Error Proofing PEOPLE SUPPORTIVE PRACTICE LEAD TIME REDUCTION 20 KEYS LEVELING/ SMALL LOT EMPLOEE INVOLVEMENT/ WHITE SHIRT PROCESS CAPABILITY SIX SIGMA Pull System SUPPLIER DEVELOPMENT Quick Set-up TOTAL PRODUCTIVE MAINTENANCE CONTAINER -IZATION/ TRANSPORTATION 8/18/00 Error Proofing Error PLANT, MACHINE, OFFICE LAYOUT WPO & VISUAL MANAGEMENT 1 Error Proofing Goals To understand the principles of ERROR PROOFING, the reasoning behind it, and the processes of developing Error Proofing (poka-yoke) devices 8/18/00 2 Error Proofing Objectives Improve quality (reduce PPM & scrap) Make the processes easier and more capable Analyze cell for possible Error Proofing opportunities Develop Error Proofing devices and ideas 8/18/00 3 Error Proofing Error Proofing Is The process of anticipating, preventing, & detecting errors which adversely affect customers & result in waste 8/18/00 4 Error Proofing Questions Will Error Proofing be more work to complicate our jobs even further? How does Error Proofing fit in the AMPS program? 8/18/00 Error Proofing Answer Error Proofing will make your job easier and safer! 8/18/00 Error Proofing How can the Error Proofing class be used? Catalyst for improvement Tool for reaching measurables Learning device 8/18/00 Error Proofing What Measurables does Error Proofing affect? PPM Scrap Process Capability 8/18/00 Error Proofing Other Benefits Safety Improvements Quality Improvements Ergonomic Benefits Promotes Design for Manufacturing 8/18/00 9 Error Proofing Therefore… Error Proofing Classes only help us reach our measurables for the overall goals established in our 20 Keys. 8/18/00 Error Proofing Error Proofing Think – Quality Think – Right First Time Think – Zero Defects 8/18/00 11 Error Proofing Why Error Proofing? Maintain customer satisfaction Reduce cost Ability to maintain Continuous Improvement production methods and smaller inventories 8/18/00 12 Error Proofing Why Error Proofing? Safety Quality – Scrap – PPM – Repairs 13 Error Proofing Safety Examples Light curtains 8/18/00 14 Error Proofing Safety Examples Light curtains 8/18/00 15 Error Proofing Safety Examples Palm buttons 8/18/00 16 Error Proofing 1-100-1000 Rule If it takes 1 hour to fix a problem where it occurs, it may take 100 hours downstream, and it may take 1000 hours at the customer What are cost implications? 8/18/00 Error Proofing Error Proofing Directly Affects World Class Benchmarks • • • • • • • • PPM Scrap Suggestions per employee % of suggestions implemented % of employees on teams WIP hours Employees Cross Trained Supplier Days Inventory 25 or less Less than 2% 15 per year 85% 100% Less than 4 hrs. 100% Less than 4 days 8/18/00 18 Error Proofing Parts Per Million • PPM of 25 22,000 credit cards will have incorrect cardholder information on the magnetic strips. 55,000 pieces of mail mishandled each month. 18 unsafe plane landings at O’Hare each year. 8/18/00 Error Proofing Parts Per Million • PPM of 25 $19,000 spent annually on CD’s and tapes that don’t play. 4,000 checks deducted from the wrong bank accounts each day 50,000 documents lost by the IRS each year 8/18/00 Error Proofing Parts Per Million If 75,000 Total shocks and struts go out the door per day, then only 1.875 can be defective to meet the goal of 25 PPM When the customer gets that defective shock or strut, do they care that the other 74,998 were good? 8/18/00 21 Error Proofing Parts Per Million If 1000 exhaust systems are produced per shift. How many defects can we have and still be at 25 PPM or less? .025 When the customer gets that defective part or assembly, do they care that the other 999 were good? 8/18/00 22 Error Proofing 3 Zeros Zero defects Zero waste Zero delays 8/18/00 23 Error Proofing Error Proofing • Error Proofing 1. Simple and inexpensive 2. Automatic, or part of process 3. Placed close to mistake, minimizing damage 8/18/00 Error Proofing Error Proofing What are some everyday examples? 8/18/00 Error Proofing Examples Cannot start the car without it being in park 8/18/00 26 Error Proofing Examples Dryer stops when you open the door 8/18/00 27 Error Proofing Examples Mower stops when you release the handle 8/18/00 28 Error Proofing Inside the Refrigerator Light goes out when you shut the door 8/18/00 29 Error Proofing Exercise 1 List examples of error proofing in room 8/18/00 30 Exercise 1 Error Proofing List Error Proofing Devices in the Room Error Proofing is the process of anticipating, preventing, and detecting errors which adversely affect customers and result in waste. 