The Lauffen-based company Extricom GmbH has been involved in the development and production of closely intermeshing screw systems for 30 years. The family-run enterprise stands for innovation power in the area of twin screw extruders. Extricom GmbH has further developed and patented this machine concept under the name of RingExtruder RE®.
In the plastics industry, twin screw extruders are an important part of the production chain. The twin screw extruders used for the preparation of melted plastics mass consist of two intermeshing screw shafts that transport the polymer through a heated cylinder. The major task of the extruder is to carry out specific substance modification processes. Extricom, which has an engineering background, offers components such as screws and kneading elements as well as barrels and shafts for a broad range of twin screw extruders. "Extricom is an alternative supplier of consumables and replacement parts for twin screw extruders," explains Michael Erdmann, head of process engineering at Extricom, highlighting that "Extricom is not only a supplier of iron and steel, but also of know-how in the area of twin screw extruders." The company has developed a proprietary extrusion system known as RingExtruder. "The RingExtruder is based on twin screw machines, with twelve rather than two screws," explains Erdmann. The RingExtruder technology is used in the company's extrusion department and laboratory in the city of Lauffen, where mixing processes are also being developed and optimised and employees and clients are being trained in extrusion.
In contrast to twin screw systems, the RingExtruder has many advantages for many applications. The system can be used in the compounding of polyolefines, the strengthening of technical plastics with glass, coal and natural fibres as well as in the production of polymer blends and alloys. "In the RingExtruder, the plastics raw materials are modified by integrating pigments and reinforcements or by carrying out chemical reactions," said Erdmann. The RingExtruder RE® XP has twelve screws that turn in the same direction and which are arranged in a ring. This set-up opens up many new possibilities for the processing and treatment of plastics.
"One of the advantages of the RingExtruder is the dispersive mixing efficiency which is enhanced by the screw-to-screw transfer of material throughout the compounding process. This means that the additives in a melted polymer mass can be better distributed and mixed homogeneously. As a result of having twelve screws, the machine is far more efficient than traditional twin screw extruders," said Erdmann, adding that such machines improve the homogeneous processing of the material and prevent temperature peaks as well as product damage. At the same time, the RingExtruder processes the material very carefully due to the reduced use of mechanical energy. The device is also very energy efficient. "The problem of many twin screw extruders is that the melted mass reaches particularly high temperatures when energy is introduced into the melted mass. And these high temperatures cannot be controlled. The geometry of the RingExtruder makes it easier to influence the temperature of the melted mass," explained the plastics expert. Another important aspect is the efficient removal of volatile byproducts such as moisture or degraded products. In many processes, it is necessary to remove volatile byproducts from the melted polymer mass with a vacuum. The RingExtruder's better surface-volume relationship leads to a considerably higher degassing efficiency.
Of course, biopolymers can also be processed with the RingExtruder technology. The machine has an outstanding effect on the highly sensitive biopolymers. “Biopolymers are often very sensitive, both with regards to temperature and mechanical strain. They tend to degrade at specific temperatures or when a strong mechanical load is applied,” explains Erdmann. The improved temperature control and more efficient energy introduction of Extricom’s RingExtruder also demonstrate the instrument’s superiority over twin screw extruders for work with biopolymers.