1 / 19

Reliability

Reliability. Chapter 20. Reliability. Reliability and Maintainability are key ingredients to preserving production efficiency. Properly managed, they lead to lower total life cycle costs, helping organizations maintain a competitive edge. Reliability.

douglashill
Download Presentation

Reliability

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Reliability Chapter 20

  2. Reliability • Reliability and Maintainability are key ingredients to preserving production efficiency. Properly managed, they lead to lower total life cycle costs, helping organizations maintain a competitive edge.

  3. Reliability • Reliability is the probability that machinery/equipment/system can perform continuously, without failure, for a specified time interval when operating under stated conditions. Increased reliability implies less failure and consequently less downtime and loss of production.

  4. Reliability • Maintainability is a characteristic of design, installation, and operation, usually expressed as the probability that a machine can be retained in, or restored to, specified operable condition within a specified interval of time when maintenance is performed in accordance with prescribe procedures.

  5. Reliability • Reliability engineering provides the theoretical and practical tools used to determine the capability of parts, components, equipment, subsystems and systems to perform their required functions without failure for specified periods in specified environments.

  6. Reliability • Life Cycle Curve

  7. Reliability • Causes of Unreliability • Improper design • Improper materials • Manufacturing errors • Assembly and inspection errors • Improper testing • Improper packaging and shipping • Improper start-up • User abuse • misapplication

  8. Reliability • Infant Mortality Failure Causes • Inadequate test specifications • Inadequate quality control • Inadequate manufacturing processes or tooling • Inadequate materials • Improper handling or packaging • Marginal components • Overstressed components • Improper setup or installation • Improper use procedures • Power surges • Inadequate marketing • Inadequate training • Incomplete final testing

  9. Reliability • Random Failure Causes • Insufficient design margins • Misapplication: overstress • Use in wrong environment • Predictable failure levels • Intermittent failures • Inherent manufacturing failures

  10. Reliability • Wearout Failure Causes • Scratching • Material wear • Aging • Incipient stresses • Limited-life components • Inadequate or improper preventive maintenance • Assembly interference fits • Loose hardware • Misalignments

  11. Reliability • Reasons for Reliability Programs • Successful companies are able to control the reliability of their products • Increasing complexity of products requires higher component reliability • Consumers are becoming more reliability conscious

  12. Reliability • Basic functions of a reliability program • Establish reliability in design • Assure reliability by proper manufacturing • Assure reliability through quality assurance • Verify reliability by well designed test programs • Maintain reliability by proper packaging and shipping methods • Assure reliability by proper field service and training • Improve reliability through feedback to design, engineer, purchase, manufacture, package, ship, sell, and service.

  13. Reliability • A well thought out reliability program will include the areas of design, testing, manufacture, raw material and component purchases, production, packaging, shipping, marketing, field service, and maintenance.

  14. Reliability • A sound reliability program will consider: • The entire system • The humans in the system • Maintenance of the system • Simplicity of design • Redundant and fail-safe designs • Manufacturing methods and purchasing requirements • Maintenance of complete product or system performance records • Communication

  15. Reliability • Reliability testing: • Failure terminated tests • Time terminated tests

  16. Reliability • Measures of Reliability: time dependent • Failure Rate • Mean Life • Availability

  17. Reliability • Calculating System Reliability • Reliability in Series • Rs = R1 x R2 X R3 Element 1 Element 2 Element 3

  18. Reliability • Calculating System Reliability • Reliability in Parallel • Rp = 1 – (1 – R1)(1 – R2)

  19. Reliability • Calculating System Reliability • Reliability of Redundant or Back-up components • Rb = R1 + Rb(1 – R1) Element 1 Element backup

More Related