Unit IV - Maintenance, System Reliability & TQM
Transcript of Unit IV - Maintenance, System Reliability & TQM
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UNIT - IV
SEMESTER - II
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Strategic Importance of
Maintenance and Reliability
Failure has far reaching effects on a firms
Operation
Reputation
Profitability
Dissatisfied customers
Idle employees
Profits becoming losses
Reduced value of investment in plant andequipment
Equipment Malfunctions have a directimpact on:
Production capacity
Production costs
Product and service quality
Employee or customer safety
Customer satisfaction
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Maintenance and Reliability Objective:
To maintain the capability of the system while controlling costs
Maintenance is all activities involved in keeping a systems equipment in working order
Reliability is the probability that a machine will function properly for a specified time
Important Tactics
Maintenance
1. Implementing or improvingpreventive maintenance
2. Increasing repair capability or speed
3. Measured by MTTR (Mean Time toRepair)
Reliability
1. Improving individual components
2. Providing redundancy
3. Measured by MTBF (Mean Time
Between Failures)
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Approaches to Improving
Machine Reliability
Overdesign - enhancing the machine
design to avoid a particular type of
failure
Design simplification - reducing thenumber of interacting parts in a machine
Redundant components - building
backup components right into the
machine so that if one part fails, itsautomatically substituted
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Rs
R3
.99
R2
.80
Reliability Example
R1
.90
Reliability of the process is
Rs= R1 x R2 x R3 = .90 x .80 x .99 = .713 or 71.3%
where R1 = reliability of component 1
R2 = reliability of component 2
and so on
Rs= R1 x R2 x R3 x xRn
Improving individual components
Reliability
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Overall System Reliability
Reliabilityofthesystem(percent)
Average reliability of each component (percent)
| | | | | | | | |
100 99 98 97 96
100
80
60
40
20
0
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Product Failure Rate (FR)
Basic unit of measure for reliability
FR(%) = x100%Number of failuresNumber of units tested
FR(N) =Number of failures
Number of unit-hours of operating time
Mean time between failures
MTBF =1
FR(N)
Providing Redundancy
Provide backup components to increase reliability
+ xProbability of
first componentworking
Probability ofneeding second
component
Probability ofsecond
component
working
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How Maintenance is Performed
OperatorMaintenancedepartment
Manufacturers field
serviceDepot service
(return equipment)
Preventivemaintenance costs less andis faster the more we move to the left
Competence is higher as wemove to the right
Maintenance Two types of maintenance
1. Preventive maintenance routine inspection and servicing to keep facilities ingood repair
2. Breakdown maintenance emergency or priority repairs on failed equipment
Implementing Preventive Maintenance
Need to know when a system requires service or is likely to fail
High initial failure rates are known as infant mortality
Good reporting and record keeping can aid the decision on when preventivemaintenance should be performed
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Maintenance Activities
Repairs
Repair activities are reactive.
Breakdowns and malfunctions typically occur when equipment is inuse.
Standby machines and parts can speed repairs.
Preventive Maintenance (PM)
Regularly scheduled inspections are performed.
PM activities are performed before equipment fails.
PM is usually performed during idle periods.
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Maintenance Strategy
Employee Involvement
Information sharing
Skill training
Reward system
Employee empowerment
Maintenance and Reliability Procedures
Clean and lubricate
Monitor and adjust
Make minor repair
Keep computerized records
Results
Reduced inventory
Improved quality
Improved capacity
Reputation for quality
Continuous improvement
Reduced variability
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Computerized Maintenance System
Output Reports
Inventory andpurchasing reports
Equipment
parts list
Equipmenthistory reports
Cost analysis(Actual vs. standard)
Work orders
Preventivemaintenance
Scheduleddowntime
Emergencymaintenance
Data entry Work requests
Purchaserequests Time reporting Contract work
Data Files
Personnel datawith skills,wages, etc.
Equipment filewith parts list
Maintenanceand work order
schedule
Inventory ofspare parts
Repairhistory file
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Totalcosts
Breakdownmaintenance
costs
Costs
Maintenance commitment
Traditional View
Preventivemaintenancecosts
Optimal point (lowestcost maintenance policy)
Maintenance Costs
To balance preventive and breakdown maintenance costs
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How Speedy Should Repairs Be?
