Screw Feeder: What It Is and How It Works A screw feeder is a device used for the controlled feeding and metering of bulk solid materials such as powders, granules, or pellets. Its primary function is to deliver material continuously and precisely into various industrial processes like mixing, compaction, extrusion, or packaging. How It Works The screw feeder operates based on the rotational movement of a helical screw (also called an auger) inside a tube or trough. As the screw rotates, it move