How to Create a Value Stream Map (With VSM Symbols)
How to Do Value Stream Mapping
This article will detail how to create a value stream map, how to go about mapping the value stream, the correct symbols to use, the data to be collected, and so on. Value Stream Mapping will help you to identify and eliminate the wastes in your processes, enabling you to make more profit and better satisfy your customers.
Developed as part of the Toyota Production System (TPS), Value Stream Mapping (VSM) is an important tool for identifying the wastes in your overall system. It is a simple process and very powerful.
By creating a map showing all your current flows of products and information, you can enable an analysis of your current state and develop your future state value stream map as something to aim towards with your improvements.
Gather Data for Value Stream Mapping
What do you need to gather the data for your value stream map? All you need is a pencil, some paper (I find post-it notes very useful as you can move them around easily), a will to go out and actually look at your processes and ask questions.
A Value Stream Map is not something that can be created from the comfort and peace of your office, you have to get out and observe the actual process, not what is written in the company manuals and other documentation. You need to go out and start to gather the actual data that reflects the reality of what goes on in your company.
Start with the customer and walk backwards through the process, record your data meticulously as you go, identifying any obvious waste as you do so and inventory levels. Record information flows as well as the flow of material. Remember, we are recording actual process data not what is written in the procedure manuals!
Typical data to be collected is as follows,
• Cycle time (time taken to make one product)
• Change over time (from last good piece to next)
• Uptime (on-demand machine utilisation)
• Number of operators
• Net available working time
• Scrap rate
• Pack size/pallet sizes
Any data that is relevant to the flow of product, information and could contribute your costs and customer service.
Value Stream Mapping Symbols
The symbols above are typical symbols used when creating a value stream map. The map is best done by hand in pencil so that you can modify and improve on it as you create it. The most important thing here is getting the data organized in a meaningful manner. There are a number of software packages that can be used to draw your value stream map, such as Microsoft Office’s Visio and other specific packages for drawing maps.
VSM Process Steps
Define Process Flows in Your VSM
The first thing to record is your actual process flow, which are the specific process steps and in what order do they come. Map out the flow from supplier in the top left to the customer in the top right. Each process should be documented in the order in which they occur.
VSM Information Flow
Define Your Value Stream Map Information Flows
Detail out the flow of information from the company to suppliers, from customer to the company and how the information flows between the different processes. Record what the information is, daily plan, customer order, monthly schedule and so on.
Value Stream Mapping Process Data
Add Process Data to Your Value Stream Map
The next thing to add is the process data for each step in the overall process. Add the data which you have gathered when you studied the process as shown in the VSM to the right. You should include the location and size of any inventory, cycle times, setup times and all other recorded data. This will give you a full outline of how your processes flow. Your lead time at each stage is calculated by multiplying the inventory by the cycle time which will tell you how long it will take to process all of your inventory through the system.
Value Stream Mapping Video
Analyse Value Stream Map
The completed map will tell us an enormous amount about our processes, it will show how we use information and schedules to push production rather than pull production. It shows how we run batches of material rather than trying to flow it through our processes. We can also look at how much our value add is as a proportion of our overall lead time, in this case we are looking at eight minutes of value adding time from a lead time of over eight days, not an untypical result.
Most Value Stream Maps show that product is worked on for 5% or less of the time that it is within our companies, most of the time it sits in inventory waiting to be processed.
Future State Value Stream Mapping
Create Future State Value Stream Map
The future state VSM is created using the same symbols and process as the current process map. However, what we need to do is try to define a process flow that better meets the needs of our customers whilst removing as much waste as possible (Muda (seven wastes), Mura (Unevenness) and Muri (Overburden)).
Firstly confirm the required process flow, what processes are required in which order? Then the actual demand of the customer, what is the Takt time? Takt time being the drum beat at which the customer actually demands product, so if the customer wants 480 items per day with an eight hour shift our Takt time is one minute. Each process must be able to meet the Takt time or we will not meet customer demand, too fast and we make inventory.
Then look at inventory, do we need to supply direct from production or will we have a finished goods stock or “supermarket”? How can we make production flow, we need to link the individual processes, ideally through a kanban system as part of Just in Time (JIT). This linking of the processes and a kanban controlled pull system will prevent the build up of work in progress (WIP) and keep the lead time low. To enable the flow with smaller batches of material we may need to look at reducing setup times through the use of SMED (Single Minute Exchange of Die.)
To make this work, we must ensure that we have repeatable reliable processes, we must introduce ideas such as 5S (5C) and Total Productive Maintenance (TPM). Without reliable, repeatable processes we will end up with stock being held as a safety buffer.
Once we have our future state map, we can plan to implement our changes, once implemented we repeat the process to gain further improvements of our processes.
Value Stream Mapping Video
How to Create a Value Stream Map Links
These links will help you to find more information regarding Lean Manufacturing and creating your current and future state value stream maps.
Manufacturing Improvements The Institute for Manufacturing in the Cambridge University Engineering department will often have fellows and students who can make themselves available for projects such as creating a value stream map of your processes.
Quality Institute The Chartered Quality Institute has many publications that could help you with your value stream map and access to many quality and business professionals who may be able to support you.
American Quality Society The American Society of Quality can also help you develop your future state value stream map and business strategies in much the same way that the UK CQI can.
Business Innovation and Skills Improvement UK Department for Business Innovation and Skills can help you find funding and training for lean tools such as value stream mapping.
Business Improvements UK Business Link is another subsidized UK service than can help your business, they may have access to other sources of funding or help other than that provided through the Manufacturing advisory service.
US Business Improvement US Business Link can provide same services that UK version can to help you improve your business.
Toyota Lean Manufacturing and TPS Toyota as the birthplace of modern Lean Manufacturing is an ideal place to keep an eye on for future developments.
Motor Manufacturers and Traders Society of Motor Manufacturers and Traders have many publications and other resources to help with the implementation of lean tools such as Value Stream Mapping; most of these ideas have originally been developed within the automotive industry.
Automotive Industry Action Group Automotive Industry Action Group is the equivalent of the SMMT and can provide similar help and support.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.