Chapter 5 – Part 3 The TQM Philosophy

Mini Case: Quality Improvement LSL USL X = Amount of Toner Toner Operation: Adding Toner to Cartridge Current Process Target Mean 20% Defective Target Toner

 What’s wrong with this operation?  How should it be corrected?  Why is this fix feasible? Mini Case: Quality Improvement

LSL USL Amount of Toner New Process – Mean Shifted to left and centered on target Target Mini Case: Quality Improvement

 Benefits?  Next step?

Amount of Toner Suppose the current process looked like this. Will adjusting the mean to the target improve the process? Mini Case: Quality Improvement LSLUSL Target 20% Defective Mean

Amount of Toner Mean adjusted to target Mini Case: Quality Improvement 10% Defective LSLUSL Mean =Target 10% Defective

Seven Tools of Quality Control  Cause-and-Effect Diagrams  Flowcharts  Checklists  Control Charts  Scatter Diagrams  Pareto Analysis  Histograms

Cause-and-Effect Diagram (Fishbone Diagram) Machines Cause Effect- problem MaterialsMethods Manpower Environment Cause 4M + E

Flowcharts

Checklist  Simple data check-off sheet designed to identify type of quality problems at each work station; per shift, per machine, per operator

Control Charts (Chapter 6)  Control charts are tools for predicting the future performance of a process.  If we can predicting performance, we can take corrective action before too many nonconforming units are produced.

Control Charts (Chapter 6)  Suppose we construct a control chart for the thickness of the gold plating of an electrical connector.  We take samples of connectors over time and compute the mean of each sample.  After several time period, we use the sample means to estimate the mean thickness.

Control Charts (Chapter 6)  We then construct two control limits:  an upper control limit (UCL) and  a lower control limit (LCL) We do this by adding subtracting 3 standard deviations to the estimated mean: LCL = Estimated Mean – 3(Standard Deviation) UCL =Estimated Mean + 3(Standard Deviation)

 We plot the estimated mean and the control limits on the control chart.  The result is called a control chart for the process mean. Control Charts (Chapter 6) Time mean Mean thickness

Control Charts (Chapter 6)  If the sample means fall randomly within the control limits, the process mean is in control.  “In control” means that the process mean is stable and hence predictable.  If at least one sample mean fall outside of the control limits, we say the process mean is “out of control.”  In this case, the process mean is unstable and not predictable.  The goal is to find out why and remove the causes of instability from the process.

Scatter Diagrams A graph that shows how two variables are related to one another Optimal Speed

Pareto Diagram Pareto Principle: 80% of the problems may be attributed to 20% of the causes. Pareto Principle: 80% of the problems may be attributed to 20% of the causes. Missing Percent of defects BubblesCracks Uneven Runs 80%

Histograms

Reliability  Reliability is the probability that the product, service or part will function as expected.  Reliability is a probability function dependent on sub-parts or components.

Reliability  Reliability of a system is the product of component reliabilities: R S = (R 1 ) (R 2 ) (R 3 )... (R n ) R S = reliability of the product or system R 1 = reliability of the first component R 2 = reliability of the second component. R n = reliability of the nth component

Example 1: Components in Series  A radio has three transistors.  All transistors must work in order for the radio to work properly.  Probability that the first transistor will work =.80  Probability that the first transistor will work =.90  Probability that the first transistor will work =.85  What is the reliability of the radio?

Solution R S = (R 1 ) (R 2 ) (R 3 ) R S = (.80) (.90) (.85) =.51 R 1 =.80R 3 =.85R 2 =.90

Example 2: Backup Components  Backup component takes over when a component fails.  Suppose only one transistor is needed for the radio to work.  In case the one transistor fails, a backup transistor has been installed.  Probability that the original transistor will work =.92  Probability that the backup transistor will work =.87

Example 2: Backup Components  The backup transistor is in parallel to the original transistor. R BU =.87 R 1 =.92

Example 2: Backup Components  Parallel components allow system to operate if one or the other fails  Increase reliability by placing components in parallel  For system with one component and a BU component: R S = R 1 + [(R BU ) x (1 - R 1 )] 1 - R 1 = Probability of needing BU component = Probability that 1 st component fails

Solution R S = R 1 + [(R BU ) x ( 1 - R 1 )] R S =.92 + [(.87) x (1 -.92)] =.92 + [(.87) x (.08)] =.9896 R BU =.87 R 1 =.92

R 1 =.80 R BU =.75 R 2 =.88 Example 3: Series with Backup Components

BU is in parallel to first component. Convert to system in series. To this by first finding reliability (probability) of components. A = Probability that first component or its BU works B = Probability that second component works = R 2 R S = A x B

Solution A = R 1 + [(R BU ) x (1 - R 1 )] =.80 + [(.75) x (1 -.80)] =.95 B = R2 =.88 R S = A x B =.95 x.88 = Part 1Part 2

Reliability Over Time - Bathtub Curve t0t0 Time Failure Rate Maturity Constant Failure Infant Mortality t2t2 t1t1

Quality Awards and Standards  Malcolm Baldrige National Quality Award (MBNQA)  The Deming Prize  ISO 9000 Certification

MBNQA- What Is It?  Award named after the former Secretary of Commerce – Regan Administration  Intended to reward and stimulate quality initiatives  Given to no more that two companies in each of three categories; manufacturing, service, and small business  Past winners:  Motorola Corp., Xerox, FedEx, 3M, IBM, Ritz-Carlton

Baldrige Criteria  Leadership (125 points)  Strategic Planning (85 points)  Customer and Market Focus (85 points)  Information and Analysis (85 points)  Human Resource Focus (85 points)  Process Management (85 points)  Business Results (450 points)

The Deming Prize  Given by the Union of Japanese Scientists and Engineers since 1951  Named after W. Edwards Deming who worked to improve Japanese quality after WW II  Not open to foreign companies until 1984  Florida P & L was first US company winner  Based on how well a company applies Deming’s 14 points

ISO 9000  Set of international standards on quality management and quality assurance, critical to international business  Data based approach to decision making  Supplier relationships  Continuous improvement  Customer focus  Leadership  Employee training  Process (operations) management