Aesops Fables – Tortoise and the Hare

Most of us, when we were young’uns, heard Aesop’s fables. Perhaps the best known is the story of the turtle and the hare: One day they decide to have a race. The hare is pretty fast and does not view the turtle as much of a challenge. He takes off but then stops along the way for a beer or two, runs fast for a bit more than has some lunch and so on. The turtle is a lot slower but is steady. In the end, the slow but steady turtle wins the race.

Packaging lines are like that sometimes. We think that running them faster will result in more output. Sometimes it does but sometimes we get the opposite.

Years ago I was a young maintenance manager in a pharmaceutical plant. One of the products was a suppository that was strip packed between two foil laminates. It was not a terribly sophisticated process and the strip packing machine was supposed to run at 60ppm. At least that is what the manual said.

When we ran it at 60ppm, there were about 25% rejects. Some of this was crushing the suppository between the jaws, some was the laminate not sealing correctly some was due to other issues.

Through trial and error when the packaging manager was not looking I found that we could almost completely eliminate the rejects by slowing the machine from 60ppm to 50ppm.

As soon as I would leave, and the packaging manager would find that I had slowed down his machine, he would crank the speed back up to 60ppm. Rejects went up as well.

Running at 60ppm with 25% rejects, meant a true output of 45 good products per minute. When the loss from damaged product and the time to rework leaking packages are included, it is considerably less. Over a 420 minute shift, it would produce 18,900 good products.

Running at 50ppm with 3% rejects true output is 48.5ppm or 20,370 good products for the shift.

I never could get the packaging manager to understand this:

Sometimes you just have to slow down to go fast.