Electrostatic Issues in Roll-to-Roll Manufacturing Operations

Presented here is a survey of electrostatic issues in roll-to-roll manufacturing operations, use of electrostatic field meters to diagnose static problems, and effective means to dissipate charge. Electrostatic issues are usually caused by tribo charging between two chemically dissimilar materials. Electrostatic issues rarely arise from static charge separated during one contact. Rather, charge accumulates from multiple contacts until there is enough to cause problems. Eliminating static charge at the source is the most cost effect solution to static problems. Materials of construction of the manufacturing equipment and the formulation of products should be selected to minimize static charge separation. The electrical conductivity of rubber or polymer covered roller should be sufficiently high to dissipate static charge in one roller revolution. Electrically conductive antistatic coatings may be included in products to minimize static problems. Because manufacturing operations can be quite complex, having a model or framework to help 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 can measure 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 field meters. Areas of high electrostatic field may be identified by portable electrostatic fieldmeter measurements along the web path during the operation of a roll-to-roll manufacturing process. Charge dissipation technology is most effective when used at locations where charge accumulation is highest.