Press releases

Uncompromising wear protection

02.08.2017
- KraussMaffei Berstorff uses new material for housing liners of the ZE BluePower twin-screw extruder series
- Wear protection gains increasing importance for compounding companies
- New powder material with outstanding properties
- Oval liners provide optimized arrangement of cooling and cartridge heater bores

(Hannover, August 2, 2017) When compounding highly-filled polymers, wear caused by abrasion and corrosion is a frequent problem as it substantially affects the service life of twin-screw extruders. Hannover-based KraussMaffei Berstorff now offers housing liners made of a new material for their ZE BluePower twin-screw extruder series. The reasonably priced new liners provide excellent wear resistance.

Wear protection gains increasing importance for compounding companies

Higher demands on plastics products in terms of performance, environmental compatibility and price bear a decisive influence on the compounds they are made from. More and more of these compounds are fiber-reinforced, contain special additives like flame retardants, or they are provided with high shares of fillers and reclaimed material to reduce costs. This in turn has effects on the processing machinery, so that wear protection is an issue of ever increasing importance for compounding companies. "We have addressed this problem and examined a large variety of metal materials available on the market. This is how we have found the perfect complement to our portfolio of materials," says Andreas Madle, process engineer in the plastics development division at KraussMaffei Berstorff.

New powder material with outstanding properties

The new 72HA material – an iron-based powder-metallurgical alloy with high shares of carbon and chrome – is manufactured using the HIP method. The chemical composition of this material ensures excellent wear protection against abrasion and corrosion and facilitates mechanical processing. "This is why the new material offers optimum wear protection when it comes to applications with abrasive and corrosive stress, plus an extremely attractive price compared to the high-performance materials used so far," explains Andreas Madle. The liners made of 72HA material are through-hardened. "We have already manufactured the first liners made of 72HA for an extruder of the ZE BluePower series and tested them in practical use – with excellent results."

Oval liners provide optimized arrangement of the cooling and cartridge heater bores

The liners of the ZE BluePower series feature a particular elliptical shape. These oval liners are the unique selling point of the state-of-the-art ZE BluePower series that convinces by a large free volume at high torques. The slim liner shape enables an optimized arrangement of the cooling and cartridge heater bores and thus highly efficient temperature control of the housing elements. In addition, the special geometry of the oval liners prevents liner deformation in the intermeshing zone. This improves the heat transfer from the external housing to the liner. A special contact collar ensures correct axial positioning of the liner inside the housing. For this reason, no leakage occurs at the housing connections of KraussMaffei Berstorff liner housings, which could be caused by different thermal expansion of liner and housing when the liners are not axially secured.

"With the new metallic material, the complex geometry of the completely through-hardened liners can be produced without any problem. We are convinced that this is a unique and uncompromising alternative when it comes to wear protection," says Andreas Madle.

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KraussMaffei Berstorff

The product brand KraussMaffei Berstorff is internationally synonymous with state-of-the-art and value-proven solutions in extrusion technology. The product range includes individual extruders with corresponding molds, upstream and downstream components and automated system solutions.