Keppel Technology & Innovation has received a verification certificate for a 3D printed deck mounted type Panama Chock (safe working load 150 tonnes) from DNV. The component, which is intended for non-class maritime applications, is the world’s largest 3D-printed shipboard fitting so far.

Panama Chocks are large shipboard fittings for towing and mooring, traditionally manufactured by casting, and are welded to a ship as a supporting hull structure. This component was manufactured by Keppel Technology & Innovation’s (KTI’s) partner AML3D using their patented Wire Additive Manufacturing process, which used medium strength structural steel grade ER70S-6 wire feedstock.

The verification by DNV follows extensive research, production and testing by KTI with end users Keppel Offshore & Marine (O&M) and AML3D and confirms that the component has met all the primary test requirements in KTI’s project material specification with satisfactory results.

‘KTI has been working on this project with Keppel O&M, DNV and AML3D since 2019, and we are proud to achieve this endorsement,’says Francois van Raemdonck, Managing Director of KTI.

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Additive manufacturing

Additive manufacturing (AM) – the industrial equivalent of 3D printing – is an emerging technology which uses 3D model data to fabricate parts, enabling, among other benefits, significant time savings. Wire Arc Additive Manufacturing, or WAAM, has the potential to enable a productivity step change in shipbuilding, and is able to 3D print marine grade metal structures at a scale well beyond other commercially available metal 3D printing technologies.

Aziz Merchant, Executive Director of Keppel Marine & Deepwater Technology, the technology arm of Keppel O&M: ‘The 3D printing of the Panama Chock shows that large components can be made available with shorter lead times and with equal standards of quality and performance. We are encouraged by the verification and we look forward to exploring how AM can be implemented on a wider scale.’

Yield strength and load tests

As part of the qualification process a 1450 kg Panama Chock was designed and produced to meet international standards and KTI’s project specific material specification. Material yield strength was twice that of the original cast material and was produced with acceptable internal soundness that was confirmed by various non-destructive testing and evaluation methods.

The part was then proof load tested to twenty per cent higher load than its design working load. Following the successful load test, non-destructive and destructive testing, the results were reviewed by all parties before the final verification statement was issued.

The printed material (Panama Chock) was subjected to extensive testing by the DNV Singapore Laboratory and the Marinelift Testing & Supply Pte Ltd. Singapore. Researchers and testing engineers utilised advanced microanalysis instrumentation to generate high quality microstructural information and images. In addition, the mechanical and non-destructive testing were assessed and compared against established marine grade cast material.

Also read: Huisman ready to scale up 3D printing of crane hooks