Title: Major components of a bar loader:
Course: Introduction to Swiss Programming

Module 2: The Bar Loader or Bar Feeder

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Major components of a bar loader:

Channel set: Available in many sizes. Often the channel set is sized for the maximum diameter a particular screw machine can accept.

Pusher bar: This bar has a collet on the end of it, that collet is sized for the barstock the machine will run. These are usually around 4 feet long and this is what lets the bar loader extend up into the back of the screw machine's spindle. A collet sized for the diameter barstock the machine will use is fitted on the end of the pusher bar. Some brands use collets that screw onto a threaded end of the pusher bar, some brands use a pin to connect the collet to the pusher bar. RRCC's C320 loader uses a pin.

Feed carriage: The feed carriage handles positioning a new bar in the loader in preparation to be fed into the machine, it also attaches itself to the pusher bar and moves the barstock and pusher bar forward. The pre feed carriage is what allows a bar loader to only be a couple feet longer than the barstock. Without the pre feed carriage, bar loaders would need to be 4 or 5 feet longer than the longest bar they are made for.

Bar gripper: The bar gripper grips the bar remnant allowing the pusher bar and its collet to be removed from the remnant. After the remnant is removed the bar gripper opens, waits a couple seconds and closes again. If the bar gripper jaws encounter a bar the loader will 'alarm out" and stop operation. The bar gripper also grips the back end of a new bar of material and holds the bar stationary while the collet at the front of the pusher bar is pressed onto the end of the bar. Some bar loaders require the gripper mechanism be adjusted for the barstock size during the bar loader setup. The C320 loader on RRCC's A-20 does not need to be adjusted.

Bar storage rails: The bar storage rails are where bars are stored while waiting to be loaded in the machine. As a bar is loaded into the machine the remaining bars all advance.

Bar lifter/separator: The bar lifter / separator system makes sure only a single bar at a time is lifted into the bar loader channel and also keeps the bars from climbing over one another as they advance down the rails. It is necessary to adjust this system for the bar diameter that will be loaded.

Bar support rollers: The C320 bar loader at RRCC has rollers in the bar loader at the 'front' of the bar loader and at the back of the screw machine spindle. These rollers are adjusted for the barstock diameter being run and depending on where the pusher bar is in the loader will automatically open and close during automatic operation. Not all loader have rollers, some use a polyurethane clam shell support.

Oil pump: Bar loaders always have an oil pump. The oil is fed to multiple locations in the channel.

Headstock synchronization system: The headstock synchronization system enables the bar loader to follow the movements of the screw machine's headstock. Some loaders like RRCC's C320 have a physical connection to the screw machine's headstock. When the synchronization system is engaged the screw machine headstock and bar loader pusher bar move together. The synchronization mechanism is engaged when the bar loader is in "automatic" mode and the front spindle collet is closed . It is not engaged when the collet is open. When the front spindle collet is open and the bar loader is in "automatic" mode the pusher bar will try to push the bar forward. Some bar loaders use electronic synchronization where the movement of the bar loader pusher bar is controlled by a servo motor slaved to the screw machine's headstock movements. All bar loaders for Swiss screw machines have a synchronization system.

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Date last modified: March 23, 2015.
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