There are 14 principles in lean thinking, with flow being one of the most important. In an organizational context, flow is used to refer to how smoothly work flows through a system. â€˜Goodâ€™ flow occurs in a system in which work moves from step to step in a steady and predictable manner, while â€˜badâ€™ flow is present in a system where the work starts and stops frequently. Consistent work flow is vital if there is to be higher production efficiency as well as reliability and greater value for customers, your team and the organization as a whole.
If a system has been set up to produce tangible items â€“ for instance, a motor vehicle assembly plant â€“ it is quite easy to identify areas that bottlenecks form and hamper the flow of progress. In the case of service industries such as education and healthcare, it can be more difficult to see flow problems. For this reason, teams in these industries require Kanban boards to help visualize flow of work through their system.
Below are three commonly used methods through which lean and Kanban flow efficiency can be achieved.
- Keep Track Of Work In Progress
Tracking of items on which work has started but is yet to be completed will help you to improve how value flows through your system. In a practical sense, the work done adds no value to your customers, your team or the organization unless it is completed. For instance, consider a team of software developers working on new features for their companyâ€™s mobile app. Whatever new features they are working on add nothing to the app until they go live and the customers can use them.
When you count and document the number of work items (cards) still unfinished within your system every week, you will get a clearer understanding of the amount of work that has been started but is not yet offering any value.
- Limit Work in Queue
Queues are formed within a process whenever there is work stuck in waiting between the different steps of the process. Because queues form a major part of any productâ€™s production life cycle, it is vital for you to know where they appear in your process and how they affect the efficiency of your team. By limiting the time that products or items spend in queues, you can reduce the entire production life cycle time and keep the work flowing smoothly.
Creating an efficacy diagram provides a snapshot comparison between the total work in progress (WIP) and the work still held up in queues. The diagram allows you to see if queued work is growing in relation to the total work in progress. This lets you pinpoint where work is stuck in a queue and identify remedial measures that will get work moving again.
- Understand Lead Time and Cycle Time
The lead time and the life cycle time are useful metrics that will help you understand the length of time it takes for work to flow from the start to the end of your Kanban system. The two measures are very similar and are often confused. Although they both measure the length of time used by the work flow, they are used within different segments of the production work flow.
- Lead Time: This is a measure of the total time that it takes for work to be moved through the entire value stream, from the time it is requested to the moment of final delivery. It is the duration of the process from start to finish.
- Cycle Time: This is a measure of the time taken for a work item in process to get from one point to the next. Because the cycle time is measured from any two points of the process, several cycle times may exist in a system. For instance, a process could have a deployment cycle time as well as a Quality Assurance cycle time.
In the case of flow, the ultimate aim has more to do with consistent economic value and efficiency that achieving the quickest cycle time or the highest throughput. Through the maintenance of a steady work flow through the Kanban system, an organization can attain higher efficiency and deliver reliable value to customers.