This value stream mapping guide aims to help you familiarize yourself with the concept of value stream mapping. It offers a detailed overview on everything related to VSM, from its origin to steps you should follow when carrying out a value stream map analysis.
Value Stream Mapping is a Lean tool that is used to visualize a production process. It helps increase the value of the product or service by identifying bottlenecks and eliminating waste.
In this value stream mapping tutorial, you will learn
- The Origin of Value Stream Mapping
- What is Value Stream Mapping
- Value Stream Mapping Symbols
- How to Do a Value Stream Map Analysis
- Value Stream Mapping Mistakes to Avoid
- Value Stream Mapping Templates
The origin of value stream mapping (then known as the “material and information flows”) can be traced back to a technique of visual mapping the Toyota Motor Corporation used to understand the material and information flow within the organization.
The term ‘value stream’ was first coined by James Womack, Daniel Jones and Daniel Roos in their book, The Machine that Changed the World in 1990. It was further popularized in Lean Thinking by James Womack and Daniel Jones in 1996.
According to them, a value stream is the “set of specific actions required to bring a specific product through the three critical management tasks of any business…the problem-solving task,…information management task,…physical information task”.
In Learning to See (1998) Mike Rother and John Shook explained in detail the application of the method in manufacturing. Then in 2004, Beau Keyte and Drew Locher discussed the extended application of value stream mapping in office and administrative processes.
A value stream map, in the simplest of terms, is a way to visualize the steps required to transform a customer request into a good or service, or in other words, a product’s production path from supplier to the customer.
A value stream map, which offers a holistic view of the process or the system, can be drawn at any scale; to map a simple administrative process as well as a complicated global-level manufacturing and sales process. It helps identify non-value adding steps that should be eliminated and areas in the process that should be improved to achieve better and faster outcomes at a lower cost in a safer work environment.
A value stream map can be divided into 3 segments,
- Production or process flow
In this section, as in a traditional process flowchart, the flow of the process is drawn from left to right. If there are subtasks or parallel tasks, they should also be drawn from left to right beneath the main flow. Drawn this way, it is easier to tell apart the major tasks that occur time and time again throughout the process, from the minor steps.
- Information or communication flow
In this section (at the top portion of the map) all the communication, both formal and informal, that occurs within the value stream is shown. There’s no standardized flow of communication as communication can flow in any direction.
- Timelines and travel distances
Timelines appear at the bottom of the value stream map. This set of lines conveys the time-related data measured in the process improvement. While the top line indicates the process lead time, the bottom line indicates the total cycle time (some maps contain labor content instead ofcycle time; when that’s the case, the line is called total work content). The other line, placed at the bottom of the map shows the travel distance (of the product or work or of the people moving) through the process.
As an effective tool to evaluate existing business or work processes, value stream mapping could be a beneficial to companies of all extents;
- They provide a glimpse at the customer’s perspective
- A common language to observe and examine the value stream
- Provide a holistic view of the entire process required to deliver a product to a customer
- Help detect inefficiencies in the process at a glance
- Help deepen employees’ understanding of the work system
- Powerful tool to improve manufacturing production workflows
There are standard symbols used in drawing value stream maps. These can be typically used to map manufacturing processes. However, in VSM you can devise your own symbols to represent different components in the process for easy understanding. As long as the team involved in the mapping process is familiar with the symbols used, you can design your own symbols to match the needs of your own organization.
Following are the most commonly used VSM symbols.
Value Stream Mapping Process Symbols
When placed in the upper left corner it represents the supplier, and when placed in the upper right corner, it symbolizes the customer.
|Dedicated process flow iconSymbolizes the continuous material flow through a department, process, operation or a machine.|
|Shared process iconRepresents a process, operation, work center or a department that is shared by other value stream families.|
|Data box iconPlaced under icons that carry significant data (such as quantity produced per day, the quantity of waste, cycle time etc.)needed to analyze and observe the system.|
|Workcell iconUsed to indicate multiple processes that are integrated into a manufacturing workcell.|
Value Stream Mapping Material Symbols
|Inventory iconsRepresents inventory between two processes.|
|Shipments iconSymbolizes the movement of raw materials from the supplier to the factory, and of finished goods from the factory to the customer.|
|Push arrow iconCan be used to indicate the ‘pushing’ of material from one process to another.|
|Supermarket iconAlso known as a Kanban stockpoint, is a symbol for a supermarket.|
|Material pull iconThis icon is used when supermarkets connect to downstream processes.|
|FIFO lane iconRepresents a First-In-First-Out inventory system that limits input. ‘MAX’ indicates the maximum number of items that can be allowed to pass through the FIFO lane.|
|Safety stock iconRepresents a safety stock that can be used to protect the system when disruptions such as downtime, system failures etc. occur.|
|External shipment iconSymbolizes shipment of raw materials to/ from the supplier or of finished goods to the customer.|
Value Stream Mapping Information Symbols
|Production control iconSymbolizes a central production scheduling or control department.|
|Manual info iconRepresents the general information flow from memos, reports etc.|
|Electronic info iconMaps the flow of electronic information such as the internet, LANs, WANs etc.|
|Production Kanban iconIs used to indicate the quantity to be produced as pulled by the customer.|
|Withdrawal Kanban iconSymbolizes instructions about transferring parts from a supermarket to the receiving process.|
|Signal Kanban iconUsed to indicate the number of items in a batch that needs to be produced to restock them in the supermarket.|
|Kanban post iconRepresents the location where Kanban signals reside for pickup.|
|Sequenced pull iconRepresents a pull system that offers instructions to subassembly processes to manufacture a product without using a supermarket.|
|Load leveling iconA tool that can be used to batch Kanbans to level the production volume.|
|MRP/ ERP iconIndicates scheduling using material resource planning and enterprise resource planning|
|Go see iconRefers to using visual means to gather information|
|Verbal information iconIndicates the flow of verbal and personal information.|
Value Stream Mapping General Symbols
|Kaizen burst iconIs used to highlight the improvements that should be done at specific processes to achieve the future state map.|
|Operator iconRepresents the requirement of an operator’s presence in a certain location.|
|Other information iconIcon to indicate other information that is useful or could be potentially useful|
A value stream map outlines the sequence from the input of raw materials to the delivery of the finished goods or services to the customer. This mapping event can be divided into 4 stages that are described in detail below.
