What is a value stream map and how is it used in Six Sigma?
Value stream mapping (VSM) is a tool that helps you to see and understand the flow of material and information as a product or service moves through the value stream.This is defined as all of the activities, both value adding and non-value adding (wastes) that are required to bring a product from raw materials into the hands of the customer. A future state map is then created which leads to the creation of an implementation plan.
VSM is sometimes referred to as an end-to-end system map because it takes into account the activity of the product in all phases of production, including the management and information systems that support the basic process.It covers all aspects of production from receiving of raw material to delivery of finished goods.You are able to gain insight into the decision making flow as well as the process flow.
Value stream mapping is actually a Lean tool.Lean is a methodology like Six
Sigma, both of which have shown time and time again that it is possible to improve cost, quality and time by focusing on process performance.They differ in that Six Sigma focuses on reducing variation and improving process yield by following a problem-solving approach using statistical tools while Lean is primarily concerned with eliminating waste (any activity that consumes resources and adds to the cost of the product but no value to the customer) and improving flow by following the established Lean principles and a defined approach to implement each of these principles.Lean gathers and displays a much broader range of information than that of Six Sigma.
Lean production tries to eliminate waste in every area of production.This includes customer relations, product design, supplier networks and factory management.The goal is to incorporate less human effort, hold less inventory, spend less time developing products, and utilizing less space while still producing quality products in the most efficient and economical manner possible.
The basic idea of VSM is to first map your process, then above it map the information flow that enables the process to occur.This is known as a Current State Map.Based on the analysis of the Current State Map, you can then develop a Future State Map by improving the value-adding steps and eliminating the non-value adding steps or waste.
In the Current State Map, the steps you would normally follow are:
1. Identify a large-quantity and high-revenue product family to map.
2. Map the material flow using appropriate icons in the VSM template.
3. Trace the material flow path of the product back from the final operation in its routing to the storage location for raw material.
4. Record relevant data for each operation, such as the current schedule and the amount of inventory in various queues.
5. Incorporate the information flow to provide demand information, which is an essential parameter for determining the "pacemaker" process in the production system.
6. After both material and information flows have been mapped, a time-line is displayed at the bottom of the map showing the processing time for each operation and the transfer delays between operations. The time-line is used to identify the value-adding steps, as well as wastes, in the current system.
When creating a Value Stream Map, you want to actually walk the production or office floor.Follow the product or service and draw a simple visual representation of the steps in the Material and Information Flows.The objective is to see where waste is occurring at the system level, and then develop a comprehensive plan to remove it.The Value Stream Map is based on actual observation, not what you think is happening. It is real, simple, and visual.
In summary, Value Stream Mapping can be a great way to develop a future state with less waste and creates a plan to implement it.