Granulators

Granulators are machines that chop smaller plastic products into very fine particles. They are mostly used in recycling facilities to prepare scrap and used plastic items for reforming, since plastic is one of few widely used non-biodegradable materials that never breaks down over time, and will overfill landfills. While shredders and grinders handle large, bulky materials, granulators are meant for smaller plastic items like drums, pipes, car bumpers, bottles, packaging materials, bags and defective plastic products. Many times, the plastic products are chopped down in shredders or grinders, and the pieces are then put through a granulator, where they are reduced to fine particles by a rotor with sharp blades, rotating at high rpm. Granulators produce material that is round, fine and of a consistent size. The loose material, called granules, are then sold to plastic product manufacturing companies, where they are melted and formed into other plastic products that are of the same quality by extrusion, injection molding or thermoforming. Most granulators are large and meant for industrial use only. However, there are small home or office granulators available for personal use.

Depending on what products are being chopped, granulators may be horizontal or vertical in construction. Long items like house siding, pipes and profile extrusions are put through horizontal granulators, while all other smaller objects are fed into vertically oriented machines. The whole or shredded plastic products are fed through an opening into the granulator housing, where sharp blades reduce the plastic into small flakes ranging from .125 to .375 inches. The granules must be small enough to fall through a screen that acts as a sifter, or they are processed a second time. Granulators are powered by an electric motor, and have the ability to change speeds and granule size easily. The closed chamber holds the blades, and is often sound absorbing to decrease the process' noise volume. In order to function properly, the interior must be cleaned and the blades oiled on a regular basis. The granulating process is the first step in plastic forming operations, which require plastic material that may be easily melted into liquid form; the smaller the granules, the faster they are able to melt. The products are often pre-shred because it saves on operating costs and granulator downtime.