The preparation step is crucial to the successful implementation of the ideal state map. This step involves getting together a competent team to carry out the mapping process. While the team should include cross-functional participants, having a value stream manager to lead the team and set guidelines would make things easier.
During the preparation period, the team and the manager should measure the scope of the mapping event, decide the business objectives and ready plans for difficulties the team might come across.
It is equally important to identify the product family that will be mapped. A product family includes a group of products of services that share the same process steps. Drawing all of your product flows in one single map would make things complicated; therefore always outline one product family in one map.
Tip: Use a product or service matrix to identify the families of products or services
Current State Map
The current state map serves as a starting point to the process improvement. The current state map visualizes the process at its existing state. It helps discover the ineffective and wasteful practices in the current system and find ways to eliminate them.
Drawing a current state map requires gathering information on the product’s production path. To do this, you need to walk down the path the product takes as it travels through the production factory.
First, draw a rough sketch of the entire value stream (of information and material flow) to help everyone involved understand the skeleton of the map.
Start from the most downstream processes (from the customer end) and move upstream as you draw the current state map. Collect the following data as you go on,
- Total time per workday
- Regularly planned downtime such as lunch breaks or meetings
- Number of people working in the process
- Quantity of work a person performs within a day
- Number of product variations
- Pack size
- Cycle time (from the beginning of the process to its completion)
- Queue time (how long a work unit waits until a downstream process is ready to work on it)
Once the process data has been collected you can proceed to draw the current state map
Begin by drawing the external (or internal) customer and supplier at the top of the page. If the customer and the supplier are separate, draw the supplier icon on the upper left-hand corner, and customer on the upper right-hand corner. Then list down their requirements.
Draw the entry and exit processes to the value stream (far right and far left portions of the page).
Create a map shell by drawing the processes (beginning from the furthest downstream point) between the entry and the exit processes.
List all the attributes of the processes.
Add queue times between each process. Use the same unit of measurement for all queue times (hours or days).
Proceed to map all the communication flows that occur within the value stream.
To identify the type of workflow, add push or pull icons.
Add any other data left to complete the map
While this sequence of steps is a generic one, you can always modify it to match the needs of your own organization’s value stream. (Refer to Template 2 for an example of a current state map)
Future State Map
Once the current state map is documented and lean metrics (which are needed to help you achieve the lean goals you have set) have been decided, the next step is to draw the future state map. While drawing the current state map you will be able to identify the areas of overproduction and of waste in the current production system. This information you gather becomes the basis of your future state map.
Planning and Implementation
The final step is creating an action plan to implement the ideal production path you have designed with the future state map. The best way to do this is by breaking down the future state map into smaller segments and proceed to implement changes within one segment at a time.
The work plan should have measurable goals as well as checkpoints. When the future state map is implemented, you will be able to create a new and improved current state map, and to keep generating better results the cycle should continue.
Tip: Hold an annual value stream review to monitor improvements
- Splitting up the mapping task among different departments in the hopes of stitching the individual segments together later at the end. This makes things complicated. When carrying out a value stream analysis, it is essential to have a cross-functional team which works together during the mapping event. Make sure that everyone involved in the mapping event is well educated in VSM. And there should be a head figure (value stream map manager) who can lead the team throughout the process.
- Rushing through the current state mapping step. If the team does not spend enough time to collect accurate data on the current state and analyze them thoroughly during this period, implementation of the future state map will not be successful.
- Drawing the value stream maps without metrics. As mentioned earlier, a VSM has three parts; workflow, information flow and the timeline. Without the timeline, it is not possible to measure the time it takes people in the process to perform tasks or to gain insight into errors that may lead to organizational chaos. Without metrics, it is also difficult to measure how much progress you have made.
Template 1 -Funnel Shape Value Stream Map
Template 2 – Toyota Production System Value Stream Map (Current State)
Template 3 – Supply Chain Management Value Stream Map
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