What Is A Value Stream?
A Value Stream is “the set of all the specific actions required to
bring a specific product through the three critical management tasks of any business:
…problem solving, …information management, …physical transformation”. --Womack
Value Stream Mapping (VSM) is a visualization tool oriented to the Toyota version of Lean
Manufacturing (Toyota Production System). It helps to understand and streamline work processes
using the tools and techniques of Lean Manufacturing.
VSM addresses material process sequences and flows as well as information flows that impact
this movement. It encourages data acquisition in a systematic manner that often gives additional
insights. The various icons and symbols have
fairly specific meanings and it requires knowledge of these symbols as well as knowledge of TPS
to interpret a Value Stream Map and use it well.
Value Stream Maps reflect a broad view of the process, usually from external supplier to
external customer at a given facility. Extended Value Stream Maps take an even broader view and
often incorporate tier two and tier three suppliers and distributors.
Like Process Mapping, VSM is most valuable in a group setting. Many of the problems it
exposes reach across organizational lines of responsibility and expertise. When a mapping team
has representation from all the different functions and specialties, it gains a common
understanding of the process and a better position for developing and implementing good
When To Use Value Stream Maps
No mapping technique fits every situation and purpose. Use Value Stream Mapping for
high-production, low-variety product mixes with few components and subassemblies and dedicated
equipment. In other situations, Process Mapping, often combined with a Group Technology analysis
may be a better choice.
Present State Mapping
A Present State Map shows work processes as they currently exist. This
is vital both to understand the need for change and to understand where opportunities lie. While
Value Stream Maps appear complex, their construction is easy when taken in logical steps. These
illustrations show how. A broad-based team should perform this exercise.