Cost ($)
Speed of Making Repairs
0
Minimum
Total Cost
of Repairs
Cost of RepairCrews & Shops,Spare Parts, and
Standby Machines
Cost ofInterruptions toProduction
Total Costsof Repairs
Slow Fast
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Increasing Repair Capabilities1. Well-trained personnel
2. Adequate resources
3. Ability to establish repair plan and priorities
4. Ability and authority to do material planning
5. Ability to identify the cause of breakdowns
6. Ability to design ways to extend MTBF
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Establishing Maintenance Policies Simulation
Computer analysis of complex situations
Model maintenance programs before they are implemented
Physical models can also be used
Expert systems
Computers help users identify problems and select course of action
Total Productive Maintenance (TPM)
Designing machines that are reliable, easy to operate, and easy to maintain
Emphasizing total cost of ownership when purchasing machines, so that service andmaintenance are included in the cost
Developing preventive maintenance plans that utilize the best practices ofoperators, maintenance departments, and depot service
Training workers to operate and maintain their own machines
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Secondary Maintenance Responsibilities
Housekeeping, grounds keeping
New construction, remodeling
Painting
Security, loss prevention
Pollution control
Waste recycling
Safety equipment maintenance
Public hazard control
Trends in Maintenance
Production machinery is becoming more and more complex and maintenancepersonnel must keep pace
Special training programs to maintain worker skill level
Subcontracting service companies
Production workers maintain own equipment
Computer assistance in maintenance
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Computer Assistance in Maintenance
Scheduling maintenance projects
Maintenance cost reports by production department, cost category, and other
classifications Inventory status reports for maintenance parts and supplies
Parts failure data
Operations analysis studies
Maintenance Issues in Service Organizations Maintenance issues are not limited to manufacturing
Transportation firms (airlines, trucking companies, package delivery services,
railroads) must keep their vehicles in top operating condition
Highway departments must maintain roadways
Office personnel are reliant on copiers, printers, computers, and fax machines
working properly
As services become increasingly automated, service firms face more and more
maintenance issues
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Determinants of Quality
Service
Ease of
use
Conforms
to design
Design
Quality is fitness for use
(Joseph Juran)
Quality is conformance to requirements
(Philip B. Crosby)
What is quality?
Quality, simplistically, means that a product should meet its specification.
Quality is the ability of a product or service to consistently meet or exceed customer
expectations.
At a Time and over a period of time.
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Quality management activities Quality assurance
Establish organisational procedures and standards for quality.
Quality planning
Select applicable procedures and standards for a particular project and modifythese as required.
Quality control
Ensure that procedures and standards are followed by the softwaredevelopment team.
Dimensions of Quality
Performance - main characteristics of the product/service
Aesthetics - appearance, feel, smell, taste
Special Features - extra characteristics
Conformance - how well product/service conforms to customers expectations
Reliability - consistency of performance
Durability - useful life of the product/service
Perceived Quality - indirect evaluation of quality (e.g. reputation)
Serviceability - service after sale
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Service Quality
Tangibles
Convenience
Reliability
Dimension Examples
1. Tangibles Were the facilities clean, personnel neat?2. Convenience Was the service center conveniently located?
3. Reliability Was the problem fixed?
4. Responsiveness Were customer service personnel willing and able to
answer questions?
5. Time How long did the customer wait?
6. Assurance Did the customer service personnel seem
knowledgeable about the repair?
7. Courtesy Were customer service personnel and the cashier
friendly and courteous?
Responsiveness
Time
Assurance
Courtesy
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The Consequences of Poor
Quality
Loss of business
Liability
Productivity
Costs
Top management
Design
Procurement
Production/operations
Quality assurance
Packaging andshipping
Marketing and sales
Customer service
Responsibility for Quality
Quality plan structure
Product introduction;
Product plans;
Process descriptions;
Quality goals;
Risks and risk management.
Quality plans should be short, succinct
documents
If they are too long, no-one will read
them.
Quality plans
Quality reviews A group of people carefully examine part or all of a
software system and its associated documentation.
Code, designs, specifications, test plans, standards, etc.
can all be reviewed.
Software or documents may be 'signed off' at a review
which signifies that progress to the next development
stage has been approved by management.
