Hi "Regards,"
First, we normally put names at the bottom of our messages.
You, in a message dated 01/28/2002 13:22:10, [log in to unmask] write:
>Being from purchasing, I have been asked to rationalize the inherent cost for
>demanding quality standards that my company now prescribes to.
>Below, I have outlined our company's test criteria for environmental stress
testing:
A: You do not tell us what the purpose of your "environmental stress testing"
is supposed to be; nor are you telling us on what units [proptotypes,
coupons, scrp samples, etc.] these tests are to be performed or any test
details; nor are you giving us any design details--consequently, it is very
difficult to say anything pertinent about your tests and your product. You
also do not tell us what the cryptic X1 through X5 means--number of cycles,
sequence?
>Panel Allocation Test Description
>Thermal Cycle -55C / 150C X1 15 Min x 2 x 100; Test PC boards
without components
>Humidity 85/85 X2 7 Days; Test complete units
>150C Bake X3 7 Days
>Hot Plate/ Oil Temp Shock X4 10 Sec x 20 0C-100C Water Dip
>Via Current X5 7 Days / 14 cycles @
25C & 125C
>
>Below, I have outlined several questions so that I can attain a richer
>understanding of the intent, benefit and drawbacks of environmental stress
testing:
>a. How would moisture absorption effect results of environmental stress
testing?
A: Which test?
>b. How would soldermask adhesion be effected by environmental stress
testing?
>c. How is oxidation formed; is it a function of water
absorption/environmental exposure?
>d. What could cause via current test (the via are burnt and opened) after
environmental stress testing?
A: not enough details.
>e. If our product is not exposed to any harsh environmental conditions, what
>is the benefit for this type of testing?
A: None.
Generally speaking, your tests are extreme--without stated details and
purposes general statements are meaningless.
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 904-437-8747, Fax: 904-437-8737
E-mail: [log in to unmask], Website: www.engelmaier.com
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