1. Poka-Yoke
Dhon G. Dungca

2. What is Poka-Yoke? Poka (Poh-Kah) Yoke (Yoh-Kay)
Inadvertent errors
Yoke (Yoh-Kay)
To avoid
Technique for avoiding simple human errors at work
“fool-proofing”
“fail-safe”
“mistake-proofing the process”

3. Shigeo Shingo
Developed the idea into a formidable tool for achieving zero defects and eventually eliminating quality inspections.

4. Poka-Yoke EVERYWHERE! Elevator alarms 110V/220V plugs
Low battery indicator
Low fuel indicator
Alarm clock

5. 3.5 Diskette
Cannot be inserted unless diskette is oriented correctly. This is as far as disk can be inserted upside-down. The beveled corner of the diskette pushes a stop in the disk drive out of the way allowing the diskette to be inserted. This feature, along with the fact that the diskette is not square, prohibit incorrect orientation.

6. File Cabinets
Can fall over if too many drawers are pulled out. For some file cabinets, opening one drawer locks all the rest, reducing the chance of the file cabinet tipping.

7. Bathroom Sinks
Even bathroom sinks have a mistake-proofing device. It is the little hole near the top of the sink that helps prevent overflows.

8. Key Holder
In China, where electric power has been scarce, hotel rooms are equipped with a room key holder which turns off the power when the key is removed. This ensures no electricity flow to the room while it is vacant.

9. ATM Machines
New generation ATMs perform transactions without the card leaving your hand because of the beeping sound once your card comes out of the machine

10. Elevators
Many elevators are equipped with an electric eye to prevent doors from shutting on people. They also are equipped with sensors and alarms to prevent operation when overloaded.

11. Why Poka-Yoke?
FACT!
Workers finish their shift & don’t remember what they have done
Even highly skilled workers get tired and start committing mistakes
Workers get distracted and forget on a valve or switch

12. TIPCO Experience Incidental Details Root Causes
Chemical valve at kneading machine left open
Wrong delivery to customer
Unaccounted requisition causes distorted inventory stock
Overflow of whitewater storage tank
Human Error
Wrong label generated and pasted on roll
Misplaced actual stock requisition form
Unable to monitor level

13. TIPCO Experience Incidental Details Root Causes Delay at truck scale
Fresh water tank emptied
Truck ran out of fuel
Forgot to put the control value to auto after cleaning the strains

14. Fact!
To Err is Human!

15. Kinds of Human Errors Forgetfulness Misunderstanding
We forget things when we are not concentrating
Misunderstanding
We make mistakes when we jump to conclusion before we are familiar with the situation

16. Kinds of Human Errors Identification Made by Amateurs
We misjudge a situation because we view it too quickly or are too far away to see it clearly.
Made by Amateurs
We make mistakes through lack of experience

17. Kinds of Human Errors Willful Errors Inadvertent Errors
We decide that we can ignore rules under certain circumstances
Inadvertent Errors
We are absentminded and we make mistakes without knowing how they happened

18. Kinds of Human Errors Due to Slowness Lack of Standards
We make mistakes when our actions are slowed by delays in judgement
Lack of Standards
Errors occur when there are no suitable instructions or work standards

19. Kinds of Human Errors Surprise Errors Intentional Errors
Equipment runs differently than expected
Intentional Errors
We make mistakes deliberately

20. How to deal with errors Errors happen Errors can be eliminated
“Errors are inevitable. The mark of character is not refusing to recognize them, but acknowledging them and taking responsibility.”
Errors can be eliminated
People make fewer mistakes if they are supported by proper training and by a production system based on the principle that errors can always be prevented.

21. 5 Best Poka Yoke Guide pins of different sizes
Error detection and alarms
Limit switches
Counters
Checklists

22. Poka Yoke Devices Vibration sensors Metal sensors Timers
Computer-activated devices

23. Approaching ZD (zero defects)
Poka Yoke…
Approaching ZD (zero defects)

24. Sampling vs 100% Inspection
Sampling inspection
“we maintain our quality at 99%”
100% Inspection
“we won’t tolerate a single defect.”

25. 3 Strategies for ZD Don’t make it! Make it to withstand any use!
The more products you make, the greater opportunity for defects to sit in inventory.
Make it to withstand any use!
Build safeguards into the production process to ensure that the product is robust from the user’s viewpoint
Once you’ve made it, use it right away
Go for continuous flow production

26. Inspection Techniques
Judgment Inspection
Separates defective products from good ones after processing
Informative Inspection
Uses data feedback to control the process and reduce the defect rate.
Source Inspection
Determines before the fact whether the conditions necessary for high quality production exist.

27. Prediction vs Detection
System acts before a defect occurs
Detection
System does not allow continuation

28. Basic Poka Yoke Functions
Shutdown
Normal operations are stopped when defect is detected or predicted
Control
Prevents defective items from passing on the next process
Warning
System signals when an abnormality is about to occur or that a single defect has already occured

29. Basic Poka Yoke Functions
Shutdown
Normal operations are stopped when defect is detected or predicted
Control
Prevents defective items from passing on the next process
Warning
System signals when an abnormality is about to occur or that a single defect has already occured

30. Where “Mistake-Proofing” works well
Manual operations were worker vigilance is needed
Where mispositioning can occur
Where adjustment is required
Where SPC is difficult to apply
Where special causes can reoccur
Where external failure costs dramatically exceed internal failure

31. Detection Method By characteristics Omitted processes Fixed values
Weight, dimension, shape
Omitted processes
Process sequence method
Fixed values
Using counter