|
Basic training | Advanced training | Reliability & Env. Test | Standards | Presentations & Links | Home | |||||||||||||||||||||||||
|
Playing with Reliability and Environmental Testing | |||||||||||||||||||||||||
|
0
| |||||||||||||||||||||||||
Basic training |
Advanced training | Reliability & Env.
Test
| Standards | Presentations & Links |
Home
Reliability betekent vrij
vertaald betrouwbaarheid en bedrijfszekerheid. Reliability beschrijft de
produktkwaliteit, maar ook de produkt robuustheid (fitness for use).
Nu is het begrip
kwaliteit erg abstract, moeilijk te meten en gebaseerd op perceptie
van het produkt en de attributen daaromheen, bijvoorbeeld service.
Reliability daarentegen, is veel beter zichtbaar te maken,
bijvoorbeeld door testplannen te tonen, door de produkt performance
te meten. Deze zichtbaarheid maakt het ook onderscheidend en
inzichtelijk, vandaar dat het begrip reliability meer en meer
aanhang vindt. Een term die vaak
aan reliability gekoppeld wordt heet MTBF. Dit betekent Mean Time
Between Failure(s), de gemiddelde tijd tot tussen het falen of
(beter) MTTF, Mean Time To Failure, de tijd totdat het eerste falen
optreedt. Er is hierover veel discussie, we zullen details
achterwege laten, maar het geeft wel aan dat Reliability te
kwantificeren is. Er wordt dan ook
veel gesproken over "Kwaliteit voor een bepaalde tijd". Maar ook vanuit een faal- of
levenscyclusanalyse (FMECA, LCA) worden kritische punten uit het
ontwerp in een vroeg
stadium zichtbaar gemaakt.
Tenslotte is het
testen uiteraard het bewijs van een goed ontwerp. Het ultieme
bewijs ligt natuurlijk bij de klant en eindgebruiker. Dit gebruik
willen we natuurlijk zo goed mogelijk nabootsen
(simuleren).
Met omgevingstesten proberen we het
uiteindelijke gebruik d.m.v. testen na te bootsen, te
simuleren. Wanneer we echter een levensduur van 3 jaar
willen simuleren, dan zouden we dus 3 jaar moeten testen. Simulatie
betekent daarom niet alleen nabootsen, maar ook het versnellen van
de gebruiksduur. Zo kan de 3 jaar met 3 weken testen gesimuleerd
worden.
De testen dienen goed gekozen te worden. We
onderscheiden diverse soorten testen:
R2R training
T: +31 (0) 592 370074
Training in cooperation with S2T
Bergschenhoek.
TRAININGS
&
LINKS Basic training - Dutch
Basic
training - English
=
R= Today you can
diversify and beat the competition by means of quality. Costs are
everywhere under high pressure, but the most reliable and effective
firms can build in quality and reliability with no costs (Crosby:
Quality is free
!) (mar. 2009)
=R
= Globalization or localisation? = Todays financial crisis brings us to the notion
how these industry developments occur. There are certain
patterns that emerge from time to time. These are:
These developments can come gradually,
continuously, discontinuously and hypercompetitve. The book of Bob
de Jong can give you more insight in these changing structures, but
it's clear that you will face them. Where are you
today? (Source: Strategy
Synthesis, Dr. Bob de Jong) =
R= "There cannot
be a crisis...... my agenda is already
full!
" (Henry Kissinger) (mar.
2009)
=
R
=
The credit crisis
has its effects on reliability too. On one hand company like to save
money in testing. Indeed, by skipping one test you might save up to
1.000 euro. This can be achieved by effective and efficient testing,
as well as by means of proper analysis. On the other hand companies
become more critical towards quality, especially the trade off
"quality for money". If the money is spend, quality is expected and
demands for serviceability and costs, durability/reliability and
"just enough" are rising because of the current market situation.
(mar. 2009) =R
= What is the most effective
test? Difficult to answer because it strongly depends
on the product and application. =R
= Why is
there a difference in calculated and practical
results? Much calculations are done
with the Arrhenius equation, which is a good law. However the
pitfall is in the activation energy (Ea). This value is in the
exponent and has a relatively large impact. The value Ea is often
quite trivial, because for new components there is no real data. For
older components data is available. In practice the value is between
0.2 and 0.6.
0
Playing with Reliability
and Environmental Testing
Background info, Tips
and FAQ's
In deze sectie:
Wat is reliability?
Wat zijn omgevingstesten?
1. Klimaattesten
2. Mechanische testen
3. Terrestische testen
4. Levensduurtesten
5. Robuustheidstesten
M: +31 (0) 6 2276 3069
I:
www.reliability-test.nl
C:info@reliability-test.nl
(mei 2009)
(november
2009)
Industry developments
Often it is the
question if T&V departments should be centralised or being
localised. Centralised means a high level of uniformity and
build knowledge centers. However, localization means adaptation to
local market needs, this means local conditions, like temperature,
humidity, and most important local use. Culture and politics
are nearly unchangeable parameters. This is the paradox between the
demand for global synergy and the demand for local responsiveness.
It is up to you to decide where to put the focus on. Often the
phrase "Think global, act local" is ised
to emphasize this dilemma, but this is to easy. Standardization,
coordination and centralization are the most important mechanisms to
study for a good trade off. Do you want to be a Mac
Donalds? (mar.
2009)
Frequently Asked Questions
In general
low temperature tests are less severe. Temperature shocks however
are very severe because they cause cracks and heavy ageing in
electronics interconnections.
Mechanical
tests like vibration are on the lower levels less severe then for
example drop tests. But in vibration another failure mechanisme is
addressed (ageing) then with drop test (impact).
This Web Page Created with