Compounding: Strand Pelletizers Improve Quality, Ease Handling

At the upcoming K 2019 show, Coperion will be introducing improved dual- bearing strand pelletizers that have been re-engineered based on field experience and current market demands. The SP140, SP240 and SP340 models in the SP series have been equipped with a variety of enhanced features for easy, rapid handling and optimized pellet quality.

Moreover, Coperion has developed a new proprietary technology for the cutting-gap adjustment that offers increased comfort and speed compared to tried and true classic systems. 

This new, patent-pending cutting gap adjustment constitutes the heart of the re-engineered strand pelletizers. Coperion says conventional solutions like eccentric screws or compression-tensioning screws present disadvantages such as non-linear movements, potential dirt pockets on the product, several setting steps or subsequent shifting from additional locking mechanisms. The unique new technical solution from Coperion offers faster and more comfortable adjustment. Fine adjustment is also simpler and more precise, as it can be done by hand without tools. Likewise, the integrated spring pre-tensioning eliminates the screws’ free clearance, markedly reducing machine setup times.

Along with the more compact design and integration of the operation panel into the machine, the reworking of the interior space positions robust cutting tools installed closer to one another, enabling a shorter, unguided strand length in the pelletizer and the best possible cutting results, especially with soft materials. This new construction results in less dead space in the interior which, together with optimized edges and fewer free surfaces, provides improved cleanability. The complete cutting area is accessible without tools and the cutting unit can be exchanged quickly and easily. This quick change minimizes machine servicing times and downtimes.

Coperion also reworked the intake area; whereas this previously used a conical construction, with the new design a straight intake allows strands to be optimally side fed into the pelletizer. Strands are therefore fed directly into the pelletizer without deflection. Side panels on the intake roller prevent individual strands from breaking free. Moreover, intake proceeds without splits or gaps so that strand tears and bevel are avoided during intake. Coperion was also able to increase the operating width by 20 mm so that higher throughputs are now possible.

Pelletizing in this new design also features improved soundproofing. Along with the more compact interior cutting space and the resulting smaller sound chamber, all motors are now housed under the base plate and are noise insulated there. In so doing, machine operation at a very low noise level is possible.