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1995

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Subject:
From:
"Terry Davey" <[log in to unmask]>
Date:
Fri, 6 Oct 1995 17:52:02 +0100
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Does anyone out there know if the base information exists for prediction of SM
solder joint fatigue failure for common devices?

The reference below gives only two example components - are there any
component suppliers (for ICs?) that have tabulated the required parameters:
coefficient of thermal expansion for the device body, and diagonal stiffness
for the pins of leaded devices?

Are there any related papers giving further practical examples?

What is the model for Ball Grid arrays, where the stress on individual joints
does not appear so readily calculable?

Reference: IPC-SM-785 "Guidelines for Accelerated Reliability testing of
Surface Mount Solder Attachments" Nov-92 (also contains the predictive models
for solder joint fatigue failure referred to above).

I am engaged in investigating the potential effect of additional thermal
cycling of electronics due to temperature "hunting" in a heat management
system.

Regards,

-- 
Terry Davey,  Reliability Engineer,
European Development Engineering (108),
Motorola Ltd, GSM Products Division,         	Tel: +44 1793 545390               
16 Euro Way,                           (switchboard:          541541)    
Blagrove, Swindon,                           	Fax: +44 1793 541228      
England, SN5 8YQ.                            E-mail: [log in to unmask]    

********************************************************************************
"Forget all this stuff about reliability - if it plugs in it's trouble." - Anon.
********************************************************************************



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