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

Level of 6 sigma 3.8 sigma: Ten sub-processes of 99% FTY will lead to 1/10 customer unsatisfied with the defect % x 99% = 90% 6 Sigma: Ten sub-processes of % FTY means 1/30000 customer unsatisfied with the defect % x % % x % =    RTY

Why take the 6 sigma as the goal?

Process of 6 sigma- DMAIC End project Improve Control Build HoQ Voice of business Prevent error Form concepts for QI Select key ones CRITERIA Pugh Methods Optimize process A1 B1 C1 AnalyzeMeasure Define : Reflect data in diagram.... Standardize process 1 Select and evaluate projects Establish project plan Organize team 2 Analyze causes Voice of customer Understand customers’ requirements Test operation Train users Put in practice Quality control system Measure the returns 3 4 Survey Measure status Analyze cost of bad quality($$$) Select those key causes Preliminary operation

--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.

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 CASE STUDY

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

Measure Current Situation Collect Data Waiting Time of Customers （ Min ） Etc Wasted time by Receptionists （ Sec ） Looking for forms 30, 45, 15 Pen got lost 10, 30 Pen is unusable 20 Answer calls 100, 140 Wrong changes 200, 50 Etc CASE STUDY

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

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

Improve Process 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. CASE STUDY

Improve Process 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 CASE STUDY

Improve Process Waiting Time (Min) Sequence of customers Average waiting time after improvement = 3 Minutes Change the promised time to 6 minutes, not 5 minutes. Improved Run Chart 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 x x x x x x x x x x x 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. CASE STUDY

Improve Process Cannot find right forms Wrong place to put pens Cannot write with pens Answer phone calls Cannot find changes Disturbed by managers Cannot open cash register Mistake the amount of money Paper out in printer Input error Service Delay Average Time (Sec) Total time (Sec) Frequency Total time after improvement 690=0.19hour Many sources of time waiting are erased. CASE STUDY

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

Control Process 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 CASE STUDY

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