Coperion has optimized the EGR eccentric pelletizer for integration with the two-stage Kombiplast compounding system. The scope of the changes included the overall system design, air supply, material conveying and pellet handling. According to the manufacturer, the new version of the unit delivers clearly improved pellet quality, especially when processing temperature- and shear-sensitive plastics. At the same time, the energy consumption of the pelletizing system itself has also been reduced. The modified design is also intended to simplify operation compared with the previous version. The pelletizing system can now be heated more quickly and product changes, including die plate replacement, can be carried out faster, which translates into higher overall equipment effectiveness, OEE. The EGR pelletizer is integrated with the two-stage Kombiplast compounding system. Both technologies were designed for the production of soft PVC, rigid PVC and HFFR formulations.
Processing and pelletizing temperature- and shear-sensitive plastics places high demands on the entire compounding process. The material must be handled as gently as possible at every stage in order to maintain consistently high pellet quality. Based on extensive simulations and practical tests, Coperion optimized the air supply system in the EGR pelletizer. As a result, pellet conveying now takes place at significantly lower feed pressure, which means gentler treatment of the material. This conveying method not only improves product quality, but also effectively reduces the risk of agglomerate formation. These changes also bring measurable economic and environmental benefits. Compared with the previous model, the new EGR reduces energy consumption for material conveying by up to 75 percent. This means both lower operating costs and a reduced carbon footprint associated with CO2 emissions.
Higher system availability
Coperion also redesigned the die plate heating system, which can now be easily separated from the die plate itself. Die plate assembly and disassembly are now much faster, which is particularly important during recipe changes. At the same time, the pelletizer can be heated up in less time, limiting production delays. According to the company, these changes increase the uptime of both the EGR itself and the entire compounding system, improving OEE.
Simplified operation and service
The redesigned EGR pelletizer also stands out for easier handling. During die plate replacement, the level of safety for operating personnel has been increased. A split, pivoting pelletizer hood provides easier access to the blade, allowing pelletizing knives to be adjusted faster and more precisely, which supports better cut quality. The optimized design also simplifies maintenance and service work, reducing the time required for routine operations and helping to minimize downtime.
An important modification is also the relocation of the EGR drive to the front side of the pelletizer hood. This solution makes it easier to install a screen pack changer between the Kombiplast discharge and the EGR pelletizer, which is often required in the production of cable compounds.
Kombiplast and EGR in one line
The two-stage Kombiplast compounder and the EGR eccentric pelletizer form a system adapted to the production of temperature- and shear-sensitive plastics such as PVC or cable compounds. The system was designed to ensure particularly gentle product handling throughout the compounding process while maintaining high economic efficiency and flexibility.
Raw materials are first fed into the process section of a ZSK twin-screw extruder by means of a ZS-B twin-screw side feeder, where they are conveyed, plasticized, mixed and homogenized. In the ZSK Mv14 configuration, with increased torque of 14 Nm/cm³, the extruder is intended to enable very gentle product handling while also achieving high throughput. Product discharge takes place via the ES-A single-screw unit, which builds up the pressure required for the EGR eccentric pelletizer.
In the pelletizing stage, the EGR cuts cylindrical product strands exiting the die plate into uniform pellets using rotating pelletizing knives. The pellets are then removed by pressure conveying, using new inflatable seals designed for this purpose. The pelletizing knives are mounted on a blade arranged eccentrically relative to the die plate. The rotational speed of this element is infinitely variable. Coperion adapts the number, diameter and geometry of the die plate holes to the material properties and the individual customer requirements.
The redesigned Coperion EGR eccentric pelletizing system delivers higher compound quality and significant energy savings in the production of temperature- and shear-sensitive plastics.
