Value stream mapping usually employs standard symbols to represent items and processes, therefore knowledge of these symbols is essential to correctly interpret the production system problems.
Value stream mapping is a lean-management method for analyzing the current state and designing a future state for the series of events that take a product or service from its beginning through to the customer. At Toyota, it is known as "material and information flow mapping". It can be applied to nearly any value chain.
Planning and preparation. Identify the target product family or service. Create a charter, define the problem, set the goals and objectives, and select the mapping team. Socialize the charter with the leadership team.
Draw while on the shop floor a current state value stream map, which shows the current steps, delays, and information flows required to deliver the target product or service. This may be a production flow (raw materials to consumer) or a design flow (concept to launch). There are 'standard' symbols for representing supply chain entities.
Assess the current state value stream map in terms of creating flow by eliminating waste.
In a build-to-the-standard form, Shigeo Shingo suggests that the value-adding steps be drawn across the centre of the map and the non-value-adding steps be represented in vertical lines at right angles to the value stream. Thus, the activities become easily separated into the value stream, which is the focus of one type of attention, and the 'waste' steps, another type. He calls the value stream the process and the non-value streams the operations. The thinking here is that the non-value-adding steps are often preparatory or tidying up to the value-adding step and are closely associated with the person or machine/workstation that executes that value-adding step. Therefore, each vertical line is the 'story' of a person or workstation whilst the horizontal line represents the 'story' of the product being created.
Value stream mapping is a recognised method used as part of Six Sigma methodologies.
A key metrics associated with value stream mapping are value adding times and no value adding times. Value adding time is called lead time.
Associated analysis methods
Hines and Rich (1997) defined seven value stream mapping tools they are:
^JANUŠKA, M., PÁLKA, P., ŠŮLOVÁ, D., CHODŮR, M. Value chain of virtual enterprise - Possible modern management concepts and value drivers identification. In Annals of DAAAM for 2009 and 20th International DAAAM Symposium "Intelligent Manufacturing and Automation: Focus on Theory, Practice and Education". Vienna: Danube Adria Association for Automation and Manufacturing, DAAAM, 2009. s. 469-470. ISBN 978-3-901509-70-4 , ISSN: 1726-9679
^Rich, Nick; Esain, Ann; Bateman, Nicola (1997). Lean Evolution: Lessons from the Workplace. Cambridge University Press.