Faraday Law

Static Charge

Accumulation of electrons on the surface of a mould or a plastic part creates a potential difference that can lead to discharge. Faraday law governs the induction of these charges when the plastic moves through an electric field, such as near a high-voltage power line or a corona treater. This buildup causes parts to stick together in the collection bin or attract dust from the factory air.

Surface Potential

Measurement of the voltage across the part allows the operator to determine if the charge exceeds the safety limits for the environment. Faraday law relates the geometry of the part to the strength of the field it generates. High surface potential can ignite solvent vapors in painting or coating operations.

Grounding Requirement

Prevention of electrostatic discharge relies on providing a path for the electrons to follow. Faraday law indicates that a conductive cage or a grounded surface will shield the interior from the external electric field. Moulders use ionising bars and conductive additives to manage these forces and maintain a safe production floor.

The law provides the basis for designing effective anti-static systems in high-speed extrusion.