8/18/00 1. ______________________________ 11. ______________________________ 2. ______________________________ 12. ______________________________ 3. ______________________________ 13. ______________________________ 4. ______________________________ 14. ______________________________ 5. ______________________________ 15. ______________________________ 6. ______________________________ 16. ______________________________ 7. ______________________________ 17. ______________________________ 8. ______________________________ 18. ______________________________ 9. ______________________________ 19. ______________________________ 10. ______________________________ 20. ______________________________ 31 Error Proofing Module 2 Error Proofing Devices and Defects 8/18/00 32 Error Proofing Error Proofing Uses techniques that prevent errors by: – Designing processes and products that cannot be incorrectly performed, manufactured, or assembled – Using devices or inspection techniques that detect errors during the work process rather than at the end of the process 8/18/00 33 Error Proofing Error Proofing Devices Simple and inexpensive devices that are used to prevent errors about to occur or detect errors and defects that have occurred. 8/18/00 34 Error Proofing Errors and Defects An example of an ERROR would be: – Loading a part incorrectly in a fixture A DEFECT would be: – if that machine were cycled and a bad part produced 8/18/00 35 Error Proofing Error Proofing Five Manufacturing examples – Guide pins – Error detection and alarms – Limit switches – Counters – Checklists 8/18/00 Error Proofing Examples 8/18/00 Guide pins allow only the correct baffle to be loaded in the press 37 Error Proofing Examples 8/18/00 Guide pins are used to check alignment of the flange. Error Proofing Examples Assembly/Mounting Error 8/18/00 39 Error Proofing Examples Limit Switch 8/18/00 40 Error Proofing Ten Causes of Errors Processing omissions – Leaving out one or more process steps. Processing errors – Process operations not performed according to the standard work procedures. Error in setting up the work-piece – Using the wrong tooling or setting machine adjustments incorrectly for the current product 8/18/00 41 Error Proofing Ten Causes of Errors Missing parts – Not all parts included in the assembly, welding, or other processes Improper part/item – Wrong part installed in assembly Processing wrong work piece – Wrong part machined 8/18/00 42 Error Proofing Ten Causes of Errors Operations errors – Carrying out an operation incorrectly; having the incorrect revision of a standard process or specification Adjustment, measurement, dimension errors – Errors in machine adjustments, testing measurements or dimensions of parts and gages 8/18/00 43 Error Proofing Ten Causes of Errors Errors in equipment maintenance or repair – Defects caused by incorrect repairs or component replacement Errors in preparation of blades, jigs, or tools – Damaged blades, poorly designed jigs, or wrong tools 8/18/00 44 Error Proofing Five Causes of Human Errors New worker – Not familiar with operation Forgetfulness – Lack of concentration and standards from one part to the next Willful errors – Operator thinks his/her way of doing things is best Lack of standards – No standardization of work implemented Surprise errors - equipment – Equipment failures or wrong setup 8/18/00 45 Error Proofing Traditional Management Cycle Error takes place A defect occurs as a result This information is fed back Corrective action is taken accordingly 8/18/00 46 Error Proofing Traditional Alternatives 100% Inspection SPC 8/18/00 47 Error Proofing Error Proofing •100% Inspection -Costly -Non-Value Added -Not fail-safe 8/18/00 Error Proofing SPC Good Part Are These Acceptable? 8/18/00 49 Error Proofing Error Proofing • 99.9% Good 20,000 incorrect drug prescriptions will be written in next 12 months 12 babies will be given to the wrong parents every day 291 pacemaker operations will be performed incorrectly this year 8/18/00 Error Proofing Error Proofing • 99.9% Good 811,000 faulty rolls of 35mm film will be loaded this year 268,500 defective tires will be shipped this year 8/18/00 Error Proofing Error Proofing • So if SPC is not acceptable.. Then? 100% inspection AUTOMATICALLY ERROR PROOFING 8/18/00 Error Proofing Exercise 2 Existing error proofing Possible defects 8/18/00 53 Exercise 2 Existing Error Proofing and Possible Defects Error Proofing Existing error proofing and its function: _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Areas where defects often occur and what they are: _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 8/18/00 54 Error Proofing Module 3 Inspection and Zero Defects 8/18/00 55 Error Proofing Who is the best inspector? 