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Costs of Quality Failure Costs - costs incurred by defective parts/products or faulty services.
Internal Failure Costs Costs incurred to fix problems that are detected before the product/service
is delivered to the customer.
External Failure Costs
All costs incurred to fix problems that are detected after theproduct/service is delivered to the customer.
Appraisal Costs
Costs of activities designed to ensure quality or uncover defects
Prevention Costs
All TQ training, TQ planning, customer assessment, process control, and
quality improvement costs to prevent defects from occurring
1924 - Statistical process control charts
1930 - Tables for acceptance sampling
1940s - Statistical sampling techniques
1950s - Quality assurance/TQC
1960s - Zero defects
1970s - Quality assurance in services
Evolution of
Quality Management
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Cost of Poor Quality Category Examples
Failure Costs Internal Prevention Costs
Re-shipping Quality Administration
Unnecessary Travel Time Quality Planning
Re-picking/Picking Quality Systems Design
Unpacking/Storing Returns Calibration and MaintenanceRe-order Time Production/Inspection Equipment
Crediting Time Vendor Assessment
Quality Training
Failure Costs External Appraisal Costs
Loss of Sales Incoming Test and Inspection
Complaints In-Process Inspection
Returns Final Inspection
Warranty Claims Sampling Procedures
Quality Audits
Costs of Quality
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Standards are the key to effective quality management.
They may be international, national, organizational or project standards.
Product standards define characteristics that all components should exhibit e.g. acommon programming style.
Process standards define how the software process should be enacted.
Quality assurance and standards
Encapsulation of best practice- avoids repetition of past mistakes. Framework for quality assurance processes - they involve checking compliance to
standards.
Provides continuity - new staff can understand the organisation by understandingthe standards that are used.
Importance of standards
They may not be seen as relevant and up-to-date by software engineers.
They often involve too much bureaucratic form filling.
If they are unsupported by software tools, tedious manual work is often involved to
maintain the documentation associated with the standards.
Problems with standards
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Malcolm Baldrige National Quality Award
1.0 Leadership (125 points)
2.0 Strategic Planning (85 points)
3.0 Customer and Market Focus (85 points)
4.0 Information and Analysis (85 points)
5.0 Human Resource Focus (85 points)
6.0 Process Management (85 points)
7.0 Business Results (450 points)
The Deming Prize
Honoring W. Edwards Deming
Japans highly coveted award
Main focus on statistical quality
control
Continuous ImprovementPhilosophy that seeks to make never-ending improvements to the process of convertinginputs into outputs.
Kaizen: Japanese
word for continuous improvement.
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International Organization for Standardization (ISO) - mission is to promote the
development of standardized products to facilitate trade and cooperation across
national borders.
Representatives from more than 146 nations.
ISO 9000 series of standards sets requirements for quality processes.
Nearly half a million ISO 9000 certificates have been awarded to companies around
the world.
ISO 14000 series also sets standards for operations that minimize harm to the
environment.
Standards
http://www.iso.org/iso/en/iso9000-14000/index.htmlhttp://www.iso.org/iso/en/iso9000-14000/index.htmlhttp://www.iso.org/iso/en/iso9000-14000/index.html -
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ISO Standards ISO 9000
Set of international standards on quality management and quality assurance,critical to international business
Series of standards agreed upon by the International Organization forStandardization(ISO)
Adopted in 1987
More than 100 countries
A prerequisite for global competition
ISO 9000 directs you to:
document what you do and then do as you documented.
9001
Model for Quality Assurance in Design, Production Installation, and Servicing.
9002
Model for Quality Assurance in Production and Installation
9003
Model for Quality Assurance in Final Inspection Test
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ISO Standards ISO 14000
A set of international standards for assessing a companys environmental
performance
Standards in three major areas
Management systems
Operations
Environmental systems
Particularly important - documents are the tangible manifestation of the software.
Documentation process standards
Concerned with how documents should be developed, validated and maintained.
Document standards
Concerned with document contents, structure, and appearance.
Document interchange standards
Concerned with the compatibility of electronic documents.
Documentation standards
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Documentation process
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This involves checking the software development process to ensure that procedures
and standards are being followed.
