Error proofing
- 1. ERROR PROOFING Quest
- 2. 1/19/99 © Johnson Controls, Inc. errorprf.ppt2 Objectives: By the end of this Workshop, be able to…. • Identify 3 approaches to inspection…. • Identify specific conditions that provoke errors (Red Flags)…. • Use Source Inspection to prevent defects…. • Name error-proofing devices and applications…. • Implement Error-Proofing in your workplace….
- 3. 1/19/99 © Johnson Controls, Inc. errorprf.ppt3 Logistics • Start/End Times • Participation • Lunch Area/Timing • Meeting Location(s) • Restroom(s) • Telephones, Messages, Pages • Call in Number • Refreshments • Timekeeper
- 4. 1/19/99 © Johnson Controls, Inc. errorprf.ppt4 3 Basic Principles • Error Proofing is Achievable Zero Tolerance For Waste • Stable Production Environment (eliminate Operator/machine possible error) • Customer “Pull” Drives Production
- 5. 1/19/99 © Johnson Controls, Inc. errorprf.ppt5 What will Quality be in the 21st Century? Continue to be defined by customers Will be less of a competitive advantage Will be ‘taken for granted’ (expected) Will require routine use of Quality tools Will require more creativity
- 6. 1/19/99 © Johnson Controls, Inc. errorprf.ppt6 Error Proofing Means “Zero Tolerance for Waste” • Fundamental belief that all errors, and the defects they cause, can be prevented = zero waste! • Waste of correction/rework is reduced (You MUST believe th is for Poke Yoke to work)
- 7. 1/19/99 © Johnson Controls, Inc. errorprf.ppt7 EVIDENCES AT&T Power Systems reduced outgoing defects by 70% (Won Deming Prize) TRW reduced customer PPM’s from 288 to 2 Washing machine drain pipe assembly line produced 180,000 units, in 6 months, with 0 defects. Your experiences? Source: Productivity, Inc.
- 8. Error Proofing Means 1/19/99 © Johnson Controls, Inc. errorprf.ppt8 “Stable Production Environment” • An error-proofed process is repeatable.. • An error-proofed process is predictable • An error-proofed process is stable. • An error-proofed process produces higher quality product. Repeatable Predictable Stable Leads to Higher Quality
- 9. 1/19/99 © Johnson Controls, Inc. errorprf.ppt9 Error Proofing Supports “Customer Pull’ • An error-proofed process “gets it right the first time” more often. • Improved flexibility to respond to customer demands. • Improved quality reduces the wastes associated with “inspecting quality into the product.” • Inspection done @ source
- 10. 1/19/99 © Johnson Controls, Inc. errorprf.ppt10 Error Proofing Opportunities
- 11. 1/19/99 © Johnson Controls, Inc. errorprf.ppt11 Error Proofing (Poka-Yoke) • Improves product quality and ensures consistent process results. • Emphasizes designing the manufacturing process to ensure zero defects. • Requires disciplined problem-solving and beliefs that defects are not inevitable in production shops. • Is effective when done in teams.
- 12. 1/19/99 © Johnson Controls, Inc. errorprf.ppt12 • Name some products, services where you are used to receiving high quality every time.... • Any bad product or service experiences? • Are high quality products achievable every time?
- 13. 1/19/99 © Johnson Controls, Inc. errorprf.ppt13 How Can We Ensure Quality in the Following Areas? Man Material Machine Method Information (4M + I)
- 14. 1/19/99 © Johnson Controls, Inc. errorprf.ppt14 5 Elements of Production 4. Method Control: Assembly Line & Work Standards 3. Machine Control: Conditions Assured Through Poka-Yoke & Everyone's Participation 5. Information Control: Visual Controls (Instruction Sheets, Kanban) 1. Me Control: Discipline, Fundamental Education, Cross-Training Assignments 2. Material Control: Source Controls
- 15. 1/19/99 © Johnson Controls, Inc. errorprf.ppt15 Inspection Techniques Judgement (inspection) Informative (inspection) Source (inspection) Remember Shaving?
- 16. 1/19/99 © Johnson Controls, Inc. errorprf.ppt16 Judgment Inspection “Then and There”
- 17. 1/19/99 © Johnson Controls, Inc. errorprf.ppt17 Informative Inspection • Feedback provided to upstream processes when defects are discovered. • Uses statistics and sampling. • Seeks to minimize defects.
- 18. 1/19/99 © Johnson Controls, Inc. errorprf.ppt18 Informative Inspection
- 19. 1/19/99 © Johnson Controls, Inc. errorprf.ppt19 Source Inspection • Operations examined for conditions that may breed defects. • Emphasis on data collection and problem solving. • 100% inspection built into each operation.
- 20. 1/19/99 © Johnson Controls, Inc. errorprf.ppt20 Self-Checking for Errors (Builds out Operator Error) • Work verified before it leaves station • Build sensory + visual aids into operation • Represents 100% source inspection • Workers responsible to implement quality control • Standards must be followed for success
- 21. 1/19/99 © Johnson Controls, Inc. errorprf.ppt21 Self-Checking for Errors
- 22. 1/19/99 © Johnson Controls, Inc. errorprf.ppt22 Successive Checking for Errors • Users of upstream work verify part or process for correctness before use • Prevents cumulative errors • Builds teamwork between operations.