8/18/00 56 Error Proofing YOU The User 8/18/00 57 Error Proofing Types of Inspection Self-checking - Before handoff Joint-inspection - During handoff Successive check - After handoff Source inspection - Immediately after mistake, but before it results in a defect 8/18/00 Error Proofing Types of Inspection Three Approaches – Judgment • Discovers defects after they have happened – Informative • Reduces defects but doesn’t prevent them – Source • Catches errors before they cause defects 8/18/00 59 Error Proofing Source Inspection An error takes place Feedback is carried out at error stage before it becomes a defect Corrective action is taken accordingly 8/18/00 60 Error Proofing Source Inspection 1. Source inspection to PREVENT errors before they cause defects 2. 100% inspection using inexpensive devices 3. Action to stop operations when defect is detected 8/18/00 Error Proofing The Eight Principles of Basic Improvement For Error Proofing and Zero Defects 1. Build quality into the processes: 8/18/00 62 Error Proofing The Eight Principles of Basic Improvement For Error Proofing and Zero Defects 2. All inadvertent errors and defects can be eliminated: 8/18/00 63 Error Proofing The Eight Principles of Basic Improvement For Error Proofing and Zero Defects 3. Stop doing it wrong and start doing it rightNOW! 8/18/00 64 Error Proofing The Eight Principles of Basic Improvement For Error Proofing and Zero Defects 4. Don’t think up excuses, think about how to do it right: 8/18/00 65 Error Proofing The Eight Principles of Basic Improvement For Error Proofing and Zero Defects 5. A 60% chance of success is good enough, Implement your idea NOW!: 8/18/00 66 Error Proofing The Eight Principles of Basic Improvement For Error Proofing and Zero Defects 6. Mistakes and defects can be reduced to ZERO when everyone works together to eliminate them: • • • Zero defects Zero waste Zero delays 8/18/00 67 Error Proofing The Eight Principles of Basic Improvement For Error Proofing and Zero Defects 7. Ten heads are better than one: 8/18/00 68 Error Proofing The Eight Principles of Basic Improvement For Error Proofing and Zero Defects 8. Seek out the true cause using the 8D (disciplines) Process: 8/18/00 69 Error Proofing The 8 Step Problem Solving Process 8/18/00 Step 1: Use team approach Step 2: Describe the problem Step 3: Implement short-term corrective action Error Proofing The 8 Step Problem Solving Process Step 4: Define and Verify root cause(s) Step 5: Implement permanent corrective action 8/18/00 Error Proofing The 8 Step Problem Solving Process Step 6: Verify effectiveness of corrective action Step 7: Prevent Recurrence Step 8: Congratulate team 8/18/00 Use Team Approach Congratulate the Team Verify Effectiveness of Corrective Action Prevent Recurrence Error Proofing Describe the Problem 8-D Implement Permanent Corrective Action Implement Short-term Corrective Action Define and Verify Root Causes 8/18/00 73 Error Proofing Error Proofing Operator discovers error Stops process Quick fix (authorized by Q.A.) Submit operational problem Team formulated ‘Run’ problem through 8D Arrive at solution Apply solution 8/18/00 74 Error Proofing Module 4 Error Proofing Devices 8/18/00 75 Error Proofing Which Operations? High error potential Vital characteristics or damage potential Failure history Complex operation or much routine detail 8/18/00 76 Error Proofing Developing an Error Proofing Device Describe defect, show defect rate, form prevention team Identify location of the defect occurrence Detail current standards/operating procedures where defect was made Identify any deviation from standard 8/18/00 77 Error Proofing Developing an Error Proofing Device Identify red flag conditions (next slide), 5 whys error happens, until root problem discovered Identify error proofing device required Create error proofing device and test for results CONTINUALLY IMPROVE 8/18/00 78 Error Proofing Red Flag Conditions Adjustments Tooling and tooling changes Dimensions/ specifications/ critical conditions Many or mixed parts Multiple steps Infrequent production Lack of an effective standard 8/18/00 79 Error Proofing Red Flag Conditions Symmetry Asymmetry Rapid repetition High / extremely high volume Environmental conditions 8/18/00 80 Error Proofing Methods for Using Error Proofing Devices Contact