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Six Sigma Overview

Six Sigma Overview. Long-Term Yield. 3 Sigma Process Capability 93.32% Historical Standard. The Classical View of Performance. Six-Sigma is a philosophy: Why i sn’t “99% acceptable ” good e nough...?? 20,000 lost articles of mail every hour.

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Six Sigma Overview

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  1. Six Sigma Overview

  2. Long-Term Yield 3 Sigma Process Capability 93.32% Historical Standard The Classical View of Performance • Six-Sigma is a philosophy: • Why isn’t “99% acceptable” good enough...?? • 20,000 lost articles of mail every hour. • 15 minutes each day of unsafe drinking water. • 5,000 incorrect surgical procedures per week. • 4 or more accidents per day at major airports. • 200,000 wrong drug prescriptions each year. • 7 hours each month without electricity. 4 Sigma Process Capability 99.38% CurrentStandard 6 Sigma Process Capability 99.99966% World-Class

  3. On target, minimum process variation History of 6 Sigma • 6 Sigma manufacturing philosophy came from Motorola They recognised that sufficient process improvement would not occur using a conventional approach to quality. It was developed to help them reduce variation within a process by focusing effort on improving inputs to a process rather than reacting to outputs. • The process was failing the customer expectations • Traditionally, processes aimed for process capability of 3 to 4 sigma (Cpk=1.0 to 1.33 or 93% to 99.3% acceptable) • The customer received 6200 defective product per million at best • Processes now aim for 6 sigma (Cpk=2) • The customer would receive 3.4 defective product per million

  4. CPK of 1 (3 sigma) CPK of 2 (6 sigma) 6 sigma Process Capability “What is it (CPK)” • 3 Sigma ( Process capability of 1 CPK ) • if the process (lorry) slightly varies then the scrap or damage will occur • 6 Sigma ( Process capability of 2 CPK ) • if the process (lorry) varies, there will be no scrap or damage Curbs = required process tolerances

  5. Understanding Variability • Variation exists in everything. Even the best machine cannot make every unit exactly the same. • Improved capability, becomes a necessity, due to the need of : • improved designs • lower costs • better performance • All of this leads to the need of tighter tolerances • This means that the ability to operate to a tight tolerance, without producing defects becomes a major advantage

  6. Improvement methodology KPIV Key Process Input Variables Controllable Inputs X1 X2 X3 Quality Characteristics: Outputs Inputs: Raw materials, components, etc. The Process Y1, Y2, etc. N1 N2 N3 Uncontrollable Inputs On target, minimum process variation

  7. Improvement methodology D M A I C Define Measure Analyze Improve Control

  8. Improvement methodology Define • Define terms of reference (Charter the project) • Team / customer / project charter • Brain storming • Mind maps • Affinity diagrams • High level Process Maps • Systematic diagrams / Fault tree • Business Process Mapping • Define customer requirements (Voice of the customer) • QFD Quality Function Deployment • To develop a team charter. • To define the customers and their requirements (CTQ Critical to Quality). • To map the business process to be improved Characteristics Product / customers Importance out of 10

  9. Define • Define terms of reference (charting a project) • What you can deliver to the customer and the support you need from the customer to facilitate a successful improvement (contract of engagement) • Brain storming, Mind maps, Affinity diagrams, High level Process Maps, Systematic diagrams / Fault tree, Business Process Mapping • Tools to explore a problem, project or current thinking. • Tools to group those ideas logically. • Then define a route map to improvement, the risk involved and how to mitigate that risk. • Define customer requirements (Voice of the customer) • QFD Quality Function Deployment, is a method of defining what the customer needs, what is critical to there business success & prioritise objectives to meet the customer need.

  10. Improvement methodology • Voice of the process • Data Collection - 7 quality tools • Tally charts • Bar charts • Pareto • Run charts • Control charts • Cause & effect • Check sheets • Evaluate measurement systems • Gauge R&R • Select measures of performance • Quality Function Deployment Measure • To measure and understand baseline performance for the current process

  11. Measure • Voice of the process (7 quality tools) • Tally charts, Bar charts, Pareto, Run charts, Control charts, Cause & effect, Check sheets. • Evaluate measurement systems Gauge R&R • Every process has variation and measurement system, tools & cmm are no exception. • Typical your measurement process needs to be ACCURATE, REPEATABLE & REPRODUCIBLE to less than 10%of the tolerance you are trying to measure to & proven to be so. • Select measures of performance • QFD Quality Function Deployment is a method of defining what the customer needs and what is critical to there business success and prioritising performance measures to support the customers need.

