What is Flow

Guide: Flow

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Author: Daniel Croft

Daniel Croft is an experienced continuous improvement manager with a Lean Six Sigma Black Belt and a Bachelor's degree in Business Management. With more than ten years of experience applying his skills across various industries, Daniel specializes in optimizing processes and improving efficiency. His approach combines practical experience with a deep understanding of business fundamentals to drive meaningful change.

Guide: Flow

In Lean manufacturing, establishing flow is important. It goes beyond the movement of products through the manufacturing process. Flow aims to synchronize every involved element, ensuring an efficient progression of products, information, and processes.

It’s not just about the speed of production, it also focuses on effective resource utilization, minimizing delays, and guaranteeing that every activity adds value. The implementation of flow is a strategic approach to streamline operations, enhancing overall efficiency and productivity in the manufacturing process.

What is Flow in Lean Manufacturing?

In Lean manufacturing establishing flow is one of the key principles, which emphasizes the efficient progression of products, information, and processes within the manufacturing system. Flow is more than just the physical movements through the process; it is a complete approach to production that looks to sync every element involved. Establishing flow in the manufacturing process should achieve the following:

By establishing a consistent flow in the manufacturing process, it will become more efficient. Efficiency is more than just the speed of the process; it is also about how effectively the resources are used, minimizing delays, and ensuring that all activities in the process are value-adding.

What are the Principles of Flow?

The principles of flow in Lean manufacturing serve as guidelines for creating a production process that is seamless and efficient.

The aim is to design a workflow process where the work-in-progress (WIP) items move from one step to the next without any unnecessary hold-ups. This involves carefully planning the process to ensure that each step is prepared to receive the input without any delays or process bottlenecks.

Additionally, achieving a continuous flow requires a deep understanding of how each step in the process interacts with the others. The objective is to ensure that there is a harmonious transition between stages, minimizing the time items spend in a ‘waiting’ state.

Implementing Flow in the Manufacturing Process

Implementing flow in a manufacturing process is a multiple-method approach that requires an understanding of various Lean tools and principles. Here’s a detailed look at each of these aspects:

Value Stream Mapping

Value Stream Mapping (VSM) is a key principle of lean “Map the value stream.” It is used to visualize the flow of materials and information from the start of the production process to the delivery of the final product. This tool is instrumental in identifying the current state of operations and designing a future state that optimizes flow.

Value Stream Map (VSM)

Value Stream Map (VSM)

VSM also helps businesses identify inefficiencies and areas of waste (“muda)” within their processes. Mapping out every step in the process allows businesses to see where delays, excess inventory, overproduction, or any other forms of the 8 wastes occur in the process.

Value stream mapping of the process also helps identify areas for process flow improvements. The VSM is a method for planning and implementing changes to enhance the flow of a lean process.

Pull Systems and Kanban

Pull systems contrast to Push Systems as production schedules are based on forecasts; pull systems align production with actual demand. This approach significantly reduces the likelihood of overproduction and excess inventory.


Kanban is another methodology that can be used to implement a pull system. Kanban is a visual tool that uses cards or digital signals to represent work items, triggering production only when there is demand. This method ensures that each stage of the manufacturing process produces only what is immediately required by the next stage.



Challenges of Achieving Flow

Achieving flow in Lean manufacturing, despite its conceptual simplicity, faces several challenges. One primary obstacle is the variability in customer demand, which can fluctuate unpredictably. This variation makes it difficult to maintain a consistent production pace, often leading to either overproduction, resulting in excess inventory, or underproduction, causing shortages and delays. Another significant challenge is the variability in production times across different products or stages, which can create bottlenecks and disrupt the smooth flow of operations. These inconsistencies in cycle times necessitate a detailed examination and optimization of production processes to ensure balance and efficiency.

Furthermore, resistance to change poses a considerable challenge. Implementing flow often requires substantial changes in processes and workforce mindsets. Overcoming this resistance involves effective communication, involving employees in the change process, providing adequate training, and demonstrating a clear commitment from leadership.


Achieving flow in Lean manufacturing is a complex yet rewarding endeavor. While it offers significant improvements in efficiency and resource utilization, it also presents challenges such as fluctuating customer demands, varying production times, and resistance to change. Overcoming these obstacles requires a comprehensive approach involving strategic planning, effective communication, and a commitment to continuous improvement.

By navigating these challenges and leveraging tools like Value Stream Mapping and Kanban, manufacturers can establish a seamless and efficient flow, ultimately leading to optimized operations and heightened customer satisfaction.


A: Flow, in the context of Lean Six Sigma, refers to the smooth and uninterrupted movement of materials, information, and activities through a process. It involves minimizing or eliminating waste, reducing delays, and optimizing the sequence of activities to achieve efficient and timely process completion.

A: Flow is important in Lean Six Sigma because it directly contributes to improving overall process efficiency and customer satisfaction. By optimizing flow, organizations can reduce lead times, eliminate bottlenecks, and deliver products or services more quickly and effectively. Flow helps to eliminate waste, reduce costs, and enhance productivity.

A: Flow can be improved in Lean Six Sigma through various methods, including:

  1. Eliminating non-value-added activities: Identifying and eliminating activities that do not add value to the customer, such as unnecessary movement, waiting, or rework.

  2. Streamlining handoffs: Improving communication and coordination between departments or individuals to minimize delays and errors during handoff points in the process.

  3. Implementing visual management techniques: Using visual tools like Kanban boards or visual indicators to manage and track work-in-progress, ensuring a smooth flow and avoiding overburdening.

  4. Implementing pull systems: Shifting from a push-based approach to a pull-based approach, where work is performed only when there is demand, reducing excess inventory and promoting a smoother flow.

  5. Standardizing processes: Establishing clear and standardized procedures to reduce variation, improve predictability, and ensure consistent flow across the organization.

A: Some common signs of poor flow in a process include:

  1. Excessive waiting times: Delays or long waiting periods between activities or handoffs.

  2. Accumulation of work-in-progress (WIP): A high level of unfinished tasks or items awaiting processing.

  3. Bottlenecks: Points in the process where work accumulates, causing congestion and delays.

  4. Unpredictable or inconsistent lead times: Significant variations in the time required to complete a process.

  5. Excessive rework or errors: The need for repetitive or corrective actions due to errors or defects.

A: Flow can be measured and monitored in Lean Six Sigma through various performance metrics, including cycle time, lead time, on-time delivery, and work-in-progress (WIP) levels. These metrics provide quantitative data on the efficiency and effectiveness of the flow within a process. Regular data collection, analysis, and tracking against these metrics enable organizations to monitor progress, identify areas for improvement, and make data-driven decisions to optimize flow.

A: Flow improvement is an ongoing process. Lean Six Sigma recognizes the need for continuous improvement to sustain and enhance flow. It involves regularly reviewing and analyzing the process, identifying new opportunities for improvement, engaging employees in problem-solving, and fostering a culture of continuous learning and growth. Flow improvement efforts should be iterative, with a focus on continuously refining and optimizing the flow to achieve operational excellence over time.


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Daniel Croft

Daniel Croft is a seasoned continuous improvement manager with a Black Belt in Lean Six Sigma. With over 10 years of real-world application experience across diverse sectors, Daniel has a passion for optimizing processes and fostering a culture of efficiency. He's not just a practitioner but also an avid learner, constantly seeking to expand his knowledge. Outside of his professional life, Daniel has a keen Investing, statistics and knowledge-sharing, which led him to create the website www.learnleansigma.com, a platform dedicated to Lean Six Sigma and process improvement insights.

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