OREANDA-NEWS. The new design highlights in the world of chairs from Vitra, the Swiss furniture manufacturer, are called Belleville. Vitra launched the product range, consisting of the Belleville chair and the Belleville armchair, as well as the accompanying tables, at the Milan Furniture

Week this spring. The products were designed by the French designer duo of Ronan and Erwan Bouroullec. The new chair creations consist of two separate components: the frame structure and the seat shell. Both are made of the polyamide Ultramid(r) B3EG6 SI from BASF and were developed with the assistance of the Ultrasim(r) simulation instrument. The slight and elegant frame, which simultaneously fulfills the highest stability requirements, demonstrates the design's technical refinement. The chair will be on display at BASF's stand at Fakuma (hall B4, stand 4306).

In the development of the new chair, whose name is taken from the artist's quarter of Belleville in Paris, Vitra sought a plastics manufacturer that not only had the requisite material expertise, but also know-how in the field of virtual component design.

With its weather- and UV-resistant material Ultramid(r) B3EG6 SI (surface improved), BASF was not only able to meet the demanding requirements in terms of mechanical strength; the polyamide also proved itself highly suitable due to its excellent surface quality and almost unlimited color possibilities through coordinated Masterbatches from BASF Color Solutions.

"This comprehensive package of product and services was the decisive factor in choosing BASF as our partner in carrying out this project," said Thomas Schneider, Project Manager Innovation Team Seating, Vitra AG.

Virtual simulation is an increasingly important element in designing components and tools. Ideally, the entire manufacturing process can dispense with real prototypes. Component geometry can be optimized, and the precise dimensions of tools determined, prior to production. For furniture manufacturers, this results in significant cost and time savings in the development of a new design.

BASF has already proven its CAE (computer-aided engineering) expertise in numerous projects, for example the MYTO cantilever chair from Konstantin Grcic and the A-Chair from Brunner, both of which were produced with the conventional injection molding procedure.

The Belleville, by contrast, was to be manufactured using the more complex GIT (gas-injection technology) production method. In this method, after the conventional injection molding process an inert gas (usually nitrogen) is injected into the shape that works something like an internal structural element, displacing the melt and creating a hollow space.

Vitra opted for this production method because it enables substantial material savings while achieving the same component stiffness. Thus in comparison to conventional injection molding, the method enables more economical and lighter design variants. At the same time, however, the technology presents extremely demanding requirements in terms of calculating component geometry, as the size and position of the gas bubbles have a significant impact on the strength of the chair.

The GIT must therefore be taken into account at an early stage and with great reliability in designing the injection molding form, not at least because the costs of tool modifications are significant.