Jidoka Defined

Product Description

The rise of Jidoka in lean  manufacturing

Over the last 80 years or so, Japan's manufacturing processes have been responsible for how the Western world has begun to approach how it manufactures and manages its manufacturing industries.  Many methodologies like Toyota's Production System & Lean have been around for some time.  But relatively recently, new techniques such as Kanban, Andon, Just In Time, and the Pull System, etc, have gently crept into everyday business terminology - particularly in company board rooms and shop floors throughout manufacturing fraternity.

One expression or word which has arisen from Japanese manufacturing production practices is Jidoka.  Toyota’s Production System, (which was studied by Rosenthal in 2002) frequently pictured possessing 2 pillars - with one of them called Just in Time and the other one labelled Jidoka.

You can find a number of definitions for the word.  In 1999, Standard & Davis translated Jidoka to indicate "quality-at-source", with Imai referring to it as "autonomation" in 1986.  The Japanese language suggests 2 different definitions for jidoka - one of these is "automation" - which explains that it’s a manual process that is converted into a machine process.  The second definition is an "automatic control of defects” which recognises the human intellect to identify, troubleshoot problems and rectify failures in a process

The Toyota Group refers to Jidoka as "Ninbennoaru Jidoka" or simply translated in English as ‘automation with a human mind. Essentially this means that it’s a technique or strategy to detect and correct manufacturing defects, which includes the following characteristics:

•A method that reveals defects or abnormalities; and

•A system that stops production or machinery when a defect or an abnormality arises.

2 methods can halt a production line. One way involves a production worker’s personal judgement and the other one where machinery shuts itself down with an in-built automatic device.

The first technique needs management to empower production staff to close down production and deal with issues as they arise.  The “tool” most frequently applied to close down production by production staff is called "andon".  Basically, an andon system brings the production line to a halt and signals to everyone on the shop floor that something’s wrong which requires immediate attention.  The problem is then typically looked at by a group of individuals.

A tool used for shutting down machinery as part of the Jidoka system is "poka yoke". In manufacturing environments, Poka yoke, alternatively called “mistake-proofing”, is a system to ensure that defects can’s arise.  Common poka yoke examples may include devices like lasers, automatic switches and jigs, etc.  When a fault or defect is detected or when a pre-specified quantity of a product's made, a warning signal is transmitted the machinery to switch off. This practice allows production staff to look after more than one piece of machinery at a time.

One example of how Jidoka is used in practice is adopted by Toyota.  Situated between processes is a custom designed mat that is similar to those that activate the doors to which open at major retail outlets.  For optimum efficiency, the production line moves at a steady speed. If a production worker doesn't or can’t complete their task in predetermined timeframes, they will jump on the nearest mat, which will close the line down.  This will centre everyone's attention and then his section to identify why it’s taking him much longer than expected.  Another case would be limit switches and lasers that sense various components or parts’ normal length.  If these parts don’t match pre- programmed settings, a warning signal would be transmitted to trigger the production line to immediately stop and production staff will start to tackle the problem.