With the knowledge that an effect on production rates would be immediate and that the cost of a specialist friction stir welding facility could be recouped within a relatively short period of time, Alnmaritec is now considering the business benefits of a switch to the novel process at its North East coast centre of operations. Such a move would take a year and a half to implement in a carefully planned programme drawn up in conjunction with TWI.
TWI has developed its expertise in friction stir welding since its invention at the company in 1991. Shipbuilding and marine were two of the first sectors to adopt the technology for commercial applications. Friction stir welding has since revolutionised the way in which high-speed ferries, hovercraft and cruise ships are built, allowing the industry to use prefabricated lightweight modules for:
- panels for decks, sides, bulkheads and floors
- hulls and superstructures
- helicopter landing platforms
- marine and transport structures
- masts and booms, e.g. for sailing boats
- refrigeration plant.
This feasibility study was carried out by TWI as part of the government's Offshore Wind Technology Transfer Project. It first examined Alnmaritec's current use of manual MIG welding to join stiffener ribs to the underside of boat deck plates by producing 100mm length stitch welds, with approximately 100mm of unwelded lengths in-between. This procedure had already been optimised to save production time and cost and to limit deck plate distortion.
Next, TWI experts looked at the viability of producing deck plate structures with extruded aluminium sections joined by friction stir welding. This technique is already widely adopted by the aluminium shipbuilding industry and brings about significant cost savings and an increase in product performance. Alnmaritec could either set up its own facility for production or could purchase friction stir welded panels from external sub-contractors. The latter would allow it to avoid the outlay costs of a new on-site resource but in so doing may not be able to guarantee continuous saving.
As well as creating new employment, establishment of a dedicated friction stir welding capability in Port of Blyth would offer multiple benefits:
During a technology implementation programme, TWI would support Alnmaritec in evaluating application, design and machinery procurement options and helping with fixture and tooling elements before site installation. Alnmaritec staff would follow a structured skills and training schedule. The year-and-a-half-long programme would culminate in certification of the new production process for the construction of the company's workboats in accordance with international standards.
For more information about TWI capabilities in this technology, please visit the friction stir welding pages on our website.