Wear Mechanisms and Performance of PET Shredder Blade with Various Geometries and Orientations

Shredder blade is the main component of a shredder machine used in plastic recycling. A comparative performance study was conducted on the shredder blade with different geometries and orientations to understand its wear and shredding mechanism. Identification of the loading distribution along the shredder blades was observed in different orientations. The microstructure and hardness of the worn cutting edge and as-received shredder blade were characterised by optical microscopy, scanning electron microscopy along with the energy dispersive X-ray, X-ray diffraction analysis and hardness testing. The wear mechanism in the shredder blades was categorised as progressive wear. The progressive wear was due to the abrasive, adhesive, and oxidation wear. Recycling efficiency, shredding efficiency, and percentage retention are the parameters used to evaluate the performance of the machine with various geometries and orientations. The best combination of the geometry and orientation is the double-edge shredder blade with spiral orientation, which exhibited recycling efficiency at 97.39 ± 0.04%, shredding efficiency at 69.53 ± 1.32%, and retention at 2.61 ± 0.04%, along with a smaller number of blades recorded severe wear.