of the process. Moreover, in the specific case of the Mini 650, it will be easier for the team to test and verify the different configurations at sea, greatly speeding up the boat’s set-up.
Direct from pellets
Lehvoss Group, with its parent company Lehmann&Voss&Co. in Hamburg (Germany), supported the process development and additionally engineered and delivered customized 3D printing materials dedicated to this technology and application. These materials, with the tradename Luvocom 3F, are based on thermoplastic polymers, such as high-performance polyamides and PEEK. To achieve the required mechanical properties, these polymers are reinforced with carbon fibers. Furthermore, the materials are modified to yield an improved layer strength, while printed parts show no warping. This leads to much stronger, more durable and precise yet at the same time lighter parts.
Ready to start
In recent weeks, many production and process optimization tests have been conducted and a bow block of the boat has been printed with a low weight and high stiffness and surface finish characteristics. The process, completely automated, took three days a day to deposit 0.6 millimeter thick layers with 1 millimeter thick walls.
The next step will be the boat’s presentation, at the end of October. By the end of 2018 the launch of the Mini 650 will take place, to then take part in the bi-annual trans-oceanic regatta, the 4000-mile Mini Transat 2019 with two stages. The departure will take place from the port of La Rochelle (France) with destination Las Palmas de Gran Canarias; after a brief stop the small Mini will leave for the second stage, which consists of the real oceanic crossing, to head towards the coasts of Le Marin (Martinique). The duration of sailing in the race is 30 days, with the sole aid of a GPS of non-cartographic position and a VHF radio to receive daily the estimated position of the other racers by the organization.