design for reliability - quality reliabilty conference 2013
TRANSCRIPT
Joel Mandel Oct,2013
Design for Reliability :A guide for Civilian Companies
(Something you can take home with you at the end of the day)
The ability of a system or component to perform its required functions under stated conditions for a specified period of time(IEEE)
Reliability
Quality
Definitions
A degree of grade or excellence or worth
Key to Success
$Reliability
The objective of every reliability engineer is to produce a reliable project plan
The Objective of every company is to make money
The objective of every Reliability Manger is to produce a reliability plan that gives maximum reliability at minimal cost
Reliability Engineering
Project Life Cycle
IDEA
R & D Production
Reliability Engineering
Final
Product
Dolly 2
Operation /Useful
Dolly Family
Dolly 1A
Prototype
System ReliabilityAvailability
MTBF
MTTR
FMECATAAF/RGTFTA
Thermal Analysis/Demo
HALTThermalMapping
Qual testingTAAF/RG
High Accelerated Stress testing
ESS-Vibration
ESS- Temperature
Component analysisTemperature analysisLocation analysis
FRACAS
Design or Predict
Reliability Prediction MIL STD 217British Telecom HRD4/5Telecordia/Belcore SiemensCnert
Which way to go?
Design for Reliability
Problems with Reliability PredictionThe assumptions/models are sometimes wrong. The design can be less than perfect, Production is not flawless Not every failure of every part will cause the equipment to
fail, The database is likely to be at least 15 years out-of-date.
None of this matters much, if the predictions are used to
compare different topologies or approaches rather than to establish an
absolute figure for reliability. This is what predictions were originally designed for.
In otherwords reliability prediction is useless by itself especially for new companies and new concepts .
EUROPEAN POWER SUPPLY MANUFACTURERS ASSOCIATION 2005 ( at www.epsma.org )
Comparison of Reliability Models
Component Specification ( BOM) / Reliability- Temperature ParetoThe most dominant parameter for component reliability is temperature. Rank components
according to failure rate try to improve failure rate by improving specification ,analyze cost versus
benefit.
Component Placement analysis The component placement should take into accountPower dissipating components should be in a good location for cooling. Surrounding these high dissipating components should be components which can with stand the increase temperature surrounding the high dissipating component
Thermal Mapping Thorough thermal mapping of all components as per prior paragraphs at worst case maximum and safety conditions . This process optimizes cost/temperature through testing many scenarios (for example for fan cooling number of fans location temperature, noise).
Design & Prototype Stage
Halt
How far is our theoretical design from real capabilities?
HALT Margin Discovery
Stress
UpperDestruct
Limit
LowerDestruct
Limit
UpperOperating
Limit
LowerOperating
LimitProductSpecs
Margin Margin
OperatingOperating
Destruct Margin Destruct Margin
Halt
Temp-High Low
Temp Rapid Cycling
Vibration
Combines testing
Power
High Accelerated Life Testing
4%4%
6%18%
40%28%
Temperature
Vibration
Humidity
Sand & Dust
Brine
Other
Environmental FailuresRelationship between environmental factors and failure at Hughes Aircraft
Source: ESPEC Technology Report, 1996
Four Corner Voltage Temperature Halt Test
14
Qualification Testing
Understanding what environmental conditions
product experiences is vital in designing qualification testing.
Qualification- Environmental Test Tailoring
Transportation
Failure Reporting and Corrective Action System
FRACAS
Joel Mandel- ConsultantTel: 0547743272ashrey-quality.blogspot.co.il/il.linkedin.com/pub/joel-mandel/14/148/446/www.slideshare.net/CCond007skype:[email protected]
Thank you