A size-reduction process used for production scrap, post-consumer plastic packaging, industrial parts, or other materials that must be downsized for further processing. Granulators consist of a feed hopper, cutting chamber, classifying screen, and rotating knives that work in concert with stationary-bed knives to reduce the plastic scrap until it is small enough to pass through the classifying screen. The resulting particles, called regrind, can vary in size from 3 mm to 20 mm. (Modern Plastics encyclopaedia 1995).