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The value stream for a product family may cross department boundaries in the company. This creates the potential for difficulties in coordinating an effective value stream project. Such problems call for creation of the position of value stream manager. This manager must have the authority to make things happen and should report to the plant manager.

It is recommended that a production person handle the job of value stream manager. This manager would monitor all aspects of the project. Being a hands-on person, the manager should be on the floor on a regular basis.

A current state map of the process is developed to facilitate process analysis. Basic tips on drawing a current state map include:

Some of the typical process data includes: cycle time (CT), changeover time (COT), uptime (UT), number of operators, pack size, working time (minus breaks, in seconds), WIP, and scrap rate. An analysis of the current status can provide the amount of lead and value-added time.

In many situations teams take on the task of data collection. Both individuals and teams find it beneficial to develop a VSM data box in advance. Examples of data boxes are shown in Table 5.24 later in this Section and in the service industry case study in Section XI.

Value-added time (VAT) - The amount of time spent transforming the product, which the customer is willing to pay for.

The future value stream map is an attempt to make the process lean. This involves creativity and teamwork on part of the value stream manager and the lean team to identify creative solutions. Everything the team knows about lean manufacturing principles is used to create the process of the future.

The final step in the value stream mapping process is to develop an implementation plan for establishing the future state. This includes a step-by-step plan, measurable goals, and checkpoints to measure progress. A Gantt chart may be used to illustrate the implementation plan. Several factors determine the speed of the plan. These include available resources and funding. The plan could take months or years to complete, and even then, there may be a need to improve upon it in the future.

There seems to be a number of questions around the differences between process mapping (commonly used in six sigma) and value stream mapping (associated with lean). Team members often ask “Which is better?” and “Which should be used in a given situation?” The answer: Both tools are completely valid and have their place in documenting and improving processes. Let’s examine the two tools.

Process mapping creates process visualizations to understand their technical and organizational interactions. It is heavily used in six sigma and other methodologies such as ISO and standard operating procedures. These maps identify all the factors that can have an effect on the process or problem area. Process mapping is very effective for complex inter-related processes that cross many functions.

By having all of the important aspects of the overall process on a single page, it is much easier to understand everything that should be considered before making any changes. If changes are being considered, one can re-draw the process map and have an easy way to compare the “before” and “after” representations.

Process maps are a wonderful way to provide a clear understanding of all the interrelationships in complex processes – like software coding, call processing, product and process design cycles, chemical and pharmaceutical processing, clinical trials, etc. where there are many interactions and “cause-and-effect” relationships. Six sigma, as a technique, heavily uses process mapping and SIPOC together to attack process variation and to improve quality.

Value stream mapping (VSM) - Also known as "Information and Material Flow Maps" is credited to Toyota Motor Company. It is best known in Learning to See by Rother and Shook. Value Stream Mapping is a scalable approach to create a visual representation of what is happening in a process. It includes detailed information at each step and across the whole value stream. VSMs are powerful tools to help identify where changes are needed to improve system performance. The two major things that VSMs focus on are material and information flow. Information flow is often independent on the “thing” being mapped in the material flow.

If an organization generates information (say processing insurance claims), one must imagine the claim as the “material” in the VSM, just as if it were a physical product. By doing this it is possible to use a VSM approach successfully in a service or office process. Using a process mapping approach to the information flow may also make sense, coupled with a material flow data box.