Melt Temperature and Pressure Control
topic
Extrusion coating melt temperature control maintains polymer melt at the target temperature within plus or minus 2 degrees Celsius through extruder barrel zone heating by ceramic band heaters with PID control responding to melt temperature thermocouple feedback, with die temperature independently controlled to maintain uniform melt viscosity at the die lip that determines coating weight uniformity and the melt draw-down ratio achievable at the target machine speed.
Role
Controls the polymer melt viscosity that determines the coating weight uniformity and processing window for extrusion coating through temperature management that must maintain the melt within the narrow temperature range where viscosity is low enough for uniform distribution across the die width but high enough to prevent thermal degradation, with temperature uniformity across the die width being critical for coating weight uniformity since viscosity variation across the die creates flow rate variation.