The line runs at the speed of one station
Take a five-station hand line where filling takes 9 seconds, capping takes 14 and everything else is quicker. Capping can produce 3600 divided by 14, which is 257 containers an hour, and nothing downstream of it will ever see more than that. The filler can do 400. It does not matter. The extra 143 an hour the filler is capable of turns into containers standing on the bench waiting to be capped, and then into the filler standing about because there is nowhere to put anything down.
This has a practical consequence that is easy to state and hard to believe until you watch it: putting a second person on the filler raises the line rate by exactly zero. It is not a small improvement. It is nothing, and it costs a full wage. The only station where an extra pair of hands changes the number is the slowest one, and the moment you fix that station the limit moves somewhere else and the arithmetic starts again from there.
Look for the pile, not the effort
The queue is the bottleneck made visible, and it is the most reliable diagnostic on the floor because it does not require a stopwatch or anyone to be honest about how fast they are working. Walk the line during a run and find where containers are standing around. Whatever is immediately after that pile is your limit. If they are piling up before the capper, capping is the limit; if the capper is idle and waiting, it is not.
| What you see | What it means | What actually helps |
|---|---|---|
| Containers stacking before one station | That station is the limit | More hands, a faster method, or a second set of tooling there |
| Someone waiting with nothing to do | Their station is not the limit | Move them to the limit, or accept the idle time |
| Everyone busy, nothing piling up | The line is balanced, which is rare | Only more people everywhere, or a different process |
| The whole line stopped | Downtime, not a station time | The uptime figure, not the station arithmetic |
The setup is usually longer than the run
On a short batch the clock is dominated by everything that is not bottling. If the line does 250 an hour and the batch is 300 containers, the run is about 72 minutes and a 90 minute setup and clean-down is longer than that. Doubling the line speed takes 36 minutes off a day that is otherwise 3 hours 12 minutes door to door, which is worth having and is not the big number. Running two batches back to back on one setup is the big number, and it is an entirely different decision from anything on the station side.
Nearby pages
The seconds per container at the case-pack station depend on how many go in a case, which is the bottles per case calculator. If you are checking fills by weight rather than by eye, the target on the scale comes from the fill weight and tare calculator, and if by eye, the fill level calculator says how visible a difference will be. What the run consumes in containers, closures and labels once rejects are counted is the packaging run loss calculator. For a single machine against a demand rate rather than several stations in series, the same shape of problem appears on the dish machine throughput calculator and the heat press cycle time calculator.
Questions people ask
Will hiring another person speed up the line?
Only if they go on the slowest station. Anywhere else the line rate is unchanged, because it was never limited by that station. Set the page to try the extra person at each position in turn and you will see most of them produce no gain at all. The one that does is the one worth paying for, and only until the limit moves to whatever is next slowest.
How do I find the bottleneck without timing anything?
Find where the containers are piling up during a run. Whatever sits immediately after the pile cannot keep up with what is feeding it, and that is the limit. It is the most reliable signal on the floor because nobody has to estimate their own speed for it to work.
What uptime figure should I use?
Your own, from a timed run. Note the clock at the first container and at the last, count the containers, and compare that rate with the station arithmetic. The gap is your downtime and it includes everything: refilling the bulk tank, running out of closures, a jam, the phone. On a hand line eighty per cent is not a pessimistic number.
The case-pack station is timed per case, not per container.
Divide by the containers in a case before entering it. If a case of twelve takes a minute to fill, seal and set aside, that is five seconds a container. Every station on this page is per container so that the rates are comparable, which is the only way to see which one is the limit.
Is it worth splitting one station into two half-stations?
Sometimes, and the page will show you. Splitting a 14 second capping operation into a 7 second placement and a 7 second tightening done by two people gives the same result as putting two people on capping, if the work genuinely divides that way. Often it does not, because the two halves are not equal and the slower half becomes the new limit at its own speed rather than at half the old one.