Most people reading this blog probably had to take a Christmas tree down in the last month. Now, my Christmas tree is a pretty cheap plastic one I picked up at the local supermarket and requires some assembly. This got me thinking about the lean concept of process flow. Let’s analyze what’s involved in getting the tree put away for next year:
- I have to take the branches off the tree
- I have to “un-spread”, or flatten, the branches. This involves me gathering all of the sub-branches together and twisting until they stay together.
- Finally, I had to put the branches in the box.
Now, in manufacturing one of the principal sources of waste can be transport and storage costs. Obviously, storage isn’t really going to cost me anything: I can just drop pieces on the floor. On the other hand, transport can be an issue: it’s easy to drop pieces on the floor, but picking them up involves bending down and I’d rather minimize that.
Now, Lean Thinking will tell you always to concentrate on making processes flow. Here’s how that would look:
- Take a branch off the tree
- Flatten it
- Put it in the box
There’s two difficulties in practice with that approach, and both are related to the final step. First, certain pieces need to go in first or it’s unlikely you’ll get them all to fit. Those pieces are large and at the centre of the tree. In other words, they’re the last pieces you get hold of taking branches off the tree. Another is that, actually, it’s much easier to put in five small pieces at a time than five in a go. (There’s another alternative here I’m not going to examine: take the box apart, put all the pieces in it and then use gaffer tape to stick it back together.)
So, now I’m flattening everything before putting it into the box. So, is process flow not working for me? Not quite.
The Whole Value Chain
The first step of lean thinking is to analyze the whole value chain. Now, value for me is defined as getting all of the Christmas stuff put away. So far, I’ve only been considering the tree. Let’s just add in the lights on the tree to the value chain.
Now, I’m very fond of my Christmas lights, but they’re a series of large (5cm) baubles connected by wire wrapped around the tree. A tree which is, itself, pretty physically complex. They catch everywhere. Taking them off is a pain in the neck and needs to be done before you start disassembling the tree.
Actually, no it doesn’t.
Here’s what you can do: find one end of the lights and pull lightly. Identify the branch on which it is caught and pull the branch off and leave it on the floor. This has the entertaining property of making it significantly easier to take the lights off and doing a fair proportion of the next step. You can then
- Take the remaining branches and flatten them before dropping them on the floor as well.
- Sit down and flatten the remaining branches
- Put the whole thing in the box.
This is definitely improved, but the two stage flattening looks inelegant. I can’t flatten the branches while I’m taking off the lights because my hands are already occupied. But what would have happened if I’d added the rest of the tree’s decorations into the analysis?
Here, we’ve got another process improvement. Removing the branch and then removing the decorations from it is probably easier than removing them from the fully assembled tree. The lights would then be easier to remove. Finally, it addresses all of the branches, making it possible to flatten them straight after removing the decorations and re-introducing some of the “flow” we lost when we realized the boxing was a batch step.
Why didn’t I do that? Simply, that bit was done by my wife and I wasn’t involved at that stage. Again, we’re seeing another aspect of lean thinking here: to correctly optimize the process flow, I can’t just concentrate on my part of the job, I’ve got to look at the whole enterprise. Of course, that’s easier to achieve when you’re part of the same company (or marriage) than otherwise, but often that’s where a lot of benefit can be found.
So, what have we seen here:
- Making processes flow is desirable, but there are cases, such as packing the branches, where it doesn’t work.
- The more steps in the value chain you include, the more likely you are to come up with an optimal solution.
- Communication with other producers in the value chain can revolutionise the process.