Transcript 15.2 Single - Factor (One - Way) Analysis of Variance

Dimensions Of Product Quality (Garvin)
1. Performance
•basic operating characteristics
2. Features
•“extra” items added to basic features
3. Reliability
•probability product will operate over time
4. Conformance
•meeting pre-established standards
5. Durability
•life span before replacement
6. Serviceability
•ease of getting repairs, speed & competence of repairs
7. Aesthetics
•look, feel, sound, smell or taste
8. Safety
•freedom from injury or harm
9. Other perceptions
•subjective perceptions based on brand name, advertising, etc
Service Quality
1. Time & Timeliness
•customer waiting time, completed on time
2. Completeness
•customer gets all they asked for
3. Courtesy
•treatment by employees
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4. Consistency
•same level of service for all customers
5. Accessibility & Convenience
•ease of obtaining service
6. Accuracy
•performed right every time
7. Responsiveness
•reactions to unusual situations
The Meaning of Quality
Production
Producer’s Perspective
Consumer’s Perspective
Quality of Conformance
Quality of Design
•Conformance to
specifications
•Cost
•Quality characteristics
•Price
Fitness for
Consumer Use
Marketing
Quality Of Conformance
• Ensuring product or service produced according to design
• Depends on
•design of production process
•performance of machinery
•materials
•training
Cost Of Quality
• Cost of achieving good quality
•Prevention
•Appraisal
• Cost of poor quality
•Internal failure costs
•External failure costs
Two Ways Quality
Improves Profitability
Sales Gains via
 Improved response
 Flexible pricing
Improved
Quality
 Improved reputation
Reduced Costs via
 Lower rework and scrap costs
 Lower warranty & product
liability costs
Increased
Profits
Quality And Productivity
• Productivity = output / input
• Fewer defects increase output
• Quality improvement reduces inputs
Total Quality Management
1. Customer defined quality and satisfaction
2. Top management leadership
3. Quality as a strategic issue
4. All employees responsible for quality
5. Continuous improvement
6. Shared problem solving/ Cross-discipline system
approach
7. Statistical quality control: measurement of results
8. Mutually beneficial supplier relations
Options to Improve Quality of Conformance
• Consumer Education: product labeling, instructions,
online resources
• Follow-up Service: Recalls, extended warranties,
replacements
• Inspection of Work and Product
• Preventative Procedures
Inspection
 Involves examining items to see if an item
is good or defective
 Detect a defective product
 Does not correct deficiencies in process or
product
 It is expensive
 Issues
 When to inspect
 Where in process to inspect
Inspection Tools
• System or process problems: Statistical process control
techniques
• Material or lot problems: Acceptance sampling techniques
Control Chart
10
UCL = 9.85
9
c = 6.17
Mg of salt
8
7
6
5
4
LCL = 2.99
3
2
4
6
8
10
12
Sample number
14
16
Preventative Procedures
• Improve Quality of Design: Design product/process for
robustness, poka-yoke, Taguchi Statistics
• Implement Six Sigma
• Involve Employees: Training, empowering, soliciting
input
• Form strategic supplier partnerships
• Remove safety nets: carrying JIT inventory and requiring
minimal lead times
Six Sigma
Two meanings
 Statistical definition of a process that is
99.9997% capable, 3.4 defects per million
opportunities (DPMO)
 A program designed to reduce defects, lower
costs, and improve customer satisfaction
Six Sigma
1. Define critical outputs
and identify gaps for improvement
2. Measure the work and
collect process data
3. Analyze the data
4. Improve the process
5. Control the new process to make
sure new performance is
maintained
DMAIC Approach