The SignaStir project will develop an effective in-process quality assurance system for the inspection of friction stir welds (FSW) predominantly used in the manufacture of aluminum rolling stock and marine vessels. The SignaStir system will determine the unique and holistic weld quality 'signature'. There is currently no capable inspection system available on the market either as a stand-alone unit or integrated with a welding machine to perform this task. Welding is an enabling manufacturing technology for joining materials, which directly affects cost, safety and reliability and therefore has significant economic impact. Production and supply of flawed or defective welds is unacceptable and may result in unsafe products of low structural integrity. To overcome the technical barriers to development of such an inspection system an SME partnership will require the services of research and technology providing organisations to deliver precompetitive research leading to the development of the product. There is a need for a low cost welding method, which can overcome the limitations of conventional fusion welding techniques. FSW has many economic, environmental and safety advantages over conventional welding but is a relatively new development and potential users require added confidence to make the initial capital investment required. The full benefit of the FSW process can only be achieved through application where weld quality is guaranteed to be correct each and every time. When developed the SignaStir system will give European manufacturers added confidence in their welded products and reduce costly off-line inspection of production parts. Scrap and re-work rates will be reduced as quality issues will be detected immediately after welding by the SignaStir system.