A granulator is a piece of high-speed equipment that uses a combination of rotary and stationary knives to take larger feed stock items and reduce them to sizes suitable for further processing. The product is ground until it is small enough to be passed through a screen to promote uniformity of size. This is what differentiates a granulator from a shredder. Many industries use granulators to help them recover their waste materials in order to reuse them in the manufacturing process or sell them to another producer. Waste materials that have been through the granulator for reuse are called regrind.