- 23. 1/19/99 © Johnson Controls, Inc. errorprf.ppt23 Successive Checking for Errors
- 24. 1/19/99 © Johnson Controls, Inc. errorprf.ppt24 Defects vs. Errors • Analyzing the production process to achieve zero defects = Distinguishing between defects and errors • Defects = results (effects of mistakes ) • Errors = sources (causes of mistakes)
- 25. 1/19/99 © Johnson Controls, Inc. errorprf.ppt25 Error Defect Not tightening lug-nuts Loose metal Setting too dark on toaster Burnt toast Failing to clean metal Dirt in paint
- 26. Some Common Manufacturing Errors Quest
- 27. 1/19/99 © Johnson Controls, Inc. errorprf.ppt27 Most Common Manufacturing Errors • Omitted processing • Processing errors • Workpiece setup • Missing parts • Wrong parts • Processing wrong workpieces • Misoperation • Adjustment errors • Improper equipment set-up • Tools & jigs improperly prepared
- 28. Why Do People Make Mistakes? Quest
- 29. 1/19/99 © Johnson Controls, Inc. errorprf.ppt29 Most Common Human Errors • Forgetfulness - Lack of task priorities • Misunderstanding - Lack of familiarity with process • Identification - Misreading visual cues • Poor training - Lack of experience, reinforcement • Intentional - Deliberate mistake • Willful - Ignoring rules without harmful intent • Inadvertent - Unaware of mistake • Slowness - Delays in judgement or physical ability • Poor Supervision - Unclear, contradictory instructions • Surprise - Errors due to abnormal events
- 30. 1/19/99 © Johnson Controls, Inc. errorprf.ppt30 Manufacturing & Human Errors • Common human errors can be eliminated through process design • Defects are not inevitable • You can achieve Zero Defects!
- 31. 1/19/99 © Johnson Controls, Inc. errorprf.ppt31
- 32. 1/19/99 © Johnson Controls, Inc. errorprf.ppt32 Red Flags (When These Things Happen…) * Adjustments * Tooling/tooling change * Dimensionality/specification/critical condition * Many parts/mixed parts * Multiple steps * Infrequent production * Lack of or ineffective standards * Symmetry * Asymmetry * Rapid repetition * High volume/extreme high volume * Environmental conditions
- 33. 1/19/99 © Johnson Controls, Inc. errorprf.ppt33 Adjustments reference pin divergence Having to bring parts, tools or fixtures into a correct relative position only by sight or feel. correct incorrect
- 34. 1/19/99 © Johnson Controls, Inc. errorprf.ppt34 Tooling/Tooling Change Defects From Malfunctions or Incorrect Tooling holder glue laminated surface Spots
- 35. 1/19/99 © Johnson Controls, Inc. errorprf.ppt35 Dimensionality/Specification/ Critical Condition Relying solely on Operator skill for proper job setup or precision work
- 36. 1/19/99 © Johnson Controls, Inc. errorprf.ppt36 Many Parts/Mixed Parts Operations without safeguards to prevent use of incorrect parts
- 37. 1/19/99 © Johnson Controls, Inc. errorprf.ppt37 Multiple Steps Work requiring many small operations or sub- tasks
- 38. 1/19/99 © Johnson Controls, Inc. errorprf.ppt38 Infrequent Production Intermittent operations, or production
- 39. 1/19/99 © Johnson Controls, Inc. errorprf.ppt39 Symmetry Model X Condition that allows parts to be installed upside down or in mirror image position
- 40. 1/19/99 © Johnson Controls, Inc. errorprf.ppt40 Asymmetry pointer boss pointer washer Where opposite sides of a part, tool or fixture look identical but can only be used correctly one way. bottom die has a flat surface
- 41. 1/19/99 © Johnson Controls, Inc. errorprf.ppt41 Rapid Repetition From Automatic Welding Machine Repeating the same work over and over so that errors are not readily detected Shaft Omitted Next Process
- 42. 1/19/99 © Johnson Controls, Inc. errorprf.ppt42 High Volume right side up upside down Operations where output is large & fast so that errors workpiece escape visual inspection
- 43. 1/19/99 © Johnson Controls, Inc. errorprf.ppt43 Environment Physical conditions around the workplace that can adversely impact quality wire stock to machine dimensional variation foreign matter tension device reel stand
- 44. 1/19/99 © Johnson Controls, Inc. errorprf.ppt44 Red Flag Conditions S S s ion io n tio n dit s on di t c on rn du on e al C ts ce c C ps ro it i nt en Con Spe arts e Ste ent P SOP ry ry epit lum me tm g l P l u f et et R o n jus lin tica ed ltip eq k o m mm id h V viro Operation Ad Too Cri Mix Mu Infr Lac Sym Asy Rap Hig En Comments
- 45. 1/19/99 © Johnson Controls, Inc. errorprf.ppt45 Quality Data Review • Review top 3 quality issues (in dollars or PPM) in our area for the previous month. • Review top 3 quality issues (dollars or PPM) in our area for the previous 3 months. • Determine which errors reoccur.
