ne of the most common methods of film manufacture is Blown Film (also referred to as the Tubular Film) Extrusion. The process involves extrusion of a plastic through a circular die, followed by "bubble-like" expansion. The principal advantages of manufacturing film by this process include the ability to:
Produce tubing (both flat and gussetted) in a single operation
Regulation of film width and thichness by control of the volume of air in the bubble, the output of the extruder and the speed of the haul-off
Eliminate end effects such as edge bead trim and non uniform temperature that can result from flat die film extrusion
Capability of biaxial orientation (allowing uniformity of mechanical properties)
Blown Film Extrusion can be used for the manufacture of co-extruded, multi-layer films for high barrier applications such as food packaging.