LR has certified Huisman’s four new 350 metric tonne (mt) crane hooks produced by additive manufacturing, also known as 3D printing, in accordance with LR’s Guidance Notes for Additive Manufacturing.  

The hooks are approx. 170 by 130cm in size, almost nine times larger than the first Huisman 3D printed crane hook. They have a weight of 1,700kg each and a loading capacity of 350mt. Each hook consists of approx. 90 kilometres of feedstock wire. 

Huisman has been employing the 3D printing technique Directed Energy Deposition (DED) to produce mid-size to large components with high-grade tensile steel. An important benefit of using this technique for crane hooks is the significant reduction in delivery time at a cost that competes with forgings and castings, and a more consistent quality level. 

Tim Kent, Marine Technical Director at Lloyd’s Register, commented on the recent certification: “A rapidly developing and disruptive field of manufacturing, additive manufacturing is being used by a growing number of businesses manufacturing parts for a wide range of industries, such as marine and offshore.  

This is a significant milestone for LR in supporting Huisman in producing one of the largest lifting hooks ever produced by additive manufacturing. This approach provides clients with a great deal of flexibility, enabling clients to produce a replacement part when needed, which has the same consistent quality level, streamlining the delivery schedule,” Kent continued.  

Bart Klos, Project Manager of Huisman says: “Thanks to years of workmanship and innovative engineering we could take the next step in this fabrication method. Our aim is to open up new applications for designing equipment. Throughout each step of the process, there was a good understanding and clear communication between Lloyd’s Register and Huisman. The result are proven in practice by the load test performed at the Huisman facility in Sviadnov.”  

Huisman plans to expand its robotic workplace of its production facility in Sviadnov, Czech Republic, which currently holds three welding robots. By upgrading its capacity, Huisman will be able to produce crane hooks with a weight up to 5,000kg. 

LR launched its goal-based additive manufacturing (AM) Guidance Notes in 2016, providing operators and manufacturers in the maritime industry added confidence in metallic equipment and components produced using AM. Revised in 2017, and further updated in 2020, LR’s certification framework offers a step-by-step approach that acts as a stabilising force for quality and safety. In addition to this, LR launched Guidance Notes for the Certification of Consumables for Wire-Arc Additive Manufacturing in November 2020, and more recently, Guidance Notes for Polymer Additive Manufacturing Certification.