There are two approaches to quality control
1. Quality reviews;
2. Automated software assessment and software measurement.
Total Quality Management
A philosophy that involves everyone in an organization in a continual
effort to improve quality and achieve customer satisfaction.
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What is TQM?
Constant drive for
continuous
improvement and
learning.
Concern foremployee
involvement and
development
Management by
Fact
Result Focus
Passion to deliver
customer value /
excellence
Organisation
response ability
Actions not just words
(implementation)Process
Management
Partnership
perspective
(internal /
external)
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Learning
LEARNING AND TQM
Process Improvement
Quality Improvement
Customer
SatisfactionShareholder
Satisfaction
Employee
Satisfaction
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BASIC PRINCIPLES OF TQM
Approach Management Led
Scope Company Wide
Scale Everyone is responsible for Quality
Philosophy Prevention not Detection
Standard Right First Time
Control Cost of Quality
Theme On going Improvement
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QC Throughout Production Systems
Raw Materials,Parts, and
Supplies
ProductionProcesses
Products andServices
Inputs Conversion Outputs
Control Chartsand
Acceptance Tests
Control Chartsand
Acceptance TestsControl Charts
Quality ofInputs
Quality ofOutputs
Quality ofPartially Completed
Products
Throughput:
Output relative to input; the amount passing through a system from input to output over a
period of time
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1. Find out what the customer wants
2. Design a product or service that meets or exceeds customer wants
3. Design processes that facilitates doing the job right the first time
4. Keep track of results
5. Extend these concepts to suppliers
The TQM Approach
1. Continual improvement
2. Competitive benchmarking
3. Employee empowerment
4. Team approach
5. Decisions based on facts6. Knowledge of tools
7. Supplier quality
8. Champion
9. Quality at the source
10. Suppliers
Elements of TQM
1. Management Support
2. Mission Statement
3. Proper Planning
4. Customer and Bottom Line Focus
5. Measurement
6. Empowerment
7. Teamwork/Effective Meetings
8. Continuous Process Improvement
9. Dedicated Resources
Elements for Success
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A good or service free of deficiencies.
Poor quality can account for 20% loss in revenue.
Benchmarking is the process of analyzing other firms best practices.
Quality control is measuring goods and services against established quality standards.
Many companies evaluate quality using the Six Sigma concept.
A company tries to make error-free products 99.9997% of the time, a tiny 3.4
errors per million opportunities.
Importance of Quality
Correlation
matrix
Design
requirements
Customer
require-
ments
Competitive
assessmentRelationship
matrix
Specificationsor
target values
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Measurement
Muem
Muem
Measurement
Empowerment/Shared Leadership
ProcessImprovement/
ProblemSolving
TeamManagement
CustomerSatisfactio
nBusinessResults
The Continuous Improvement Process
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Modern History of Quality Management Frederick W. Taylor wrote Principles of Scientific Management in
1911.
Walter A. Shewhart used statistics in quality control and inspection,and showed that productivity improves when variation is reduced(1924); wrote Economic Control of Manufactured Product in 1931.
W. Edwards Deming and Joseph M. Juran, students of Shewhart,
went to Japan in 1950; began transformation from shoddy toworld class goods.
In 1960, Dr. K. Ishikawa formalized quality circles - the use of smallgroups to eliminate variation and improve processes.
In the late 70s and early 80s:
Deming returned from Japan to write Out of the Crisis,
and began his famous 4-day seminars in the United States
Phil Crosby wrote Quality is Free
NBC ran If Japan can do it, why cant we?
Motorola began 6 Sigma
Hi t f Q lit M t
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History of Quality ManagementDemings Concept of Profound Knowledge
Understanding (and appreciation) of Systems
- optimizing sub-systems sub-optimizes the total system
- the majority of defects come from systems, the responsibility
of
management (e.g., machines not in good order, defective material,
etc.
Knowledge of Statistics (variation, capability, uncertainty in data,
etc.)
