Planetary roller extruder
Planetary roller extruders are machines from plastics technology and belong to the upper group of extruders . It was invented by Ludwig Wittrock early 1950s and was first widely used in the PVC - calender -Industrie. Today the planetary roller extruder covers the entire range of processing and reaction technology.
Structure of the planetary roller extruder
In the planetary roller extruder, a central spindle is driven on which the individual planetary spindles, which can be varied in number, roll. The rotating planetary spindles are also guided via an internally toothed bush. The temperature is controlled both via the central spindle and via the roller cylinder. The planetary spindles grasp the material as the central spindle revolves, and by dipping the spindle teeth into the corresponding tooth gaps, the input material is rolled out into thin layers and transported forward by means of the helical teeth. The repeated thin-film rolling with the planetary spindles and the large heat-exchanging surface of the extremely thin-walled roller cylinder ensure optimal plasticization, dispersion and homogenization.
Standard planetary roller extruder for the plastics industry
To give an idea of the exchange area of a planetary roller extruder, let us consider the standard size of a calender feed extruder. With one revolution of the central spindle, this planetary roller extruder exchanges approximately an area of two tennis courts per minute.
particularities
The manufacture of the cylinder liners by means of deep erosion has various advantages compared to the conventional manufacturing methods of drawing, whirling or grinding. On the one hand, an exact geometry of the involute toothing, even in hardened material, on the other hand, a minimal wall thickness of the cylinder liner. In particular, this minimization of wall thickness together with the repeated thin-film rolling enable the most precise and gentle material processing of all (processing) extruders . With this system, even material mixtures with large differences in viscosity can be processed without any problems.
Another special feature is the modular design of the planetary roller extruder. With the modular design, several roller cylinders are coupled one behind the other and thus the process path is multiplied or the process technology is adapted to the respective requirements. As a result, the planetary roller extruder, in contrast to other conventional preparation extruders, has the option of switching entire process chains in series. Several reactions (such as degassing, injecting liquids or adding filler and solid components) can be carried out one after the other during a process.
Areas of application
Planetary roller extruders can be used in the following areas of application due to their precise and gentle material preparation:
- Plastics industry - z. B. all PVC formulations, ABS, TPO, TPU, filled polyolefins, prepex, rubber processing, elastomer adhesives
- Paint industry - z. B. epoxy, polyester, acrylic and similar paints
- Chemical industry - z. B. Mixtures with endothermic and exothermic reactions
- Food industry - z. B. all thermally sensitive recipes, cocoa-sugar dispersions, ice cream, specialty malts
- Pharmaceutical industry - z. B. Granulation of hydrophobic and lipophilic active ingredients
- Special applications - z. B. Sewage Sludge Treatment, Wood Plastic Composite
Manufacturer
- ENTEX Rust & Mitschke GmbH
- battenfeld-cincinnati Germany GmbH
- Troester GmbH & Co. KG, Hanover Germany
Selected literature
- Polymer processing and plastic compounding / Harald Rust, Klemens Kohlgrüber, Michael Bierdel / Hansa Fachbuch / 1st edition 10/2019
- Erwin Baur, Sigrid Brinkmann, Tim A. Osswald, Ernst Schmachtenberg: Saechtling plastic paperback / 30th edition. 11/2007
- Specialist knowledge of plastics technology, learning areas 1 to 14 / 2nd edition 2010
- Friedrich Johannaber, plastic machine operator, Hanser Verlag / 4th edition. 12/2003