New shapes: Submarine components from the 3D printer

^{4 December. 2019}

Industrial components from state-of-the-art 3D printers have decisive advantages over conventionally produced components. The naval experts at thyssenkrupp in Kiel are therefore working intensively to make 3D-printed components economical for submarine construction as well. The necessary quality and safety standards have already been set - together with a team of specialists from thyssenkrupp in Mülheim, they are now focusing on a major goal: the first series-produced submarine components.

3D printing – called “additive manufacturing” in the industry – permits the production of components that are difficult or impossible to produce using conventional processes – and which are often more stable, resilient and lighter than conventionally produced components. The conventional process step of tool or mould making is also eliminated. Another important advantage of the high-tech printing process is the time factor – fewer process steps mean that components can be produced much faster.

The submarine experts at the thyssenkrupp shipyard in Kiel have therefore long since stopped seeing 3D printing as a “gimmick”. Their goal is to take it seriously – and finally print safety-relevant components for their ships as standard. This is quite realistic: Even today, standard parts from the 3D printer are installed in submarines – without any special reliability requirements. Printed components are also already being used in retrofitting campaigns. However, one of the project managers at the Kiel site sees this as only the first step on the way to the long-term goal: “3D printing should make economic sense for the company – and will soon be used as a matter of course. Since research in this area is subject to strict security requirements, we do not mention the responsible employees by name in this article.

The advantages of 3D printing: less weight, yet fast and flexible

In an interview, the 3D printing experts from thyssenkrupp’s marine business explain that the 3D printer should only be used if it makes sense in terms of economy, work processes and quality: “We are faster, can save costs and be more flexible. And we can produce other materials and reduce installation space. The weight savings also allow us to reduce costs and give the shipyard and the customer more freedom in designing the boat.” An example: A hydraulic block from the printer can save 83 percent in weight. This also makes everyday working life easier for production employees: “Of course, it makes a difference whether someone has to screw on 14 or 2.1 kilos,” according to the experts.

In addition to reducing the weight of the components, flexibility is a major advantage of the process. The 3D printer makes it possible to produce all elements with fewer process steps, to design them individually and to adapt shape and material individually. This is completely in contrast to the current process, in which components are manufactured from many small elements that come from different manufacturing processes. Mechanical processing is still necessary, but only in a few places.

The challenge of series production: When does 3D printing start to make sense?

According to our submarine experts, at the moment it’s “first of all to find the parts in the submarine that could come out of the printer. They have to be parts for which printing is possible and sensible, i.e. economical. The design of these parts must be adapted to the boundary conditions of the manufacturing process”.

The team has already successfully installed plastic bundle holders for tubes from the 3D printer in thyssenkrupp submarines. Just like printed steel components – for example the housing cover of a venting system This steel printing is currently only possible within the Group at the thyssenkrupp site in Mülheim an der Ruhr. The steel parts to be installed in the Kiel submarines are therefore produced in close cooperation with the local Tech Center Additive Manufacturing.

Working together to achieve the goal: cross-divisional cooperation

The Tech Center in Mülheim is the central contact point for 3D printing in the thyssenkrupp Group and therefore also an important contact point for submarine experts. The Kiel shipyard has several small 3D printers for plastic components – but no metal printers yet. After all, printing steel requires a high level of quality, for example in terms of air conditioning, premises and safety precautions.

The cooperation between Kiel and Mülheim therefore runs hand in hand, according to their marine colleagues: “We work together directly and have a close connection to each other. We pre-design the parts – the Tech Center then prints them.” The team in Mülheim is also responsible for training the engineers in Kiel and training them in 3D printing: “We involved Mülheim in order to be able to guarantee all the necessary quality and technical requirements for 3D serial printing – and to take additive production seriously.

Setting milestones: This is how components can come onto the market as standard

The fact that the people of Kiel now want nails with heads when it comes to 3D printing is also illustrated by their own certificate, which the project managers developed together with the renowned classification society DNV GL and the Tech Center Mülheim. The team carried out various tests, printed numerous test versions and tested the printed material again and again.

“Together, we designed a quality seal that makes us the first supplier in the marine sector worldwide to be able to print components and place a ‘stamp’ on them that guarantees the material properties of the finished component according to defined standards by independent testing bodies,” said the responsible persons. This is an important step on the way to series production – because the materials used in the Kiel submarines are of high quality.

A look into the future of 3D serial printing for marine solutions

Due to the high flexibility, the fast, individual production and the low weight of the components, some customers are already interested in the products from the 3D printer. “Many customers expect benefits for their business,” say the experts. Their goal is clear: “Next year we would like to plan the first parts for series production. This ultimately means that the components will be installed as a matter of course. In this way, the certificate for the material parameters is a major stage victory.

According to the Kiel experts, it will also be interesting in the distant future “to reprint individual spare parts on request. We are still a bit away from this at the moment. At some point, however, a 3D printer will simply be used to print the required part on site at the customer’s premises.”

A promising cooperation

Together with Wilhelmsen Marine Products, we want to offer 3D printing components for marine vehicles. We combine our expertise in additive manufacturing with the experience of Wilhelmsen Marine Products in the maritime industry and their work in the development of 3D printing for ships. For this cooperation we use the combined competence of the recently inaugurated thyssenkrupp Tech Center in Singapore and the Tech Center for Additive Manufacturing in Mülheim an der Ruhr, which was awarded the Approval of Manufacturer certificate by the quality assurance and risk management company DNV GL. For Jan Lueder, CEO of thyssenkrupp Asia Pacific, the cooperation with Wilhelmsen is a milestone in the field of additive manufacturing: “After securing the world’s first certified 3D printing production facility for marine applications, we joined forces with one of the world’s largest shipping companies to offer our expertise in additive manufacturing to customers worldwide.