The Toyota Production System (TPS) is the philosophy which organizes manufacturing and logistics at Toyota, including the interaction with suppliers and customers. The TPS is a major part of the more generic "Lean manufacturing". It was largely created by the founder of Toyota, Sakichi Toyoda, his son Kiichiro Toyoda, and the engineer Taiichi Ohno; they drew heavily on the work of W. Edwards Deming and the writings of Henry Ford. When these men came to the United States to observe the assembly line and mass production that had made Ford rich, they were unimpressed. While shopping in a supermarket they observed the simple idea of an automatic drink resupplier; when the customer wants a drink, he takes one, and another replaces it. The main goals of the TPS are to design out overburden (muri), inconsistency (mura) and eliminate waste (muda). There are 7 kinds of muda targeted in the TPS:
- over-production
- motion (of operator or machine)
- waiting (of operator or machine)
- conveyance
- processing itself
- inventory (raw material)
- correction (rework and scrap)
Toyota was able to greatly reduce leadtime and cost using the TPS, while improving quality at the same time. This enabled it to become one of the ten largest companies in the world. It is currently as profitable as all the other car companies combined and became the largest car manufacturer in 2007. It has been proposed that the TPS is the most prominent example of the 'correlation', or middle, stage in a science, with material requirements planning and other data gathering systems representing the 'classification' or first stage. A science in this stage can see correlations between events and can propose some procedures that allow some predictions of the future. Due to this stellar success of the production philosophy's predictions many of these methods have been copied by other manufacturing companies, although mostly unsuccessfully.
