Harish Jose asked about value stream mapping:
Is this “tool” used and abused by lean manufacturing practitioners? Why is this tool not explained in Ohno, Monden or Shingo’s books? Shingo does talk about the process and operations flow. The closest I have seen is process flow in Suzaki’s books.
Harish recently started a blog called Onward Solutions and wrote about this topic today, arguing that spaghetti charts can be used for material and information mapping as well. Both are great tools for visualizing the process flow, but there is an important difference in that the value steam map is 2-dimensional (info flow top-down, material flow side-to-side) while the spaghetti chart is 1-dimensional (side-to-side). If you are new to value stream mapping, Ron Pereira has a series of how-to articles on value stream mapping at the Lean Six Sigma Academy.
Where did value stream mapping come from?
John Shook and Mike Rother co-authored the book Learning to See, published by the Lean Enterprise Institute. They were pioneers in introducing material and information flow diagramming and how to develop lean thinking using that practice. This book made material and information flow widely accessible and applicable outside of Toyota for the first time. Value stream mapping is a flexible tool that let’s us put all of the information in one place in a way that is not possible with process mapping or other tools.
How long as value stream mapping been around?
My guess is that this is a relatively recent addition to the TPS toolbox. It probably did not make an appearance in the early books on TPS because it was not in use until about 20 years ago. The mapping of information flow in parallel to material flow may have become more useful as TPS expanded beyond the factory to cross multiple factories, suppliers and distribution centers. This required a more deliberate depiction of information flow between these locations. Or it could have been related to increased application of electronic information flow, requiring a way to show a wider variety of information flow methods than just the intuitive and visual kanban card signals. Another theory is that it was not formalized until Toyota began translating their system into English and needed to give the scribbles on material and information flow diagramming an official name.
What makes value stream mapping so special?
The interesting thing is that many of us got along just fine doing kaizen for years without value stream mapping. Mike Wroblewski is a seasoned lean and six sigma practitioner and sensei who says value stream maps are muda, while also recognizing the value in value stream mapping. Even at Toyota there was a time before material and information flow diagramming was widely used. So do we really need it?
Has the value stream map made continuous improvement easier or better?
That’s a question each of us has to answer. Like any tool it’s success lies in how we use it. Stakeholder maps are essential tools of change management but only as useful as what you do with the findings. Inventory maps show where cash is tied up as stock, but we still need to take actions to address the root causes rather than just push the triangles back up the supply chain. We should make use of every available improvement tool to the extent that it helps us see the situation, understand the situation and do something about the situation.