In modern buildings sofisticated window sealing systems are used to provide good air and water tight qualities. Finding an optimal seal shape is not an easy task, sinse the severe technical requirements concerning this qualities should be meet without decreasing neither the simplicity of use, nor the estethic aspects.

In many similar studies,  non-linear analyses are performed to calculate for different configurations the deformed shape and estimate the sealing surfaces. Forces required to close the window is estimated as well.

Another concern in window design is its acoustic transparency. Especially in urban areas, noise has became a major enemy of the quality of life. Influence of window seals on acoustic transparency can not be ignored any more.

Coupled vibro-acoustic study have to be performed to access the acoustic transparency. First, structural model including the frame, the seals and the glasing is created and an eigenvalue analysis is performed. The modes are used in coupled Sysnoise simulation.

After the seal geometry design is completed meeting all the technical requirements, extrusion line must be set-up in such a way that a efficient quality production can be performed. Complex seal profile shapes includes zones which have very different thicknesses, and therefore the rubber flow is not uniform, being accelerated in wide zones and decelarated in thin zones. In such cases, the extruded profile at the die exit is not stright, and it is difficult to stabilise the production meeting the requirements for dimension tolerances. Extrusion die optimisation technique consists of modifying the upstream part of the die so tha the flow is accelerated in thin zones. This is very tricky process, performed by specialists on a trial and error procedure. Using simulations, the number of die design iterations is drastically reduced.

Finite element model of the flow domain in extrusion die and part of the feeding system is presented, together with Polyflow simulation results for both non-optimised and optimised die configurations.