Bottle Fillers - Understanding the Fill Cycle

For those that currently use a liquid filling machine, or even those that have researched liquid fillers, you have probably come across the term "fill cycle". Generally speaking, the term defines the time it takes for one set of bottles to run through the filling machine and receive product, from entering the fill area to exiting. But understanding what actually makes up the fill cycle can help a packager to achieve maximum efficiency with their equipment.


Of the many components that make up the fill cycle, the indexing is that time in which the bottles move into the fill area and under the fill heads, as well as the time it takes the bottles to exit the fill area once they have been filled with product. In other words, the indexing times are really the travel time for the bottles. Fine tuning the indexing times can save fractions of seconds or even seconds on each fill cycle, which can mean a lot of saved time when hundreds of cycles are run every day. Almost all automatic filling machinery will include an automatic indexing set up in the PLC. Operators simply line up bottles and press a button to achieve ideal indexing times. These times can also be saved on a recipe screen on automatic fillers, to be recalled each time the bottle is used in production. So the first step in finding a cycle time, and the first component of the cycle time, is the amount of time the bottles will spend indexing in and out of the fill area.


Delay and duration times include all of the different times and pauses that will occur while the fill is taking place. While the fill time itself would be considered a duration time, we will discuss that below by itself. Delay and duration times may include many different components, including, but not limited to:

  • Container Available Delay - The filler will include a sensor to see bottles as they move into the fill area. This setting generally delays the start of the fill or head dive until the sensor has seen a bottle for the indicated time, ensuring that bottles are in place and ready for the fill.
  • Head Release/Up Delay - When using diving heads, this setting allows the operator to enter a slight delay from the end of the fill time to the time that the heads begin to rise out of the bottles. The delay allows for the release of pressure and the settling of product, to help ensure there are not spills, drips or other issues when the fill heads release.
  • Exit Gate Duration - Though the index times are set for the travel of the bottles, the operator must ensure that the gate that holds bottles in the fill area remains open long enough for filled bottles to exit, while also closing to stop the next set of empty bottles. The exit gate duration is set to achieve this goal when using pin indexing.

Of course, many other delay and duration settings may be included on any given filling machine. Those that will be included will depend on a number of different factors including indexing type, containers being used, the product itself and even the type of filling machine being used. Now in addition to the indexing time, we have all the delay and duration settings to add to the fill cycle time.


Again, the fill time would be considered a duration time as noted above, but each and every filling machine will have some variation of this setting. The fill time is also what most people immediately think of when talking about a fill cycle. Quite simply, the fill time is the amount of time necessary to put product into the bottles. We isolate the fill time here to show that the fill cycle consists of much more than just the time taken to fill the bottle. Of course, the larger the container, the more fill time that will be necessary. But most automatic filling machines will include assistance in setting up the fill times as well as the recipe screens to save these times once they are set.

Now taking these three items discussed above, we can create a sample fill cycle. Bottle first index in to the fill area, taking exactly four seconds to enter. From here, the heads will not dive until the container available sensor delays for 0.5 seconds and the heads take 0.5 seconds to dive. Assume it takes 10 seconds to fill the bottles with product and then the heads release, taking 0.5 seconds to raise. The exit gate opens and bottles index out for four seconds, completing the cycle. (The exit gate will shut after allowing the last bottle to leave the fill area, and by this time, the new bottles will likely be entering the fill area, starting a new cycle).

Taking the times from the simplistic example above, you can see this project will take twenty seconds to complete a fill cycle, able to complete three cycles per minute. The importance of this calculation becomes appartent when trying to determine production schedules. If a ten head filler runs three cycles per minute, the machine will fill 30 bottle per minute of the given container. In other words, understanding the fill cycle can help make the machine efficient while also assisting in planning production schedules to make the company efficient. For questions or for more information on fill cycles or filling machines in general, contact Liquid Packaging Solutions, Inc. today.