Understanding Indexing Systems for Automatic Packaging Machinery

Indexing systems on automatic packaging machinery allow bottles or other container to be properly aligned for the packaging process at hand.  Indexing systems will typically always be found on automatic container cleaning equipment and automatic filling machines, and less typically on capping machines and other equipment.  Different indexing systems exist to meet the specific needs of the project at hand.  

 

 

Pin indexing, sometimes referred to as gate indexing, is a popular indexing system that uses two cylinders to position containers in the proper location.  The entry gate will open to allow only the correct number of bottles or containers into an area, this number will usually be equal to the number of rinse heads or fill heads on the machine.  Once the right number of containers enter, the entry gate will close to stop additional containers from entering the packaging zone and relieve any back pressure that may be created absent the gate.  The exit gate will remain closed as bottles enter the packaging zone to help align containers, opening after the rinse, fill or other process is completed to allow containers to continue down the power conveyor system.  

 

 

A starwheel is simply a grooved wheel used to position containers in a rinse, fill, cap or other packaging zone.  As containers move down a conveyor, one will enter each groove on the starwheel.  A pin in the wheel will engage and release to allow the correct number of containers to enter or exit.  Starwheels are also used on automatic chuck cappers and monoblock packaging systems, taking advantage of servo motors to start and stop the wheel with containers in the correct position for capping or other packaging functions.  This type of indexing allows a little more speed than pin indexing on an inline packaging system by removing the need to sychronize the conveyor belt speed and removing the slight gap between groups of containers that is necessary with pin indexing.

 

 

Screw indexing uses a large, turning screw that will start and stop to move containers in to position for the packaging process.  A timing screw may be employed over both pin and starwheel indexing for a couple of specific reasons.  First, a timing screw will often offer better container control and can also act as a bottle orienter.  In addition, screw indexing can remove the need to adjust rinse or fill heads for different bottles or containers, though it may be necessary to change screws for containers that vary greatly in size or shape.

 

 

Shuttle indexing makes use of two conveyors that will run parallel to each other.  As one set of bottles is rinsed, filled or otherwise processed, the second set will move into postion on conveyor number two, basically "on deck" for the rinse or fill.  Shuttle indexing will remove a fraction of the indexing time of the pin indexing system but the need for dual conveyors makes this type of indexing less popular than the others above.

 

The indexing system used on any piece of packaging machinery will be determined by any number of factors.  These include, but are not limited to, container type, container size, speed requirements and space limitations.  For questions regarding indexing systems, or packaging machinery in general, call LPS toll free at 1-888-393-3693.