method Fixed-value method Motion-step method Warning method 8/18/00 81 Error Proofing Methods for Using Error Proofing Devices Contact Methods Works by detecting whether a product makes physical or energy contact with a sensing device 8/18/00 82 Error Proofing Contact Method Example Guide pins align flange and also make it impossible to put the flange upside-down 8/18/00 83 Error Proofing Contact Method Example 8/18/00 Tab aligns opening 84 Error Proofing Contact Method Example Notch in aligns flange 8/18/00 85 Error Proofing Contact Method Example Rubber O-ring centers tubing 8/18/00 86 Error Proofing Contact Method Example Notch ensures proper seam alignment for welding 8/18/00 87 Error Proofing Contact Method Example Notch is visible showing a correctly loaded part 8/18/00 Notch is not visible showing an incorrectly loaded part 88 Error Proofing Contact Method Example Guide pins align blank for stamping 8/18/00 89 Error Proofing Methods for Using Error Proofing Devices Fixed-Value Method Can be used when a fixed number of parts or operations needs to be performed 8/18/00 90 Error Proofing Fixed Value Method Counter counts the number of welds made and lights after six welds 8/18/00 91 Error Proofing Methods for Using Error Proofing Devices Motion-Step Method Used to sense whether a motion or step in the process has been carried out within a certain expected time 8/18/00 92 Error Proofing Methods for Using Error Proofing Devices Warning Method Activate a light, buzzer, etc. to signal operator of abnormalities 8/18/00 93 Error Proofing Types of Sensing Devices Physical contact sensing devices Energy sensing devices Sensors that detect changes in physical conditions 8/18/00 94 Error Proofing Types of Sensing Devices Physical Contact Sensing Devices Detect the actual presence or lack of presence of a device or part 8/18/00 95 Error Proofing Physical Contact Sensor No Part Part Present Touch switch used to sense that the full length of 8/18/00 stock has been fed into the press 96 Error Proofing Physical Contact Sensor Contact switch used to detect if a rod is too long 8/18/00 97 Error Proofing Types of Sensing Devices Energy Sensing Devices Use energy (photoelectric etc.) to determine whether an error is occurring 8/18/00 98 Error Proofing Energy Sensing Devices Photoelectric switches – proper size or color – passage of an object – proper supply of parts – proper feeding of parts Beam sensors Proximity switches 8/18/00 99 Error Proofing Photoelectric 8/18/00 100 Error Proofing Types of Sensing Devices Change in Physical Conditions Detect changes in pressure, temperature, electrical current, etc. 8/18/00 101 Error Proofing Change in Physical Condition Pressure Temperature Electrical current pH 8/18/00 102 Error Proofing Error Proofing – Case Study Problem 1 Processing Omissions Problem: An operator is responsible for drilling six holes. Sometimes he/she loses count and drills too few holes. Suggestions To Improve: 8/18/00 103 Error Proofing Error Proofing – Case Study Problem 2 Processing Errors Problem: In the final assemble/packaging of shocks, customer part numbers change several times a day, operators sometimes use the incorrect component package. Suggestions To Improve: 8/18/00 104 Continuous Improvement Activity Sheet Team Line Facility Before Improvement Problem Implemented Item After Improvement Date Submitted Team Contact W. O. # 8/18/00 Error Proofing Idea # Date Required Date Completed Effect Champion Error Proofing 8/18/00 Error Proofing Exercise 3 Brainstorming and proposed solutions 8/18/00 107 Error Proofing Module 5 Tracking and Identification 8/18/00 108 Error Proofing Detailed Description of the Problem Action Taken Error Proofing Date Completed Person Responsible 8/18/00 109 DATE & SHIFT Total DIMPLER (4.5) ROBOT (4.5) PROJ WELDER (4.5) GREEN BODY CELL END CAP (4.5) PRESS (4.5) BODY ASS'Y (4.5) GREEN ROD CELL OUTER BRKT ASSY'S (1.5) CUT ITC TUBE (2.) BINDERS (15.5) BAD SEALS (15.5) SPINNER WELDER (15.5) FULL STRUTS (15.5) COMP HEADS (.30) INNER CYLINDERS (.36) WELDED ROD ASSY'S (2.6) PISTON RODS (2.3) SCRAP Error Proofing ` 8/18/00 110 Error Proofing Tally Sheets Hour 1 2 3 4 5 Seam Split III II IIII II IIIII Wrinkles I II I III I Bell Split I Tool Marks I Off Gauge Burn Holes II II I I III Porosity I Burrs IIII ID Incorrect I Ding II Sub Total 8 7 8 I II 19 III I 12 II I 6 I 6 III II I 6 I 9 10 II I I III II 14 I I 2 I 6 I 14 12 2 I 9 6 4 9 Total 8/18/00 Total 5 I 9 9 76 Error Proofing Multiple Counters Counters are attached to the point of use. 8/18/00 112 Error Proofing Ask “Why” Five Times Problem: The Cup won’t fit on the Tail End of The Tail Pipe. 1. Why? 2. Why is the tab too wide? 3. Why does it flatten out? 4. Why is the temp wrong? 