A vibratory feeder is a self-contained device designed to manipulate parts of the same type into a specific orientation. It consists of a specially shaped bowl with ramps and other features designed for the parts being fed. Usually included is an out feed accumulation track (linear or gravity) to convey parts along and discharge into the assembly machine comes in many shapes and sizes. The drive unit, available in
piezoelectric, electromagnetic and
pneumatic drives, vibrates the bowl, forcing the parts to move up a circular, inclined track. A vibrating drive unit, upon which the bowl is mounted and a variable-amplitude control box controls the bowl feeder and can adjust the flow of parts to the out feed track via sensors. The tooling (hand made) is designed to sort and orient the parts in to a consistent, repeatable position. The track length, width, and depth are carefully chosen to suit each application, component shape and size. Special bowl and track coatings are applied according to shape, size and material of the component. These aid traction, reduce damage to the parts and lower acoustic levels. Vibratory feeders rely on the mechanical behaviour of a part, such that when gently shaken along a conveyor chute that is specially designed for the part, many will be gradually become aligned properly, and the rest will fall back into the bowl. Thus a stream of parts leave the feeder's conveyor one-by-one, all in the same orientation. This conveyor then leads directly to the following assembly or packing machine. Orientation relies on the shape and mechanical behaviour of an object, particular the position of its
centre of mass in relation to its centre of volume. It thus works well for parts such as
machine screws, with
rotational symmetry and a clear asymmetry to one heavy end. It does not work for entirely symmetrical shapes, or where desired orientation depends on a feature such as colour. The ramps within a bowl feeder are specifically designed for each part, although the core mechanism is re-used across different parts. The exit orientation of a bowl feeder depends on the part's shape and mass distribution. Where this is not the orientation needed for the following assembly step, a feeder is often followed by a twisted conveyor that turns the part over, as needed. ==Use==