4. Process modeling

4.1 What can be expected from modeling

It is a tool for sizing calenders: drive power of cylinder motors, rigidity of the frame and cylinders. Above all, it is a tool for predicting calendering defects: sheet profile, conditions under which defects occur and, therefore, a priori calculation of the working conditions required to remedy them. This modeling is preferably applied to the gap between the last two cylinders of a PVC calender or to the gap between the two cylinders of a calender for polyolefin or thermoplastic polyurethane formulations.

Modeling requires:

• a good geometric description, which is fairly simple in calendering compared to other polymer shaping processes (extrusion-injection). However, we...