Electrostatic Issues in Roll-to-Roll Manufacturing Operations

We present a survey of electrostatic issues in roll-to-roll (RtR) manufacturing operations, use of electrostatic fieldmeters to diagnose static problems, and effective methods to dissipate charge. Electrostatic issues are usually caused by tribocharging between two chemically dissimilar materials but rarely arise from static charge separated during a single contact. Rather, charge accumulates from multiple contacts until there is enough to cause problems. Eliminating static charge at the source is the most cost-effective solution to static problems. Construction materials for manufacturing equipment, equipment design, and product formulation should be selected to minimize static-charge separation. The electrical conductivity of rubber- or polymer-covered rollers should be sufficiently high so that the charge dissipates within one roller revolution. Electrically conductive antistatic coatings may be included in film products to reduce static problems. Because manufacturing operations can be quite complex, having a model or framework in which to organize information is most valuable. An existing model for charge separation and accumulation is extended to include common issues in RtR manufacturing operations. From this model, it is apparent that static monitors are valuable tools to track the charge present in a manufacturing process. High static levels resulting from assignable causes can be identified by control charting the readings from permanently mounted electrostatic fieldmeters. Areas of high electrostatic field may be identified by using appropriate portable electrostatic-fieldmeter measurements to identify where to install charge-dissipation technology to make it most effective.