Denmark explores path to 3D printing

30 Oct 2017
Delegates to the seminar were given an advanced briefing on MAN Diesel & Turbo's 3D printing experiences by Roland Herzog

Delegates to the seminar were given an advanced briefing on MAN Diesel & Turbo's 3D printing experiences by Roland Herzog

There are so many potential applications for 3D printing in shipping, it can be difficult to know where to start. One Danish project is hoping to explore some of the most promising avenues.

Threat or opportunity? Like any new technology, 3D printing is both. At the same time as it promises to simplify supply chain management and improve the accessibility of spare parts, it also raises serious questions over intellectual property, product liability and even suppliers’ business models. That’s before you factor in the peculiar requirements and constraints of the shipping industry such as the ‘marinization’ of 3D printing equipment, to withstand life at sea, and the classification of printed products.

One of the most serious attempts to address these issues in the maritime realm entered its second phase this year. Green Ship of the Future (GSF), the Danish public-private project that includes several of the biggest names in shipping and marine engineering, had already comprehensively assessed the potential for 3D printing during a first phase. The second stage is to involve four more practical and focused projects, which were revealed during a seminar at Maersk’s headquarters in Copenhagen last month. The Motorship was the sole shipping media at the event.

One of the most immediately apparent uses of 3D printing, also known as additive manufacturing (AM), in shipping is the printing of spare parts at sea. This year’s edition of the Wohlers Report, a respected annual study of the AM industry, estimates that – across industrial sectors – around 70% of stock parts are never used. That figure raised no objection from Sverre Vange, head of performance management at bulk and gas carrier owner J. Lauritzen, who described a project led by the shipowner to investigate 3D printing onboard ships.

Vange said: “As a representative of a ship owner, my first thought about 3D printing was that when you look at the storage room, you have a feeling that a lot of the spare parts in there will never get used. So I wanted to look at how we could use 3D printing to address this. We are focusing on bringing a small 3D printer aboard and seeing how it works.”

One of the advantages of the GSF framework is the partners available to participate in the projects. Here, the combined resources of J Lauritzen, Maersk Line and Maersk Drilling mean that the printers can be trialled not only across multiple ships, but with multiple ship types.

CROSS-SEGMENT COLLABORATION

Vange explained: “You often hear people say after a project, ‘that’s fine in that segment but it would never work here’. Within this project we cover a lot of the vessel segments, with Maersk Line and Maersk Drilling.

“Initially the idea was to bring perhaps one to three printers onboard to see how it worked. But when Maersk joined that made it a much wider project. So instead of looking at just three printers we had to rearrange the budget to buy 10 printers, on different kinds of vessels – rigs, containerships, bulk carriers and LPG carriers.”

Other partners include class society DNV GL for quality assurance and Copenhagen Business School, which will be looking at the impact of onboard 3D printing down the supply chain. MAN Diesel & Turbo has a crucial role in the intellectual property element of the project, as does Create It Real, a software company with a potential solution to the rights protection issue.

“Printing ‘original’ spare parts is an extremely interesting part of the project,” Vange said. “Create it Real has made some software that will enable MAN to create a file, encrypt it so that it can only be printed by a certain printer – for three copies or valid for two days, for example. That is so that MAN know that a file is not going to be misused. It is targeted just at that vessel and that they can print it a limited number of times. When MAN knows which vessels the printers will be on, they will pinpoint a part for each to test.”

The project aims to install printers on vessels by January 2018, and testing will conclude in June. That limited timeframe means that the partners had to keep the project simple. “The way crewing works, if we need to have crew trained onshore for a week or two, it just couldn’t happen,” noted Vange.

The chosen printer is quite basic, producing plastic parts with a maximum size of 15x15x15cm. The printer can be assembled and used within five minutes and the filament spool, holding the raw plastic thread that will be used in printing, can be changed easily. There are several options for printing material, including some which Vange says are quite strong, “though none that you would be able to plug into an engine”.

QUALITY CONTROL

Quality assurance will be a key aspect of the project. “Printing on shore and then testing for quality is one thing, but you have some restrictions on a vessel. We plan to test quality as much as possible – we don’t want to bring a lot of testing equipment onboard, but we have thought asking the crew to print the same item every month and then look into the quality.”

The crew response will also be important, and staff will be encouraged both to use readymade product plans (usually as stereolithography or STL files), to source their own from a wealth of online resources, or to use design software to develop their own parts.

“We are not talking engine parts, but for something relatively simple like a door handle it might be faster to print than wait for the purchasing department to process the order,” Vange said.

The work group will produce a final report with findings and recommendations at the conclusion of the project in June.

