Value stream mapping (VSM), one of the most powerful tools in the lean toolbox, is used to identify, analyze, and remove waste from your operation. The VSM process helps you to create a one-page picture of your current state and allows you to plan the future state.
The current picture will lay out how your operation is currently functioning. When drawing the picture and entering your information, you will quickly see where you have waste within your operation. Traditionally, VSM documents the entire process from the moment the customer places an order to the moment the order is shipped. However, you can also apply a VSM to an individual process or step within your company.
To get started, select an area where you are not meeting your performance metrics or where you receive negative customer feedback. Next, you’ll want to select your VSM team. Make sure the team is cross functional, representing individuals from process functions and supporting business functions like engineering, finance, or sales.
Once the team is assembled, review the VSM process so everyone is familiar with it. This will set the scope so everyone understands what the VSM will cover and what is outside the scope.
Then, go to the area and walk through the entire process. This is a key function for the VSM to work. Take notes and document the process as you observe it. Time each step with a stopwatch. You cannot skip process steps, take shortcuts, or make assumptions, as that will manipulate your data If you notice deviations from what the team expects, ask the people working in the area why they are doing it a different way and document that.
Next, draw the current state on a wall or white board, showing it exactly as it was observed by the team. If there are discrepancies, go back and redocument the process. It is critical the team agrees on what they saw.
Once the current state is drawn, add a lead-time ladder line below the current state. A lead-time ladder line is a horizontal line with a 90-degree step up for each value-added task and a 90-degree step down for each non-values-added task.
When it is complete, add up the times and list the sums on the right side. The top number is the total value-added time, and the bottom number is the total non-value-added time.
Once you have the process visually in front of you, total the value-added and non–value-added times to determine your current state time. Now, review the non-value-added time and start brainstorming ideas and Kaizen approaches to reduce or eliminate the time spent on those tasks. Go through every process step and ask why. Why is this done? Why is it done that way? Why are we doing that?
As you go through this step, place sticky notes with improvement ideas by each step. Do not analyze ideas at this point—just post them.
After you have worked through the entire process, you and the team can assign the ideas to team members to analyze and implement.
Then, when all ideas have been implemented, redo your VSM and see how much of an improvement was made—how much non-value-added time you were able to remove.
The reduction translates into improved throughput time, better on-time delivery, and a more robust process, as well as cost savings, improved customer satisfaction, and better shop-floor control.
When doing a VSM, go into the process with the understanding that it may take multiple days, or even months, to work through. Also, make sure you document any process changes as you implement ideas.
If this is your first VSM, you may want to focus on a smaller process as you will learn as you go. Then, once you get the hang of it, move onto a larger process in your operation.