VIDEO: Large-Format 3D Printing Outperforms Casting for Large Marine Parts
James Anderton posted on March 05, 2018 |
Who needs sand casting when you can use a giant welding robot to build large metal parts?

At the new Autodesk tech center in Birmingham, England, you’ll meet all kinds of interesting people with all kinds of fascinating applications. We chatted with Vincent Wegener, managing director of RAMLAB, an additive manufacturing company picking up serious steam in the Rotterdam marine manufacturing market.

Unlike many deep-pocketed, ambitious, but questionably useful additive manufacturing enterprises out there, RAMLAB seeks to fulfill an unsatisfied market for a better way to source large, expensive marine parts like propellers in the bustling port of Rotterdam. Here, additive manufacturing can eliminate wasteful part inventories. “Often you have to order more than one part. You have large batch that you keep in stock. Warehouses in port of Rotterdam are filled with parts that are sometimes never used. This is a waste of energy and resources.”

To service this need, WAAMpeller was created. The name stands for wire arc additive manufacturing (WAAM) propeller. The project was developed by a consortium of organizations which included Autodesk, Damen Shipyards, Promarin, Bureau Veritas and, of course, RAMLAB.

The WAAMpeller is a very large part, additively manufactured in bronze. How did they do it?

Additive manufacturing is typically considered for small parts, but with WAAM, additive manufacturing is highly scalable, as the welding robot can be put on a track. “We currently have a track of 6m, so the reach is 6m x 2m x 2m. The biggest factor is time; how many kilos per hour can you melt? Of course, you can add more robots, but then you have all kinds of other challenges, such as heat input, cooling time, but there is an advantage that the bigger the part, the bigger the heatsink, so the more you can deposit. We think it’s about 1-10m is about the scope of this technology,” said Wegener.

Can Additive Compete with Casting?

One of the advantages of wire arc AM is that welding robotics is a well-established technology. Combined with Autodesk PowerMill software, it’s possible to lay metal bead in complex geometries, building up large, fully dense parts layer by layer in multiple axes.

It’s a relatively low-cost machine which uses relatively low-cost materials—welding wire is considerably less expensive than the powder used for other metal additive processes. The bottom line is that WAAM can cost less per printed kilogram of parts. This is part of what makes the technology competitive with traditional processes like sand casting.

With old casting technology, the lead time, minimum order and supply chain are big challenges.

There are also known issues with the quality of castings, such as porosity. According to Wegener, better material properties are possible with wire arc additive.

Coordinating the programming of an industrial robot with the required toolpath for metal deposition is a complicated challenge. RAMLAB uses Autodesk PowerMill Additive software for designing the print, then loads that strategy into Panasonic’s desktop programming and simulation system (DTPS) Software for programming the robot motion.

For more on large format additive manufacturing, check out Cincinnati Inc. Goes Big and Small with 3D Printing

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