The lean approach is not merely a methodology, but a strategic approach that increases efficiency by eliminating unnecessary processes. As discussed in our previous article introducing the fundamentals, the essence of lean is eliminating waste and creating maximum value for the customer.
In this article, we present the 5 principles of lean in detail, highlighting what they mean in everyday manufacturing practice and why they are essential for competitiveness.
1. Defining value (Value)
The process begins with a precise understanding of customer needs. In manufacturing, this means allocating resources only to functions or services that the customer is willing to pay for. Any other activity that the customer does not value (such as excessive administration or warehousing) is considered waste.
(It is therefore very important that the customer articulates their needs as precisely as possible.)
- For an automotive parts manufacturer, the value is the precisely machined metal surface itself. The fact that the part sits
in the warehouse for three days before machining has no
value for the customer, making it a waste to be eliminated.
2. Value stream mapping (Value Stream Mapping)
This step involves the visual representation of the product’s entire journey from raw material procurement to finished product delivery. In practice, this helps identify bottlenecks, unnecessary waiting times, or needless material handling. When we see where the process gets stuck, we can intervene in a targeted manner to increase efficiency.
- During Value Stream Mapping, it may be revealed that a workpiece travels 500 meters between two workstations. The lean solution here is to modify the layout of the machines (creating U-shaped cells) to minimize material handling.
3. Ensuring continuous flow (Flow)
The goal is for production to proceed without interruptions and detours. On an ideal production line, parts move from one workstation to the next without waiting. This eliminates congestion and reduces lead time, allowing the company to respond more quickly to orders.
(It is clearly evident that the Value Stream Mapping and Flow steps are closely interconnected.)
- In an electronics assembly plant, by applying “Single Piece Flow,” circuit boards are not moved in batches of 100, but as soon as one is completed, it immediately goes to the next station. This reduces the risk of defects, as errors are discovered at the first piece rather than at 100 pieces.
4. Establishing a pull system (Pull)
Traditional manufacturing produces for inventory. In contrast, lean is based on the “pull” principle: production only begins when the customer or the next workstation signals a need. This drastically reduces inventory, which would only tie up capital and mask process defects.
- When a box of screws runs out on the assembly line, the operator sends a card (Kanban) to the warehouse or the preparation area. Only in response to this signal will another batch be delivered or manufactured. This prevents unnecessary inventory from accumulating beside the line.
5. Striving for perfection (Perfection/Kaizen)
Lean is not a one-time project, but a never-ending process. According to the Kaizen philosophy, small improvement opportunities must be sought every day. The goal is the complete elimination of errors and constant refinement of processes, involving the ideas of operators working on the production line.
- A machine operator notices that a part can also be installed backwards, leading to defects. In the spirit of Kaizen, they design a simple physical stop or template that physically makes backward installation impossible. This continuous refinement leads to perfection.
Why are these principles important in manufacturing?
Applying lean principles is not merely a theoretical matter, but brings measurable business benefits:
- Cost reduction: Instead of expensive investments, it frees up resources by optimizing existing processes.
- Shorter lead time: The product reaches the customer faster, which represents a huge competitive advantage.
- Built-in quality: Errors are not checked at the end of the process, but their occurrence is prevented during production.
- Employee commitment: When workers see that their ideas improve their work environment, turnover decreases and morale improves.
Implementing lean therefore builds a crisis-resistant organization capable of continuous learning and adaptation to market changes.
Summary
The 5 principles of lean – Value, Value Stream, Flow, Pull System, and Perfection – provide a framework with which any organization can become more agile and profitable. Starting with small steps supports continuous improvement.
Frequently asked questions
The primary goal of lean is to maximize customer value while eliminating waste. This means that any activity the customer would not pay for must be eliminated, making processes faster and more accurate.
This process is the visual representation of the product’s entire journey from raw material to delivery. It makes bottlenecks visible, for example, if a part travels an unjustifiably long distance within the factory.
While traditional manufacturing produces for inventory, in the pull system production only starts when there is actual demand. This minimizes unnecessary inventory and capital tie-up.
Kaizen represents continuous improvement, where small enhancements are made with the involvement of workers. An example is the application of poka-yoke, where physical constraints prevent incorrect assembly.
Implementing lean results in significant cost reduction, shortens lead times, improves product quality through built-in controls, and increases employee commitment.
