Joe was having trouble with his bean can codes and I agreed to see what I could do to help.
He was using an inkjet coder on the can ends and the codes were wrapping in a circle. Not only were they round, the dots were stretching out, sometimes to illegibility.
“What can I do?” he asked.
We went to the floor and the problem was so obvious that it bit my ankle.
“Fiddlesticks on round codes!” I roared. “You can’t code in gravity.”
“The cans are rolling down a gravity chute on their way to the labeler. As the can rotates, the code forms a circle. A second problem is that the linear speed of the can varies as it falls down the chute. Too slow and the ink dots bunch up. Too fast and they stretch out. Either way, you get an illegible code.”
“The simple solution is to relocate the conveyor to a point on the line where they are conveyed single file at a consistent speed. The conveyor after the labeler looks like a good bet.
“If you must code in the chute, add a short pair of powered belts in the chute. These will capture each can and transport it past the inkjet head at a consistent speed without rotating.
A high proportion of packaging problems occur because of package handling issues rather than machine problems. Get the package under consistent control and you will solve most of your problems.
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].