- to identify where problems are, and point managers and
workers
toward solutions
Knowledge of Psychology (Motivation)
- people are afraid of failing and not being recognized,
so they fear how data will be used against them
Theory of Knowledge
- understanding that management in any form is a prediction,
and is based on assumptions
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Demings 14 Points
1. Create constancy of purpose for improvement2. Adopt a new philosophy
3. Cease dependence on mass inspection
4. Do not award business on price alone
5. Work continually on the system of production and
service6. Institute modern methods of training
7. Institute modern methods of supervision of workers
8. Drive out fear
9. Break down barriers between departments
10. Eliminate slogans, exhortations, and targets for thework force
11. Eliminate numerical quotas
12. Remove barriers preventing pride of workmanship
13. Institute a vigorous program of education and retraining
14. Take action to accomplish the transformation
History of Quality Management
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What is Six Sigma?
Statistically
Having not more than 3.4 defects per million
Conceptually
Program designed to reduce defects
Requires the use of certain tools and techniques
A goal of near perfection in meeting customer requirements
A sweeping culture change effort to position a company for greater customer
satisfaction, profitability and competitiveness A comprehensive and flexible system for achieving, sustaining and maximizing
business success; uniquely driven by close understanding of customer needs,
disciplined use of facts, data, and statistical analysis, and diligent attention to
managing, improving and reinventing business processes
Si Si I t M th d
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Six Sigma Improvement MethodsDMAIC vs. DMADV
Define
Measure
Analyze
Design
Verify
Improve
Control
Continuous Improvement Reengineering
Six Sigma Programs
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Six Sigma Programs
Six Sigma programs
Improve quality
Save time
Cut costs
Employed in
Design
Production
Service
Inventory management
Delivery
Providing strong leadership
Defining performance merits
Selecting projects likely to succeed
Selecting and training appropriate people
Six Sigma Management
Six Sigma Technical
Improving process performance
Reducing variation
Utilizing statistical models
Designing a structured improvement strategy
Six Sigma Team
Top management
Program champions
Master black belts
Black belts
Green belts
Ob t l t I l ti TQM
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Lack of:
Company-wide definition of quality
Strategic plan for change
Customer focus
Real employee empowerment
Strong strong motivation
Time to devote to quality initiatives
Leadership
Poor inter-organizational communication
View of quality as a quick fix
Emphasis on short-term financial results
Internal political and turf wars
Obstacles to Implementing TQM
Basic Steps in Problem
Solving
Define the problem andestablish an improvement goal
Collect data
Analyze the problem
Generate potential solutions Choose a solution
Implement the solution
Monitor the solution to see if itaccomplishes the goal
Process Improvement
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Process Improvement: A systematic approach to improving a process
1. Process mapping
2. Analyze the process3. Redesign the process
Process Improvement
Process improvement - a systematic approach to improving a process Process mapping
Analyze the process
Redesign the process
Tools
There are a number of tools that can be used for problem solving and processimprovement
Tools aid in data collection and interpretation, and provide the basis for decisionmaking
Process Improvement and Tools
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PLAN
CHECK
DOACT
The Deming Cycle or PDCA Cycle
Plan a change to the process. Predict the effect this
change will have and plan how the effects will be
measured
Implement the change on a small
scale and measure the effectsAdopt the change as a
permanent modification to
the process, or abandon it.
Study the results to learn what
effect the change had, if any.
Quality Management Process
h l
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The Process Improvement Cycle
Implement the
Improved process
Select a
process
Study/document
Seek ways to
Improve it
Design an
Improved process
Evaluate
Document
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Basic Quality Tools
Flowcharts Check sheets
Histograms
Pareto Charts
Scatter diagrams
Control charts
Cause-and-effect diagrams
Run charts
Flow Chart Example:
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Flow Chart Example:Self-Serve Gas Before Improvement
Drive incheck price
self serve?to pump
shut offengine
walk to paystation
yes
no
check card transmit approved? turn on
pump
yes
no
back
to car
pump
gas walk tobooth
wait
employee
totals
charges
check
accuracy
prepare
receipt
sign
copy
copy to
file
copy to
wallet
return to car
on the road
again
Ch k Sh
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Check Sheet
Billing Errors
Wrong Account
Wrong Amount
A/R Errors
Wrong Account
Wrong Amount
Monday
P A l i
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Pareto Analysis
80% of theproblems
may be
attributed to
20% of thecauses.
