Download Ch5 TQM Part 3

Chapter 5 – Part 3
The TQM Philosophy
Mini Case: Quality Improvement
Operation: Adding Toner to Cartridge
Current Process
USL
LSL
20% Defective
Mean
Target
Target Toner
X = Amount of Toner Toner
Mini Case: Quality Improvement

What’s wrong with this operation?

How should it be corrected?

Why is this fix feasible?
Mini Case: Quality Improvement
New Process – Mean Shifted to left
and centered on target
USL
LSL
Target
Amount of Toner
Mini Case: Quality Improvement

Benefits?

Next step?
Mini Case: Quality Improvement
Suppose the current process looked like this.
Will adjusting the mean to the target improve
the process?
LSL
USL
20% Defective
Amount of Toner
Mean
Target
Mini Case: Quality Improvement
Mean adjusted to target
LSL
USL
10%
Defective
10%
Defective
Amount of Toner
Mean =Target
Seven Tools of Quality Control







Cause-and-Effect Diagrams
Flowcharts
Checklists
Control Charts
Scatter Diagrams
Pareto Analysis
Histograms
Cause-and-Effect Diagram
(Fishbone Diagram)
Methods
Materials
Cause
Cause
Cause
Cause
Cause
Cause
Environment
Cause
Cause
Cause
Cause
Manpower
Cause
Cause
Machines
4M + E
Effectproblem
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)
Control Charts (Chapter 6)
We plot the estimated mean and the control
limits on the control chart.
 The result is called a control chart for the
process mean.
Mean thickness

mean
Time
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
Speed vs. Yield
30
Yield
25
20
15
10
5
0
0
10
20
Speed
30
40
Optimal Speed
Pareto Diagram
80% of the
problems
may be
attributed to
20% of the
causes.
Percent of defects
Pareto
Principle:
80%
Runs
Bubbles Missing Cracks
Uneven
Histograms
Histogram for Diameter
45
40
35
30
LSL
USL
25
20
15
10
5
0
<=0.077
.077.277
.277.477
.477.677
.677.877
.8771.077
1.0771.277
Diameter
1.2771.477
1.4771.677
1.6771.877
1.8772.077
>2.077
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:
RS = (R1) (R2) (R3) . . . (Rn)
RS = reliability of the product or system
R1 = reliability of the first component
R2 = reliability of the second component
.
. .
Rn = 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
R1 = .80
R2 = .90
RS = (R1) (R2) (R3)
RS = (.80) (.90) (.85) =.51
R3 = .85
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.
R1 = .92
RBU = .87
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:
RS = R1 + [(RBU) x (1 - R1)]
1 - R1 = Probability of needing BU component
= Probability that 1st component fails
Solution
RS = R1 + [(RBU) x (1 - R1)]
R1 = .92
RS = .92 + [(.87) x (1 - .92)]
= .92 + [(.87) x (.08)]
= .9896
RBU = .87
Example 3:
Series with Backup Components
R1 = .80
RBU = .75
R2 = .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 = R2
RS = A x B
Solution
A = R1 + [(RBU) x (1 - R1)]
= .80 + [(.75) x (1 - .80)]
= .95
Part 1
Part 2
.95
.88
B = R2 =.88
RS = A x B = .95 x .88 = .836
Reliability Over Time - Bathtub Curve
Infant Mortality
Failure Rate
Maturity
Constant Failure
t0
t1
t2
Time
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

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Data based approach to decision making
Supplier relationships
Continuous improvement
Customer focus
Leadership
Employee training
Process (operations) management