W&H 3 layer extrusion line
|Machine||W&H 3 layer extrusion line|
|Type of extruder||Blown|
|Number of layers||3|
|Diameter die||500 mm|
|Lip opening||2,2 mm|
|Diameter screw(s)||2 x 70 mm
1 x 90 mm
|L/D ratio screw(s)||1:30|
|Material & Min – Max thickness||LLDPE/LDPE/HDPE/PP/Borstar/
|Max. film width||2600 mm|
|Min. – Max. film thickness||20 - 200 micron|
|Max. output||850 kg/hour|
|Rewind manufacturer||W&H Filmatic S|
|Max. rewind reel diameter||1200 mm|
|Rotating, which part||Take off|
|Dosing unit||INOEX Raw Material suction, loading
and dosing systems Computerized gr/m2
line speed and kgh throughput Control
system with integrated supervisory computer
|Thickness measurement||Yes, Kundig|
|Corona treater||Yes, AFS|
|Including||- Cooling ring: Multicool airing 2800
- VAREX PROCONTROL supervisory data computer
Extrusion in the flexible packaging industry can roughly be devided in three kinds of extrusion: blown film extrusion lines, cast film extrusion lines and BOPP extrusion lines.
Blown Film Extrusion
Blown film extrusion is the most common technology to produce plastic film. Blown film extrusion is typically carried out upwards vertically.
Film is made out of polymer material. These polymeres are generally in the form of granulate. This material is melted and then forced or extruded through a die. Air is blwon thourgh a hole in the center of the die. This pressure causes a bubble. This bubble is a thin layer of film. The film is pulled upwards from the die to cool down and winded on the a roll.
Blown film extrusion exists in various layers, the more layers the thicker the film. The process with more layers is called coextrusion.