The most common form of automatic parts feeder is the vibratory bowl feeder. Other automatic feeders include the hopper feeder, centrifugal hopper, barrel hopper, magnetic feeder, and elevating hopper feeder. These parts feeders are specialized and the feeding mechanism is designed to handle unique parts. The device which converts the bulk random orientation of parts into flow of orientated parts in these automatic feeders often takes the form of a fork or blade.
The movement of parts in a vibratory bowl feeder is created by a drive
unit which induces vertical and angular vibration to the bowl.
Parts are momentarily caused to leave the track surface during the
vertical phase of vibration. The angular vibration moves the
track and the part falls onto a track portion beyond the initial
position of the part. Incorrectly orientated parts are rejected
at the bowl tooling stage by passive devices and returned to the bowl
base. These mechanisms of operation make the bowl feeder unsuitable for
automatic feeding of parts dosed with viscous fluids because the
vertical vibrational force is not sufficient to lift the part from the
track, due to the adhesion of the viscous fluid. The continuous
rejection of parts at the tooling stage and the vibration of the track
against the part tends to damage delicate parts. Parts with print faces
and delicate projections are particularly affected.