A diagram, usually hand drawn that shows the series of steps required to bring a product of service to a customer; also known as material and information flow diagram.
Value stream mapping is a lean manufacturing technique used to analyze the flow of materials and information currently required to bring a product or service to a consumer. At Toyota, where the technique originated, it is known as "material and information flow mapping".
Identify the target product, product family, or service.
Draw 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.
Draw a future state value stream map.
Implement the future.
Where is it used?
Value stream mapping is a helpful method that can be used in Lean environments to identify opportunities for improvement in lead time.
Although value stream mapping is often associated with manufacturing, it is also used in logistics, supply chain, service related industries, healthcare, software development, and product development.
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.
Hand drawn versus tools
The goal is to create a map, with minimum delay, while observing the target process in situation. Thus, value stream maps are usually drawn by hand in pencil to keep the mapping process simple and allow for simple correction.
However, software tools are emerging as an alternative. A variety are available either as stand alone products or stencils/add-ons to products such as Microsoft Visio, allCLEAR and iGrafx FlowCharter.
Associated analysis methods
Hines and Rich (1997) defined seven value stream mapping tools they are:
Process Activity Mapping
Supply chain responsiveness matrix
Product Variety Funnel
Quality filter mapping
Forrester effect mapping
Decision point analysis
Overall Structure Maps