JEC COMPOSITES MAGAZINE - Issue #48 - May 2009 - 23

performance level as the current series concepts (Fig. 11). Fig. 11: Use of carbon fibres in crash structures. Based on these results and promising initial cost estimations, a lay-out for an automated production process using prepreg pressing technology was developed. In order to avoid costintensive manual processes and to achieve cycle times compatible with automotive series production, a higher degree of automation was implemented. This concept consists of two steps: stacking of the prepreg plies, followed by a forming and curing process. are not practical to produce using hand lay-up, improved material utilization. However, hand lay-up is still needed in a number of cases for the following reasons: • some part designs require materials (fabrics) that cannot be processed using automated equipment, Fig. 13: Optimized cycle-time processes with automated • part configuration (e.g. tight continuous steps. radius, multiple ply drop), • low production rates, The next step involves forming and • many small parts (e.g. composite curing the prepreg stacks in a pressing shims, brackets, angles) are not practical process. Once again, the process is highly to produce using automation, automated by the use of handling robots. • lower capital investment. An adhesive is then applied onto the CFRP components, which then can be The deciding benefits of automation for assembled into steel or aluminium Hitco were enhanced capabilities, structures (Fig. 13). increased competitiveness (reduced part unit cost), improved product throughput, While such automotive approaches were and time-to-market improvement. driven by public interest for lightweight constructions and high crash security, automated aeronautic technologies were initially developed for the military sector quite a while ago. They are now making massive inroads into commercial aerospace. Future key technologies The future key technologies for producing carbon composite parts for the Boeing 787 and the A 350 will be based on automated processes, taking the market away from competitors focused on hand lay-up. SGL has decided to invest massively in automated tape laying and fibre placement, as well as in other automated technologies (Fig. 14, 15) at its 100% affiliate company Hitco Carbon Composites. The primary reasons for investing in automated composite processing methods are: • increased productivity: an average laminator can lay-up 1-1.4 kg of material in an hour while automation typically begins at 3.5-5.5 kg per hour depending on the equipment type and part complexity, • reduced component manufacturing costs, • repeatable quality of components, • reduced in-process inspection costs, • many large parts (e.g. fuselage panels) Fig. 14 et 15: Automated composite processing system at SGL Hitco (AFP) Fig. 12: Automated continuous stacking of prepreg plies in a special calender. Conclusion Based on the above-mentioned advantages, hand lay-up will retain a certain market share in specific niches, but will lose the dominating role it has held in the past. Carbon composites are on the way to true industrialization, but there is it still a lot of work to do. It is now up to the scientists, engineers and managers in our industry to deliver. Failure is not an option. More information: www.sglgroup.com Part One: JCM N°47, pages 24-25 First of all, the geometry and fibre orientations are optimized by FE analysis with the resulting parameters being used as the basis for the stacking operations. These are necessary as automotive parts are usually too thick to be made from a single ply. The plies are thus stacked in a special calender system which is highly automated. At the end of this station, the stacks are cut into the desired shape and eventually stored (Fig. 12). No48 May 2009 / jec composites magazine 23

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JEC COMPOSITES MAGAZINE - Issue #48 - May 2009

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #48 - May 2009