KraussMaffei: Modern recompounding line now available at R&D centre
For some months now, KraussMaffei’s R&D centre at the Hanover site has been equipped with an advanced industrial-scale recompounding system. With the new system KraussMaffei substantially extends its capacities for customer trials and its own testing activities associated with recycling and recompounding processes. Interested customers can carry out industrial-scale trials on the new EdelweissCompounding line in at the R&D centre. The line is composed of two ZE 65 BluePower twin-screw extruders and designed for a maximum output rate of 2,000 kg/h. The combination of two twin-screw extruders enables high degassing capacities, efficient odour removal, ideal dispersive and dispersing mixing effect, gentle melt treatment at a high throughput rate, the company says.
In the first stage, a twin-screw extruder degasses the starting material and removes any adhering odorous substances. This is particularly important when recycling post-consumer waste. Odour minimization can be intensified by using water, nitrogen or even carbon dioxide as entrainer for degassing, made possible by metering and degassing options. “In addition, the first twin-screw extruder ensures optimum homogenization of the input material that is often characterized by rather inhomogeneous quality,” says Carl-Philip Poepel, Director Product Management Extrusion Technology at KraussMaffei. Via a melt pipe, the melt is conveyed into the second twin-screw extruder where the actual compounding process takes place. “Filling, reinforcing, pigmenting and incorporation of additives – the twin-screw extruder is designed for any given process task. This is why our extruders are equipped with all auxiliary units for metering pellets, powder, fibres and liquids,” adds Poepel. The twin-screw extruders are provided with gravimetric metering systems for various media as well as with the appropriate downstream equipment such as fine filters, pumps and pelletizing unit from BKG-Systems from the Nordson Corporation.
Another new feature of the Edelweiss line is the cutter-compactor unit, which KraussMaffei has recently integrated into its portfolio. While rigid fractions with an apparent density of over 0.3 kg/l can be easily fed directly into the first twin-screw extruder, particularly light and fluffy material fractions need to be prepared for further processing. Light fractions, such as fibre and film scrap with high input moisture contents of up to 10 % are first dehumidified, compacted and homogenized in the cutter-compactor before it they are transferred into the extruder. In contrast to known concepts that have been available on the market so far, the new cutter-compactor unit is operated offline and the agglomerate material produced is discharged onto a belt weigher. “This enables gravimetric metering with an accuracy of 99.8 %,” says Poepel. Metering variations that tend to occur with light fractions are thus excluded. With this solution, all post-consumer LDPE, HDPE, PP or PS fractions can now be easily processed into high-quality recompounds and used as a substitute for new material in both injection moulding and extrusion applications.
The EdelweissCompounding line installed in the R&D centre is completely integrated into a turnkey module. The new turnkey module can be installed in any hall. Neither different levels of installation nor a special hall construction are required, as the module of well-conceived design contains all elements required for recompounding. When delivered, the line only needs to be connected to the local power, water and compressed air supply and production can be started immediately. In the event of relocation, the module can be transported as a whole and is immediately ready for production without any changes being required.