Sigma (𝝈) is the Greek letter representing a statistical unit of measure that defines the standard deviation (SD) of a population. The poka-yoke system is a mistake-proofing tool that was first invented by Shigeo Shingo in the 1960s. It has since found a very wide variety of applications and it can be used to prevent an opportunity of error all across an industry.
In this article, we will be learning
- what is poka- yoke system
- Poka-yoke system Examples
- How to apply the poka yoke system in manufacturing industries
- Types of Poka-yoke system
- Poka yoke Principle
- Poka yoke techniques
- Benifits of Poka yoke
What’s Poka- Yoke?
- Poka- Yoke means” error proofing” or” mistake-proofing”. It came from the word” Poka” which means” mistake”and”Yoke ”which means” to avoid” and
it’s a Japanese term.
- It’s any machine in any process that helps for” mistake-proofing “or” error-proofing”.
- We can remove product defects by preventing it, correcting it, or detecting is as they do.
- It’s one of the Lean Manufacturing Tools
- This concept was accepted, by Shigeo Shingo as part of the Toyota Production System.
- Shigeo Shingo used the word “Poka_yoke” in the 1960s to prevent human error during industrial processes design.
Poka- Yoke Example
Here are few examples of the poka-yoke that we are experincing daily basis.
- A simple illustration is when we start a car having manual gearbox, we must have to press on the clutch pedal before starting. This prevents us
against the unintended movement or jerk of the car during the starting
- Seat Belt wearing Indicator.
- Auto-locking of the door at the certain speed of the car.
- Bar code for correct product identification
How to apply Poka-Yoke in manufacturing?
- Identification Problems
- Seek root cause
- find and implement solution
- measure the resul
- What are the types of poka- Yoke?
Types of Poka-Yoke
Shigeo Shingo acknowledges three types for detecting and preventing mistake in a process as mentioned below.
- Constant Number (or fixed- value) Metho
- Sequence (or motion step) method
The contact method
The contact method identifies defects using a part’s shape, color, size, and other physical attributes. It can also include limit switches and Emrgency detectors.
The constant number (or fixed-value) method
- When certain movements aren’t made also this error-proofing or mistake-proofing tool informs the operators. This method is known as the constant
number (or fixed-value) method. Counters can be used for this at each step of the process as necessary.
The sequence (or motion step) method
- This method ensures the sequence fo the process step before moving to the coming step.
- This is known as the sequence (or motion step) method. The sequence method isn’t allowing the mistake to be made in the first place.
The illustration of sequence method is color coding and trailing and this parameter are checked at each step before moving forward.
Poka- Yoke Principles
- Quality Processes
- Utilize a Team Environment
- Elimination of Error
- Eliminate the Root Cause
- Do It Right The First Time
- Eliminate Non-Value Added decision and activity
- Apply a Continual impro vement Approach
Make a robust process design for zero defect manufacturing.
Utilize a Team Environment
For any improvement, communicate with the teammates so we can use their knowledge and experience to apply our improvement.
Elimination of error
Use several problem- solving methodologies or ways for reducing defect and drop defect to zero.
Eliminate the Root Cause
Eliminate the root cause of any problem by implement this tool.
Do It Right The First Time
Make the process very effective to perform functions rightly for the first time.
Eliminate Non-Value Added decisions and activity
Identify all non-value added decisions and activity and remove them.
Apply a Continual improvement Approach
We can’t get 100 result in a single pass.So, apply improvement effort immediate and concentrate on continual improvement so we can get a 100 result.
Six Poka- Yoke Techniques Explained with Exemplifications
Primarily concentrate on elimination. In Elimination, we’ve to remove the step that’s responsible for the mistake Remove. Non-Value Added activity Redesign the product and revision of the process (as applicable)
Poka-yoke Example: Replace manual data entry with barcode scanning
If elimination isn’t possible the alternate option is Replacement. In Replacement, we’ve to replace the step with a more dependable mistake- evidence one. Automation of repetitious motion activities
Poka Yoke Example: Welding Robotics for an automotive manufacturer
- If the above two methods aren’t possible also the 3rd option is the prevention
- Change product or process (as applicable) so that mistake is prevented.
- Prevention is a physical boundary to help uninvited action.
Poka Yoke Example: Safety guards on lifts, plugs for 110V & 220V, Printer cartridges, and Go/ No Go Needles, etc.
If the above three methods aren’t possible also the 4th option is facilitation. Facilitation is to help someone take the right decision. We can facilitate any process or product by visual controls like color coding, markers, lines, signs, etc.
Poka Yoke Example: Warning signs, checklist, Traffic lane markings, Color- enciphered parts or tools, etc.
If the above four methods aren’t possible also the 5th option is facilitation. Detection is to identify or detect the wrong product or process immediately after it happens. We can give detection by Detectors, limit switches, or light detectors.
poka - Yoke Example: Safety guard limit switches to help the machine run in an open condition, Computer warning if all information isn’t filled in.
If the above five methods aren’t possible also the 6th option is mitigation. Mitigation is to minimize the effects of mistakes or failures. This method is used when the mistake can not be eliminated.
Poka - Yoke Example: Personal defensive equipment, Airbags in cars, Electrical Fuses, An eraser on a pencil, etc.
Benefits of Poka- Yoke implementation
- Elimination of numerous operations related to quality control
- Increase the motivation of an employee
- Reduce the overburden of operators from repetitious operations
- A reduced number of rejects
- Immediate action when a problem occurs
- 100 build-in quality control.
- Lower time spent on training workers
- Promotion of the work improvement-oriented approach
The use of the poka-yoke system tool significantly reduces the risk that an error could take place and therefore improves the success rate in assembling machines or products. In this way, it can save costs, increase productivity and quality, and create a better working environment in factories and offices alike – ultimately benefiting any organization business which makes an effort to apply this powerful technique.