SUPPLY CHAIN I OBSOLESCENCE
parts. Furthermore nickel is a heavy metal and there must be questions about its longer-term availability before being affected by legislation. The growth in composites for
structural airframe components brought a sea change in volume airframe technologies. But this increased demand for composites brings with it other issues: those of world supply/demand, affects of green legislation upon the production of composite materials and composite components, and the recycling of waste.
The growth in world demand for
composites comes from three sectors (see figure 1): 60% – industrial – low/ medium modulus fibres (including automotive, marine, civil engineering, medical, wind energy); 20% – aerospace – high modulus; 20% – sports applications – low/medium modulus. Total carbon fibre production in 2008
was about 30,000 tonnes and is predicted to rise to 70,000 tonnes/year in 2015. Indications are that this could rise to 300,000 tonnes/year by 2020, driven by demands from the industrial sector, increasing that sectors’ market share and market influence. Focusing on the aerospace sector; in 2009 the prediction was that by 2014 the sector needs just over 17,000 tonnes/year of high modulus fibre. The predicted demand from four major civil projects (see figure 2) for the same period shows fly away demand of approximately 16,500 tonnes/year. The timeline may be modified due to fiscal
issues but indications show these levels being reached within two to three years. Applying a fly/buy ratio of 60%, the actual material demand is nearer to 27,500 tonnes/year; significantly outstripping supply for four projects alone. By comparison a modern major military project with a production rate of 600 aircraft would have a ‘lifetime’ buy for first time build of about 5,000 tonnes.
One obsolescence implication is that
materials used in the design, test and qualification of a project may not be available for its lifetime with future build and in-service support (spares and repairs) needing vey robust long-term plans. Lifetime buys of fibre may be an option but lifetime buys of resin is not and the cost-effectiveness of lifetime buys is questionable. In October 2003, Ted Dowling,
technical manager, QinetiQ Consulting was quoted as saying: “A system is obsolete when it no longer fulfils a significant stakeholder need and cannot be made to do so in a cost-effective way.” Composites could then be viewed
Figure 1: Civil aircraft carbon fibre demand table
as facing obsolescence in 5-10 years. Add that aerospace projects that don’t use common fibre/resin combinations (especially on military projects), and it’s feasible to see a long-term consolidation of specifications focusing in on supplying a few major civil programmes. The process of producing carbon fibre materials from the Polyacrylonitrile
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precursor through carburisation into carbon fibre isn’t efficient as it uses high levels of energy, hazardous chemicals and produces significant waste even before fly/buy ratios are considered. Transforming Polyacrylonitrile into carbon fibre is at best 50% efficient and there is little reasonable potential to increase its worldwide supply to meet the demand for raw carbon fibre at the 2020 predicted levels. Taking a holistic view, the supply/ demand figures for carbon fibre over the next 5-10 years are significantly imbalanced. Production methods are at odds with environmental precepts of reducing hazardous materials usage, energy demands and reliance upon oil- based products. Metallic technologies face similar issues. Whilst some aluminium small part production is moving towards alternative technologies, a solution to replace chromic acid anodising for large scale airframe aluminium products with a robust, economic and electrically conductive alternative, remains outstanding. In conclusion, aerospace programmes,
in service, build, design or at the concept phase now need to focus firmly upon the potential obsolescence of the airframe
due to material supply issues. ❙ ● With thanks to Professor Andrew Walker, CEO National Composites Certification and Evaluation Facility, University of Manchester for assisting with the analysis of composite material supply and demand figures.
AEROSPACEMANUFACTURING | JULY 2010 13
Figure 2: Sector use of carbon fibres in tonnes/year
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