Transcript Fundamental Concepts of JIT

Chapter 11 – Part I
Total Quality Management
COB 300
Busing
Problems Hidden by Inventory
Simplifying the Process
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Plant layout
Group technology
U-shaped layout
Reducing setup time
Total preventive
maintenance
Strategy and JIT
• Quality and reliability
• Flexibility
– product
– volume
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Dependability
Asset utilization
People utilization
Cost minimization
Internally Oriented
Definitions of Quality
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Quality is the degree to which a specific product
conforms to a design or specification
Differences in quality amount to differences in the
quantity of some desired ingredient or attribute
Externally Oriented
Definitions of Quality
• Quality is fitness for use
• Quality consists of the capacity to satisfy wants
A Definition of Quality Used by
Many Companies
Quality is consistently
meeting or exceeding the
customer’s needs and
expectations.
Dimensions of Service Quality
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Reliability
Responsiveness
Assurance
Empathy
Tangibles
Dimensions of Quality for Goods
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Performance
Features
Reliability
Conformance
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Durability
Serviceability
Aesthetics
Perceived Quality
Costs of Quality
• Prevention
– Planning
– Procedures
– Training
• Appraisal
– Testing
– Inspection
– Audits
• Failure
– Internal
• Scrap and rework
• Retests
• Down time
– External
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Returns
Warranty work
Goodwill lost
Lost sales
The Background of TQM
• W. Edwards Deming
– System causes most
defects
• Joseph M. Juran
– Quality planning,
quality control, quality
improvement
• Philip Crosby
– Quality is free, zero
defects
• Genichi Taguchi
– Taguchi methods,
robust design
Components of TQM
• Focus on the customer
• Everyone responsible for
quality
• Team problem solving
• Employee training
• Fact-based management
• Philosophy of continuous
improvement
Components of
Continuous Improvement
• Standardize and document procedures
• Assign teams to identify areas for
improvement
• Use methods analysis and problem-solving
tools
• Use the Plan-Do-Check-Act cycle
• Document improved procedures
The Plan-Do-Check-Act Cycle
Baldridge Award
• Baldridge Award Criteria for 00
ISO 9000 Standards
9000-1: Guidelines
9001: Design through installation and
testing
9002: Production through installation
and testing
9003: Distributors
9004-1: Model of quality management
system
Comparing Baldrige,
ISO 9000 and TQM
• Baldrige
– U.S. Quality Award
– Focus on outcomes
• ISO 9000
– International standards
– Focus on documentation of processes
• TQM
– Organizational quality philosophy
– Foundation of Baldrige criteria
Chapter 11 – Part II
Quality Control
COB 300 C - The Operations Dimension
Busing
Causes of Variation
• Random Causes
– difficult or expensive
to control
– e.g., outside humidity,
line voltage
• Assignable Causes
– easier to correct
– e.g., employee error,
new materials
Comparing Process Variation to
Tolerance Limits
High Process Capability After
Technological Process Change
Control Charts
• Variables - concentrates on mean for some
measurable characteristic.
– diameter
– length
• Attribute - data is based on counts or the number
of times we observe a particular event.
– proportion defective/non-defective
– go/no go
– proportion pass/fail
Control Limits - Variables Charts
X-Bar Chart
U C L x    3
X  A2 R
LCLx    3 x
 X  A2 R
R Chart
UCLR  D4 R
LCLR  D3 R
x
Variables Control Chart Examples: Compute the 3 control charts for X and R from 15 samples of
size n=3. Plot the control limits and the X and R values and comment about the underlying process.
Sample
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15
OBSERVED DIMENSIONS (cm)
4.843
4.863
4.859
4.925
4.882
4.891
4.866
4.914
4.873
4.852
4.883
4.88
4.92
4.884
4.821
4.915
4.902
4.898
4.887
4.892
4.858
4.868
4.888
4.842
4.904
4.863
4.866
4.921
4.92
4.894
4.914
4.884
4.899
4.892
4.896
4.887
4.866
4.829
4.88
4.85
4.875
4.872
4.867
4.9
4.885
Variables Control Chart Examples: Compute the 3 control charts forX
and R from 15 samples of size n=3. Plot the control limits and the
X and R values and comment about the underlying process.
S a m p le
O B S E R V E D D IM E N S IO N S (c m )
m ean
ra n g e
1
4.843
4.863
4.859
4.855
0.020
2
4.925
4.882
4.891
4.899
0.043
3
4.866
4.914
4.873
4.884
0.048
4
4.852
4.883
4.88
4.872
0.031
5
4.92
4.884
4.821
4.875
0.099
6
4.915
4.902
4.898
4.905
0.017
7
4.887
4.892
4.858
4.879
0.034
8
4.868
4.888
4.842
4.866
0.046
9
4.904
4.863
4.866
4.878
0.041
10
4.921
4.92
4.894
4.912
0.027
11
4.914
4.884
4.899
4.899
0.030
12
4.892
4.896
4.887
4.892
0.009
13
4.866
4.829
4.88
4.858
0.051
14
4.85
4.875
4.872
4.866
0.025
15
4.867
4.9
4.885
4.884
0.033
4.882
0.037
Factors for Control Limits
(Slide 1 of 2)
Sample of Size
n
2
3
4
5
6
7
8
9
10
A2
D3
1.880
1.023
0.729
0.577
0.483
0.419
0.373
0.337
0.308
0
0
0
0
0
0.076
0.136
0.184
0.223
D4
3.268
2.574
2.282
2.114
2.004
1.924
1.864
1.816
1.777
x-bar Chart Example (cont’d)
UCLx  4.882  1.023(.037)  4.920
LCLx  4.882  1.023(.037)  4.844
S ix S i g m a C o n tro l C ha rt ( x -b a r)
4 .9 3 0
4 .9 2 0
4 .9 1 0
4 .9 0 0
S a m p le M e a n
4 .8 9 0
cm
U p p e r C o n tro l L im it
L o w e r C o n tro l L im it
C e n te r L i n e
4 .8 8 0
4 .8 7 0
4 .8 6 0
4 .8 5 0
4 .8 4 0
0
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8
O b s e r v a tio n
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Range Chart
D4 R  2.57  .037  .0951
D3 R  0  .037  0
Range Example
0.12
0.1
0.08
Upper Control Lim
Center Line
0.06
Lower Control Lim
Sample Range
0.04
0.02
0
0
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4
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12
14
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Warning Conditions
• Two successive points
near limit
• Run of five above or
below mean
• Trend
• Erratic behavior
Process Control for Attributes
Proportion defective:
p
p( 1  p )
n
UCL p  p  3 p
LCL p  p  3 p
Number of defects per unit:
c  c
UCLc  c  3 c
LCLc  c  3 c
P-Chart
observation proportion defective
lower control limit
center line
0.14
upper control limit
0.12
proportion defective
0.1
0.08
0.06
0.04
0.02
0
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observation
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Homework
• Chapter 11 – 4, 8, 9