"Lean" was developed by Toyota for the automotive industry. The developer of the production system we know today as TPS was Taichi Ohno. He recognized that the process of car production, from order entry, through production, to delivery and invoicing, took far too long and much non-value-added work was being done. The son of the company's founder, Toyoda, had already started to "streamline" the manufacturing process during the wartime period in the middle of the century and to cope with the difficult conditions by "just-in-time" delivery.
Taichi Ohno developed these ideas further after the Second World War. He got his inspiration from the USA and the assembly line production of Ford. Finally he recognized the added value of this type of production, but also saw that the "push" principle used there was not very suitable. With these preconditions and influences in his head, he developed and perfected the TPS over the years, which made Toyota the largest car manufacturer in the world.
The actual term "Lean" only came into being in the 1990s. The two American economists James P. Womack and Daniel T. Jones examined the superior TPS and worked out the principles scientifically. This review of TPS led to the development of the term "lean" and its practical implementation through "lean production".
In the course of the spread of lean production in the automotive industry, other economic sectors have also addressed the topic and made their processes and workflows "lean". As a result, an overarching management philosophy was formed in the form of "Lean Management", which is now applied in all economic sectors.
The book "Lean Thinking" by Womack & Jones has not only coined the term Lean, but also the 5 principles behind Lean. Although various sources and papers have often expanded on the 5 Lean Principles, generally only these 5 principles are defined for Lean:
What does the customer really want and for what is he really willing to pay money? This question should be asked again and again in order to always be able to work in a customer-centered and needs-oriented manner.
Once the customer added value has been defined, the next step is to analyse and optimise the underlying process. For this purpose, the activities are divided into three categories: "value-adding", "necessary" and "wasteful". Process optimization aims at maximizing the value-adding work, minimizing the necessary activities and eliminating waste.
The optimized process should be kept in a continuous flow and ensure a smoothed flow. Buffers and intermediate storage should be avoided, as well as uneven degrees of utilization.
Production should be on demand and on call! This means that the flow of information runs contrary to the production flow and the last "station" thus requests the performance of the previous one.
Kaizen is Japanese and means "continuous, never-ending improvement". Because nothing is so good that it cannot be further improved. This principle should be applied to everything according to Lean. The four preceding lean principles should also be reviewed and questioned again and again.
Here you will find all details about the five lean principles.