The basis of defect-free production is the method of protection against errors, called Poka-Yoke. Poka-Yoke system Also Says “Mistake proof”.
Main the idea is to stop the process as soon as a defect is discovered, determining the cause, and preventing the recurrence of the source of the defect.
Therefore, no statistical sampling is required. Key part the procedure is that an inspection of the source of the error is carried out as an active part of the production process in order to identify errors before they become defective. Error detection or stops production until it is corrected, or the process is corrected to prevent the appearance of a defect. This is carried out at each stage of the process by monitoring potential sources of errors.
Thus, defects are identified and corrected at their source, not in the later stages.
Naturally, this the process became possible with the use of tools and mechanisms with immediate feedback (in the process avoid using staff because of his ability to make mistakes). However, the use of personnel essential to identify potential sources of errors. In a 40-year-old Age Shingo studied and largely used statistical methods of quality control, but 20 years later, in 1977, he said that he had finally freed himself from their magical charm.
This is happened when he watched with his own eyes as he was on the assembly line drainpipes at the Matsushita washing machine factory in Shizuoka, which employed 23 workers, managed to work continuously without a single defect for a month, thanks to installation of “Poka-Yoke” devices that prevented the appearance of Defects. Shingo argues that without defectiveness can be achieved using defect control and system control “Poka-Yoke”. Together they make up ‘Zero Quality Control’ (Zero Quality Control)”.
The concept – ZERO Defects!
This concept of “zero defects” is different from what is usually associated with the name of the American mentor Philip Crosby. Shingo’s concept focuses on achieving without defectiveness by using good engineering preparation of production and research into production processes, not through appeals and slogans that are associated with quality campaigns conducted American and Western European firms.
Shingo himself, like Deming and Juran, who demonstrates concern about this American approach, claiming that the publication of defect statistics only introduces misconception and that instead it is necessary to hunt for defective elements of the production process that give rise to the majority product defects.
The ” Defect-free production ” system is the basis of defect-free production.
Defects in production, for the most part, arise from an increase in variability in the characteristics of the process, the spread of which, in turn, may be a consequence of:
- incorrectly developed standards or documented procedures.
- use of low-quality or outdated equipment.
- the use of unsuitable materials.
- wear and tear of tools.
- operator errors.
For all these causes of defects, with the exception of the latter, maybe corrective and preventive actions have been applied. Preventing the same operator errors is hard enough.
At the heart of ideology Defect-free production lies the fact that making mistakes for people in the process work – of course. And this is not an indicator of unprofessionalism. Operator. The goal of poke-eka is to find ways to protect against unintentional Errors. List of typical actions of operators leading to the appearance of defects are presented in the table.
Key Principles
The poke-eka method is based on seven principles:
- Use design to create efficient processes.
- work in teams: this is the only way to make the most of the knowledge of employees.
- Eliminate errors by also using design: this will bring the number of errors closer to zero.
- Address the root causes of defects by applying method 5 “Why”.
- Act at once, use all possible resources.
- Eliminate activities that do not add value.
- Implement improvements and immediately think about further improvements.
Applying Defect-free production system does not rely on operators to find the error themselves. Therefore, when performing work, touch sensors and other are used Device. This helps to effectively identify defects that are missed Operators.
The poke-eka method should be used as an input method control, and throughout the process. The effect of its implementation depends on which stage of the process – incoming control or control in Process progress – this method has been used. In this case, if discrepancies have been identified, warning signals are received or, Even, the equipment can be stopped.
Implementing the Method Poke-eka in input control is called the proactive approach. Detection mistakes in this case will occur before certain or other things have been committed. operations, use warning signals or even, equipment Can be stopped at output control.
Method
An approach in which the poke-eka method is used at other stages of the production process, called reactive. In this case, this method is used:
- immediately after the completion of the process.
- during the performance of work by the operator.
- when transferred to the next stage of the process.
Reactive the approach is effective because its application contributes to prevention of the transfer of defective products to the next stage of the process. But, nevertheless, does not allow to achieve such a high degree of protection against errors, as in the case of a proactive approach. Application of Poke-eka methods in the process of searching for the causes of defects does not give high results, but at the same time it is much more effective than selective Control.
There are other approaches to using the method poke-eka: controlling and warning. With a controlling approach, if a defect is detected, an automatic stop occurs Equipment. The preventive approach is based on the application of all kinds of signaling means (light and sound signals), which inform the operator about a possible error. Stopping equipment often does not options for a warning approach are included.
The Approach
The devices used in poke-eka, according to the method underlying their work, are divided into:
- Contact.
- readers.
- sequential movement.
All three types of devices can be used in both the monitoring approach and the warning approach.
The principle of the operation of contact method devices is based on determining. Whether the sensing element is in contact with the object being check. Example such devices can serve as limit switches. If a contact is violated, then a sound signal is triggered, for example.
See also devices operating by the contact method include transmitters and receivers, photoelectric switches, piezoelectric sensors, and Devices don’t have to be high-tech. Simple passive devices are sometimes the best. They don’t allow Take the details to the wrong position during the process.
Reader’s devices are may when there is a fixed number of operations in process and a fixed number of parts in the product. The sensor multiple times calculates the details and skips the product to the next process only, if the number of details is correct.
The third type of devices – sensors, determining whether a process operation has been perform. If the operation fails or is executed incorrectly, the sensor signals that should be stopped equipment. According to this principle, many sensory and Photovoltaic devices are associated with a hardware timer. The use of such devices is most effective when in the process many parts. Like each other in shape and size are used.
Consistently the use of the Defect-free production system can significantly reduce the number of errors made by operators. Which helps to reduce costs and increased customer satisfaction.