SOMOS® GramixIndividual weighing and dosing of bulk materials

The SOMOS® Gramix gravimetric dosing and mixing system continuously and highly accurately determines the weight of flowable bulk polymer materials, resulting in reproducible mixtures complying with predefined formulations. Continuous nominal/actual comparison in the controller automatically detects fluctuations in bulk density and, in the event of any deviation, corrects the speed of the discharge screw (loss-in-weight principle). Signal coupling to the extruder controller (functional coupling of dosing and conveying) ensures that any abrupt changes in throughput are identified and control behavior is optimized accordingly.

The SOMOS® Gramix dosing system feeds extruders in numerous applications with throughputs of up to 2,500 kg/h. Gramix ExactDos is available as an option for dosing small volumes of additives at a throughput of as little as 200 g/h, as is an attachment for dosing regrinds with a bulk density of as little as 150 g/l.
This smart dosing technology is Industry 4.0 capable and available in three models with different throughputs: Gramix E (up to 300 kg/h), Gramix S (up to 1,200 kg/h) and Gramix S2000 (up to 2,500 kg/h). Throughputs are based on pellets with a bulk density of 0.6 kg/l.

Modular design ensures flexibility

Each Gramix model is designed to handle up to nine metered components and is capable of accurately processing pellets, powders and regrind. The modular design means components can be simply added or removed. The components used within the Gramix product group are interchangeable. A PLC-based touchscreen controller with a graphical user interface ensures user-friendly operation and is also capable of controlling extruder throughput. The servo dosing drives have a wide control range (up to 1:1,000), so minimizing dosing screw changes and thus reducing line stoppages and production downtime.


  • High-accuracy small-volume dosing
  • High-temperature version for up to 160°C
  • PLC-based basic controller with touch operation
  • PLC-based plus controller with touch operation
  • Automatic filling with SOMOS® suction conveyors
  • Regrind version
  • Powder version for individual components
  • Water-cooled inlet for thermally sensitive materials

Are you interested in receiving additional information? Then feel free to call us or send us an e-mail.
Phone: +49 6251 77061-0

SOMOS® Gramix TwinDos

Twin screw extruders

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SOMOS® Gramix FlakeDos

PET bottle flake

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SOMOS® Gramix ExtremeDos

Challenging regrinds

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SOMOS® Gramix ExactDos

Gravimetric ultra-small-volume dosing

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