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Quality improvement

Quality improvement. What is 6 sigma?. Level of 6 sigma: 3.4 DPMO (Defects Per Million Opportunities) Indexes concerned: FTY (First Time Yield) RTY(Rolled Throughput Yield) RTY=FTY 1  FTY 2  FTY n. RTY. 1. 2. 4. 3. 5. 10. 7. 9. 6. 8. 90%. 99% x. 99% x. 99% x. 99% x.

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Quality improvement

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  1. Quality improvement

  2. What is 6 sigma? • Level of 6 sigma: • 3.4 DPMO (Defects Per Million Opportunities) • Indexes concerned: • FTY (First Time Yield) • RTY(Rolled Throughput Yield) • RTY=FTY1FTY2FTYn

  3. RTY 1 2 4 3 5 10 7 9 6 8 90% 99% x 99% x 99% x 99% x 99% x 99% x 99% x 99% x 99% x 99% = 3.8 sigma:Ten sub-processes of 99% FTY will lead to 1/10 customer unsatisfied with the defect.    1 2 10 9 99.9966% 99.9997% x 99.9997% = 99.9997% x 99.9997% x 6 Sigma: Ten sub-processes of99.9997% FTY means 1/30000 customer unsatisfied with the defect. Level of 6 sigma

  4. Why take the 6 sigma as the goal?

  5. Define: Measure Analyze Understand customers’ requirements Analyze causes • Measure • status 6 4 5 8 Build HoQ 1 Select and evaluate projects 9 Analyze costof bad quality($$$) 2 Establish project plan 7 • Reflect data • in diagram Survey 10 Select those key causes . . Organize team . 3 . Voice of customer Voice of business Improve Control 11 12 Select key ones 13 Prevent error 14 Optimize process 16 Standardize process Form concepts for QI 17 Test operation 18 Train users 19 A1 Put in practice B1 Pugh Methods C1 20 Quality control system CRITERIA Measure the returns 21 15 Process of 6 sigma- DMAIC Preliminary operation 22 End project

  6. --A service business A middle-sized service company Yearly revenue of about $0.5 billion 2000 employees Headquarter and 50 branches 5 receptionists each subsidiary Problems（low customer satisfaction） Yearly customer investigation shows that customers’ satisfaction goes down, due to bad service of most branches. And complaints are focused on long waiting time.

  7. CASE STUDY Define a Project Aim： Promise and guarantee to customers that the maximum waiting time is 5 minutes Plan：A manager will lead the project. Measure waiting time and service time with a customer sample of 60 to identify sources of problems and opportunities to improve, with Time Action technology. Team：The manager (Green Belt) and four recorders

  8. On-site Two recorders note time used and actions taken by receptionists Two recorders note queue time of each customer Receptionists First customer Queue Reception Area CASE STUDY MeasureCurrent Situation

  9. Collect Data Waiting Time of Customers（Min） Wasted time by Receptionists（Sec） • 4.5 • 6 • 6.3 • 1.5 • 7 • Etc Looking for forms30, 45, 15 Pen got lost10, 30 Pen is unusable20 Answer calls100, 140 Wrong changes200, 50 Etc CASE STUDY MeasureCurrent Situation

  10. CASE STUDY MeasureCurrent Situation The waiting time of customer No. 25, 34, 55, 60 exceeds 12 minutes. Describe Data The problem is fluctuation, not average value. Run Chart 12 8 Waiting Time (Min) Waiting time of each customer on average = 5 Minutes 4 0 0 10 20 30 40 50 60 Sequence of customers 10am 11 Noon 1 2 3pm

  11. CASE STUDY AnalyzeCurrent Process • Usually, process measurement can provide large amount of analysis proofs. • Run Chart shows that the main problem is the large fluctuationwith the average service time of 5 minutes. • Time and Action Measurement identifies the specific sources of fluctuation.

  12. CASE STUDY ImproveProcess 6 Sigma tool is used by the team to identify reasons and erase sources of time waste. • People • Managers are trained not to disturb receptionists’ work unless emergencies. And no actions for reducing mistakes of receptionists are raised. • Method • Bring electronic and paper forms into indexes and organize them together. Standardize the place to put materials. • Material • Set up strict material replenishment procedures. • Utility • Establish daily maintenance plan.

  13. CASE STUDY ImproveProcess • Conduct test run of the improved process with same measurement method • Record data of 60 customers in 3 hours, not in 5 hours. • Record results

  14. Improved Run Chart 12 x x Change the promised time to 6 minutes, not 5 minutes. x x x x x x x x x 8 x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 4 Average waiting time after improvement = 3 Minutes 0 0 10 20 30 40 50 60 Sequence of customers CASE STUDY ImproveProcess Test run shows that average waiting time and fluctuations get decreased greatly. But 6 times’ waiting time exceeds the target of 5 minutes. The team decides to change the promised time to 6 minutes. Waiting Time (Min)

  15. CASE STUDY ImproveProcess Many sources of time waiting are erased. Average Time (Sec) Total time (Sec) Service Delay Frequency Cannot find right forms 30 15 2 450 60 Wrong place to put pens 20 10 0 200 0 Cannot write with pens 20 5 0 100 0 Answer phone calls 120 5 0 600 0 Cannot find changes 100 5 1 500 100 Disturbed by managers 60 6 0 360 0 Cannot open cash register 180 2 0 360 0 Mistake the amount of money 50 7 7 350 350 Paper out in printer 300 2 0 600 0 Input error 15 12 12 180 180 690=0.19hour Total time after improvement

  16. CASE STUDY ImproveProcess The promotion of customer satisfaction helps the rise of business. In the following years, real revenue is 5 million USD higher than expected.

  17. CASE STUDY ControlProcess Keep the gains! Get more economic income! • Periodically sample and record waiting time • If waiting time rises, repeat time and action observations to identify potential sources of problems Try to solve problems once they appear

  18. Thanks! DU Xue-mei:xuemei.du@163.com

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