Lean Tools: Value Stream Mapping

When we look at the entire process behind a product, we get the overhead view of a “value stream.” We can break it up into all of its component pieces. Most processes start with a request for “action” or a product and end only when the product or service has been delivered. Value Stream Mapping looks all the way from the finished product backwards through the process to the raw materials or initial request for action. Now we can really see parts fitting together!

If your process is person-to-person, person-to-machine, or machine-to-machine, Value Stream Mapping can help you to clearly understand—and therefore communicate—all of the steps in a process. Value Stream Mapping also allows you to identify any hidden wastes that exist within a process. Often, hidden wastes are the largest cost of providing services or making products, so when you use Value Stream Mapping to identify the Value Added and Non-Value Added steps, the non-value added steps within your process—which are waste —are highlighted.

From the raw materials storage to delivery of a finished product or service, materials flow throughout a process and are handled by many people and machines. Information also flows all the way from initial request for a product or service to the end, which is the customer’s reception of the product or service. Most flow-charting or mapping processes do not include this crucial element called information flow. Value Stream Mapping not only includes information flow, but also shows how it is intertwined with material flow, machines, and manpower.

An organization’s information system is the communication link that holds together the manpower, machines, and materials. Do not underestimate its importance.

Your Value Stream Map is first drawn in terms of its current process condition. This “Current State Map” identifies the process exactly as it exists today. Then, your Value Stream Mapping process will go on to identify a vision of how the process could be improved and is shown as such in a “Future State Map.”

All of the elements can usually be displayed on a single sheet of paper, which gives an overhead view of the entire process and provides a clearer understanding of how all the steps and wastes co-exist in the system.

Use symbols that are agreed upon and understood by the workers and management. Keep the symbols simple and draw them with a pencil before committing them to a computer or complicated drawing. (It works best when each team member uses an 11×17 sheet of paper and draws a picture of how he or she sees the process first, just to get people thinking visually.)

Then, as a team, they can compare their drawings and discuss the accuracy of each. This usually requires a few trips back to the shop floor to verify the facts. Most processes are not laid out as we have them pictured in our minds. Even if you have to go back and check the facts, and even if the facts aren’t pretty, draw it as it actually is. This exercise often reveals many hidden wastes and opportunities for improvement, and you won’t see them unless you’re open to seeing them.




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