What is poke yoke
In Lean Six Sigma and Six Sigma, Boga-yoke (po-ka yo-ke) is a tool used to identify error-prone steps in a process. Poka-yoke vs error-proofing differences It allows organizations to change to avoid mistakes before operations begin. It is a simple yet powerful tool applicable to any function in any industry.
Also known as error-proofing or mistake-proofing, Poke-yoke is considered a key ingredient in the Six Sigma toolbox. Project teams use Poke-yoke in Lean, which focuses on eliminating waste, as well as Six Sigma, which focuses on eliminating defects.
In both cases, the ultimate goal is the same: to identify and eliminate potential problems in a process before they occur, or to correct faults in an existing process.
When to use error checking
If a process is identified where errors or deficiencies in processes are due to human error, particularly the employee’s attention, skill, or experience.
In a service operation, a customer may make an error that affects output Poka-yoke vs error-proofing differences
During the handover phase in a process, when the output (or, for service processes, the customer) is transferred to another worker
When a small error at the beginning of the process causes major problems later in the process
When the consequences of an error are costly or dangerous
Error checking process
Obtain or create a flowchart of the process. Poka-yoke vs error-proofing differencesReview each step and think about where and when human error might occur.
For each potential error, work backwards through the process to find its source. For each error, think of possible ways to prevent the error from occurring. Consider:
Deletion: Deletion of the step causing the error.
Substitution: Replacing the grid with a non-faulty grid.
Convenience: It is much easier to take the right action than the wrong one.
If you can’t prevent the error from happening, think about ways to detect the error and minimize. Poka-yoke vs error-proofing differences its consequences. Consider the study methods, organizational function and regulatory function explained in detail below.
Choose the best fault-blocking method or device for each fault. Test it and then implement it. Three types of survey methods provide quick feedback:
A subsequent inspection is done by the next employee at the next stage of the process. Self-checking is when workers check their work immediately after it is done. Proofreading verifies that conditions are correct before steps in the process occur. Often this is automatic and blocks the process until conditions improve.
Organizational and regulatory functions
System functions are methods of checking a process parameter or product characteristic for errors:
- The contact or physical method often checks physical properties such as diameter or temperature using a sensor.
- The speed-step or sequencing method checks the process sequence to ensure that the steps are performed in sequence.
- A constant value or grouping and counting method counts iterations or parts or weighs an object to ensure completeness.
- Sometimes a fourth organizational function is added, information development, which ensures that information is available and understandable when and where it is needed.
Regulatory functions are signals that alert workers that an error has occurred:
Warning functions include bells, sounds, lights and other sensory signals. Poka-yoke vs error-proofing differences Consider using color-coding, shapes, symbols, and specific sounds. Control functions block the process until the error is corrected (if the error has already occurred) or until the conditions are correct (if the probe is a source probe and the error has not yet occurred).
Error checking example
The Parisian Experience restaurant wants to ensure a high level of service by checking for mistakes. Poka-yoke vs error-proofing differences They reviewed the seating process sequence chart (a detailed flowchart showing who does each step) shown below and identified human errors that could cause restaurant staff or customer service issues.
There are two approaches to Poka yoke devices:-
Control Approach: This approach identifies a problem and stops the line or process so that corrective action can be taken immediately, thereby Avoiding gradual defect formation.
Alert Approach: This approach indicates a trend of variation or divergence by means of increasing buzzers, lights or other warning devices. However, unlike the control method, the warning method does not stop the process in every instance.
Poka-yoke devices include three effective methods to ensure fault detection and prevention:
- Contact method
- Constant value method
- Moving step method
Each method can be used in a control approach or a warning approach.
The contact method detects any deviations in shape, dimensions, form, position or other physical properties by means of direct contact with the part. Poka-yoke vs error-proofing differences The communication method can be used in fast repeating situations, low production or environmental problems such as poor lighting, critical temperature, dust, noise.
Fixed cost method is used in jobs where the same operation is repeated many times. This method uses automatic counters or optical instruments and controls the number of moves, speed and length of move and other important operational parameters.
The operation step method is useful for processes that require a single operator to perform several operations sequentially. This method ensures that the operator does not accidentally perform any actions that are not part of normal operation.
Benefits of poka yoke
The biggest advantage of Boka-Yoga is that it reduces the possibility of human error in a process. Poka-yoke vs error-proofing differences This ensures that all conditions are correct before the next step of the process occurs. The end result is that there will be little or no defects in the process.
Apart from this, Poka-Yoke comes with the following other benefits:
Improving Quality: Poka-yog improves quality without causing any defects in the process. This means increased stakeholder and customer satisfaction as confidence increases in your process to consistently produce quality products.
Cost reduction: The biggest problem with defective products is that they increase the amount of waste. And since they have to be replaced, the cost of production increases as the number of defects increases. Fewer defects mean lower costs.
No high-skill requirements: If a process has a high probability of error, operators must be highly skilled to run it. If the operator lacks the skills, the company may have to spend resources to train them or hire a skilled worker. Mistakes and errors are automatically prevented by Poka-Yoke, significantly reducing skill requirements.
Improves Safety: Safety is a major concern in the workplace, especially when employees are handling hazardous materials. Since Poka-Yoke eliminates human error, safety in the workplace is greatly improved.
Reduces the need for quality checks: With a debugging tool or method built into the process, extensive quality checks are not required. Poka-Yoke detects or predicts any problems without relying too much on inspectors.
Speeds up the process: Less manual inspection required, work moves faster without sacrificing quality. Additionally, employees tend to focus on the work they do best, making work boring and repetitive.
Read more >>>>>>> History and origin of poka-yoke methodology Global Manufacturing
How did Poka-Yoke begin?
Toyota engineer Shigeo Shingo coined the term Boka-yoke in Japan in the 1960s. Shingo is one of the great pioneers of continuous process improvement and operational excellence. His many achievements include developing the concept of a single minute transfer of dye and using Boka-Yoga techniques to correct and prevent defects.
Poka-yoke focuses on solutions that permanently fix an ongoing or anticipated problem, rather than fixing a problem in a single instance. Poka-yoke vs error-proofing differences It is part of the Toyota Production System (TPS) as a feature in Jitoka that allows workers or automated machines to stop a process if it detects the possibility of a defect or error.