To this point, we’ve examined the mechanics of the Value Stream Map (VSM). We’ve looked at the the flow of the process, at the data boxes, at the flow of communication and the overall assessment of value adding vs. non-value adding.
All of this has been to reach the point that leaders can make informed decisions about how to use their limited Lean assets to improve flow.
There are two key points I’d like to make before addressing those decisions.
- First, the VSM is a leadership tool. While everyone is encouraged to read and understand it, VSMs are not intended to be used by others in the organization. Why? Because only senior leaders (or the Value Stream Manager) control the Lean Assets (discussed below) needed to improve the value stream.
- Second, Value Stream Analysis (VSA) needs to be performed from the customer backwards. Remember: the VSM is a tool used to identify obstructions to flow and then remove them. Not all obstructions will impact the customer equally when removed. So, the order in which we remove them is from the customer back to the supplier.
Removing Obstacles to Flow
This last bullet (above) may not seem intuitive, so let me use an example: Picture a value stream in which Takt Time (TT) = 22 seconds. Cycle Time (CT) at operation #2 is 45 seconds; more than twice TT. Meanwhile, CT on operation #5 also exceeds TT, but only by 15 seconds. Some might want to attack the larger problem (operation #2) first, but let’s examine what would happen.
Hypothetically, we’d conduct a Kaizen event to get CT at operation #2 down to TT or less. But ask yourself, how much faster will product flow to the customer? It will flow at the pace of the slowest operation closest to the customer, in this case, operation #5. Why? Because we didn’t remove that obstacle. So, all the product we can now push through operation #2 will just jam up between operations 2 & 5.
If, however, we get the CT at operation #5 to TT first, it will start draining the lake of inventory in front of it.
Then, when we remove the obstruction at operation #2, product will flow at TT all the way to the customer. So, with rare exception, correct problems closest to the customer first, then work your way back to the supplier, one operation at a time.
REMEMBER: The goal isn’t just to get Value Stream flow down to TT or less, but to do it in such a way that value is pulled from each successive operation.
As I said above, VSMs are a leadership tool. In the event that your organization hasn’t been structured into individual value streams, with their own Value Stream Managers, the senior leaders at the site should be the ones reviewing the VSM. This review is most often referred to as a Value Stream Analysis, or VSA.
Reviewers, which include the senior leader and their staff (or the VS Mgr and their staff), should analyze the VSM no less frequently than monthly. Obviously, if there is a VS Mgr, he or she should be reviewing the VSM as a tool of constant feedback.
What’s magical about a monthly review? In a Lean organization, a month is a long period of time and during that period at least one Kaizen event should occur. Every time you conduct a Kaizen event, you change one or more dynamics in the VSM; hence, the cause for review.
What are Lean Assets? When I refer to “Lean Assets,” I’m referring to some or all of the following:
- Your Continuous Improvement (CI) Manager* and any staff under his or her direction;
- Any process or equipment that will need to be taken offline so as to conduct an event;
- Any product you’ll need to build ahead so you can shut the process or machine down for the event, including any overtime you’ll have to approve to build that product;
- The team that will be assembled to conduct the event and perform any follow-on activities.
So, in this post we’ve examined Who uses the VSM, What they are looking for and How Often they will conduct their reviews. In the next post, we’ll examine how leaders will use the VSM to allocate their Lean assets.
*NOTE: The title for the senior Lean person is immaterial. What is important is that you have one and that they report directly to the senior person at the site. Even when you have VS Managers, an overarching Lean leader (CI Manager) is critical and becomes a key resource to the VS Managers.
