Highlight at the K 2007 plastics and rubber trade fair this year will be the new high-performance MX Kneader generation by Buss AG, Pratteln, Switzerland (hall 16, stand A59). This further development of the universal Buss MKS Kneader – optimized for high grade polyolefin-based cable compound processing and special master batch production – offers several advantages:

• Throughput is 2.5 times more without any size increase, thus reducing investment outlay and processing costs accordingly.

• Halogen-free flame-retardant cable compound quality is better than ever, even with very high fillers content up to 68 % by weight. In particular mechanical strength is improved, flame resistance is more effective, and further processing is simplified.

• Specific power consumption for compounding is about 15 % lower thanks to more efficient energy utilization

This decisive technological advance is mainly due to the new four-flight screw and the redesigned kneading chamber with greater volume. As in all Buss Kneaders, the screw oscillates axially each time it rotates, generating a combined motion that intensively but gently mixes the product. Thanks to the compounding technology improvements and individual processing zone optimizations, the mass temperature rise as a function of screw speed is significantly less than before. This enables screw speeds up to 800 rpm without exceeding the maximum admissible temperature of 190 °C for cable compounds.

Buss has also innovated the MX Kneader drive, comprising a compact combination of four water-cooled induction motors actuating the screw shaft through epicyclic and linear gearing. After compounding in the MX Kneader, the product is taken over a by a rugged flanged-on extruder screw. This is specially designed to build up the necessary pressure for melt filtration and product granulation by water-cooled die-face cutting. All modules downstream of the MX Kneader, such as the extruder screw, screen changer and granulating unit, are flexibly displaceable on two axes in a linear system. This not only facilitates access to each module for cleaning and maintenance purposes, but also enables rapid product changes. Buss high-performance MX Kneaders already comply with tomorrow’s strict noise protection norms, and the PC control interface with visualization ensures intuitive operator guidance.