Advanced Continuous Tow Shearing in 3D (ACTS3D): Advanced fibre placement technology for manufacturing defect-free complex 3D composite structures

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The aerospace industry is the key sector for growth of the UK economy. The potential market share of the UK, which is specialised in the most complicated and high tech aircraft parts, is estimated to be around $600 billion. This enormous market demand was also driven by the environmental issue, which requires the lightweight composite aircraft structures to meet the future CO2 emission regulations.The automated fibre placement (AFP) process is the core technology that underpins the UK's aerospace industry. This process can lay up carbon fibre tape (or tow) materials on a three dimensional mould surface using a robotic or a computer-controlled gantry machine at high speed, which is mainly used in the aerospace industry to manufacture composite structural components such as fuselages, wings, and spars. The AFP machine's capability of feeding individual tows at different speeds enables steering the fibres within the tows along curved paths, and such fibre steering allows for manufacturing composite structures with complex geometry as well as realising ultra-high structural efficiency beyond the limit of the conventional straight fibre lay-up design. However, it has a few fundamental limitations in fibre steering to produce complex composite components. First, since the AFP machine steers the fibres by bending the tow tape, fibre-buckling defects are always generated. Second, it needs to frequently cut the tows when laying up on a doubly-curved surface that cannot be perfectly tessellated with the finite width tows, which also creates defects such as fibre discontinuity and resin pockets. Such process-induced defects are a critical barrier that reduces the production speed and complicates the design process in the aerospace industry. Furthermore, as the shape of the composite components becomes more complex, the minimisation of such defects in fibre steering process is getting more important.This project aims to develop a new game-changing fibre placement technology that can produce defect-free doubly-curved composite components, based on fundamental understanding of the impregnation and deformation characteristics of tow materials. The new head mechanism to be developed will be capable of producing variable width tows on-the-fly to cover tessellated sections of a complex 3D surface without gaps. The scientific knowledge on tow-level deformation characteristics will be integrated with an advanced head mechanisms as well as a new head control algorithm in order to realise the buckling free fibre steering using the continuous tow shearing mechanism on complex 3D surfaces. Finally, a prototype head will be tested on a robotic platform programmed using the developed head control algorithm, and the lay-up quality and accuracy will be evaluated using various inspection methods. This establishes a proof-of-concept manufacturing process for complex 3D composite components.Although the industry is making various attempts to solve the quality problems by modifying the process parameters or the tow material, there are no existing AFP technologies that can either steer the tow without defects or control the tow width. The successful development of this unique and disruptive AFP process will provide the UK aerospace industry with a fundamental solution to the quality problems that they are facing, which enable the UK to be at the forefront of next-generation automated composites manufacturing technology.