Steps Involved in Value Stream Mapping

Outline the steps involved in value stream mapping

The lean management tool Value Stream Mapping (VSM) is simply a sequence of steps required to add value to the service/product for the final customer. It is used to visualise potentially complex processes to better understand the steps involved, where value is added and where waste can be eliminated ^[1]. An example of a VSM is shown in figure 1 ^[2].

Figure 1: Example of value stream mapping (VSM) which shows significantly more information that a normal flow chart. The value of each process can be identified making it easier to evaluate and improve overall efficiency of delivering the product or service. Actions can be value adding or non-value adding, shown in the process cycle timeline at the bottom of the diagram ^[2].

The number of steps involved in VSM ranges from 6 to 10 steps ^{[3, 4, 5, 6]}, but ultimately will always reach the same end goal of creating an ideal VSM. The steps involved in VSM are below:

1. Understanding value and the concept of ‘value-adding activities’. These must fit the customer needs, be completed right the first time and the material/information is transformed to the final product. If the activity does not fit these criteria it is seen to be ‘waste’ and should be avoided^[3].

2. Determine the focus of the map, it should not track all the possible process paths but instead track one part, service or a product family (share the same process steps) ^[3].Tools such as a ‘Product family matrix’ can help choose which product/families/services will be of most value ^[6]. Value will be measured by customer return rates, product complexity and greatest proportion of units ^[3]. Process must be bound, determining the scope and start and end points ^[4].

3. Defining steps remaining within the boundaries outlined in step 2. Involves drawing a current state map and walking through the process i.e. various operations to achieve the end goal. Gemba can be used to draw a skeleton of the process ^[4]. This is often completed in reverse, starting from the customer working back towards the supplier to avoid creating just a flow chart that tracks the different parts of the process ^[3].

4. Add information flows (one main advantage of VSM), that include how to order to product, frequency and method of this and how to translate that back to the supplier (figure 2) ^[4,5].

Figure 2: Example of an VSM with information flows between the customer, production control and the supplier. This allows communication of requirements to the processes through the weekly schedule to ensure value in the product for the customer ^[3].

5. Fill in process data beneath each step; depending on the project this can include inventory, cycle time, number of operators, batch size, shifts, defects, rate etc ^[3].

6. Fill in Waiting (Queue) Times between each process to create a timeline which will give information about Process cycle time and lead times for inventory throughout the process ^[3]. The inventory, demands and stock in each day are used to calculate the total lead time and the cycle time for one product is calculated and added to give the total process cycle time ^[4].

Figure 3: Example of an VSM with queue times outlined in red. There are separate cycle times for Value adding (VA) and Non-Value Adding (NVA) time, critical to calculating the %VA of the VSM explained later. The middle layer shows the material flow and the top layer shows the information flow ^[3].

7. Identify seven wastes of lean (motion, inventory, waiting, defects, overproduction, transportation and over processing) ^[6]. Calculate the percentage of value adding activities (%VA) to identify where value is added or wasted and how to improve this ^[3]:

8. Create a future/ideal VSM – identify and eliminate where possible bottlenecks/constraints, low uptime, excessive time set up/long cycle times and poor quality ^[3]. Improvements are made to the current state map to create the ideal state map with a leaner, more effective process ^[4].

Overall, the final VSM will help to create a roadmap for continuous improvement projects to get the process to the desired state and achieve the most value for the customer ^[3].

References:

1. Scaledagileframework (2019). Value Streams – Scaled Agile Framework. [online] Available at: https://www.scaledagileframework.com/value-streams/ [Accessed 31 May 2019].
2. Plutora. (2019). Learn the 10 Key Steps to Value Stream Mapping (VSM) – Plutora.com. [online] Available at: https://www.plutora.com/blog/value-stream-mapping [Accessed 31 May 2019].
3. Sixsigma DSI. (2019). 10 Easy Steps to Complete a Value Stream Map. [online] Available at: https://sixsigmadsi.com/10-steps-to-complete-a-value-stream-map/ [Accessed 12 Jun. 2019].
4. Lean Manufacturing Tools. (2019). Creating A Value Stream Map. [online] Available at: http://leanmanufacturingtools.org/551/creating-a-value-stream-map/ [Accessed 12 Jun. 2019].
5. Pearson, S. (2019). Value Stream Mapping: Definition, Steps, and Examples – Tallyfy. [online] Tallyfy. Available at: https://tallyfy.com/value-stream-mapping/ [Accessed 12 Jun. 2019].
6. Athuraliya, A. (2019). Value Stream Mapping Tutorial | Value Stream Mapping Explained. [online] Creately Blog. Available at: https://creately.com/blog/diagrams/value-stream-mapping-guide/ [Accessed 12 Jun. 2019].
7. Lucidchart.com. (2019). [online] Available at: https://www.lucidchart.com/pages/value-stream-mapping [Accessed 12 Jun. 2019].