The RHEOGRAPH 25 E is a high-pressure capillary rheometer for determining the viscosity of thermoplastic materials under clean room conditions. The rheometer is also used as RAM Extruder for the production of implants in the pharmaceutical industry.

The RHEOGRAPH 25 E was developed from our standard high-pressure capillary rheometer especially for use in clean rooms. The instrument can be used as a capillary rheometer for determining viscosity as well as a RAM Extruder or piston extruder for manufacturing rod-like products. For example, implants made of biodegradable plastics can be produced as drug carriers.

Why using a RAM Extruder instead of continuous working screw extruder?
A RAM Extruder uses the platform of a capillary rheometer, a well proven testing instrument in the polymer industry. High precision temperature control guaranties stable condition within the reservoir.
The heating process in the reservoir is very gentle, compared to undefined mixing in a continuous extruder which might lead to unwanted shear heating. The linear speed driven ram guaranties a constant and stable diameter of the extrudate, which cannot be reached with the pulsating flow in a screw-driven extruder.
The batch process of a RAM extruder guaranties minimum off spec material and product waste. High-cost products like temperature-sensitive medicine can be processed in small quantities with less than 100 ml per extrusion cycle.

The device is completely made of stainless steel and designed according to protection class IP64. This makes it easy to clean and disinfect the unit. It is designed for operation in Class A clean rooms.

With the die-swell measurement, the diameter of the extruded product can be checked automatically. The melt cutting device can be used to cut off the extrudate at defined intervals.

Advantages of discontinuous RAM extrusion:

  • Processing of very small quantities of material
  • Highly accurate volume output by pistons - barrel - capillary system
  • Nearly residue-free use of the material used
  • Limited shear heating
  • Easy cleaning (removal of the barrel)
  • Easy documentation and tracking of individual batches
  • Simple combination with die swell measurement and cutting device
  • RABS or isolators formation are possible
Technical specifications
  • Complete stainless-steel design for operation in class A clean room conditions
  • Piston speed from 0.00004 to 40 mm/sec over the entire force measurement range of 25 kN
  • Test barrel diameter 20 mm, others on request
  • Temperature control from +30 °C to +250 °C
  • Measuring mode "constant speed" or "constant force"
  • Measurement of the piston force, calculation of viscosity
  • Parameterization, control and measurement with software LabRheo, evaluation via software WinRheo II
  • SCRIPT-control for freely definable automatic measurement and production procedures
Optional Units
  • Die-Swell measurement with optional automatic melt cutting device

RAM – vs. Screw Extrusion?

Advantages of the discrete, discontinuous RAM extrusion compared to the conventional screw extrusion in the clean room production.


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