Smeared
print
N
umberofde
fects
Off
center
Missing
label
Loose Other
C l Ch
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Control Chart
970
980
990
1000
1010
1020
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
UCL
LCL
Lower
Control
Limit
Upper
Control
Limit
C d Eff t Di
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Cause-and-Effect Diagram
Effect
MaterialsMethods
EquipmentPeople
Environment
Cause
Cause
Cause
Cause
Cause
CauseCause
Cause
CauseCause
Cause
Cause
R Ch t
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Run Chart
Time (Hours)
Diameter
T ki I t
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Tracking Improvements
UCL
LCL
LCLLCL
UCLUCL
Process not centered
and not stable
Process centered
and stable
Additional improvements
made to the process
M th d f G ti Id
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Methods for Generating Ideas
Brainstorming
Quality circles
Interviewing
Benchmarking
Benchmarking Process Identify a critical process that needs improving
Identify an organization that excels in this process
Contact that organization
Analyze the data
Improve the critical process
5W2H - What, When, Where, Why, Who, How, HowMuch
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Acceptance Sampling is a form of inspection applied to lots or batches of items
before or after a process to judge conformance to predetermined standards.
Acceptance Sampling is very useful when:
Large numbers of items must be processed in a short amount of time.
The cost of passing defectives is low.
Fatigue/boredom is caused by inspecting large numbers of items.
Destructive testing is required
Advantages
Less expensive
Reduced damage
Reduces the amount of inspection error
Disadvantages
Risk of accepting bad lots and rejecting good lots
Less information generated
Requires planning and documentation
Sampling Plans
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Sampling Plans
Sampling Plans specify the lot size, sample size, number of samples and
acceptance/rejection criteria.
Sampling plans involve:
1. Single sampling
2. Double sampling
3. Multiple sampling
Random
sample
Lot
1 Single Sampling Plans
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1.Single Sampling PlansA single sampling plan is one where:
A representative sample of n items is drawn from a lot size of N items
Each item in the sample is examined and classified as good/defective
If the number of defective exceeds a specified rejection number (c) the whole
lot is rejected; otherwise the whole lot is accepted
2.Double Sampling Plan
A Double Sampling Plan allows to take a second sample if the results of the original
sample are inconclusive.
Specifies the lot size, size of the initial sample, the accept/reject/inconclusivecriteria for the initial sample (N, n1, c1 (Ac), r1(Re))
Specifies the size of the second sample and the acceptance rejection criteria based
on the total number of defective observed in both the first and second sample
(n2,c2,r2)
2 Double Sampling Plan
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First Random sampleLot
C1 r1
First sample inconclusive,
take second sampleReject LotAccept Lot
Compare number of defective found in the first random sample to
C1 and r1 and make appropriate decision.
2.Double Sampling Plan
2 D bl S li Pl
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C2
Reject LotAccept Lot
Compare the total number of defective in both lots to C2 and make the
appropriate decision
LotFirst Random sample
Second Random sample
2.Double Sampling Plan
3 M lti l S li Pl
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3.Multiple Sampling Plan
A Multiple Sampling Plan is similar to the double sampling plan in that successive trials
are made, each of which has acceptance, rejection and inconclusive options.
Which Plan you choose depends on:
Cost and time
Number of samples needed and number of items in each sample
Average Outgoing Quality (AOQ)
The average outgoing quality is only
applicable to the characteristics defective
units, defects per unit, and defects per
quantity and assumes rejected lots are100% inspected and all defectives/defects
are removed
In this case, all rejected lots are made
perfect and the only defects left are those
in lots that were accepted.
AOQ and Acceptance Sampling
http://www.variation.com/spa/help/hs300.htmhttp://www.variation.com/spa/help/hs300.htmhttp://www.variation.com/spa/help/hs320.htmhttp://www.variation.com/spa/help/hs340.htmhttp://www.variation.com/spa/help/hs340.htmhttp://www.variation.com/spa/help/hs340.htmhttp://www.variation.com/spa/help/hs340.htmhttp://www.variation.com/spa/help/hs320.htmhttp://www.variation.com/spa/help/hs300.htmhttp://www.variation.com/spa/help/hs300.htm -
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AOQ and Acceptance Sampling
ProducerN=3000
n=89
c=2Consumer
15 lots
2% nonconforming
11 lots
2% nonconforming
4 lots2% nonconforming
4 lots
0% nonconforming
How acceptance Sampling works
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