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
- 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)