Home > Online Close-Loop Monitors Four Cast Film Extruders during Production

Online Close-Loop Monitors Four Cast Film Extruders during Production

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article image Online Closed Loop Concept at a Blow Moulding Plant

Rheology Solutions  is a sales and service organisation that specialises in material characterisation, temperature control, polymer testing and viscometry instruments among others.  

Applying the close-loop concept, a raw material producer’s off-line laboratory is enabled to perform continuous online metering. This continuous control makes it possible for the manufacturer to optimise the process while making immediate amendments.  

Even producers of high-end films monitor 100% of the extrusion process, detecting problems in raw material or the process quickly. This way, in case there are any changes in the process, they can take measurements without delay.  

Following the principle of the close-loop concept, the conventional off-line laboratory is connected to the production process right online, so the producer can control process and quality.  

Small quantities of raw material are taken during processing to obtain representative information to oversee the entire production. Before the introduction of the close-loop concept, data on the quality of production could take an entire shift before it was available.  

Such enormous costs from waste production can’t be tolerated nowadays. With Return on Investment (ROI) ranging far below one year, this is a standard concept today.    

The approach of online quality control

Online quality control comprises two areas: measurement of the granules and measurement of the extruded cast or blown flim.  

Measuring the granules produces information on LAB colour value, Melt Index (MI), pellet size distribution (pellet size and shape distribution systems) as well as dust/abrasion and contamination (pellet scan systems).  

Yet, measuring the extruded film online makes statements on bittiness (gel count), additive content and physical properties (IR spectroscopy), brilliance (glossmeter) and/or the value of turbidity (hazemeter).  


Closed loop today is a standard concept applied in raw material production.  

Not only does it monitor qualities, it controls and optimises the production process. It thus reduces ROI to less than one year.  

Even to produce sophisticated sheets, most producers control 100% of extrusion and refinement, detecting raw material faults immediately.

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