- 46. 1/19/99 © Johnson Controls, Inc. errorprf.ppt46 Production Shop Exercise (60 min.) • Form teams. • Decide on line/area to review. • Review operation(s) to Red Flag, using standard form. • Consolidate ideas into groups. • Present for discussion.
- 47. 1/19/99 © Johnson Controls, Inc. errorprf.ppt47 Team Debrief • Describe Red Flag Conditions Found in Your Area. • How Do These Conditions Affect Quality?
- 48. 1/19/99 © Johnson Controls, Inc. errorprf.ppt48 Implementation of Error- Proofing • Identify product defect & collect data • Track defect at: – Point Discovered – Point Created • Review SOP at defect creation point • Identify any deviations from SOP • Identify Red Flag condition at creation point • Implement error-proofing device to prevent error or defect • Check results & make process adjustments
- 49. 1/19/99 © Johnson Controls, Inc. errorprf.ppt49 Describe Product Defect & Collect Data Problem: Missing Nut Bracket Screws Defects 25 20 15 10 5 0 1 2 3 4 5 6 7 8 Hour Are You Capturing This Information?
- 50. 1/19/99 © Johnson Controls, Inc. errorprf.ppt50 Identify Two Key Locations Defect creation & discovery points
- 51. 1/19/99 © Johnson Controls, Inc. errorprf.ppt51 Review SOP at Creation Point Is there an SOP? Deviations? I've been using I've been using slot Phillips head head screws! screws! Service Manual
- 52. 1/19/99 © Johnson Controls, Inc. errorprf.ppt52 Error-Proofing Devices • Level 1 (Prevention: Ideal!) Eliminate error at the source • Level 2 (Detection) Detects errors in the process of occurring, before it has become a defect • Level 3 (Detection) Detects a defect after it has been made but before it leaves the station
- 53. 1/19/99 © Johnson Controls, Inc. errorprf.ppt53 Prevent Defects by: • Shutdown (Level 1) - Processing stopped until error is corrected. • Controls (Level 1) - Only allowing parts to fit into jigs, fixtures in the correct position.
- 54. 1/19/99 © Johnson Controls, Inc. errorprf.ppt54 Error & Defect Detection • Error Detection (Level 2) – Detects errors as they are being made. • Defect Detection (Level 3) – Detects defects before they leave station.
- 55. 1/19/99 © Johnson Controls, Inc. errorprf.ppt55 Common Detection Function & Devices Detection Functions Device Pressure gauges, pressure-sensitive switches Temperature thermometers, thermostats, thermistors, thermocouples Electric Current meter relays, current eyes Vibration vibration sensors Cycles counters, stepping relays, fiber sensors Time times, delay relays, timing units, time switches Information buzzers, lamps, flashing lamps
- 56. 1/19/99 © Johnson Controls, Inc. errorprf.ppt56 Error-Proofing Devices: Visual Devices
- 57. 1/19/99 © Johnson Controls, Inc. errorprf.ppt57 Jigs Desired Drilled Holes Groove Jig Limit Switch Groove L/S Workpiece Correct L/S Workpiece Incorrect
- 58. 1/19/99 © Johnson Controls, Inc. errorprf.ppt58 Photoelectric Devices & Optics
- 59. 1/19/99 © Johnson Controls, Inc. errorprf.ppt59 Contact Devices
- 60. 1/19/99 © Johnson Controls, Inc. errorprf.ppt60 Counters 000004
- 61. 1/19/99 © Johnson Controls, Inc. errorprf.ppt61 Checklists Packing Checksheet Hubcap Covers (4) Owner's Manual (1) Radio Manual (1) Floor Mats (4) Tire Manual (1) Plant Decal (1)
- 62. 1/19/99 © Johnson Controls, Inc. errorprf.ppt62 Shop Floor Application • Describe defect (error). (Write it down, draw it, etc.) • Plot defect rate. (Pareto charts, histograms) • Identify where defect is discovered and made • Detail SOP (What is SOP here?) • Identify deviations from SOP • Identify causes for deviations (Fishbone? Brainstorming?) • Identify Red Flag conditions • Identify source errors • Propose ideas to eliminate or detect errors • Propose possible error-proofing devices
- 63. 1/19/99 © Johnson Controls, Inc. errorprf.ppt63 Summary • Zero defects are possible if you build 100% inspection checks into every process. • The production process can be designed to prevent & detect human errors. • Team skills facilitate error-proofing.
- 64. 1/19/99 © Johnson Controls, Inc. errorprf.ppt64 Summary • Source inspection & successive checking are the foundations of error- proofing. • Error-proofing should be considered where an operation contains Red Flags. • Error-proofing devices need not be expensive or high-tech.
- 65. 1/19/99 © Johnson Controls, Inc. errorprf.ppt65 HAVE FUN!
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