Jidoka is the Path to Zero Defect

The Toyota Production System is a house with two pillars. One pillar represents just-in-time (JIT), and the other pillar the concept of JIDOKA.

The house will not stand without both pillars. Yet many of us focus on the mechanisms of implementation--one piece flow, pull production, takt time, standard work, kanban--without linking those mechanisms back to the pillars that hold up the entire system.

JIDOKA is the key to making the entire system stick.

•       Build in  mechanisms to prevent mass-production of defective work

•       Autonomous check for the abnormal in a process

•       Machines with capability to detect defects and respond accordingly

•       Transfer human intelligence to automated machinery/systems.

•       Not limited to machine processes; can be used with manual operations.

•       Human support system to execute continuous improvement through prevention activities.

•       Illuminates the causes of problems by stopping the process exactly as it was when a defects or abnormality was detected

Never pass defects to next operation

•        Detecting abnormalities

•        Responding immediately

•        Eliminating causes

Fig.

Why Jidoka must be implemented?

•       Process capabilities.

•        Containment. Defects are quickly identified and contained in the zone.

•        Feedback. So that quick countermeasures can be taken.

(Catch the killer on the spot is better then finding from the clue after escaped of the killer.)

Jidoka is one of the factors for the success of Lean implementation

•        High defect rates lead to frequent line stoppages, which will make the flow and pull difficult.

•        Defects will jeopardize the takt time and make the process unevenness, increase lead time and cost.

The root of the problem solving approach embedded in Jidoka thinking

is PDCA.

PDCA has its roots in the Scientific Method:

The scientific method has four steps

1. Observation and description of a phenomenon or group of phenomena.
2. Formulation of an hypothesis to explain the phenomena. In physics, the hypothesis often takes the form of a causal mechanism or a mathematical relation.
3. Use of the hypothesis to predict the existence of other phenomena, or to predict quantitatively the results of new observations.
4. Performance of experimental tests of the predictions by several independent experimenters and properly performed experiments.

Jidoka drives a four step process that engages when abnormalities

occur:

•       Detect the abnormality

•       Stop – bring attention to the problem

•       Fix or correct the immediate condition

•       Investigate the root cause and install a countermeasure

Application of Jidoka

Fig.

A true human support system must be created as a part of any Jidoka implementation.

•       The resources necessary to respond, fix, and root cause analyze must be in place

•       Expectations of 5 W’s and 1 H defined and adhered to

•       Performance linked to expectations

Jidoka Benefits

•       Ensures & maintains safety

•       Improved quality

•       Empowers people 

•       Prevent defective items being delivered to next production phase

•       Recognises abnormalities in automated production so adjustments/repairs can be made quickly

•       Enables separation of machine and human work

•       Eliminates the need for operators to continuously watch machines just in case defects occur

•       Key driver for major gains in productivity