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

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

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

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.

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).

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

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

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

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

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.

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

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

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

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.

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

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.

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.

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.

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

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

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

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

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

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

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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