Indexing Options to Assist in Rinsing, Filling, Capping and More

Indexing of bottles is necessary to help position and account for containers when entering what we will call an action zone on a packaging machine. For example, an inline liquid filler cannot accurately dispense liquid in to a moving bottle. An indexing system is used to allow the correct number of containers to enter the fill zone, as well as to hold those bottles in the correct position during the fill. An automatic chuck capping machine may use a starwheel to correctly position bottle and cap under the capping head. Below we will look at a few of the indexing options available and give a brief description of each.

PIN INDEXING SYSTEMS

Pin, or gate, indexing is a system of indexing that uses cylinders to halt and hold bottles in place. Pin indexing would be a popular choice for the filling machine example listed above. Generally speaking, an entry pin will open to allow a certain number of bottles to enter the fill area. Once the specific number of bottles passes, the entry gate closes to hold back additional bottles from entering the fill area. On the opposite side of the filler, an exit gate will remain closed to stop bottles from continuing down the conveyor and hold them in place under the fill heads. Once the fill is completed, the exit pin retracts and bottles can continue down the conveyor to the next packaging machine. Pin indexing can also be used on other packaging equipment, with rinsing machines often utilizing this system as well.

STARWHEEL INDEXING SYSTEMS

Starwheel indexing can also be used on multiple types of packaging machinery, including filling machinery, but a great example is the chuck capper referred to at the beginning of this article. A starwheel is simply a grooved wheel, with the grooves serving as pockets to stabilize and move containers through a packaging process. With the chuck capper, as a container moves down the conveyor, it will enter a groove in the starwheel for the capping process. As it moves around the wheel, the bottle will first receive a cap, then be positioned under the chuck head. Once the chuck head descends to tighten the cap, the newly sealed container will continue - in the same groove - around the starwheel and exit once again to the main conveyor to be moved to the next phase of packaging.

SCREW INDEXING SYSTEMS

Timing screws, or feed screws, may also be used to move and position containers in a specific area during a packaging process. Typically used on a filling machine, the screws offer a little more speed than pin indexing, but can also require different screws for different bottle sizes where a wide gap exists between the largest and smallest containers. As the screw turns, it also offers some bottle control not available with pin indexing as well as the ability to act as an orienter if necessary.

SHUTTLE INDEXING SYSTEMS

The best way to describe a shuttle indexing system is to call it a dual conveyor system. To compare it to the pin system on a filling machine described above, a shuttle system will line up bottles on conveyor running parallel to the filler conveyor. As one set of bottles is being filled, another set is being prepared on the second conveyor. When bottles move out of the fill position down the main conveyor, the next complete set of containers is pushed into position from the other conveyor. Different designs may be used, but basically a shuttle system will have a complete set of containers ready and waiting to be pushed in to place after a fill. Shuttle indexing allows a packager to create a slightly lower indexing time than can be done with the pin indexing system, meaning a slightly better cycle time and an increase in production speed.

Not all packaging machinery will use an indexing system. A spindle capper, for example, allows for continuous capping as bottles pass through the machine on the main conveyor. Each machine, and the indexing used on those machines, will depend on a number of factors, including product, containers, desired speed and more. To learn more about indexing and packaging equipment, call the offices of Liquid Packaging Solutions to speak with a Packaging Specialist today.