Tension and Speed Synchronisation in Extrusion Coating
topic
Extrusion coating line speed and tension synchronisation maintains constant substrate speed at the coating nip through precision drive control coordinating unwind, coating, and rewind tensions with dancer roll tension feedback systems, with the draw-down ratio between die exit speed and substrate speed controlling the final coating thickness and the neck-in width reduction of the extrudate that determines the edge coating quality and usable coated width.
Role
Governs the coating weight and width achieved at the substrate by controlling the ratio between the polymer melt exit velocity from the die and the substrate speed that together determine the draw-down stretching of the melt film that controls coating thickness, with draw-down ratio optimisation being the primary parameter adjustment for achieving target coating weight while managing the neck-in effect that reduces the usable coated width from the nominal die width.