R2R Operational Insights: Oscillations and Resonances

Web lines can encounter excessive oscillations due to resonances. Resonances require two separate conditions to be met:

1. Presence of a periodic excitation; this could be from eccentricity in the rollers, eccentricity or out-of-roundness in wind/unwind, processes such as embossing
2. Presence of web line natural frequencies within the range of operating points. These frequencies are influenced by the web’s mechanical properties, dynamic effects from dancers, and of course the feedback controllers

The resulting oscillations can be seen in measured tension, speeds, dancer positions, or even machine frame. Such oscillations can have negative effects on the quality of the product. MapleSim’s web handling simulation tool enables you to study the dynamic system behaviour, understand the source of vibration and test out mitigating ideas.

Using MapleSim, engineers can evaluate the eigenfrequencies, determine the relationship of the eigenfrequencies and mechanical parameters, and have a virtual testbed to verify the changed configurations e.g. the length of a dancer arm or decreased roller inertias etc.