Another arm of the project, led by fuel injection and turbocharger service specialist PJ Diesel Engineering, will investigate the use of two well-established 3D printing techniques to repair engine parts. If viable, this application could mean that shipowners could be able to recondition parts that would otherwise have to be replaced or sent back to the manufacturer.

The project team looked at several selection criteria – including lead times, cost and unit size – and eventually chose as its test item the turbine wheel of a KBB turbocharger. “We took a damaged wheel that would normally be thrown out and approached KBB,” noted Rasmus Elsborg-Jensen, general manager, PJ Diesel. “They would usually produce a replacement wheel, but this type was not in production anymore, so they saw value in repairing the units using 3D printing technology.”

The selection of 3D printing technologies was also crucial, and the group eventually settled on two methods. Laser cladding uses a high-powered laser to melt metal powder onto a base metal, creating a small melt pool with which to fuse the materials together. In cold spraying, metal particles are accelerated to high speed and the kinetic energy is used to fuse the particles.

Elsborg-Jensen explained: “These are relatively mature technologies compared to some more hyped 3D printing technologies. We chose them to keep the costs down, and to be able to use it within our timeframe of a year. We couldn’t use brand new technologies that are expensive and have not been tested.”

3D PRINT GUIDELINES

As with the onboard printing work, partners will be crucial. The project is a milestone for DNV GL, marking the first time that their draft guidelines on additive manufacturing have been employed. AM specialists Force Technology and Dycomet will be testing the components – as too will KBB. Meanwhile the Technical University of Denmark is performing a lifecycle assessment.

Finally, if all testing is successful, the reconditioned components will be installed on an engine on a Maersk vessel. “This is a unique project because it is a whole value chain collaboration, from the makers to the users. It is also small and focused - with a timeframe of one year and an R&D budget of $100,000. We have tried to work well as partners and have stayed away from non-disclosure agreements. We want to learn from each other.”

If the repair project has relied on new applications of well-proven technologies, the same could not be said of a further project investigating the potential for large-scale 3D printing in shipbuilding. The reason for that is simple, said Anders Ørgård-Vinding of naval architect and marine engineering firm OSK Shiptech: There has just not been as much investment to date in large-scale AM projects.

“We have struggled to identify experts to help us in large-scale 3D printing,” said Ørgård-Vinding. “While the use of 3D printing for small scale applications has grown exponentially, the growth in scale of 3D printing technology is linear and quite slow.”

That is not to say that large scale 3D printing does not exist. In the US, a plastic submarine has been printed offering many benefits over traditional steel subs – not least the fact that it cannot be detected by sonar. But 3D printing big projects remains expensive and inefficient compared to the use of steel plates in traditional shipbuilding, for example.

Nevertheless, there are potential uses for 3D printing in shipyards according to OSK, which was tasked to lead a project exploring ‘front of ship’ applications of AM technology. Their solution has been to look at one of the most common energy saving devices – the bulbous bow – and explore how to improve it.

CHANGING THE BULB

Ørgård-Vinding explained: “Ships are built with a bulb optimised for a certain speed – for some containerships that is between 18-24 knots. But if you go much slower the hydrodynamics change dramatically and the bulb can add resistance.”

Ideally ship owners would want two or three interchangeable bulbs on-hand, to attach depending on their voyage profile. Such bulbs could also be 3D printed during a voyage and dropped quayside for a vessel’s arrival.

“We believe we could save a large container vessel around 3% in fuel savings,” Ørgård-Vinding told seminar delegates. “Maersk Line use 1.5 million tonnes of fuel a year, so this would mean a saving of around US$12 million. And there are ten times more containerships worldwide.”

The company is applying for patents and has received positive feedback from four out of the five countries in which its application is pending. Meanwhile a second generation is already on the drawing board. But there is a long way to go until a prototype will be made. Before then OSK needs to secure a brave ship owner, and before that they must complete a risk evaluation that has already started – exploring, among other things, what could happen if a detachable bow were to fall off.

In ten years’ time, OSK could be exploring bulbous bows that do not need to be exchanged, but can instead change shape when triggered by an electric charge. At the Copenhagen seminar Ivar Motke of Create.dk outlined the principles of 4D printing - the 3D printing of products that can change in response to triggers including heat, electricity and pressure. This could be particularly useful for applications such as valves and vents, although Motke challenged delegates to think of other novel applications. A project led by Clorius Controls – the fourth in GFS’ 3D printing initiative - is working on a three-way valve activated by heat that could be used as part of a thermostat in a boiler, for example.

Four-dimensional printing may seem a step too far for some in the conservative shipping industry. But the companies behind Green Ships of the Future believe it is time that shipping shook of that ‘conservative’ label and started embracing the advantages that cutting edge technologies – including 3D printing – can bring.