History and outline of the Six Sigma and DFSS methodology
Six Sigma is increasingly popular method of enhancing all business processes. The term „six standard deviations” refers to the quality concept ensuring developing processes with the smallest possible number of defects (3.4 defects per million opportunities). Six Sigma is not ‘pure’ statistics, but structural and group approach to the topic and appropriate selection of tools.
History of Lean Manufacturing
The term Lean Management was first used by the scientists from Massachussets Institute of Technology in Boston: James P. Womack, Daniel T. Jones and Daniel Roos. In 1991 they published their famous work „The Machine That Changed the World”, where they compared parameters of expenditures and result in Japanese, American and European companies. The Japanese company Toyota Motor Corporation with their Toyota Production System was announced the leader. Authors considered this system the first lean manufacturing system and named it Lean Manufacturing. According to the authors, lean manufacturing: „provides a way to do more and more with less and less – less human effort, less equipment, less time, and less space – while coming closer and closer to providing customers exactly what they want”.
In 1913 Henry Ford created flow production; he established the first assembly line ever used for large-scale manufacturing. Model T revolutionized manufacturing system, at the same time contributing to the beginning of flow production. Ford, however, faced the problem of being unable to provide diversity demanded by the client and competiton. Model T was limited only to one colour and specification. The first model T manufactured in 1908 was in fact no different than the previous one that was manufactured in 1926. A few years later Kiichiro Toyoda and Taiichi Ohno decided to use the original Ford’s idea and created Toyota Production System. In 1937 roku Sakichi Toyoda set up Toyota Motor Company, whose first president was the eldest son of the Kiichiro Toyoda founder. They formulated two basic concepts of lean manufacturing:
- Jidoka – providing machines and operators the ability to detect when an abnormal condition has occurred and immediately stop work. This enables operations to build in quality at each process and to separate men and machines for more efficient work.
- Just In Time is a production strategy that strives to improve a business’ return on investment by reducing in-process inventory and associated carrying costs.
Both concepts were put into practice by one of the directors in Toyota, Taiichi Ohno. Besides, Toyota as the first company in the world managed to launch the product development process, supply chain management and processing orders from clients. When in 1950s of the 20th post-war crisis could be noticed, Eiji Toyoda (Sakichi Toyoda’s son) visited Ford’s factory Rouge in Detroit. The factory manufactured 7000 cars daily while Toyota manufactured only 2685 within 13 years. This visit and shared observations made him realize that even though mass production will not be successful in Japan, the system can be improved. Toyota Production System was based above all on the elimination of all waste.
Lean Manufacturing is a management philosophy focused on the constant elimination of all waste, defined as all activities, investments and process that do not add any value to the product or service from the client’s point of view. In other words, the essence of Lean Manufacturing is constant improvement of work efficiency in order to enable the company to successfully compete in the market. It is not achieved by the reduction in employment or increasing labour load, but thanks to the involvement of every employee in the process of system improvement, process based above all on common sense.