Aluminium coils are made from rolled sheets of aluminium, with a hollow cylinder inside upon which the material is wound to create the 
interior diameter.
They are used in a range of industry sectors, meaning that they often need to undergo surface treatment so that they are suitable for different applications.
This coil coating process can include cleaning, etching, colouring and sealing before the coil is rewound. However, the ends of the coils often need to be joined together, with adhesive taping being the usual method. Adhesive taping is not only time-consuming, creates material waste and creates and element of risk.
TWI investigated using refill friction stir spot welding (Refill FSSW) for this purpose, and you can find out more here: Improved efficiency for aluminium coil processing
