Lean manufacturing is a production management system in the company, which aims to reduce waste and eliminate unnecessary operations and procedures in the production process, while providing products and services of the highest quality expected by customers and maintaining low production costs, low usage of raw materials, etc. The philosophy behind Lean manufacturing is derived from the Toyota production system.
Implementation of Lean manufacturing in the company significantly increases its production efficiency, shortening the duration of this process and contributing to the elimination of surplus stocks. Main step of implementation is diagnosis and removal of all the factors causing the loss, and then improvement of key production processes. To minimize the losses managers should significantly reduce waste. It is necessary to involve all employees during implementation of lean manufacturing. Effective improvement of processes causing waste and optimization of production requires involvement of employees at all hierarchy levels in the company.
It is important to state, that Lean manufacturing is aimed at increase of company profits. It is the most common misunderstanding about Lean. The Lean impacts organizational culture and changes attitude of workers and managers, however the bottom line is: it has to pay off. Other approach was presented in Toyota production system which was aimed mainly on engineering issues. That can be the source of misunderstanding.
The five principles of lean thinking
- Value should be determined from the perspective of the end user.
- Managers should specify the value stream for each product category.
- Next steps of adding value must be combined to achieve a smooth flow of production.
- Customers should be able to obtain what they want.
- Management must be targeted to achieve perfection - all the action and the means must create value.
If managers specify value from the end-user perspective, it turns out that only a small part of the activities and time contribute to the creation of value
Improvement of the processes requires:
- decentralization of the decision-making processes,
- training of staff, in order to fully exploit their potentials,
- standardization of workplaces, providing employees with access to the necessary equipment at their place of work,
- reduction in the inventory and the production of parts to satisfy only current demand,
- implementation of quality control at every stage of production process,
- striving for continuous improvement.
Value stream mapping
Value stream mapping is a method used to analyse the production system. It shows the value stream, i.e. the identification of all operations (adding value, as well as those that do not add values) taken in the process of product manufacturing, starting from process of acquiring material and ending with the finished product. See separate article Value stream mapping.
Ideas based on lean
The Lean concept is now widespread. There are several ideas using it, e.g.:
Lean manufacturing tools
The 12 pillars of Lean manufacturing are:
- Konnyaku stone - smoothing, eradication of small imperfections
- Jidoka - allowing immediate removal of production problems
- Hansei - self-awarenes in order to improve
- Andon - visualisation of process and problems related to quality
- Just in time - pull production system; reducing inventory kept during the production process
- Poka yoke - reducing number of occasions for defects
- Heijunka - production levelling
- Kaizen - continuous improvement
- Genchi genbutsu - modification of organizational culture
- Nemawashi - change management
- Kanban - organization of production process
- Muda mura muri - concept of removal of waste
- Gemba - transparency of processes and work in workplace
Examples of Lean manufacturing
- Just-In-Time (JIT) Production: Just-in-time production is a system that schedules production based on customer orders, rather than on forecasts. It reduces the amount of raw material that needs to be stored in inventory, as well as the need for work-in-process inventory.
- Kanban: Kanban is a production scheduling system based on identifying, tracking, and managing inventory levels. This system helps to reduce overproduction by only producing what is demanded.
- Value Stream Mapping: Value Stream Mapping is a process for mapping out the entire production process from start to finish. It helps to identify any inefficiencies or wastes in the process, which can then be eliminated.
- Total Quality Management (TQM): Total Quality Management is a system that focuses on continuously improving the quality of products and services. It is based on the idea that everything in the production process should be done with a focus on quality.
- Standardized Work: Standardized work is a system that focuses on standardizing work processes, which can help to reduce waste and increase efficiency. It also helps to ensure that all products are made with the same quality and consistency.
Advantages of Lean manufacturing
Lean manufacturing has a range of advantages for businesses, such as:
- Improved productivity and efficiency: Lean manufacturing can help businesses reduce unnecessary steps in the production process, which can lead to improved efficiency and a reduction in production times.
- Reduced costs: Lean manufacturing can help businesses reduce costs by eliminating wasteful materials, processes and labor, as well as streamlining inventory management.
- Quality improvement: Lean manufacturing can help businesses improve their products by focusing on defects and implementing corrective measures.
- Increased customer satisfaction: Lean manufacturing can help improve customer service and satisfaction by focusing on the customer's needs and providing better products and services.
- Improved employee morale: Lean manufacturing can help businesses improve employee morale by creating a sense of belonging and a culture of continuous improvement.
Limitations of Lean manufacturing
The limitations of Lean manufacturing include:
- Limited customization options: Lean manufacturing focuses on the production of standardized goods, which limits the availability of customization options.
- Difficult implementation: Implementing Lean manufacturing requires a full organizational commitment, which can be difficult to achieve.
- Difficult to measure performance: Since Lean manufacturing is focused on continuous improvement, it can be difficult to measure the performance of a system.
- High cost of training: Training employees in Lean manufacturing techniques can be costly and time-consuming.
- Difficulty in sustaining results: Lean manufacturing is a continuous process that requires sustained effort to ensure consistent results.
- Risk of over-simplification: Lean manufacturing can lead to over-simplification of processes and products, which can reduce quality levels.
The following approaches are related to Lean manufacturing:
- Kaizen: Kaizen is a Japanese term that refers to continuing improvement of all areas of an organization. It is based on the idea of making small but continual improvements to processes and systems, which eventually lead to greater productivity, cost savings, and quality improvement over time.
- Six Sigma: Six Sigma is a business strategy designed to improve quality and productivity by reducing the number of defects and errors in the production process. It uses a set of techniques and tools to identify and eliminate root causes of problems and reduce variability in processes.
- Value Stream Mapping: Value Stream Mapping is a lean manufacturing technique that uses a flow diagram to map out the steps in a production process and identify areas for improvement. This can help to identify and reduce waste, improve communication between departments, and increase efficiency.
- Just In Time (JIT): Just In Time is a lean manufacturing technique that aims to reduce waste and improve efficiency by ensuring that only the necessary materials and components are available when they are needed. This helps to reduce inventory costs and increase productivity.
In summary, Lean manufacturing is a production management system which focuses on reducing waste, improving quality, and lowering costs. Related approaches such as Kaizen, Six Sigma, Value Stream Mapping, and Just In Time are also used to further improve the overall performance of the production process.
- Womack J., Lean Thinking: Banish Waste and Create Wealth in Your Corporation, Free Press, New York 2003.
- Womack J., Lean Solutions: How Companies and Customers Can Create Value and Wealth Together, Free Press, New York 2005.
- Shah R., Wart P.T. (2003) Lean manufacturing: context, practice bundles, and performance, Journal of Operations Management, 21(2)