One Piece Flow Video…It’s Misleading (A Discussion of One Piece Flow and Supermarkets)

Rick Bohan
20.04.2019

First, take a look at the video.  (I saw it recently on a LinkedIn post.)  Then, let’s discuss below the fold.

As I mentioned, I saw this recently, shared in a LinkedIn Post. It’s a simple illustration and, like most simple illustrations, it’s not meant to convey all the possibilities and nuances of the thing it’s trying to illustrate. (Got all that?) But…the comments below the post say things like “A simple but very effective illustration.”

I actually think the illustration is a bit misleading (and, yes, I’ve used similar illustrations myself) because the process illustrated exists just about nowhere. I’ve had one client to which this illustration was directly relevant. That client assembled counter top kitchen appliances along a line of assemblers. The value of one piece flow was evident to anyone who watched the assemblers for a few minutes.

One piece flow isn’t so easy to achieve in most other operations. The video conveniently shows process steps that have the same cycle time. What if, instead, the first operation runs at 100 units/hour while the second operation runs at 10 units/hour and the last operation runs at 250 units/hour? And what if all those operations are also needed for other products? Do we schedule all four operations to run one product? Might that prove difficult if all the operations aren’t available at the same time?

So, maybe I’m being a bit too picky…as I said earlier, no illustration is perfect. My problem is that illustrations like this are provided without the needed caveats or further discussion as to the circumstances in which the illustration is and is not applicable. Managers see illustrations like this one, realize that it doesn’t fit their own conditions, and decide (wrongly) that lean methods have no application in their organizations.

In my own work, I’ve found that “supermarkets” are more applicable that one piece flow. Supermarkets are a bit tougher to illustrate than one piece flow but the concept is more widely applicable. Here’s a video that I just found that does a good job of describing the use of a supermarket. It’s short, so take a look at it.

The short video doesn’t go into all the benefits of the supermarket, but you can see that different cycle times between the two operations won’t matter much and that scheduling is a lot easier.

In my next post, I’m going to get into some of the nuances of supermarkets in a bit more detail.

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