Extrusion Line synchronization

Since 2006, MEAF’s extrusion lines are equipped with the control system EXTRUSOL, which increased the user-friendliness, ease of control, extensive diagnosis and remote assistance possibilities. Besides the implementation of this control system, MEAF has developed two types of synchronization systems for extrusion lines.

By implementing one of the two systems (either volume based or weight based), the outputs of multiple (co-)extruders are synchronized with the calander speed, whilst maintaining the layer thickness ratio of the sheet.
Advantages for utilizing a synchronization system

  • Less material loss during extrusion line start-up;
  • Improved thickness control of individual sheet layers;
  • Less usage of masterbatches and additives;
  • Easier operation of the entire extrusion line.

VOLUME BASED SYNCHRONISATION OF CO-EXTRUDERS

The volume-based-synchronization requires the extrusion line to be equipped with MEAF’s EXTRUSOL and works most accurate when all (co-)extruders are fitted with a meltpump. If there is no meltpump integrated into the extruder, the operator has to produce his own calculations in order to attain a certain screw speed (our latest version of EXTRUSOL has an integrated calculator, simplifying such calculations).

 

Volume based synchronisation diagram

 

Advantage

  • Economical solution

Disadvantages:

  • When using different kind of materials and/or mixing of virgin regrind;
  • Volume differences lead to weight differences and layer thickness variations;
  • Manual entering of material specific weight for each material calibrating extruder output

WEIGHT BASED SYNCHRONISATION OF CO-EXTRUDERS

The weight-based synchronization provides a solution that requires minimum input from the operator’s side.  It only requires the desired output of the extruder (in kg/hr) for the total sheet extrusion line and the layer thickness of each layer (in percentage of total sheet thickness) and the extruder will automatically adjust itself to meet this requirements, independent of material type, specific weight, material mix or variations.

 

Volume based synchronisation diagram

 

Advantages:

  • Variations in material composition does not effect the layer thickness ratio;
  • No calibration of extruder output needed when using new materials.

Disadvantage

  • Extra components such as weight hoppers are needed, which require a higher investment.

Gallery

  • Extrusol visualisation of synchronisation

Open gallery

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Quick specs

When the extruder needs to be synchronized, the following steps have to be undertaken:

The extruder melt pump and extruder speed are set manually and the take-off speed is set to reach a good quality and sheet thickness. A few minutes after start up, the machine is set into Auto-mode, that means that the extruder screw speed is regulated automatically, to reach a constant pressure before meltpump.

The second step of synchronization is to couple co­extruder output and main-extruder output, to ensure that the total layer thickness remains the same if the total output of the extruder is changed.

The third step of synchronization is to integrate the total extruder output with the line speed. If the line speed changes (speed of rollers), the extruder speed also changes automatically which ensures that the total thickness remains the same and the layer thickness also stays unchanged.

Summarizing:

The customer has one speed button (speed dial) which represent output (kg/hr) and if he increases this output then everything in the extrusion line will follow: co­-extruder(s), line speed of chromium rollers rubber rollers and winders.

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