0. Mistake Proofing (Poka-Yoke)
No support files or supplies needed.

1. The Breakthrough Strategy® And The Control Phase
1. Select Output Characteristic
2. Define Performance Standards
3. Validate Measurement System
4. Establish Baseline Process Capability
5. Define Performance Objectives
6. Identify Variation Sources
Screen Potential Causes
Discover Variable Relationships
Establish Operating Tolerances – Implement Improvements
10. Validate Measurement System
11. Determine Final Process Capability
12. Implement Process Controls
Implement controls on the key Xs

2. Module Objectives
By the end of this module, the participant will be able to:
Understand the concept of Mistake Proofing as a control method
Apply Poka-Yoke methods as a control on identified key xs
Reduce and/or eliminate process errors from occurring
Reduce and/or eliminate process defects from occurring
Understand “red flag” conditions 1 2 3 4 5 6 7 8 9 10 11 12 D M A C I

3. Why Is Mistake Proofing Important?
Improved quality and customer satisfaction
Prevents error occurrence
Prevents defect occurrence
If defects occur, ensures effective action
Little or no formal training
Cost effective
Easy to implement
Mistake proofing is also a critical piece of any JIT system.
Mistake Proofing is one of the most cost effective and reliable controls that can be used to assure that our key Xs remain at our optimum project defined settings. It can also be used directly on the Y.

4. What Is Mistake Proofing (Poka-Yoke)?
Japanese phrase:
Yokeru (to avoid), Poka (errors)
A strategy for preventing errors in processes
Makes it impossible for defects to pass unnoticed
Corrects problems as soon as they are detected
Technique detects defects
Prevents defects from moving into next area
Developed by Dr. Shigeo Shingo to achieve zero defects
Mistake Proof devices cannot be implemented until the key Xs needing to be controlled have been identified and settings established (Establish Operating Tolerances, Step 11).

5. What’s The Secret Of Poka-Yoke?
“What’s the secret? It’s a mystery to me – Our plant is as sophisticated as you can get, yet with all this innovation at our disposal we still make defects. I can’t believe all those statistics about parts per million and zero defects coming from Japan. There must be a gimmick. With all the variability of parts coming from hundreds of vendors and going through fifty different processes with a hundred machines, it is impossible not to produce some defects. So what’s the trick? Where is the hidden weapon?”
Norman Bodek
Publisher
Poka-Yoke, Improving Product Quality by Preventing Defects

6. The Secret Of Dr. Shigeo Shingo
“It is not one Poka-Yoke device, but the application of hundreds of these very simple fail-safeing mechanisms that, day after day, has brought the quality miracle to industries around the world.
Each one is relatively simple – Something you easily could do on your own. But it is the totality, the hundreds of devices, that is almost frightening to behold.”
Dr. Shigeo Shingo

7. Common Examples Of Mistake Proofing
Guide pins of different sizes
Optical magnification
Different colored tags for pressure ranges
Look up tables for data base entry
Spell check
Limit switches
Error alarms
Counters
Checklists
Asymmetric parts
Build error checking into control logic
Exact part count

8. Mistake Proofing Business Processes
Xdthx th xth yj
fyjdtyj
______
dxrt
____
rtjh
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Mistake Proofing is the primary means of control for many business processes
Check digits
Pull down menus
Check sheets
Required fields d
tsthy sety
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__________

9. Basics Of Mistake Proofing
Effective Mistake Proofing requires two basic concepts
A focus on controlling the factors which cause errors – Not fixing the resulting defective output (Sigma Lean Concept)
Inspection which is effective and tireless
This IS NOT traditional 100% inspection by inspectors
This IS a mechanical or process improvement that automatically performs the inspection with little to no human interaction
Emphasize what we said in week 1: “100% inspection is not 100%” still applies to traditional inspection and that mistake proofing is not traditional inspection
Can not do it wrong.
Can only do it one way.
If wrong, detected 100%.
Can not be passed into next area.

10. What Does Mistake Proofing Do?
The ideal process is mistake proofed at three stages:
Input
Process
Output
3. Output
1. Input
2. Process
Ideal:
1. This process will not accept any bad parts
2. This process will not make any bad parts
3. This process will not pass on any bad parts

11. Error Proofing In Action
What are the error opportunities in these everyday items?
How have they been error proofed?
How could they be further error proofed?
Size of the nozzle to prevent wrong gas from being pumped
Cord attached to the cap to prevent loss
Cap can be placed in green holder to keep cap from marking paint
Cap clicks into place to signal locked avoid over tightening
Spout has a spring loaded cover to keep out elements
Has anti-siphon protection
Cap even tells which grade of gas to pump (premium or regular unleaded)
Gas pump handle has overfill trigger to spillage

12. Error Proofing In Action
What are the error opportunities in these everyday items?
How have they been error proofed?
How could they be further error proofed?
Has limit switch to avoid damaged from over opening
Has pressure sensors if door strikes something it stops
Some have electronic eye beam that if tripped stops door
Light turns on when door opens, stays on for set time then turns off
Remote has unique code to avoid other remotes from opening it
Note plug, 3 prong only one way to insert

13. Class Exercise Round Robin: Let’s go around the class twice.
The first time each participant will list a Mistake Proofing idea from one of the following:
Home (e.g., auto shut off on flat iron)
Auto (e.g., car won’t start unless transmission is in park/neutral)
Sport/Recreation (e.g., dead man’s lanyard on personal watercraft)
Amusement Parks (e.g., sensors on roller coaster tracks)
Work/Commerce (e.g., pull down menus on forms)
Etc.
The second time around, you will be asked to identify a possible Mistake Proofing for some potential vital X from your project
If you plan on skipping the optional exercise at end of module consider providing additional comment on type of defect being addressed by the poke-yoke. Also perhaps an additional round might be appropriate.

