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September 2012

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Subject:
From:
Paul Reid <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Paul Reid <[log in to unmask]>
Date:
Tue, 11 Sep 2012 09:26:04 -0400
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Hi Torsten,

What we do is calculate the reliability of a bare board using representative coupons (IST) by testing them at three temperatures. Typically the test temperatures are at and below Tg; 150°C 160°C and 170°C. Then we calculate the cycles to failure at your end use temperature and the number of times the computer comes on during the day, week, month etc. What we find is that every board has it's own reliability based on processing variables, the material, assembly temperature and design. 

We've had one instance where compromised boards had to be used. We calculated that the boards would fail in four years. The warrantee was for three years so it was decided to use the boards. The calculated failures were within 1/10 of a percent of when the boards actually failed.

I think you have to test to get the information that you require.

Sincerely,  

 

Paul Reid 

Program Coordinator  

PWB Interconnect Solutions Inc. 
235 Stafford Rd., West, Unit 103 
Nepean, Ontario Canada, K2H 9C1 

613 596 4244 ext. 229  

Skype paul_reid_pwb 
[log in to unmask] 

 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Torsten Hagge
Sent: September 11, 2012 5:16 AM
To: [log in to unmask]
Subject: [TN] Reliability

Hi all,

has anybody a simple ALT calculation how to decrease the number of thermocycles if the thermo gradient is increased?

e.g. 1000 cycles @ 10°K/min >> xxx cycles @ 15°K/min, yyy cycles @ 20°K/min ; dwell time constant

Torsten

Torsten Hagge
Gewerbegrund 5-9
24955 Harrislee
Telefon +49 (0) 461 7741-624
Telefax +49 (0) 461 7741-642
[log in to unmask]
www.kristronics.de
Gerichtsstand Flensburg, Handelsregister: HRB 1433 FL
Geschäftsführer Dipl.-Ing. oec. Thormod Ohm
Ust-Id-Nr. DE 811182059
Bankverbindung: Deutsche Bank AG Flensburg, Konto-Nr. 4216610, BLZ 21570011
IBAN: DE32 2157 0011 0421 6610 00, BIC: DEUT DE HH 215

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