How to know if your thermoplastic extrusion process is under control ?

Good question?!

We need to check all parameters, right?

But two of them allow to have a global vision of the process.

The first one is material pressure.

Pressure value gives valuable information on the molten thermoplastic flow:

– high or low value value indicates too viscous or too fluid flow,

– variation in value indicates unstable melting process in extruder.

The second is motor load.

Motor load indicates how much power the extrusion screw needs to push material in the extrusion head. Motor load gives valuable information on the solid material flow:

– high value indicates difficult pellets packing and melting,

– low value indicates low extruder efficiency, the screw is only used to push the material,

– variation in motor load indicates unstable pellets feeding, packing and/or melting.

Points described above can have different and multiple origins, from temperature settings, screw design, to thermoplastics characteristics.

General rules are available but your specific process (thermoplastic, extruder, head and tools) needs a specific analysis.

But the very first parameter is the consistency of the extrudate, right?

What are the other parameters you check to ensure your process is under control?

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