Lean thinking does not provide a new management program. It is instead a way of management thinking for managers. In this sense, the National Institute of Standards and Technology (USA) defines lean as “a systematic approach to identifying and eliminating waste through continuous improvement flowing the product at the pull of the customer in pursuit of perfection”. At the same time, Lean thinking is considered to be a toolset and management system, a method for continuous improvement, employee engagement, and problem-solving, Spear & Bowen (1999). Moreover, Lean thinking is a way to continuously improve, adapt to change, and eliminate waste. It is implemented through different tools like total quality management, agile method, Six sigma. Lean is opposite to large quantities production and to the economy of scale. Lean answers customer needs and the customer is able to pull the product easily.
- Value: is the value offered to a customer at a specific time and for a specific price, it depends on each customer.
- The value stream: is the set of activities from design, different stages of production to the final product delivered to the customer. There are three types of value stream:
- Value added: these activities generate value,
- Type one Muda: this Muda (waste) is unavoidable,
- Type two Muda: activities with no value and can be avoided.
- The Flow: achievement of tasks along the value stream so that a product proceeds from design, different stages of production to the final product delivered to the customer with no stoppages, scrap or backflows.
- The pull: in a pull system instructions goes from downstream to upstream, which means nothing is produced by the upstream supplier until the downstream customer signals a need.
- Perfection: is a total elimination of Muda so that all undertaken activities along the value stream create value.
Many studies assessed the differences and similarities between TQM and Lean methodology, (Anderson et al. (2006), Anvari et al. (2011), Hines et al. (2004)). Hines et al. (2004) state that TQM can be a tool or a technique for Lean. Anvari et al. (2011) provided a comparative study between TQM and lean. TQM or Six Sigma both fit very well with Lean and vice versa.
We present below similarities and differences between Total Quality Management and lean thinking based on the studies of Anderson et al. (2006), Anvari et al. (2011), Hines et al. (2004).
- Both originated in Japan;
- Everyone in the company from different levels is committed and participates;
- Use of analytical tools;
- Increase customer satisfaction;
- Long-term implementation;
- TQM focuses on uniforming processes, lean thinking aims to improve flow in processes;
- As TQM has a primary effect to increase satisfaction lean thinking aims first to reduce lead time, reduce inventory and increase productivity;
- For lean thinking customer satisfaction is a secondary effect;
- TQM leads to slow change; however lean thinking may lead to dramatic change.;