Casala introduced a new collection of chairs at the Orgatec 2008 fair in Cologne, Germany. Among those chairs are the Onyx and Sfinx chairs designed by Dutch design duo Kommer & Kors. Both chairs are available with identical plastic seating shells. BPO has optimised this shell for both the BIFMA strength norms as well as seating comfort.

Seating comfort is a basic element of the design of any chair. It is a complex symphony of rounds, corners, material and wall thicknesses, which is therefore also hard to define. This is especially the case when a chair is still in the (preliminary) design phase. To get a feeling for the seating comfort as well as the amount of support for the user in an early stage of development BPO has compared its analyses with measurements of an existing wooden seating shell of Casala. Based on user experiences with this shell the amount of support the new shell offers could be quantified. In combination with guidelines from the highest international standards for project furniture this shaped the set of requirements for the strength and stiffness of the plastic shell.

Using this set of requirements BPO optimised the seating shell that was designed by Kommer & Kors. Because of its pleasant haptics, the way it feels to the touch, PP was preferred over engineering plastics like Nylon (PA). To reach the required strength and stiffness characteristics a 15 [%] glass fiber reinforcement was used. The weight gain this introduces has been compensated by optimising the wall thicknesses on different parts of the shell. Advanced optimisation software was used to achieve the optimal wall thickness distribution in the shell.

The result is a plastic seating shell with comfortable support, pleasant haptics and good seating comfort. The shell is used on both Onyx, a modern chair for pubs and company restaurants, as well as Sfinx, an auditorium chair with a patented coupling system. The sweeping lines of the shell give both chairs a modern, timeless look befitting any environment.