I overheard a conversation the other week at a between a couple of people who talking about lean. Naturally, my ears pricked up and I just hard to eavesdrop a little bit. They were making a list of their 'lean projects' they had completed already, which was quite a list. They were then going to set their sights on their next 'lean project' and how they would define the benefits that would bring to that area of the business.
The Projects(s)
I couldn't help myself, I had to ask, how many lean projects they had done in the last 12 months, and where. Turns out they had done 7 lean projects across the business, putting out fires and fixing issues, involving the team. They had been having a great time and had seen some output improvements as a result. Now they were about to start on the 5th operation in the production line, they had done the 4 downstream operations already, and now it was time to fix operation 5.
Every inquisitive I probed a bit, what were the issues with the operations before the 5th one? What changes had they made in their projects? Turns out the first 2 stages in the process were just messy, and they had rearranged the area to reduce the movement of operators and create more logical places for input and outputs to go into the next operations. Operation 3 had a high failure rate, so they introduced some mistake proofing concepts and new tools and had managed to drive up the quality to the target level. Operation 4 was their masterpiece; however, they had managed to half the time that the operation took, and so they had to fix operation 5 because, well, it was a bottleneck now that operation 4 could go twice as fast. My next question was, can operations 1-3 keep up with 4?.. “Yep”, was the answer, “in fact they can go even faster than 4 so we are just pushing the bottleneck to the last stage of the process as part of the project plan”.
A little perplexed, I asked how is the actual flow of the entire process, I asked? Is operation 5 the ultimate bottleneck on the process? They skipped the answer to my 1st question but told me that, operation 7 was the real bottleneck, but they hadn't got there yet.
How's the flow?
Even more perplexed, I came back to my question, how is the flow? They considered it and said, oh, it'll be fine when we finish each of the projects to improve each operation.
The thing is, lean is all about flow, your process needs to flow in the same way as a river does, where it's got obstacles, it becomes turbulent, and things get choppy. So, where you have bad quality or uneven operations, you get turbulence in your process. There is no such thing as projects in lean, you are either taking a lean thinking approach or you aren't. Where you focus your attention is key.
If you improve the processes at the start of your operation and the issue is at the end of the operation, then you haven't improved anything because your output hasn't gone up. Yes, it may look nicer, you would have less scrape (which is always positive) but in terms of where it's hurting, it's the bottleneck.
They two, very capable, keen young engineers had stated at the start of the line which sounds like it makes sense but in fact what they were doing was waste. All the improvements they made did not increase the flow of the line, it was just creating a bigger issue in the middle, that wasn't there before.
Always think flow
If you think about our river analogy, if you wanted to get a faster flowing river you wouldn't try to push more water in, would you? Which is exactly what was happening by improving the 1st set of operations, you push more into the upstream operations (even if they are operating on pull you still effectively push where the other operations move faster).
To speed up your flow you look for what is blocking it, what is creating turbulence, remove the logs, and debris and then work back up the river to the source, you start at the end not the beginning. It's the same with your operation.
By first examining an understanding the last operation, you know immediately how fast everything else most go. If you see this operation is waiting then move further upstream, there isn't anything to see at the last one, go further and keep going until you find the blockage. Start your thinking there.
Unblocking flow, starts with thinking, not doing. We are all programmed to jump into action, but before you act, think (remember – Plan > Do > Check > Adjust) Consider what happens when you speed up this bottleneck, what are the implications on flow, both up and down stream.
Once you understand the issue and the ramifications of any changes you are going to make, then and only then start the work.
Never forget balance
Ultimately, the last operation is the one you want to be the slowest, you want the bottleneck being there. Sometimes it isn't possible, in that case think about what else you can do to balance all the other operations to the same rate as the bottleneck. If your bottleneck has a 5-minute cycle, then every other operation should be tuned up to get as close to a 5-minute cycle as possible.
This may mean that you split or combine all or some of the other operations. Line balancing on its own while not increasing output can remove waiting time and unnecessary movement, and so eliminate a lot of waste while freeing up people to be able to work on something else.
It's never a project.
The word project suggests a start and an end point, that's not how lean works. Lean is a transformation that your organisation makes in the way it thinks. Everything else, every other lean tool or technique that you ever hear of, is second to the way you think. Which reminds me of a great quote from Henry Ford, I'm sure you have heard it: