Filling Machine Options - Indexing Systems

Filling Machine Options - Indexing Systems

While all automatic filling machines will be equipped with an indexing system, the type of indexing system to be used can vary based on need.  Different indexing systems may be used  for different machine speeds, different bottle size or shape, or simply the personal preference of the packaging company.  Most automatic liquid fillers will use pin indexing, with star wheel indexing a close second choice. However, other alternatives do exist for unique or custom projects.

Pin Indexing

Pin Indexing, or Gate Indexing, uses two cylinders to move and stabilize bottles as they move through the filling machine.  An entry gate will open to allow the correct number of bottles into the fill area.  Once that number has entered, the entry gate closes to hold back additional bottles.  At the other end of the filler, the exit gate extends to stop bottles in the correct position to receive product.  Once filled, the exit gate will retract, allowing bottles to move down the conveying system to the next packaging machine.  

Star wheel Indexing

Star wheel indexing uses a grooved wheel to index containers in and out of the fill area.  As bottles move down the conveyor, each will enter one groove on the star wheel.  The stop pin in the star wheel allows the correct number of containers to be indexed for each fill cycle.  Star wheel indexing allows a little more speed than pin indexing in that the need to synchronize the conveyor belt speed disappears with the star wheel indexing, as well as the fact that no gap need exist between containers entering and exiting the fill zone.

Screw Indexing

Screw indexing works just like it sounds.  A timing screw is used to move bottles into the filling area of the packaging machine.  The timing screw generally offers better bottle control, including the ability to act as an orienter.  This type of indexing can also take away the need to adjust fill head positions for different bottles, though different bottles may also require different timing screws.

Shuttle Indexing

Shuttle indexing will normally take advantage of two conveyors running parallel to one another.  As one set of bottles receives product from the bottle filler, the second set of containers will move into position on the second conveyor, one bottle along each container being filled.  After the filled bottles move out of the way on the power conveyor, the set behind them is pushed into position, removing a fraction of the indexing time required using pins or gates.
Again, the indexing to be used on any given filling machine will depend in part on the speed, bottle and a number of other factors.  Analyzing each packaging system to understand the unique needs of the project will help to identify the ideal indexing solution.