Bar feeders are perhaps the most common automation accessories used in metalworking. Generally applied to turning machines they, are designed to deliver a continuous supply of raw machining stock in the form of round, hex, square, and extruded shapes for the manufacture of parts of rotation. Able to accommodate stock of 20, 12, 6 and 4 foot lengths, the bar feeder attached to the machine tool at its headstock end.
There are two common types of bar feeds available: hydrostatic and hydrodynamic. In hydrostatic bar feeds, the bar rests in a series of channels that clamp down on the top and bottom of the stock to hold it in place. In the hydrodynamic bar feeds, the stock is held in a feed tube surrounded by pressurized oil. This allows for faster spindle speeds, but it also increases change-over time from one bar diameter to another.
Increasingly, bar feeders are being equipped with "magazine" storage units that are capable or significantly increasing the amount of stock that can be run unattended through the machine tool. In some "light's out" untended machining operations these magazine feeders can supply enough stock for a machine to run a full shift without intervention. Historically bar feeders are applied in single spindle turning machine tools, multi-spindle machines and some rotary transfer machines. Several machine builders have recently incorporated the bar feeder on vertical machining centers. Among the drivers for this development are simplified fixturing for the machining center, continuous supply of blank material for longer production runs, and the ability to perform 5 and 6 sided machining to produce complete parts.
Bar Feeder Trends:
Quick change guide channels
Remnant reduction
Bar fed machining centers
Short length bar feeders
Magazine fed bar feeders
Untended light’s out machining
Swiss type bar feed response
Double pusher design
Bar whip reduction