Lean does not focus on activity, but on value creation and flow.
I recently had the opportunity to observe a production process. An operator was busy with assembly. At one point, a certain component for the product he was working on (A) was temporarily unavailable at his workstation — he had to wait for internal logistics to replenish it. In the meantime, he picked up another type of product (B) for which all the parts he needed were available.
When I pointed out that this was not exactly Lean, the production manager did not see the problem. After all, work is continuing, isn't it?
Why this is not Lean:
- Flow is interrupted: the assembly of product A is stalled. When the operator starts with product B and sets product A aside, you have two half-assembled products. So twice nothing, instead of one finished product.
- Invisible lead time: the turnaround time for item A is longer than necessary, jeopardizing the delivery promise.
- Overloading other departments: this method causes an interruption in the work of internal logistics.
- Root cause missed: by continuing to work, the root cause (required component not at the station on time) is concealed and therefore nothing is done about it.
- Lack of standardization: who assembles which item and when is random, meaning that output is unpredictable.
Work smarter, not harder
In my experience, the root cause of waste is often hidden. We don't like stagnation and we encourage initiative and responsibility. This keeps things running smoothly, but it also means that problems persist.
My people are not going to like this
Standardization and reducing variation are important principles within Lean Six Sigma. But we also want enjoyable work. If you reduce your people to robots, you will lose them. The key lies in offering people variety in their work, without just doing whatever we feel like doing at that moment. That also demands something from a manager.
Observe vs measure
Observe
Lean starts with observing, understanding the process, and talking to the people who actually do the work. The qualitative description of this process already shows that there is waste involved.
If there are rush jobs, this is a clear sign of trouble ahead. Almost always, this is caused by waste in the preceding process.
Measure
A good next step is to create a Value Stream Map. Here, you not only note down the process steps, but you also look at and distinguish between Value-Added Time vs. Non-Value Added time and issues such as buffer levels (WIP).
Metrics that support the process and reveal the above dynamics:
- Flow Efficiency: Value Added time / Lead time
- WIP ratio: number of orders in progress / total open orders
- At product level: variation (sigma) in lead time
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