JEC COMPOSITES MAGAZINE - Issue #47 - March/April 2009 - 37

Decision-making aids a composite version of its door panels for a van model. A CAD solution was used to determine the total surface of the flat patterns (2D), and the data was fed into the system, adding a global coefficient of 80% "fabric efficiency". From there, the total project cost was estimated. But the reality turned out to be a nightmare: not only were the parts too big, but the actual fabric efficiency was only 66%, i.e. 17% off the estimation – and the fabric represented more than 85% of the total project cost. Not having the time to finish a prototype correctly can also generate extra cost. The search for an "ideal” shape can lead to neglecting other possibilities. But what is ideal? Is it the best possible? Or is it the best possible within given tolerances? Just imagine being able to optimize an existing prototype within its specification tolerances, with an eye on cost control, instead of just obtaining a good result at whatever cost. Few companies today explore this enough, even though it is achievable with the latest generation of tools. But there is more. Lectra, the world leader in integrated technology solutions dedicated to industries using soft materials, has developed a new, powerful tool called DesignConcept. This tool can not only flatten 3D surfaces into 2D patterns, but also analyze the fabric behaviour (stress, strain, pressure). Combined with a series of integrated, highly automated and associative features (ensuring pattern industrialization, fabric analysis, costing calculations, preproduction preparation and advanced rendering options), this software enables the creation of 100% virtual prototypes. For the first time, it is possible to use the computer to achieve a virtual prototype offering all aspects of the physical one. What you see is what you get. The CAD operator can check the final result without the need to cut a single pattern. Fig. 3: Technical document/project overview. Fig. 2: Comparison original design/version A/version B. New possibilities with new-generation tools A traditional in-line process might seem to be the natural way to handle the development of a product based on physical elements. First-generation CAD programs made it possible to generate 2D patterns (often digitized paper unwraps), industrialize them, and prepare the patterns for a prototype cutter. Once the fabrics were mounted onto a core (or draped into a mould), it was possible to check the feasibility, design and other aspects. Second-generation CAD tools now add the possibility to unwrap 3D surfaces. The added value of this software generation is to be found in the first phase of a project. Rough 2D shapes are available directly from a 3D CAD model, ready for the shape industrialization phase. However, in the absence of the necessary analysis tools, a physical prototype to validate the results is still required here, and the trial-and-error method is improved, but not completely eliminated. Dr. Sybille Krzywinski from the TU-Dresden conducted a study comparing the different software available on the market in 2005 and pointed out the importance of a complete (closed) process chain. The possibility to create a virtual prototype (and not simply a rendered picture of a designer study), including all feasibility and costing aspects, opens revolutionary possibilities. For example, predicting the exact cost of a finished element without precise data on its fabric consumption clearly remains an impossible exercise. An integrated nesting module provides the necessary key figures, rather than an estimative coefficient applied to simple surface calculations. The possibility of generating associative visualisations (rendering, pattern nesting, feasibility analysis, etc.) of a newly modified edge – a change that is necessary when adapting the style to a specific fabric, for example – allows immediate validation of the project by all departments involved. With such features integrated into a single CAD program serving the complete development process, cost is no longer the sum total of a chain of operations, but key information used to make design decisions for each operation involved. Tasks can be carried out almost simultaneously, yet with perfect knowledge about the influence of any modification on all other development stages. Modified process organization Process chains will certainly be modified as crucial information becomes available incredibly quickly and, more importantly, No47 March-April 2009 / jec composites magazine 37

JEC COMPOSITES MAGAZINE - Issue #47 - March/April 2009

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #47 - March/April 2009