Such problems are a thing of the past for operators of Hellweg Maschinenbau’s completely redesigned LSZ 150/100 edge strip shredder that feeds and shreds the strips in a single step with no blade, no screen, no infeed device, and no resharpening of the toothed rollers. Years of low-maintenance and trouble-free operation combined with low cleaning requirements mean the shredder is also economic to run.
Four robust toothed rollers provide tension
The key elements behind these advantages are the four hardened toothed rollers machined from solid tool steel billet. Mounted in pairs in a steel housing, these provide a working width of 150 mm. Thanks to not requiring a separately driven, failure-prone infeed device, they forcefully guide the edge strips away from the sheet material during production while keeping them under tension, regardless of strip geometry. An infinitely variable roller speed enables feed speeds of between 0.8 m/min and 6 m/min, so allowing granulation to be perfectly adapted to the production process.
Due to their optimized arrangement and shape, the rollers’ teeth shred the edge strips without interruption into a readily flowable, uniform regrind with an edge length of around 5 mm to 10 mm. This can then be added directly to virgin material. As a result, there is also no need for a separate screen as required by other systems for separating over- or undersized regrind.
Profiled edge strips are typical in the manufacture of sheet webs that, following extrusion, are thermoformed into products such as dimpled sheet or green roof matting. This results in projections on both edges that not only interfere with feed but also delay feed operations during intermediate thermoforming operations. The system’s approx. 600 mm long, rotatably mounted probe arm oscillates to compensate for such variations. An integrated momentary-contact switch that switches the unit on and off prevents the edge strips from being ripped apart. The machines can be equipped with an optional integrated extraction system.
Granulators for any plastics application
In addition to the LSZ 150/100 edge strip shredder, Hellweg Maschinenbau also offers the servomotor-driven R 200/20 Servo edge trimming system for continuously pre-shredding one or two edge strips from film or sheet production. Also known as a chipper or guillotine, it is designed for a working width of 200 mm with cutting thicknesses of up to 20 mm. The resulting chips, which are some centimeters in size, are further processed by a downstream granulator into millimeter-size regrind or flakes as required. Hellweg’s portfolio includes granulators for every plastics application, from small machine-side granulators for sprues up to high-performance systems for solid parts, film and sheet with throughputs of five metric tons per hour and above.
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