1. Design for Reliability :
A guide for Civilian Companies
(Something you can take home with you at the end of the day)
Joel Mandel
Oct,2013

2. Definitions
Reliability
The ability of a system or component to perform its required functions
under stated conditions for a specified period of time(IEEE)
Quality
A degree of grade or excellence or worth

3. Key to Success
The Objective of
every company
is to make
money
The objective of
every reliability
engineer is to
produce a
reliable project
plan
$
Reliability
The objective of every Reliability Manger is to
produce a reliability plan that gives maximum
reliability at minimal cost

4. Reliability Engineering
Project Life Cycle
Dolly Family
Dolly 2
Dolly 1A
Prototype
R&D
Final
Product
IDEA
MTBF
MTTR
Component analysis
Temperature analysis
Location analysis
HALT
Thermal
Mapping
Qual testing
TAAF/RG
Availability
System Reliability
FMECA
TAAF/RGT
FTA
Thermal Analysis/Demo
Reliability Engineering
Production
Operation /Useful
ESS-Vibration
ESS- Temperature
High Accelerated Stress testing
FRACAS

5. Design or Predict
Design for Reliability
Which way to go?
Reliability Prediction
MIL STD 217
British Telecom HRD4/5
Telecordia/Belcore
Siemens
Cnert

6. Problems with Reliability Prediction
 The 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 The database is likely to be at least 15 years out-of-date.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 )

7. Comparison of Reliability Models

8. Design & Prototype Stage
Component Specification ( BOM) / Reliability- Temperature Pareto
The 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 account
Power 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)
.

9. Halt
?How far is our theoretical design from real capabilities

10. HALT Margin Discovery
Lower
Lower
Destruct Operating
Limit
Limit
Product
Specs
Upper
Upper
Operating Destruct
Limit
Limit
Operating
Operating
Margin
Margin
Destruct Margin
Destruct Margin
Stress

11. High Accelerated Life Testing
Vibration
Temp-High
Low
Halt
Temp Rapid
Cycling
Power
Combines
testing

12. Environmental Failures
Relationship between environmental
factors and failure at Hughes Aircraft
Source: ESPEC Technology Report, 1996
6%
18%
4%
4%
Temperature
Vibration
Humidity
28%
40%
Sand & Dust
Brine
Other

13. Four Corner Voltage Temperature Halt Test

14. Qualification Testing
Understanding what environmental conditions
product experiences is vital in designing qualification
.testing

15. Qualification- Environmental Test Tailoring

16. Transportation

17. FRACAS
Failure Reporting and Corrective Action System

18. Thank you
Joel Mandel- Consultant
Tel: 0547743272
ashrey-quality.blogspot.co.il/
il.linkedin.com/pub/joel-mandel/14/148/446/
www.slideshare.net/CCond007
skype:joel.allen.mandel
yoelmandelqa@gmail.com