An Introduction to the Toyota Production System and Principles

What is Jidoka?

The Toyota Production system was a major precursor of Lean Manufacturing, founded on two conceptual pillars: 'Just-in-time' and 'Jidoka'. Jidoka, otherwise known as Automation with a Human Touch, was first built off the approach created by the founder of Toyota, Sakichi Toyoda and his son, Kiichiro Toyoda.

Jidoka highlights the causes of problems that arise when work stops immediately if a problem occurs. This leads to improvements in the processes that build in quality by eliminating the root causes of defects. As mentioned, Jidoka sometimes is called autonomation, meaning automation with human intelligence.

The two pillars of the Toyota Production System

The Two Pillars of TPS: Just in Time and Jidoka

The Toyota Production System is grounded on two main conceptual pillars:

Just-in-time – or, "Making only what is needed, only when it is needed, and only in the amount that is needed"

With 'Just in Time', a product is efficiently built within the shortest possible period of time by adhering to the following:

When an order is received, a message to start the process must be sent to the beginning of the production line as soon as possible.

The assembly line must be stocked with no more or less than the required number of all needed parts so that any type of product available can be assembled quickly.

The assembly line must replace the parts used by retrieving the same number of parts from the parts-producing process - this way, only what is needed is replaced, and over-stocking is reduced.

The preceding process must be consist of small numbers of all types of parts, producing only the numbers of parts that were retrieved by an operator from the next process.

Jidoka – (Autonomation) or, "Automation with a human touch"

For the Just-in-Time system to function, all parts that made and supplied must be meeting predetermined quality standards. This is achieved through Jidoka.

Jidoka means that a machine stops safely, as soon as the normal processing is completed. It also means that if a quality / equipment problem arises, the machine will be able to detect the defect on its own and stop, preventing more defective products from being produced, thus reducing Muda. As a result, only products satisfying quality standards will be passed on to the following processes on the production line, preventing a pile up of malfunctioning products.

As the machine automatically stops when processing is completed or when a problem arises and is communicated quickly, operators can confidently continue working away at another machine, as well as easily identifying the cause of the problem. This means that each operator can be in charge of many machines, resulting in higher productivity, while continuous improvements lead to greater processing capacity.