Large-scale additive manufacturing could cut offshore wind component lead times by 78%

Background

Whittaker Engineering is an Aberdeenshire-based business specialising in components and equipment for the marine and offshore industries.
Following an earlier project with the National Manufacturing Institute Scotland (NMIS), which demonstrated how large-scale additive manufacturing could reduce manufacturing times for oil and gas components from months to days, Whittaker explored how the technology could be applied to the growing floating offshore wind sector.

The project focused on gypsy wheels – large rotating components used in mooring systems to guide anchor chains. Traditionally produced through casting or forging followed by extensive machining, these components can have lead times of around 20 weeks, rising to 40 weeks in some cases.

Challenge

Whittaker approached NMIS to assess whether large-scale additive manufacturing could provide a faster and more flexible manufacturing route for gypsy wheels, with the potential to reduce long lead times and provide a more flexible manufacturing route.


The project was funded through the CAN DO Scottish Offshore Wind Innovation Feasibility Challenge Call, delivered by Scottish Enterprise. The initiative aims to reduce the cost of offshore wind generation while strengthening Scotland’s supply chain and its potential to export innovation globally.

What did NMIS do?

NMIS engineers assessed the design, cost, lead time, embodied carbon and business impact implications of manufacturing a gypsy wheel using wire arc additive manufacturing (WAAM), compared with conventional casting and machining.


The team developed a model comparing the two manufacturing routes, combining data from Whittaker’s demonstrator build with industry benchmarks for casting, tooling, machining, lead times, costs and carbon emissions.


Whittaker manufactured a full-scale, two-half gypsy wheel demonstrator using WAAM, with an ER70S-6 steel core and an Inconel 625 overlay applied to the areas in contact with the chain. This approach used the higher-performance material where greater wear and corrosion resistance were needed, while using a more cost-effective material for the main structure.

Impact

The full-scale part was produced in around 4 weeks, from the start of the main build through to completion of the wear-resistant overlay. A typical casting and machining route takes around 20 weeks, indicating a potential 78% reduction in lead time for the first component. As the figures cover different stages of the manufacturing process, the comparison is indicative. 


For a single component, WAAM was estimated to cost £8,942, compared with £16,003 for casting and machining, around 44% less. This is largely because WAAM avoids the roughly £10,000 pattern tooling cost required for casting, making it a more responsive option for urgent, low-volume replacements.
At 50 components, WAAM was estimated to cost £8,060 per part, compared with £4,733 for casting and machining. Assuming a downtime cost of £20,000 per week for an asset awaiting its first replacement part, the combined manufacturing and downtime cost was around £147,500 lower for WAAM across a 50-unit order. 
At an order quantity of 50 components, WAAM was estimated to cost £8,060 per component, compared with £4,733 for casting and machining. However, assuming a downtime cost of £20,000 per week while an asset awaits its first replacement part, the combined manufacturing and downtime cost was around £147,500 lower for WAAM across a 50-unit order.


The modelling indicated an indicative 21% reduction in embodied carbon per component within the modelled boundary, driven mainly by lower material input. 
The project provided Whittaker with design outputs and real production data to support further development and progress WAAM towards commercial use.  

“The project has helped us build on our previous work with NMIS and explore how WAAM could be applied to larger components for offshore wind. The combination of measured demonstrator build data and NMIS’s expertise has given us a clearer understanding of the technology’s potential to reduce lead times and support a more resilient supply chain.”

Scott Macdonald, additive manufacturing engineer at Whittaker Engineering

 

“Our modelling shows the case for WAAM is strongest at low volumes, where avoiding tooling and long foundry queues outweighs a higher unit cost. The next step is qualification, so that this responsiveness can be offered to operators as an assured route rather than a promising one.”

Dr Misael Pimentel, project lead and senior engineering team lead at NMIS