Poka-yoke
Encyclopedia
poka yo-ke is a Japanese term that means "fail-safing
" or "mistake-proofing". A poka-yoke is any mechanism in a lean manufacturing
process that helps an equipment operator avoid (yokeru) mistakes (poka). Its purpose is to eliminate product defects by preventing, correcting, or drawing attention to human errors as they occur. The concept was formalised, and the term adopted, by Shigeo Shingo
as part of the Toyota Production System
. It was originally described as baka
-yoke, but as this means "fool-proofing" (or "idiot-proofing
") the name was changed to the milder poka-yoke.
More broadly, the term can refer to any behavior-shaping constraint
designed into a process to prevent incorrect operation by the user. Similarly, a constraint that is part of the product (or service) design is considered DFM
or DFX
.
that holds pieces for processing might be modified to only allow pieces to be held in the correct orientation, or a digital counter might track the number of spot welds on each piece to ensure that the worker executes the correct number of welds.
Shigeo Shingo recognized three types of poka-yoke for detecting and preventing errors in a mass production
system:
Either the operator is alerted when a mistake is about to be made, or the poka-yoke device actually prevents the mistake from being made. In Shingo's lexicon, the former implementation would be called a warning poka-yoke, while the latter would be referred to as a control poka-yoke.
Shingo argued that errors are inevitable in any manufacturing
process, but that if appropriate poka-yokes are implemented, then mistakes can be caught quickly and prevented from resulting in defects. By eliminating defects at the source, the cost of mistakes within a company is reduced.
Poka yoke system is generally known as PKS.
, the agents can provide the customers with all the required disclosures using pre-recorded audio files. By integrating the Agent-assisted Automation with the customer relationship management
software, you can ensure that the agent cannot process/complete the order until the required disclosures are played.
Fail-safe
A fail-safe or fail-secure device is one that, in the event of failure, responds in a way that will cause no harm, or at least a minimum of harm, to other devices or danger to personnel....
" or "mistake-proofing". A poka-yoke is any mechanism in a lean manufacturing
Lean manufacturing
Lean manufacturing, lean enterprise, or lean production, often simply, "Lean," is a production practice that considers the expenditure of resources for any goal other than the creation of value for the end customer to be wasteful, and thus a target for elimination...
process that helps an equipment operator avoid (yokeru) mistakes (poka). Its purpose is to eliminate product defects by preventing, correcting, or drawing attention to human errors as they occur. The concept was formalised, and the term adopted, by Shigeo Shingo
Shigeo Shingo
, born in Saga City, Japan, was a Japanese industrial engineer who distinguished himself as one of the world’s leading experts on manufacturing practices and the Toyota Production System. Shingo is known far more in the West than in Japan, as a result of his meeting Norman Bodek, an American...
as part of the Toyota Production System
Toyota Production System
The Toyota Production System is an integrated socio-technical system, developed by Toyota, that comprises its management philosophy and practices. The TPS organizes manufacturing and logistics for the automobile manufacturer, including interaction with suppliers and customers...
. It was originally described as baka
Baka (fool)
Baka is a frequently used Japanese word meaning "fool; idiot; jerk; dolt; imbecile; foolish; stupid; worthless; absurd; ridiculous; idiotic".-Word:...
-yoke, but as this means "fool-proofing" (or "idiot-proofing
Idiot Proof
In modern English usage, the term "idiot proof" describes designs which inherently or by use of defensive design principles cannot be misused. The implication is that the design is usable even by someone of low intelligence who would not use it properly. The term came into use in the late 1970s to...
") the name was changed to the milder poka-yoke.
More broadly, the term can refer to any behavior-shaping constraint
Behavior-shaping constraint
A behavior-shaping constraint, also sometimes referred to as a forcing function or poka-yoke, is a technique used in error-tolerant design to prevent the user from making common errors or mistakes. One example is the reverse lockout on the transmission of a moving automobile.The microwave provides...
designed into a process to prevent incorrect operation by the user. Similarly, a constraint that is part of the product (or service) design is considered DFM
Design for manufacturability
Design for manufacturability - is the general engineering art of designing products in such a way that they are easy to manufacture. The basic idea exists in almost all engineering disciplines, but of course the details differ widely depending on the manufacturing technology...
or DFX
Design for X
Under the label Design for X, a wide collection of specific design guidelines are summarized. Each design guideline addresses a particular issue that is caused by, or affects the characteristics of a product...
.
Implementation in manufacturing
Poka-yoke can be implemented at any step of a manufacturing process where something can go wrong or an error can be made. For example, a jigJig (tool)
In metalworking and woodworking, a jig is a type of tool used to control the location and/or motion of another tool. A jig's primary purpose is to provide repeatability, accuracy, and interchangeability in the manufacturing of products. A jig is often confused with a fixture; a fixture holds the...
that holds pieces for processing might be modified to only allow pieces to be held in the correct orientation, or a digital counter might track the number of spot welds on each piece to ensure that the worker executes the correct number of welds.
Shigeo Shingo recognized three types of poka-yoke for detecting and preventing errors in a mass production
Mass production
Mass production is the production of large amounts of standardized products, including and especially on assembly lines...
system:
- The contact method identifies product defects by testing the product's shape, size, color, or other physical attributes.
- The fixed-value (or constant number) method alerts the operator if a certain number of movements are not made.
- The motion-step (or sequence) method determines whether the prescribed steps of the process have been followed.
Either the operator is alerted when a mistake is about to be made, or the poka-yoke device actually prevents the mistake from being made. In Shingo's lexicon, the former implementation would be called a warning poka-yoke, while the latter would be referred to as a control poka-yoke.
Shingo argued that errors are inevitable in any manufacturing
Manufacturing
Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale...
process, but that if appropriate poka-yokes are implemented, then mistakes can be caught quickly and prevented from resulting in defects. By eliminating defects at the source, the cost of mistakes within a company is reduced.
Poka yoke system is generally known as PKS.
Implementation in Service Industries
Poka-yoke can also be implemented in service industries. Call Centers have long had a challenge with compliance. Poor training, fatigue, forgetfulness, and the limits on human consistency all can lead to agents skipping key steps in the process. Disclosures are a good example. When a consumer makes a purchase of some kind, the call center agent is often required to provide the customer with key information. What the customer purchases dictates the disclosures that are required. It can be hard to train the agents in all the required combination of disclosures or the agents can sometimes forget to read the disclosures. Using Agent-assisted automationAgent-assisted automation
Agent-assisted automation is a type of call center technology that automates elements of 1) what the call center agent does with their desktop tools and/or 2) says to customers during the call...
, the agents can provide the customers with all the required disclosures using pre-recorded audio files. By integrating the Agent-assisted Automation with the customer relationship management
Customer relationship management
Customer relationship management is a widely implemented strategy for managing a company’s interactions with customers, clients and sales prospects. It involves using technology to organize, automate, and synchronize business processes—principally sales activities, but also those for marketing,...
software, you can ensure that the agent cannot process/complete the order until the required disclosures are played.
External links
- Poka-Yoke Example Written by Shmula
- Mistake-Proofing Example Wiki