RICOH manufacturing DX Practical Lab
What is Poka-yoke?
Easy-to-understand explanation of how to create a mistake proof factory.
Human errors lead to defective products and accidents in manufacturing tasks such as assembling items and operating machines. Implementing poka-yoke is an effective solution for these issues.
This article provides an overview of Poka-yoke in the manufacturing industry, its advantages, disadvantages and case studies.
Poka-yoke refers to a system that prevents human errors from occurring in manufacturing and service industries. Poka-yoke includes such systems which prevent non-standard products from being passed on to the next process, or a system that alerts workers whenever a defective product is detected.
Eliminating human errors enhances efficiency, consistency, and safety in production.
The cause of poke may be grouped into these 5 categories.
| Behavioral mistake | Incorrect methods and procedures for executing tasks. |
|---|---|
| Memory mistake | Failing to recall or memorize necessary instructions and processes. |
| Judgement mistake | Inability to judge situations accuratly. |
| Cognitive mistake | Misinterpreting information or false information. |
| Rule violation | Neglecting established rules or manuals. |
Mistakes such as assembling parts in the wrong shape or position or pressing the wrong buttons when operating a machine. Behavioral mistakes like these may occur depending on the proficiency and experience of the worker. It is also more likely to occur if the work environment isn’t taken care of.
Mistakes such as forgetting to check the work procedure manual or remembering work instructions incorrectly. Memory mistakes can occur due to the worker lacking concentration and attention. It is also more likely to occur when the workload is heavy or when the work is complex.
Mistakes such as continuing with the work despite identifying an error that may lead to dangerous situations. Mistakes in judgment can stem from the confidence build in the worker though the experience and knowledge they hold. The occurrence of such mistakes tends to increase when there is a strict deadline to the process or when the process is complicated and takes a long take a lot of time to for workers to judge.
Mistakes such as misreading blueprints or misunderstanding instructions. Cognitive mistakes can occur due to the worker lacking concentration and attention. It is also more likely to occur if the work environment isn’t taken care of.
Mistakes such as working without considering safety measures or working without preparing the proper work environment. Violation of rules may occur due to worker’s lack of awareness and motivation.
As you may notice, even if the workers are being extra careful, mistakes are prone to occur in manual processes.
By introducing Poka-yoke, you may receive the following four benefits.
You may prevent defective products through improved quality control, leading to a better customer satisfaction.
In the manufacturing industry, poka-yoke is used to prevent assembly mistakes and contamination of foreign materials.
If the administrator must explain how the processes should be conducted each time a worker is replaced, it will become a hassle for the administrator. By simplifying work procedures and manuals with Poka-yoke, you may reduce training costs.
Work efficiency can be improved by preventing failures and mistakes in advance.
This not only improves the process involved in it, but also increases the productivity of the entire line.
Poka-yoke helps reduce the possibility of accidents in the manufacturing site. Especially processes that include the use of hazardous materials hold a potential of causing serious damage. By introducing poka-yoke, accidents can be prevented, ensuring the safety of workplaces.
The disadvantages of introducing Poka-yoke are as follows.
On-site workers and managers may not fully understand the importance and effects of poka-yoke, and some may feel reluctant switching from existing processes to new ones.
To deepen collaboration and understanding of Poka-yoke, it is necessary to fully collaborate with on-site workers and managers to help them understand the mechanism and equipment of Poka-yoke. Furthermore, even after successfully introducing Poka-Yoke, continuing education for workers will help deepen collaboration and understanding.
Even after poka-yoke is introduced, there are many cases where it is not showing full effectiveness. To make the most out of Poka-yoke, it is important to keep in mind the following five points.
By checking the circumstances of mistakes, you may introduce the most effective poka-yoke mechanisms and devices for your work site.
For example, if mistakes in the part assembly process occur frequently in the manufacturing field, introducing a system where the shape and position of each part are displayed in an easy-to-understand organization may be effective.
By eliminating individualized tasks, a certain level of quality can be maintained regardless of the experience and skills of the workers.
To eliminate individualized tasks, clarifying work procedures and introducing atomization might be effective.
Using the right tools can reduce the burden put on the operator and prevent mistakes. For example, by using an appropriate torque wrench when tightening screws, you may prevent mistakes caused by loosening or over-tightening the screws.
5S activities are activities that combine five activities: sorting, tidying up, cleaning, cleanliness, and discipline. By spreading awareness of the 5S activities, you may boost worker’s concentration and prevent mistakes.
Hazard prediction training is a type of training which teaches you how to predict dangers in workplaces and to take appropriate countermeasures. By conducting hazard prediction training, you may greatly prevent accidents at worksites. To conduct this training, we shall learn how to identify work hazards through sorting out current problems.
When introducing Poka-yoke, there are many cases where jigs are used. Jigs are tools and devices used to make work more efficient and accurate. By using jigs, we can prevent workers from making mistakes such as following incorrect work procedures.
As an example of poka-yoke, we introduce jigs which prevent mistakes in assembling.
Before the introduction of jigs, workers were required to check for the correct shape and position of the parts each time a product was assembled. Though, mistakes could not be prevented as the shape and positioning of the parts were complex.
After introducing a jig which matches the shape and position of the parts, the production line was able to significantly reduce assembly mistakes.
In manufacturing, Poka-yoke is essential to prevent human errors from producing defective goods and causing accidents in tasks like assembling components and operating machineries.
The RICOH SC-20 camera is specifically designed for work inspections, enabling real-time quality assessments during the assembly process. The assembly status, including similar parts, missing parts, and work order, can be automatically verified for error prevention.
