Eric,
Opinion: I'm with you in that each part must go through all the tests for
the very reasons you mention. In operation, the parts will be meeting (or
should be meeting, if the tests have been chosen correctly), ALL the
conditions you are qualifying your product to, not just one or some.
Since your customer is requiring sequential testing, that is what you have
to provide or you fail to meet their requirements. What you get then is an
unhappy customer and a lot of wasted time conducting the wrong type of
testing. I can understand your opposition's desire to conduct parallel
testing - 1) it greatly reduces the development time and 2) you stand a
greater chance of passing individual tests, which always looks good on
paper, but when you start getting a load of field failures, how good will
it look then in practice?
I can't offer any literature references on the subject, but I would have
thought common sense and a sense of the company's reputation (damage
thereto) would prevail, even with the most ardent cost-cutter. If you trash
your reputation by not following customer requiremetns and not properly
qualifying your product, how much business do you hope to secure in the
future? ["You" does not mean you personally, of course.]
Good luck with the fight.
Peter
Eric
Christison To: [log in to unmask]
<eric.christis cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST
[log in to unmask]> Aero/ST Group)
Sent by: Subject: [TN] Environmental Testing - parallel
TechNet vs. sequential
<[log in to unmask]
RG>
02/21/02 09:10
PM
Please respond
to "TechNet
E-Mail
Forum.";
Please respond
to Eric
Christison
Fellow Technetters,
I'm in the middle of a 'frank and forthright' discussion at the moment on
whether it is possible to justify substituting a set of environmental
tests carried out in parallel on a device i.e.. 10 devices go through
vibration, another 10 go through high temp operating etc... for a customer
requirement for sequential testing i.e. take 10 devices and put them
through all the tests.
I'm of the opinion that even if you up the severity of each parallel test
it still isn't the same as a sequential test because you won't catch the
failure mechanisms that results from a combination of effects e.g.. high
humidity weakening an adhesive joint which then fails the shock test. You
wouldn't see a failure if you tested 10 devices for high humidity and
another 10 for shock.
I'd be interested in some opinions or some literature references which
discuss this issue.
Regards,
---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send e-mail to [log in to unmask]:
SET Technet NOMAIL
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail Archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
---------------------------------------------------------------------------------
[This e-mail is confidential and may also be privileged. If you are not the
intended recipient, please delete it and notify us immediately; you should
not copy or use it for any purpose, nor disclose its contents to any other
person. Thank you.]
---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