5. Why set improperly? 8/18/00 Error Proofing Ask “Why” Five Times Problem: The bracket on the struts will not hold. 1. Why? 2. Why is the weld breaking? 3. Why is the bracket misaligned? 4. Why is the fixture misaligning the bracket? 5. Why is the weld slag built up? 8/18/00 Error Proofing B.O.S. Chart Is a one page chart showing data trends identifying key factors, tracking projects and monitoring improvements 8/18/00 Error Proofing Why Use The B.O.S. Chart Tool? B. O. S. charting is a standard tool used to support visual control One page summary which facilitates management at a glance Ensures real activities are occurring to improve the areas identified as important to the company Is an excellent communications tool – to employees – to management 8/18/00 Error Proofing B.O.S. Chart Format Key Measurable – Target – Trend Line Data Analysis – Pareto 8/18/00 Improvement Activities Improvement Tracking Error Proofing B.O.S. Key Measurable: PPM 300 Ref # 250 200 1 150 2 100 3 50 4 0 Jan Feb Mar Apr May Jun Actual Jul Aug Sep Oct Nov Dec Description Redesign finished goods packaging Procure new component parts Resp. End Date AM 7/18/95 JK containers Improve weld in process weld monitoring system 6/30/96 SL Replace current controller on paint system GA 7/24/95 9/20/95 Target 50 40 Ref # Description Jan Mar May 1 Damaged Assembly 51 48 45 2 Cracked Casing 20 20 18 20 19 3 Broken Weld 19 17 21 18 1 4 Paint Blister 14 19 18 10 14 30 20 Jul 39 Sept 5 10 0 Damaged Assembly Broken Weld 8/18/00 Cracked Casing Paint blister Error Proofing Error Proofing Identification Description of Error Proofing device P1 Description of Error Proofing device P2 Description of Error Proofing device P3 8/18/00 119 Error Proofing Error Proofing Identification The “P” symbol shall be approximately 3inches (75mm) wide and 4 inches (100mm) tall, and attached on or near the Error Proofing device. 8/18/00 120 Error Proofing Error Proofing Identification * SOURCE INSPECTION * P1 Device (Green) An Error Proofing device that prevents an error from occurring P1 8/18/00 121 Error Proofing Error Proofing Identification * INFORMATIVE INSPECTION * P2 Device (Purple) An Error Proofing device that detects an error in time to allow rework before it becomes a defect and prevents further errors of the same type P2 8/18/00 122 Error Proofing Error Proofing Identification * JUDGEMENT INSPECTION * P3 Device (Blue) An Error Proofing device that detects a defect and eliminates it from the flow of good products before it reaches the customer. P3 8/18/00 123 Error Proofing Error Proofing Of the three types of Error Proofing devices mentioned, which is the best one to use? 8/18/00 124 Error Proofing Continuous Improvement P1 This does not mean that they all have to be P1’s, a P3 is better than nothing, but we should continually improve all of the error proofing devices * SOURCE INSPECTION * 8/18/00 125 Error Proofing Critical Operations or Points Identify where a – defect is most likely to occur – error proofing device is CRITICAL POINT (Gray) needed but has not yet been developed 8/18/00 126 Error Proofing What happens if an Error Proofing Device Fails? A lot of defective parts could be produced SCRAP SCRAP SCRAP SCR SCRAP SCRAP SCRAP 8/18/00 127 Error Proofing Maintain the Error Proofing Devices Error proofing devices: – can and do sometimes fail – need to be checked at the beginning of each shift – need to be properly maintained 8/18/00 128 Error Proofing Testing Error Proofing Devices Keep safety in mind Understand the function of the device and what it detects May need to have a defective part to cycle and see if defect is detected 8/18/00 129 Error Proofing Exercise 4 Label error proofing devices and critical operations Implementation plan 8/18/00 130 Exercise 4 Error Proofing Implementation Plan Begin immediately, including all cell operators Utilize data from the before condition Remember 60% is good enough for starters Activities Week 1: ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ Activities Week 2: Person(s) Responsible ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ Activities Week 3: Person(s) Responsible ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ Activities Week 4: 8/18/00 Person(s) Responsible Person(s) Responsible ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 131