The case of the bobbling bottle

“KC,” Billy told me at the dairy, “we have a random problem with the capper. Everything seems fine, but we get frequent problems with misaligned caps. It happens randomly and we are at wit’s end.”

“Fiddlesticks on ‘random problems,’ Billy!” I exclaimed. “In my experience, there is no such thing. Every problem has a cause. Finding it can be hard; fixing it is often fairly simple. Let me get these eyeballs on the machine.”

Legendary outfielder Casey Stengel said you can see a lot just by looking. It’s as true in packaging as it is in baseball–it just takes a while sometimes.

After an hour of observation, a pattern began to emerge. The problem was periodic, not random. A stopwatch and counter revealed that there was usually a multiple of 168 between cocked caps.

It was an older rotary filler/capper with 24 valves and seven capping heads. Could it be a coincidence that 7×24 gives 168? Probably not. Delving deeper showed that most problems came when valve No. 13 aligned with chuck No. 5.

It turned out that there was a damaged tooth on the main bull gear. When aligned just right, the bottle would bobble and the cap would cock. Fixing the gear fixed the problem.

Always drink your milk. It will make you grow up strong (and smart) like me.

KC Boxbottom, packaging detective, is on the case to solve tough packaging puzzles. He is the alter-ego of John Henry, CPP. Known as the Changeover Wizard, Henry is the owner of Changeover.com, a consulting firm that helps companies find and fix the causes of inefficiencies in their packaging operations. He produces a free monthly newsletter called Lean Changeover, which contains articles and tips on changeover and related issues. Reach him at [email protected].