Manag., December-2019 – Q2
- Option : C
- Explanation : Jidoka: The Toyota Production System the practice of designing processes and empowering workers to shut down a process when an abnormal condition occurs:
sometimes called autonomation.
The Japanese word “joke” is often translated as “autonomation”, which is a contraction of the words “autonomous” and “automation.” Jidoka is sometimes translated as “automation with a human touch (or human mind)”. According to Ohno (1978), the original jidoka device was a loom developed by Sakichi Toyoda (1867-1930), the founder of the Toyota Motor Company. This loom stopped instantly if any one of the threads broke so defective products were not built and so problems could be seen immediately. According to Ohno (1979), Toyota sold the patent for his loom in 1930 to the Platt Brothers in England for $500,000 and then invested this money in automobile research, which later led to the creation of the Toyota Motor Company.
Originally, jidoka focused on automatic methods for stopping a process when an error the condition occurred; however, it is now used to describe both automated and human means for stopping a process when a problem occurs. For example, a process can use limit switches or devices that will automatically shut down the process when the required number of pieces have been made, a part is defective, or the mechanism jams. This same process can be operated with policies that allow the operators to shut down the machine when a warning light goes on.
Quality benefits of jidoka: Jidoka causes work to stop immediately when a problem occurs so defective parts are never created. In other words, Jidoka conducts 100 percent inspection highlights the causes of problems, forces constant process improvement, and results in improved quality. Whereas automation focuses on labour reduction, jidoka (autonomation) focuses on quality improvement. Note that jidoka is closely related to Shigeo Shingo’s concept of poka yoke.
Poka Yoke
An industrial engineer at Toyota Motor Corporation, Mr Shigeo Shingo introduced the concept of Poka Yoke in 1961. Poka The yoke is a concept of mistake-proofing processes to result in zero defects. The initial the term was baka-yoke, which means ‘foolproofing’. In 1963, a worker at Arakawa Body The company refused to use ba ka-yo ke mechanisms in their work area, because of the term’s dishonorable and offensive connotation. Hence, the term was changed to Poka Yoke, which means ‘mistake-proofing’. Poka-Yoke is a quality assurance technique developed to eliminate defects in a product by preventing or correcting mistakes as early as possible. Poka-Yoke has been used most frequently in manufacturing environments. The concept of Poka-Yoke is simple. It is the concept of common sense and common practice. Poka-Yoke depends on creating simple and effective methods to prevent the repetition of mistakes. Shigeo Shingo argued that Poka-Yoke depends on three different types of inspection as:
1. Judgment inspection—Inspecting the acceptable product.
2. Informative inspection—Inspecting self-work.
3. Source inspection—Inspecting production environment.
Principles of Poka Yoke
In general, there are six types of Poka Yoke principles.
Elimination: Eliminates the possibility of errors. So, redesign the process in such a way that the task of Poka Yoke is not required.
2. Replacement: Substitutes a more reliable process for the existing process. This may include the use of robotics or automation that prevents a manual assembly error.
3. Prevention: Modifies the product design so that it is impossible to make a mistake or that a mistake becomes a defect.
4. Facilitation:Adopts such techniques (like color-coding) so that the work becomes easier to perform.
5. Detection: Identifies a mistake before further processing occurs so that the operator can quickly correct it.
6. Mitigation: Minimises the effect of the mistake. This includes mechanisms that reduce the impact of an error. Devices for Poka Yoke
1. Prevention device: The prevention devices are the devices designed in such way that it is impossible to make a mistake at all, e.g. USB or pen drive for computers.
2. Detection device: The detection devices are the devices designed in such way that the alarm blows or the signals start whenever the user makes a mistake. Then it can be quickly corrected.
