Value stream mapping
Value stream mapping is a lean manufacturing technique used to analyze and design the flow of materials and information 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". It can be applied to nearly any value chain.
- Identify the target product, product family, or service.
- 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.
- Draw a future state value stream map.
- Work toward the future state condition.
Value stream mapping has supporting methods that are often used in Lean environments to analyze and design flows at the system level (across multiple processes).
Although value stream mapping is often associated with manufacturing, it is also used in logistics, supply chain, service related industries, healthcare, software development, product development, and administrative and office processes.
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 metric associated with value stream mapping is lead time.
Hand drawn or software tools
One common method to deepen one's understanding of a value stream is to draw a map. In current-state mapping this is done while observing the actual value stream in situ. The value stream maps are often drawn by hand in pencil; the mapping process is simple, real-time, and iterative, as this method allows for simple correction.
An effective way of working as a group is to cover a wall with paper, such as butcher paper, and provide adhesive notes to each work team, ideally color-coding each group. Each group writes their tasks on individual notes and applies them to the paper in sequence. Lines are drawn between the steps to indicate the work flow. This way the tasks can easily be moved around as other steps come to mind.
However, software tools can also be used. A variety are available either as stand-alone products or stencils/add-ons to products.
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
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- Graban, Mark (2011). Lean Hospitals: Improving Quality, Patient Safety, and Employee Engagement. Boca Raton, FL: CRC Press. ISBN 9781439870433.
- Graban, Mark; Swartz, Joseph (2011). Healthcare Kaizen: Engaging Front-Line Staff in Sustainable Continuous Improvements. Boca Raton, FL: CRC Press. ISBN 9781439872963.
- Plenert, Gerhard (2011). Lean Management Principles for Information Technology. Boca Raton, FL: CRC Press. ISBN 9781420078602.
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- Mascitelli, Ronald (2011). Mastering lean product development: a practical, event-driven process for maximizing speed, profits and quality. Northridge, CA: Technology Perspectives. ISBN 9780966269741.
- Keyte, Beau; Locher, Drew (2004). The Complete Lean Enterprise: Value Stream Mapping for Administrative and Office Processes. New York: Productivity Press. ISBN 9781563273018.
- Shingo, Shigeo (1985). A Revolution in Manufacturing: The SMED System. Stamford, CT: Productivity Press. p. 5. ISBN 0915299097.
- "Value Stream Mapping" Article Source: http://www.isixsigma.com/index.php?option=com_k2&view=itemlist&layout=category&task=category&id=90&Itemid=222#
- Rich, Nick; Esain, Ann; Bateman, Nicola (1997). Lean Evolution: Lessons from the Workplace. Cambridge University Press.