  12. Improvement methodology • Investigate source of variation (Special cause / Common causes) • Stratification of data to get information • Cause & effect • CP & CPK • Fault tree • Contingence analysis • FMEA (Failure Mode Effect Analysis) • Design of experiments (DOE) • Detailed process maps Analyze Seek to:- Prioritise Understand Clues Causes Monitor improvements Look for signals

  13. Current Window of Consideration Cause Failure Mode Effect FMEA (failure mode effect analysis) Why Battles are Lost Lost Nail Lost Shoe Lost Horse Lost Soldier Lost Battle • FMEA • Identifies the ways in which a product or process can fail • Estimates the risk of specific causes with regard to these failures • Prioritizes the actions that should be taken to reduce the chance of failure

  14. A1 A2 B1 B2 C2 C1 D1=D2 DOE - (design of experiments)will help us identify... • factors which shift the average • factors which affect variation • factors which shift the averageand affect variation • factors which have no effect

  15. LSL USL DOE - (design of experiments) Measure the Process Establish the performance baseline Controllable Inputs X1 X2 X3 Quality Characteristics: Outputs Inputs: Raw Materials, components, etc. The Process Y1, Y2, etc. N1 N2 N3 Uncontrollable Inputs

  16. X1 X2 X3 LSL USL N1 N2 N3 DOE - (design of experiments) Analyse the Process Controllable Inputs Quality Characteristics: Outputs Inputs: Raw Materials, components, etc. The Process Y1, Y2, etc. Uncontrollable Inputs

  17. X1 X2 X3 LSL USL LSL USL N1 N2 N3 DOE - (design of experiments) Improve the Process Controllable Inputs X Quality Characteristics: Outputs X Inputs: Raw Materials, components, etc. The Process Y1, Y2, etc. X Uncontrollable Inputs

  18. Controllable Inputs X1 X2 X3 N1 N2 N3 Uncontrollable Inputs DOE - (design of experiments) Control the Process Error Proofing Quality Characteristics: Outputs LSL USL Inputs: Raw Materials, components, etc. Y1, Y2, etc. The Process Work Instructions 5 C’s Check Lists

  19. Analyze • Investigate source of variation (Special cause / Common causes) • Special cause variation are the one off, occasional and obvious cause of a process / quality problems. • Common cause variation are the day in day out causes of process problems, because the process is not stable enough, they are hidden (these form 80% of process problems) • Conventional non-conformance management systems seek to solve special cause variation (e.g. concessions) - but these only represent 15 - 20% of the total variation. • 6 Sigma addresses all variation.

  20. Improvement methodology • Prioritise improvements • Impact Vs Effort • Brainstorming • Affinity diagrams • Solution selection matrix • Tactical implementation plans • Deliver improvements (reduce variation systematically) Improve Customer protection Get control Improve process

  21. Improve • Prioritise improvements • Tool commonly in uses are, Impact Vs Effort, Brainstorming, Affinity diagrams, Solution selection matrix. • These tools help define the best method to meet the customer need (as defined in the QFD) • Tactical implementation plans • Deliver improvements to reduce variation systematically i.e. make a change, note the improvement and make the next improvement. • Critical we need to establish that any change is a change for the good.

  22. Improvement methodology • Control the process • Recover • Control plans • Escalation process • Prevent • Poke yoke (mistake/ error proof) • Monitor • Control charts • Checksheets • Documentation and Standardisation Control

  23. Control • Control the process • Recover, Control plans, Escalation process. • Prevent by Poke yoke (fool proof the process) to fundamentally remove the rood causes of process variation. • Monitor, Control charts, Checksheets, Documentation and Standardisation, to ensure that stable process is maintained and that the process does not degrade. • The objective is to remove the root causes of process variation, management are only left with a few critical input variables in the process that need controlling and not all inputs as before.

  24. Lean and 6 Sigma both seek to deliver business improvement They are different in the methods used and tools employed Lean typically address the total manufacturing environment 6 sigma typical address the root cause of process variation There is significant benefit from using the most appropriate tools and improvement methodology to meet the customer requirements Where does 6 Sigma fit with Lean 6 Sigma improvements Lean improvements

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