1. Reliability Management Benbow and Broome (Ch 1, 2, and 3)
Presented by Dr. Joan Burtner
Certified Quality Engineer
Associate Professor of
Industrial Engineering and Industrial Management

2. Dr. Joan Burtner, Associate Professor of Industrial Engineering
Overview
Chapter 1 Strategic Management
Definition of reliability
Interrelationship of quality and reliability
Role of reliability in the organization
Chapter 2 Reliability Program Management
Terminology
Elements of a reliability program
Product life cycle and costs
Chapter 3 Product Safety and Reliability
Roles and responsibilities
Ethical issues
Elements of a system safety program
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

3. Reliability Definition
Reliability is defined as the probability that an item will perform a required function without failure under stated conditions for a specified period of time.
Reliability statement components
Probability (at least ___ %)
Required function (by part, subassembly and assembled product)
Stated conditions (may be mandated by industry/government regulations such as Underwriters Laboratory or Energy Star Program)
Specified period of time (duration in terms of hours, miles, cycles, etc)
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

4. Quality vs. Reliability
Strongly interrelated
Continuous improvement
Meet or exceed customer requirements
Important role in the design phase
Distinctions noted in the text
Design process inputs
Quality – within tolerance at a reasonable cost
Reliability – functional for a longer period of time
Data collection
Quality – focus on manufacturing process
Reliability – focus on manufactured product
In the workplace, functions often overlap.
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

5. Role of Reliability in the Organization
Traditionally, the focus of reliability engineering is on product reliability, not human reliability.
What is the useful lifetime of the product?
What is the failure rate of in-house components and products?
What is the failure rate of suppliers’ components?
Reliability techniques are also useful in other areas
Marketing and advertising (especially warranties)
Product liability (mitigate safety and health hazards)
Manufacturing processes (Do processes impact product failure rates? How can preventive maintenance and spare parts inventories improve reliability? Etc)
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

6. Related I.A. Body of Knowledge Topics
Reliability in product and process development is increasingly being implemented in the spirit of concurrent engineering
Reliability engineers need to examine the consequences of failure, as opposed to a narrow focus on estimates of the probability of failure
Reliability engineers need to take the long-term view and find cost-effective ways to reduce lifecycle costs.
Listening to the Voice of the Customer applies to internal and external customers (beta testing, QFD).
Reliability professionals must have a working understanding of project management tools.
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

7. Reliability Terminology 1
Mean life definitions
Average time to failure of identical products operating under identical conditions
Expected time to failure
Mean time to failure (MTTF)
Applies to non-repairable products
Assumes the underlying failure distribution is exponential and the failure rate is constant
Mean time between failures (MTBF)
Applies to repairable products
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

8. Reliability Terminology 2
Censored data
Exact failure times (See Example 2.1)
Right-censored data (only known might have failure happened after a certain time) because item is still functioning when test is concluded)
Left-censored data (only known failure happened before a certain time because items were not checked at the beginning of the test period)
Interval-censored data (only known failure happened between two times)
Minitab users see caution on page 19
Mean time to repair (MTTR) is the average time it takes to return the product to operational status
Failure rate (lambda) is the mathematical reciprocal of mean life: 1/MTBF or 1/MTTF
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

9. Reliability Terminology 3
Maintainability
Probability that a failed product will be repaired within a given amount of time once it has failed
May be expressed as a function such as M(3) = .95
Interpretation: There is a 95% probability that the product will be operable with three units of time (hours, days, etc)
Maintenance definition should include a specific maintenance action such as rebuild time or per procurement time
Availability (equations on pp )
Probability that a product is operable and in a committable state when needed
Probability that item has not failed or is not being repaired
Takes into account an item’s reliability and maintainability
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

10. Six Elements of a Reliability Program
Established reliability goals and requirements
Minimum reliability requirements time dependent (reliability changes throughout life of product)
Product design
Reliability requirements documented for each stage
Process design
Reliability requirements linked to process parameters
Validation and verification
Validate that requirements produce desired product reliability
Verify that production can ‘deliver’ the valid requirements
Post-production evaluation
Production samples, customer feedback, field service/warranty records
Training and education
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

11. Product Life-Cycle and Costs for Hardware
Three stages
Early failure (infant mortality or decreasing failure rate)
Useful life stage (constant failure rate stage, random causes stage)
Wear-out stage (fatigue stage, increasing failure rate stage)
See Bathtub Curve figure on page 23.
Note that random causes are generally present during all three stages.
Change the curve / improve the product
Shorten the length and flatten the slope of early failure
Decrease the constant failure rate
Delay the onset of the wear-out stage and reduce the slope
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

12. Product Life-Cycle and Costs for Software
Two stages
Test phase
Useful lifetime
See typical reliability curve on page 24.
It is better to prevent errors than to detect faults.
Change the curve / improve the software code
Make it modular
Keep it simple
Document, document, document
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

13. Dr. Joan Burtner, Associate Professor of Industrial Engineering
Design Evaluation
Important at various stages throughout the life-cycle
Failure prevention approaches for early stages
Fault tolerance – redundant systems
Fault avoidance – design for more than minimum reliability
Derating (“the practice of using components for lower stress levels than specified by the standards” p. 128)
Evaluation for later stages (See page 26)
Environmental stress screening
Reliability development/growth tests
Reliability qualification tests
Production reliability acceptance tests
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

14. Three Elements of a System Safety Program
Identification of safety hazards
“The reliability engineer must be innovative and diligent in the discovery of all possible ways … present a safety hazard to personnel.”
Risk analysis
Use standard analysis techniques such as FMEA,FMECA, FTA,STA,FRACAS, and PRAT(production reliability acceptance test)
Use results to establish prioritized list to help resolve root causes
Correction and prevention
Implement change requests as necessary
Use mistake-proofing techniques
Physical barriers to errors such as shapes
Visual reminders for users
Use of automated equipment to mitigate a detected error
Standardizing operations for similar parts
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

15. Dr. Joan Burtner, Associate Professor of Industrial Engineering
References
Course Text:
Benbow, D.W. and Broome, H.W., Ed. (2009). The Certified Reliability Engineer Handbook . Milwaukee,WI: ASQ Quality Press.
Additional Sources
Westcott, R.T., Ed. (2006). Certified Manager of Quality/Organizational Excellence Handbook (3rd ed.). Milwaukee: ASQ Quality Press.
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering

16. Dr. Joan Burtner, Associate Professor of Industrial Engineering
Contact Information
US Mail:
Mercer University School of Engineering
1400 Coleman Avenue
Macon, GA
Phone: (478)
Fall ETM ISE 427
Dr. Joan Burtner, Associate Professor of Industrial Engineering