14. My New Spell Checker
Eye halve a spelling chequer It came with my pea sea It plainly marques four my revue Miss steaks eye kin knot sea. Eye strike a key and type a word And weight four it two say Weather eye am wrong oar write It shows me strait a weigh. As soon as a mist ache is maid It nose bee fore two long And eye can put the error rite Its rare lea ever wrong. Eye have run this poem threw it I am shore your pleased two no Its letter perfect awl the weigh My chequer tolled me sew.

15. Evolution Of Defectives And Application Of Mistake Proofing
ERRORS
DEFECTS
The Value of Mistake Proofing
DEFECTIVES

16. Ten Common Errors That Lead To Defects (Things That Can Cause Your Key X To Go Astray)
Errors are the cause of defects
Processing errors
Error in setting up job
Processing omissions
Assembly omissions (missing parts)
Inclusion of incorrect component
Incorrect job
Operation error
Tool or equipment error
Defects in job components
Measurement error
ERRORS
DEFECTS
DEFECTIVES
Consider Mistake Proofing against these having any impact on your Key Xs.

17. Human Errors That Lead To Potential Key X Variation
Forgetfulness
Errors due to misunderstanding
Errors in identification
Errors made by untrained workers
Willful errors (ignore rules)
Inadvertent errors (distraction, fatigue)
Errors due to delay in decision making
Errors due to lack of standards
Surprise errors (malfunctions)
Intentional errors (sabotage)
ERRORS
DEFECTS
DEFECTIVES
Also consider Mistake Proofing against these having any impact on your Key Xs.

18. Red Flag Condition What is a Red Flag condition?
You will find that in some projects, after you have identified the Key Xs and their optimal settings, one or more of them may be extremely difficult to control. The control plan should attempt to provide robust control mechanisms, however it may be difficult to do so without Mistake Proofing. Some examples:
Training was found to be critical, but the operation has 150% turnover
Cycle Times are very long, so the operators tend to lose concentration and Key X breakdowns may not be observed even though gages/process measurements show the issue
The second example could benefit from a loud bell or siren
Mistake Proofing is a good control application for conditions such as these.

19. Common Red Flag Conditions
Frequent changes to a job
Complex processes
Lack of standards
Lack of measurement systems
Lack of training
Long Cycle Times
Infrequent jobs
High output
Environmental conditions
Attitude (motivation)
If one of these conditions exists in your process, consider Mistake Proofing as a control for your KPIVs
e.g., Lack of Training – Establish a system where only trained operators get engraved name plaques which are placed in a clearly visible slot on the machine/work station:
Untrained operator  No plaque
No plaque  Management Awareness Management Awareness  Action

20. Implementation Road Map For Mistake Proofing
(Key X)
Describe the defect or potential defect including the rate
Apply Five Why analysis to the error conditions to determine root causes
(Process Map)
Identify where
the defect is likely to occur
Identify (using a team approach) Mistake Proofing strategies
(Process Map)
Analyze current tasks associated with the operation
Discuss how the efficiency of the mistake proofing actions can be evaluated… Nice opportunity to review some tools from previous weeks.
(FMEA)
Identify error conditions contributing to the defect
Verify the efficiency of the Mistake Proofing actions

21. Mistake Proofing Strategies
Detect defects before they move to next step
Detect errors during processing
Prevent errors from occurring
Instructor should describe, in discussion with the class, various examples of the above boxes.
e.g.
1’st box -In manufacturing a light that comes on when a part is automatically tested as it comes off a machine and is found defective and is kicked out of the process (a screw that has poor threads).
2’nd box – The tooling coolant for the screw machine plugs up and a warning on the machine control comes on (if we run without coolant, we will get poor threads).
3’rd box – A automatic purging system is installed in the cooling system that senses high line pressure ( a sign of a plugged line) and purges/cleans the lines.
Good
Best

22. Optional Class Exercise
Pick a project from your team. On a flip chart create a column of the ten common error types. Create one or more columns of defects
Complete the matrix (next page), first identifying defects that can be caused by the errors, then brainstorm and capture Poka-Yokes for the error/defects

23. Optional Exercise Data Matrix
Errors
Processing errors
Error in setting up job
Processing omissions
Assembly omissions
Incorrect component
Incorrect job
Operation error
Tool or equipment error
Defects in job components
Measurement error
Defect 1
Defect 2
Poka-Yokes

24. Key Learning Points This is what you’re hoping to get out of them…
Where can you use Mistake Proofing?
Identify “Red Flag” conditions
Human
Process
Analyze for root causes
Two levels of Mistake Proofing
Detection
Prevention

25. Objectives Review The participant will be able to:
Communicate the concept of Mistake Proofing as a control method
Apply Poka-Yoke methods as a control on identified key Xs
Reduce and/or eliminate process errors from occurring
Reduce and/or eliminate process defects from occurring
Explain “Red Flag” conditions

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